CN113015495A

Movatterモバイル変換

Info

Publication number: CN113015495A
Application number: CN201980074339.7A
Authority: CN
Inventors: 维伦德·K·夏尔马; 凯文·霍尔布鲁克; 霍尔格·弗里德里克; 埃里克·史蒂文·费恩
Original assignee: Akkacht Ltd
Current assignee: Akkacht Ltd
Priority date: 2018-09-11
Filing date: 2019-09-11
Publication date: 2021-06-22
Also published as: AU2019338398A1; EP3849448A1; EP3849448A4; JP2022511318A; WO2020056031A1

Abstract

Translated fromChinese

心脏消融导管，包括外球囊，该外球囊定位在导管的远端处并且配置为具有设置于其中的内球囊。用第一流体使外球囊膨胀，该第一流体具有小于100摄氏度的温度，同时用加热的蒸汽使内球囊膨胀。两个球囊之间的接触区域，包括小于任一球囊的总表面积的表面积，产生热区，用于通过将热能从接触区域传递到心脏组织来消融心脏组织。

A cardiac ablation catheter includes an outer balloon positioned at a distal end of the catheter and configured with an inner balloon disposed therein. The outer balloon is inflated with a first fluid having a temperature of less than 100 degrees Celsius, while the inner balloon is inflated with heated steam. The contact area between the two balloons, including a surface area less than the total surface area of either balloon, creates a thermal zone for ablating cardiac tissue by transferring thermal energy from the contact area to the cardiac tissue.

Description

Heating steam ablation system and method for treating heart disease

Cross citation

The present application is a continuation-in-part application entitled "ablation catheter with integrated cooling" U.S. patent application No. 15/600,670 filed on 5/19/2017, which claims priority to U.S. provisional patent application No. 62/425,144 entitled "method and system for ablation" filed on 11/22/2016 and U.S. provisional patent application No. 62/338,871 entitled "cooling coaxial ablation catheter" filed on 19/5/2016.

Priority of the present application also claims priority of U.S. provisional patent application No. 62/729,777 entitled "cardiac ablation system and method" filed on 11.9.2018, and it further claims priority of U.S. provisional patent application No. 62/844,222 entitled "steam ablation system and method for treating cardiac disorders" filed on 7.5.2019.

All of the above-referenced applications are incorporated herein by reference in their entirety.

Technical Field

The present description relates to systems and methods configured to generate and deliver vapor for ablation therapy (ablation therapy). More particularly, the present description relates to a new catheter and steam generation system for providing steam-based ablation therapy to cardiac tissue via pulmonary vein ablation for the treatment of cardiac disorders such as cardiac arrhythmias and atrial fibrillation, and for the treatment of Left Atrial Appendage (LAA) disorders by LAA ablation.

Background

Ablation in this specification involves the removal or destruction of body tissue via the introduction of a destructive agent, such as radio frequency energy, electroporation, laser energy, ultrasonic energy, a cryogen, or steam. Ablation is commonly used to eliminate diseased or unwanted tissue such as, but not limited to, cysts, polyps, tumors, hemorrhoids and other similar lesions of cardiovascular tissue including those resulting from arrhythmias, or to eliminate certain entities of certain tissues, particularly electrical conductivity.

Atrial fibrillation (a-fib) refers to a condition of abnormal heart rhythm originating in the apical chamber of the heart (also referred to as the atrium). In the case of a normal heart beat, the electrical impulses in the heart originate in the sinoatrial (SA or sinus) node in the right atrium of the heart. These electrical impulses set the rate and rhythm of the heart beat. In patients with atrial fibrillation, the electrical rhythm of the heart is not guided by the SA node, but instead many different pulses are delivered quickly at once, causing a very fast, chaotic rhythm in the atria. There are different approaches to treat a-fib, including drugs that slow heart rate, antiarrhythmic drugs, and anticoagulants that can reduce the risk of stroke. However, one of the effective methods of treating atrial fibrillation is pulmonary vein ablation (also known as pulmonary venous ventricular isolation or PVAI). PVAI involves ablation of a portion of the patient's pulmonary veins, including the PV ostium or atrial tissue at the junction of the left atrium and pulmonary veins. PVAI is best suited for paroxysmal patients, in some cases with persistent a-fib symptoms even after drug treatment, and for patients prone to complications with antiarrhythmic drugs. It has been observed that almost 80% of paroxysmal a-fib patients without other heart diseases can be completely cured with a single PVAI approach. When patients had normal sinus rhythm without any dependency on the drug, they were considered to be cured of a-fib after treatment. Even patients with long-term presence of a-fib are noted to have a cure success rate of 50% -70% with the help of PVAI, depending on their underlying heart disease and other factors.

During the PVAI procedure, the ablation device is guided to a precise location therein. These spots are then isolated and destroyed. This ensures that some cardiomyocytes in the border area of the distal end of the insulated wire cannot re-trigger the a-fib. However, it is difficult to locate and thus isolate the location in order to accomplish coherent damage. Most of the a-fib signals are known to come from the openings (ostia) of the four pulmonary veins in the left atrium. The PVAI process isolates these veins from the rest of the heart and prevents any pulses from these veins from entering the heart.

A variety of methods of locating and isolating a-fib signals are known in the art. One of the methods involves fabricating a circular Radio Frequency (RF) ablation line around each pulmonary vein opening to isolate the pulmonary veins. However, it is difficult and time consuming to fabricate the circular lesions to achieve complete isolation. Delivery of ablation energy through cryo-, laser-, or ultrasound-based catheters is sometimes used to encircle the venous opening and create a circular lesion. Another approach, known as segmental catheter ablation, uses pulmonary vein potentials to localize and eliminate a-fib signals. Once the region of the pulmonary vein identified as having any electrical potential is ablated, the electrical potential disappears. Typically, the path taken by the a-fib signal from the pulmonary veins is outside the pulmonary vein opening and is ablated outside that opening. One or more procedures known as "anatomy-based peripheral pulmonary vein ablation" or "left atrial ablation" emphasize the creation of an obstructive lesion in the left atrium, similar to peripheral ablation. A high wattage large diameter pipe is dropped and dragged to produce a circular linear lesion. Other balloon-based methods, such as cryoballoon ablation, laser ablation, and High Intensity Focused Ultrasound (HIFU) ablation, may be used to ablate cardiac tissue. Electroporation using pulsed field ablation has also been used to achieve pulmonary vein isolation.

Idiopathic Pulmonary Arterial Hypertension (IPAH) is known to be characterized by elevated mean Pulmonary Artery (PA) pressure (PAP) and Pulmonary Vascular Resistance (PVR). PA denervation (PADN) is sometimes used in patients with IPAH to eliminate the increase in PAP by inducing local damage to baroreceptors or sympathetic nerve fibers. PADN is also known to have been used in patients with a combination of pre-capillary and post-capillary pulmonary hypertension (cpch). PADN surgery also involves locating and ablating a target within the PA using the catheter ablation methods described above.

The Left Atrial Appendage (LAA), including the small sac in the wall of the left atrium, may be the source of atrial arrhythmias and emboli that may cause stroke. The left atrial appendage occlusion and ligation device is used to remove arrhythmias and emboli from clots in the atrial appendage. While methods exist for closing the LAA, the use of any form of ablation to control LAA embolization by reducing or eliminating the lumen of the LAA has not been described in the prior art.

Steam-based ablation systems, such as those disclosed in U.S. patent nos. 9,615,875, 9,433,457, 9,376,497, 9,561,068, 9,561,067, and 9,561,066, disclose ablation systems that controllably deliver steam through one or more lumens to a tissue target. One problem with all such steam-based ablation systems is the potential overheating or burning of healthy tissue. Steam passing through the channels in the body cavity heats the surfaces of the channels and may cause the outer surfaces of the medical tool to become overheated rather than the end of the working tool itself. As a result, a physician may inadvertently burn healthy tissue when the exterior of the device is accidentally in contact with the healthy tissue rather than the operative distal end of the tool. U.S. patent nos. 9,561,068, 9,561,067, and 9,561,066 are incorporated herein by reference.

Double balloon ablation catheters having an inner balloon and an outer balloon, such as the catheters disclosed in U.S. patent nos. 7,727,228, 7,850,685, 8,425,456 and 8,679,104, maintain the outer balloon under vacuum with little space between the inner and outer balloons. The purpose of this construction is to provide a back-up cover (outer balloon) in the event of catastrophic failure of the inner balloon. Thus, during operation, the size of the inner and outer balloons and the shape of the inner and outer balloons are substantially the same, and during operation of the catheter, the outer balloon fits over the inner balloon like a glove.

There is a need for a catheter that is configured to simultaneously direct ablative steam heat to cardiac tissue, securely position the catheter in the right cardiac tissue location, avoid burning healthy or non-target tissue, including blood, and controllably deliver ablative energy to the target location. It is also desirable to have a steam-based ablation device integrated into the catheter safety mechanism that prevents unwanted thermal damage to the patient and operator during use. It would also be desirable to provide a method of increasing or enhancing the natural cooling process, thereby reducing processing time. It is also desirable to create dynamic or variable ablation (thermal) and cooling regions that can vary with and adapt to the anatomy of the patient. Finally, it is desirable to provide an easily accomplished heated ablation region and cooling mechanism that does not rely on a separate medical tool to deliver fluid to cool the treatment region.

Disclosure of Invention

The present specification discloses a method of ablating cardiac tissue, the method comprising: positioning a catheter adjacent cardiac tissue of a patient, wherein the catheter comprises an elongate body having a lumen, a proximal end, and a distal end, and wherein an outer balloon and an inner balloon are positioned at the distal end such that the inner balloon is positioned within the outer balloon; inflating the outer balloon with a first fluid to increase the pressure of the outer balloon to a first outer balloon pressure; injecting heated steam into the inner balloon to increase the pressure of the inner balloon to a first inner balloon pressure, wherein injecting the heated steam into the inner balloon creates an ablation zone, and wherein a surface area of the ablation zone is defined by a portion of the inner balloon that contacts a portion of the outer balloon, thereby allowing heat to transfer from the heated steam in the inner balloon through the ablation zone to the cardiac tissue; maintaining the first inner balloon pressure for a first predetermined period of time to ablate cardiac tissue to a predetermined extent; stopping the injection of the heating steam, wherein stopping the injection of the heating steam causes the pressure of the inner balloon to decrease to a second inner balloon pressure; and deflating the outer balloon to a second outer balloon pressure.

The cardiac tissue may be a pulmonary vein, a portion of a pulmonary vein, an ostium of a pulmonary vein, an atrium, tissue proximate the ostium of a pulmonary vein, or a left atrial appendage. Optionally, the method further comprises recording the degree of pulmonary vein occlusion achieved by inflating the outer balloon.

The first outer balloon pressure may be between 0.01atm and 5atm, preferably between 0.1atm and 5atm, or any range or increment therein.

Optionally, the method further comprises inflating the inner balloon with a second fluid prior to injecting the heated steam into the inner balloon, wherein the second fluid is air or CO₂。

Optionally, the first predetermined period of time is between 1 second and 5 minutes. The first outer balloon pressure may be maintained for a first predetermined period of time.

Optionally, the surface area of the ablation region is a function of the surface area of tissue positioned at the junction between the pulmonary vein and the left atrium of the patient.

Optionally, the method further comprises removing fluid resulting from condensation of the heated vapor in the inner balloon, wherein the removal of fluid reduces the pressure of the inner balloon to a third inner balloon pressure, and wherein the third inner balloon pressure is less than or equal to the first inner balloon pressure.

Optionally, the catheter includes a plurality of electrodes positioned proximate the distal end, and the heated vapor is generated by directing saline through the lumen and over the plurality of electrodes.

Optionally, the method further comprises recording the extent of removal of the pulmonary vein occlusion after deflating the outer balloon.

The first fluid may be air or CO₂。

Optionally, the heated steam comprises water steam, and the temperature of the heated steam is at least 100 ℃.

Optionally, the method further comprises placing a guidewire or pacing catheter in the patient's heart and placing the catheter over the guidewire or pacing catheter. Optionally, the method further comprises sensing or stimulating the pulmonary vein using a guidewire or pacing catheter to determine the degree of pulmonary vein isolation.

Optionally, the distal tip of the catheter is configured to deflect from a linear configuration to a curved configuration, wherein the curved configuration is defined by the distal tip adapted to bend up to 150 degrees over a radius in a range from 0.5 inches to 2.5 inches.

Optionally, the inflated outer balloon contacts a portion of the pulmonary vein ostium and occludes at least a portion of the pulmonary vein 2mm to 15mm distal to the pulmonary vein ostium.

Optionally, the ablation region has a width of 2mm to 15mm and a curved length defined at least in part by a degree of contact between the inflated outer balloon and the surface of the cardiac tissue.

Optionally, the distance between the outer surface of the inflated outer balloon and the outer surface of the uninflated inner balloon is in the range of 1mm to 25 mm.

Optionally, the method further comprises determining a degree of contact between at least two of the inner balloon, the outer balloon, and the cardiac tissue using at least one of fluoroscopy, three-dimensional mapping, or endoscopic surgery.

Optionally, the catheter further comprises at least one sensor. Optionally, the at least one sensor is configured to monitor contact of the inner balloon with the outer balloon, or configured to monitor temperature or pressure of the outer balloon or temperature or pressure of the inner balloon.

Optionally, the method further comprises introducing a catheter through a venipuncture in the femoral vein of the patient, and advancing the catheter into the left atrium of the patient, through the transseptal puncture into the pulmonary vein or left atrial appendage.

Optionally, the ablation zone is positioned no more than 100mm away from the source of generation of the heating steam.

Alternatively, the ablation zone is only created when the pressure against the surface of the outer balloon is greater than 0.1 psi.

Optionally, the method further comprises repeating the steps to ablate cardiac tissue for a second predetermined period of time, wherein the second predetermined period of time is equal to 50% to 250% of the first predetermined period of time.

Optionally, ablation is performed to treat atrial fibrillation or to ablate the left atrial appendage in the patient.

Optionally, upon inflation, the outer balloon has a pear-shaped configuration, wherein the pear-shaped configuration includes a proximal body that narrows to a tapered distal end.

Optionally, upon inflation, the shape of the outer balloon is defined by a curve of the surface of the outer balloon, the curve further defined by a plane intersecting the entire length of the catheter, wherein the curve is characterized by a first point, a second point, and a third point located sequentially and extending along the length of the catheter between a proximal point and a distal point, wherein a first slope between the proximal point and the first point has a first value, a second slope between the first point and the second point has a second value, a third slope between the second point and the third point has a third value, a fourth slope between the third point and the distal point has a fourth value, and wherein the absolute value of the first value is greater than the absolute value of the second value, greater than the absolute value of the third value, or the absolute value of the fourth value, greater than the absolute value of the third value; and, when inflated, the inner balloon has the shape of an oblate spheroid with a minor or major axis coincident with the longitudinal axis of the catheter and a major or major axis perpendicular to the catheter.

Optionally, upon inflation, the shape of the outer balloon may be defined by a first distance from a central axis of the outer balloon to a first proximal point on the outer surface of the outer balloon, a second distance from the central axis to a second proximal point on the outer surface of the outer balloon, a third distance from the central axis to a third point on the outer surface of the outer balloon, a fourth distance from the central axis to a first distal point on the outer surface of the outer balloon, and a fifth distance from the central axis to a second distal point on the outer surface of the outer balloon, wherein each of the first proximal point, the second proximal point, the third point, the first distal point, and the second distal point are sequentially located and extend distally along the length of the central axis from a proximal location, wherein the second distance is greater than the first distance, the third distance, and the fifth distance, and wherein the fourth distance is greater than the first distance, the second distance, the third distance, and the fifth distance, A third distance and a fifth distance.

Optionally, the ablation region has a width and a curved length defined by a degree of contact between the outer balloon and a portion of the cardiac tissue when the inner and outer balloons are inflated.

The present specification also discloses a system for ablating cardiac tissue, comprising: a catheter adapted to be positioned adjacent cardiac tissue of a patient, wherein the catheter comprises: a distal end; a proximal end; a first lumen; a second lumen comprising a heating element; an inner balloon positioned at the distal end of the catheter and in fluid communication with the second lumen; and an outer balloon positioned at the distal end of the catheter and surrounding the inner balloon, wherein the outer balloon is in fluid communication with a first fluid source via a first lumen, and wherein an ablation region is formed at a contact region of the inner balloon and the outer balloon when the outer balloon is inflated with the first fluid and the inner balloon is inflated with heated steam; and a controller, wherein the controller comprises program instructions that when executed result in: a first fluid is to be injected into the outer balloon; and the second fluid is to be directed through the second lumen and placed in contact with the heating element to form a heated vapor.

Optionally, the outer balloon is not fixedly attached to the inner balloon in the contact region.

Optionally, the contour of the surface region of the ablation region is a function of and dependent on a portion of the pulmonary vein of the patient.

Optionally, the ablation region is defined by a surface area, and the size of the surface area ranges from 5% to 95% of the surface area of at least one of the inner balloon or the outer balloon.

Optionally, the ablation region has a width in the range of 1mm to 20 mm.

Optionally, the first fluid is air or CO₂。

Optionally, the second fluid is brine or carbonate, the heated steam is water vapor, and the heated steam has a temperature of at least 100 ℃.

Optionally, the heating element is flexible and comprises a plurality of electrodes positioned within the second lumen. Optionally, the heating element is defined by a distal end, wherein the distal end is positioned at a distance in the range of 0mm to 80mm from the proximal end of the outer balloon.

Optionally, the heating element comprises a plurality of electrodes configured to receive an electrical current activated by the controller. Optionally, each of the plurality of electrodes includes at least one edge adapted to be exposed to fluid present in the second lumen.

Optionally, the system further comprises one or more insulating regions, wherein each of the one or more insulating regions is defined by a surface area of the outer balloon proximal or distal to the ablation region, and wherein an average temperature of each of the one or more insulating regions is less than an average temperature of the ablation region. Optionally, each of the one or more insulating regions has a width of at least 0.1mm and extends along the curved length in a range of 1mm to a perimeter of the outer balloon.

Optionally, the inner balloon is configured to be movable within the outer balloon along a horizontal longitudinal axis, and the catheter further comprises a mechanism configured to move the inner balloon within the outer balloon.

Optionally, the controller further comprises program instructions that, when executed, cause the outer balloon to expand to a first pressure and to remain at the first pressure during ablation. Optionally, the controller further comprises program instructions that, when executed, cause the inner balloon to inflate to a second pressure during ablation, wherein the first pressure is equal to or less than the second pressure. Optionally, the first pressure is between 0.01atm and 5atm, preferably between 0.1atm and 5atm, or any range or increment therein.

Optionally, the system further comprises one or more pressure valves in fluid communication with the first lumen, wherein each of the one or more pressure valves is configured to control movement of fluid into or out of the outer balloon based on a predetermined pressure level.

Optionally, the controller further comprises program instructions that, when executed, cause the ablation zone to remain for a period of between 1 second and 5 minutes.

Optionally, the controller further comprises program instructions that, when executed, cause the outer balloon to expand to a first volume and the inner balloon to expand to a second volume, and wherein the first volume is greater than at least 10% of the second volume.

Optionally, the system further comprises a mapping member positioned at the distal end of the catheter and configured to map the region of cardiac tissue responsible for the arrhythmia, wherein the mapping member comprises a plurality of sensors, detectors or electrodes. Optionally, the mapping member comprises a range of 1 to 64 electrodes configured to record signals from or pacing in the pulmonary vein.

Optionally, the system further comprises at least one sensor, wherein the at least one sensor is positioned at the distal end of the catheter or at the proximal end of the catheter. Optionally, the sensor comprises a temperature sensor configured to monitor the delivery of thermal energy to the cardiac tissue. Optionally, the sensor comprises a pressure sensor configured to measure pressure inside the inner balloon.

Optionally, the outer balloon is defined by a pear shape and is configured to be positioned in a pulmonary vein of a patient to occlude the pulmonary vein.

Optionally, the outer balloon has an axis extending along a length of the outer balloon and through a center of the outer balloon when inflated, and a distance from the axis to an outer surface of the outer balloon varies along the length.

Optionally, upon inflation, the shape of the outer balloon is defined by a curve of the surface of the outer balloon, the curve further defined by a plane intersecting the entire length of the catheter, wherein the curve is characterized by a first point, a second point, and a third point located sequentially and extending along the length of the catheter between a proximal point and a distal point, wherein a first slope between the proximal point and the first point has a first value, a second slope between the first point and the second point has a second value, a third slope between the second point and the third point has a third value, a fourth slope between the third point and the distal point has a fourth value, and wherein the absolute value of the first value is greater than the absolute value of the second value, greater than the absolute value of the third value, or the fourth value, and the absolute value of the fourth value is greater than the absolute value of the third value; and, when inflated, the inner balloon has the shape of an oblate spheroid with a minor or major axis coincident with the longitudinal axis of the catheter and a major or major axis perpendicular to the catheter.

Optionally, the inner balloon has a spherical, oval, conical, disc, elliptical, rectangular prism, or triangular prism shape.

Optionally, the outer balloon is characterized by at least one first radial length when inflated extending from a center point on an axis extending longitudinally along the catheter and through the outer balloon to a point on a surface of the outer balloon, wherein the inner balloon is characterized by at least one second radial length when inflated extending from a center point on an axis extending longitudinally along the catheter and through the inner balloon to a point on a surface of the inner balloon, and wherein the at least one first radial length is different from the at least one second radial length. Optionally, the at least one first radial length is greater than the at least one second radial length by any amount or by at least 10%.

Optionally, the ablation region has a width and a curved length defined by a degree of contact between the outer balloon and the cardiac tissue when the inner and outer balloons are inflated.

The present specification also discloses a method of treating atrial fibrillation, comprising: positioning a catheter in a pulmonary vein leading to a left atrium of a heart of a patient, the catheter comprising an elongate body having a proximal end and a distal end, wherein an outer balloon and an inner balloon are positioned at the distal end such that the inner balloon is located within the outer balloon; inflating the outer balloon to a first pressure to occlude blood flow in the pulmonary vein; initiating steam flow into the inner balloon to inflate the inner balloon, wherein upon full inflation the inner balloon is in contact with a predetermined circumferential region of the outer balloon such that thermal energy is transferred from within the inner balloon through the outer balloon into surrounding cardiac tissue in contact with the predetermined circumferential region of the outer balloon; stopping steam delivery to the inner balloon after a predetermined time, thereby causing the inner balloon to contract and separate from the outer balloon; and deflating the outer balloon.

Optionally, steam is supplied to the inner balloon by a flexible heating chamber positioned in-line within the body adjacent and proximate to the outer balloon.

Optionally, the first pressure is greater than the mean pulmonary vein pressure and less than 5 atm.

Optionally, the flow of steam to the inner balloon increases the temperature within the inner balloon to equal to or greater than 100 degrees celsius, and the pressure between the inner balloon is greater than the pressure in the outer balloon.

Optionally, air or CO after steam flow to the inner balloon₂Cycling in and out of the outer balloon to maintain a portion of the outer balloon at a temperature below 60 degrees celsius.

Optionally, air or CO after steam flow to the inner balloon₂Is aspirated out of the outer balloon to maintain the pressure within the outer balloon at a first pressure.

Optionally, the thermal energy transfer causes a temperature of a portion of the cardiac tissue to rise to at least 60 degrees celsius.

Optionally, the inner balloon is moved within the outer balloon along the length of the body to better position the inner balloon at a target extent of the circumferential region of the outer balloon.

Optionally, when inflated, the length of the outer balloon is greater than the length of the inner balloon, and the diameter of the inner balloon is similar to the diameter of the outer balloon, and the volume of the outer balloon is greater than the volume of the inner balloon.

The present specification also discloses a method of ablating cardiac tissue, the method comprising: positioning a catheter in a pulmonary vein of a heart of a patient, the catheter comprising an elongate body having a proximal end and a distal end, wherein an outer balloon and an inner balloon are positioned at the distal end such that the inner balloon is located within the outer balloon; inflating the outer balloon to a first pressure to occlude blood flow in the pulmonary vein; initiating steam flow into the inner balloon to inflate the inner balloon and raise the temperature within the inner balloon to greater than or equal to 100 degrees celsius to raise the second pressure within the inner balloon to greater than or equal to the first pressure, wherein upon full inflation the inner balloon contacts a circumferentially defined target area of the outer balloon such that thermal energy is transferred from within the inner balloon through the outer balloon into the cardiac tissue in contact with a predetermined circumferential area of the outer balloon; by introducing air or CO₂Or coolant is drawn out of the outer balloon to maintain the pressure within the outer balloon to a first pressureForce; stopping steam delivery to the inner balloon after a predetermined time, thereby causing the inner balloon to contract and separate from the outer balloon; contracting the outer balloon; and removing the catheter from the pulmonary vein.

Optionally, the first pressure is greater than the mean pulmonary vein pressure and less than 5atm, and the second pressure is greater than or equal to the first pressure.

Optionally, air or CO after steam flow to the inner balloon₂Or a coolant is circulated into and out of the outer balloon to maintain a portion of the outer balloon at a temperature below 60 degrees celsius.

Optionally, the inner balloon is moved within the outer balloon along the length of the body to better position the inner balloon at a circumferentially defined target region of the outer balloon.

Optionally, prior to removal of the catheter and during ablation, electrical pacing of the pulmonary vein is performed to confirm achievement of the at least one therapeutic objective. In some embodiments, the therapeutic objective is electrical isolation of one or more pulmonary veins.

Optionally, the at least one treatment objective includes elevating a temperature of 25% of the endocardium around the periphery to at least 60 degrees celsius and maintaining the temperature for greater than 10 seconds.

The present specification also discloses a method of ablating cardiac tissue to treat an arrhythmia, the method comprising: positioning a catheter in a pulmonary vein of a heart of a patient, the catheter comprising an elongate body having a proximal end and a distal end, wherein an outer balloon and an inner balloon are positioned at the distal end such that the inner balloon is located within the outer balloon; inflating the outer balloon to a first pressure to occlude blood flow in the pulmonary vein, wherein the first pressure is greater than the mean pulmonary vein pressure and less than 5 atm; initiating steam flow into the inner balloon to inflate the inner balloon and raise a temperature within the inner balloon to greater than or equal to 100 degrees CelsiusUpon full inflation, the inner balloon contacts the outer balloon to create an ablation region, and wherein thermal energy is transferred from within the inner balloon through the outer balloon into the cardiac tissue in contact with the ablation region; by passing air or CO₂Or circulating a coolant into and out of the outer balloon to maintain a temperature of a portion of the outer balloon below 60 degrees celsius; stopping delivery of steam to the inner balloon after a predetermined time, thereby causing the inner balloon to deflate and separate from the outer balloon; by sucking air or CO from the outer balloon₂Or a coolant to shrink the outer balloon; and removing the catheter from the pulmonary vein.

Optionally, air, CO after steam flow to the inner balloon₂Or coolant is drawn out of the outer balloon to maintain the pressure within the outer balloon at the first pressure.

Optionally, the inner balloon is moved within the outer balloon along the length of the body to better position the inner balloon at the ablation region.

Optionally, the inner balloon is inflated with air or CO prior to the instillation of steam₂Pre-expansion.

Optionally, prior to removal of the catheter, the pulmonary vein is electrically paced to confirm that at least one therapeutic purpose is achieved. Optionally, the at least one treatment objective includes elevating a temperature of 25% or more of the endocardium around the periphery to at least 60 degrees celsius and maintaining the temperature for greater than 10 seconds.

The present specification also discloses a method of ablating cardiac tissue to treat atrial fibrillation and meet at least one treatment objective, the method comprising: positioning a catheter in a pulmonary vein of a patient's heart, the catheter comprising an elongate body having a proximal end and a distal end, wherein an outer balloon and an inner balloon are positioned at the distal end such that the inner balloon is located within the outer balloon, and wherein at least one flexible heating chamber is positioned in-line in the body adjacent and proximal to the outer balloon Internal; inflating the outer balloon to a first pressure to occlude blood flow in the pulmonary vein; initiating steam flow into the inner balloon to inflate the inner balloon and raise the temperature within the inner balloon to greater than or equal to 100 degrees celsius, wherein upon full inflation the inner balloon moves along the length of the catheter to contact the outer balloon at a desired location to create an ablation region at the desired location, and wherein thermal energy is transferred from within the inner balloon through the outer balloon into the cardiac tissue in contact with the ablation region such that the temperature of a portion of the cardiac tissue is raised to at least 60 degrees celsius; by passing air or CO₂Or circulating coolant into and out of the outer balloon to maintain the temperature of the outer balloon below 60 degrees celsius at a location remote from the ablation region; stopping the delivery of steam to the inner balloon, thereby causing the inner balloon to contract and separate from the outer balloon; contracting the outer balloon; and removing the catheter from the pulmonary vein.

Optionally, after steam flows to the inner balloon, air is drawn out of the outer balloon to maintain the pressure within the outer balloon to the first pressure.

Optionally, prior to removing the catheter, the pulmonary vein is electrically paced to confirm achievement of the at least one therapeutic objective. Optionally, the therapeutic objective is electrical isolation of the pulmonary veins. Optionally, the at least one treatment objective includes elevating a temperature of 25% or more of the endocardium around the periphery to at least 60 degrees celsius and maintaining the temperature for greater than 10 seconds.

Optionally, the length of the outer balloon is greater than the length of the inner balloon when inflated, and the diameter of the inner balloon is similar to the diameter of the outer balloon, the volume of the outer balloon being greater than the volume of the inner balloon.

The present specification also discloses a method of ablating cardiac tissue to treat atrial fibrillation and meet at least one treatment objective, the method comprising: positioning a catheter in a pulmonary vein of a heart of a patient, the catheter comprising an elongate body having a proximal end and a distal end, wherein an outer balloon and an inner balloon are positioned at the distal end such that the inner balloon is located within the outer balloon, and wherein at least one flexible heating chamber is positioned in-line within the body adjacent and proximal to the outer balloon; inflating the inner balloon to a first pressure to occlude pulmonary stasisBlood flow in the vessels; inflating the outer balloon to a second pressure to remove blood from the first balloon, wherein the second pressure is equal to or less than the first pressure, initiating steam flow to the inner balloon to heat the inner balloon and raise the temperature within the inner balloon to greater than or equal to 100 degrees celsius, and a third pressure, wherein the third pressure is equal to or higher than the first pressure, wherein the inner balloon contacts the outer balloon at a desired location to create an ablation region at the desired location, and wherein thermal energy is transferred from within the inner balloon through the outer balloon into the cardiac tissue in contact with the ablation region such that the temperature of a portion of the cardiac tissue is raised to at least 60 degrees celsius; by passing air or CO₂Or circulating coolant into and out of the outer balloon to maintain the temperature of the outer balloon below 60 degrees celsius at a location remote from the ablation region; stopping the delivery of steam to the inner balloon, thereby causing the inner balloon to contract and separate from the outer balloon; contracting the outer balloon; and removing the catheter from the pulmonary vein.

Optionally, after steam flows to the inner balloon, air is drawn out of the outer balloon to maintain the pressure within the outer balloon at the first pressure.

Optionally, prior to removing the catheter, the pulmonary vein is electrically paced to confirm achievement of the at least one therapeutic objective. Optionally, the therapeutic objective is electrical isolation of the pulmonary veins. Optionally, the at least one treatment objective includes elevating a temperature of 25% of the endocardium around the periphery to at least 60 degrees celsius and maintaining the temperature for greater than 10 seconds.

Optionally, the intersection of the shapes of the inner and outer balloons determines the shape and/or size of the ablation region.

Optionally, the hardness of the inner balloon is different from the hardness of the outer balloon.

The present specification also discloses a method of ablating left atrial appendage tissue to treat a left atrial appendage condition including atrial fibrillation and for at least one treatment purpose, the method comprising:positioning a catheter in a left atrial appendage of a patient's heart, the catheter comprising an elongate body having a proximal end and a distal end, wherein an outer balloon and an inner balloon are positioned at the distal end such that the inner balloon is located within the outer balloon and a third balloon is positioned distal of the outer balloon, and wherein at least one flexible heating chamber is positioned in-line within the body adjacent and proximal to the outer balloon; inflating the outer balloon to a first pressure to occlude blood flow to the left atrial appendage; inflating the third balloon to a second pressure to expel blood out of the left atrial appendage; initiating irrigation of the left atrial appendage with fluid through a catheter distal to the third balloon to flush any remaining blood between the third balloon and the left atrial appendage out of the left atrial appendage, followed by applying suction through a lumen in the catheter to draw in any excess fluid and blood and to hold the left atrial appendage against the third balloon; initiating a flow of steam to the third balloon to heat the third balloon and raise a temperature within the third balloon to greater than or equal to 100 degrees celsius, and a third pressure, wherein the third pressure is equal to or greater than the second pressure, wherein the third balloon contacts at least 10% of the left atrial appendage to produce a transmural ablation of at least 10% of the left atrial appendage. Optionally, the method further comprises delivering steam to the inner balloon, wherein thermal energy is transferred from within the inner balloon through the outer balloon into the cardiac tissue at the opening of the left atrial appendage in contact with the ablation region such that a temperature of a portion of the cardiac tissue is elevated to at least 60 degrees celsius; by passing air or CO₂Or circulating coolant into and out of the outer balloon to maintain the temperature of the outer balloon below 60 degrees celsius at a location remote from the ablation region; stopping the delivery of steam to the third balloon and the inner balloon, thereby causing the third balloon and the inner balloon to deflate and causing the inner balloon to separate from the outer balloon while the outer balloon remains in contact with the left atrial appendage ostium and prevents blood flow into the left atrial appendage ostium; contracting the outer balloon; and removing the catheter from the left atrial appendage. Optionally, the method further comprises inserting an acellular matrix or scaffold into the left atrial appendage to promote tissue growth in the left atrial appendage to reduce the surface area or circumference of the left atrial appendage.

Optionally, prior to removing the catheter, the left atrial appendage is electrically paced to confirm achievement of the at least one therapeutic objective. Optionally, the therapeutic objective is electrical isolation of the left atrial appendage. Optionally, the at least one treatment objective includes elevating a temperature of 25% of the endocardium around the periphery to at least 60 degrees celsius and maintaining the temperature for greater than 10 seconds.

Optionally, the hardness of the inner balloon is different from the hardness of the outer balloon. Optionally, the outer balloon has a hardness that is the same as the hardness of the third balloon.

Alternatively, different forms of ablation, such as cryoablation, RF ablation, or electroporation using the methods described above or using any commercially available ablation catheter, may be used to ablate the left atrial appendage to treat conditions of the left atrial appendage.

In one embodiment, 25% or more of the surface area of the left atrial appendage is ablated. In another embodiment, 25% or more of the thickness of the left atrial appendage is ablated.

The present specification also discloses an ablation catheter comprising: a shaft having a plurality of individual channels extending therethrough; an inner balloon having a first inflation volume in fluid communication with a first one of the plurality of individual channels; an outer balloon having a second inflation volume in fluid communication with a second of the plurality of individual channels, wherein, when inflated, the inflation volume of the outer balloon is equal to or greater than 105% of the inflation volume of the inner balloon, wherein, when inflated, the inner balloon is positioned entirely within the inflation volume of the outer balloon, wherein, when inflated, the outer balloon is configured to occlude a pulmonary vein of the patient, wherein the inner balloon is configured to receive water vapor, and wherein, when inflated, an outer surface of the inner balloon contacts an inner surface of the outer balloon to form an ablation region on the surface of the outer balloon.

Optionally, the surface area of the ablation region is less than 50% of the total surface area of the outer balloon.

Optionally, the ablation region is positioned closer to the distal end of the outer balloon than the proximal end of the outer balloon.

Optionally, the location of the ablation region varies based on the anatomy of the patient.

Optionally, the location of the ablation region is based on the physiology of the patient.

Optionally, the shaft, each of the plurality of individual channels, the inner balloon and the outer balloon are made of the same material. Alternatively, the same material is Arnitel (thermoplastic polyester elastomer). Optionally, the same material has a softening temperature of 100 ℃ or higher.

Optionally, the circumference of the inner balloon at its inflated volume does not change by more than 10% after a single use.

The foregoing and other embodiments of the invention are more fully described in the accompanying drawings and detailed description provided below.

Drawings

These and other features and advantages of the present invention will be further appreciated as the same becomes better understood by reference to the detailed description when considered in connection with the accompanying drawings wherein:

fig. 1 illustrates an ablation device according to one embodiment of the present description;

FIG. 2 is a flow chart listing the steps involved in hollow tissue or organ ablation using an ablation device according to one embodiment of the present description;

FIG. 3 shows a graph illustrating the latent heat of vaporization and melting (late heat) of water according to one embodiment of the present description;

FIG. 4A shows a multi-lumen ablation catheter according to one embodiment;

FIG. 4B is a flow chart illustrating the basic process steps for using the ablation catheter of FIG. 4A according to one embodiment of the present description;

FIG. 5A is a first graph illustrating a process of ablating tissue according to one embodiment;

FIG. 5B is a second graph illustrating a process of ablating tissue according to another embodiment;

fig. 5C is a flow chart illustrating a number of steps associated with the ablation process of fig. 5A and 5B;

fig. 6 is a flow chart illustrating an ablation method for cardiac tissue according to some embodiments of the present description;

FIG. 7A is an illustration of a cooling conduit according to one embodiment of the present description;

FIG. 7B is a cross-sectional view of the shaft of the cooling conduit of FIG. 7A;

fig. 8A illustrates a first ablation catheter in accordance with an embodiment of the present description;

FIG. 8B is a cross-sectional view of the shaft or elongate body of the catheter of FIG. 8A;

fig. 9A illustrates a second ablation catheter in accordance with an embodiment of the present description;

FIG. 9B is a cross-sectional view of the shaft or elongate body of the catheter of FIG. 9A;

FIG. 10A illustrates a third ablation catheter in accordance with an embodiment of the present description;

FIG. 10B is a cross-sectional view of the shaft or elongate body of the catheter of FIG. 10A;

fig. 11 illustrates an ablation catheter in accordance with an embodiment of the present description;

FIG. 12 illustrates a connection between a syringe and a catheter according to one embodiment of the present description;

FIG. 13A is a cross-sectional view of a flexible heating chamber according to one embodiment of the present description;

figure 13B illustrates a transverse cross-sectional view and a longitudinal cross-sectional view of a first electrode array and a second electrode array of a flexible heating chamber, according to one embodiment of the present description;

fig. 13C is a transverse cross-sectional view of the heating chamber of fig. 13A including an assembled first electrode array and second electrode array, according to one embodiment of the present description;

fig. 13D is a longitudinal cross-sectional view of the heating chamber of fig. 13A including an assembled first electrode array and second electrode array, according to one embodiment of the present description;

FIG. 13E is a first longitudinal view of the two heating chambers of FIG. 13A arranged in series in a conduit tip in accordance with one embodiment of the present description;

FIG. 13F is a second longitudinal view of the two heating chambers of FIG. 13A arranged in series in a conduit tip in accordance with one embodiment of the present description;

FIG. 13G illustrates a discontinuous electrode such that it may be longer than the bend radius, but flexible at the point of discontinuity, according to one embodiment of the present description;

fig. 13H illustrates another embodiment of an electrode arrangement according to one embodiment of the present description that may be configured within a flexible heating chamber to be incorporated at or in a distal portion or tip of a catheter;

FIG. 13I illustrates another embodiment of a serrated electrode configuration that may be configured within a flexible heating chamber to be incorporated at or in a distal portion or tip of a catheter, according to one embodiment of the present description;

fig. 14A shows a cardiac ablation catheter in accordance with an embodiment of the present description;

fig. 14B illustrates cardiac ablation performed by the cardiac ablation catheter of fig. 14A;

FIG. 14C is a flow chart illustrating the steps involved in one embodiment of a method of ablating cardiac tissue using the catheter of FIG. 14A;

fig. 14D shows a cardiac ablation catheter in accordance with another embodiment of the present description;

fig. 14E shows a mapping balloon with mapping electrodes of the catheter of fig. 14D;

FIG. 14F shows a cross-sectional view of the intermediate shaft portion of the catheter of FIG. 14D;

FIG. 14G shows a cross-sectional view of the distal tip section of the catheter of FIG. 14D;

FIG. 14H is a flowchart illustrating steps involved in one embodiment of a method of ablating cardiac tissue using the catheter of FIG. 14D;

fig. 14I shows a cardiac ablation catheter in accordance with yet another embodiment of the present description;

FIG. 14J is a cross-sectional view of the intermediate shaft portion of the catheter of FIG. 14I;

fig. 14K illustrates cardiac ablation performed by the cardiac ablation catheter of fig. 14I;

FIG. 14L is a flow chart illustrating the steps involved in one embodiment of a method of ablating cardiac tissue using the catheter of FIG. 14I;

fig. 14M illustrates a cardiac ablation catheter including at least one flexible heating chamber of fig. 13A-13D according to one embodiment of the present description;

FIG. 14N is a flow chart illustrating the steps involved in one embodiment of a method of ablating cardiac tissue using the catheter of FIG. 14M;

fig. 15 illustrates a steam ablation catheter introduced into the left atrium of the heart via a trans-septal approach (trans-septal approach) in accordance with an embodiment of the present description;

fig. 16A shows a cardiac ablation catheter with a first distal appendage, according to one embodiment;

Fig. 16B shows a cardiac ablation catheter with a second distal appendage, in accordance with an embodiment;

fig. 16C shows a cardiac ablation catheter with a third distal appendage, in accordance with an embodiment;

fig. 17 illustrates one embodiment of a cardiac ablation catheter traversing the left atrium of the heart and into the pulmonary veins, according to one embodiment of the present description;

FIG. 18A is a flow chart listing the steps involved in one embodiment of a cardiac ablation method;

fig. 18B illustrates a perspective view of a dual balloon cardiac ablation catheter in accordance with an embodiment of the present description;

FIG. 18C illustrates another perspective view of the catheter of FIG. 18B according to one embodiment of the present description;

FIG. 18D illustrates blood flow to the left atrium via the pulmonary veins of the heart, according to one embodiment of the present description;

FIG. 18E illustrates the catheter of FIG. 18B positioned in a pulmonary vein with the outer balloon inflated to block blood flow, according to one embodiment of the present description;

fig. 18F illustrates a perspective view of the catheter of fig. 18B performing cardiac tissue ablation in accordance with an embodiment of the present description;

FIG. 18G illustrates the pulmonary vein with ablated cardiac tissue of FIG. 18D according to one embodiment of the present description;

Fig. 18H illustrates another perspective view of the catheter of fig. 18B performing cardiac tissue ablation in accordance with an embodiment of the present description;

FIG. 18I is a flow chart illustrating steps of a method of ablating cardiac tissue to treat an arrhythmia using the catheter of FIG. 18B according to one embodiment of the present description;

fig. 19A illustrates a side cross-sectional view of an embodiment of a cardiac ablation catheter, wherein the distal appendage includes an inner balloon positioned within an outer balloon;

FIG. 19B illustrates a channel within the catheter of FIG. 19A, according to one embodiment;

fig. 19C shows the flow mechanism of the catheter as it passes through the inner and outer balloons, according to one embodiment;

fig. 20A shows a side cross-sectional view and a perspective view of the inner balloon when the balloon is in an undeployed state, according to one embodiment.

Fig. 20B shows a side cross-sectional view and a perspective view of the inner balloon when the balloon is in an expanded state, in accordance with one embodiment;

fig. 21A shows a side cross-sectional view and a perspective view of an outer balloon according to one embodiment;

fig. 21B shows a side cross-sectional view of an outer balloon according to another embodiment;

fig. 22 illustrates a side view, a side cross-sectional view, and a perspective view of a pressure-resistant luer lock at a proximal end of a catheter in accordance with one embodiment of the present description;

Fig. 23A illustrates a longitudinal cross-sectional view and a lateral perspective view of a dual balloon cardiac ablation catheter, according to some embodiments of the present description;

fig. 23B illustrates a plurality of views of the outer balloon of the catheter of fig. 23A, according to some embodiments of the present description;

fig. 23C illustrates various views of the inner balloon of the catheter of fig. 23A, according to some embodiments of the present description;

fig. 23D illustrates a longitudinal cross-sectional view and a transverse cross-sectional view of the elongate body of the catheter of fig. 23A, according to some embodiments of the present description;

fig. 24A illustrates a longitudinal perspective view and a lateral perspective view of a dual balloon cardiac ablation catheter, according to some embodiments of the present description;

fig. 24B illustrates a longitudinal cross-sectional view and an enlarged view of a portion of the catheter of fig. 24A, according to some embodiments of the present description;

fig. 24C illustrates a transverse cross-sectional view of the elongate body of the catheter of fig. 24A, according to some embodiments of the present description;

fig. 24D illustrates a transverse cross-sectional view and a longitudinal cross-sectional view of an outer catheter of the catheter of fig. 24A, according to some embodiments of the present description;

fig. 24E illustrates a transverse cross-sectional view and a longitudinal cross-sectional view of the inner catheter of the catheter of fig. 24A, according to some embodiments of the present description;

Fig. 24F illustrates a transverse cross-sectional view and a longitudinal cross-sectional view of a cooling tube of the catheter of fig. 24A, according to some embodiments of the present description;

fig. 24G illustrates a lateral perspective view and various perspective views of the outer balloon of the catheter of fig. 24A, according to some embodiments of the present description;

fig. 24H illustrates a lateral perspective view and various perspective views of the inner balloon of the catheter of fig. 24A, according to some embodiments of the present description;

FIG. 24I illustrates an angled perspective view, a side perspective view, and a longitudinal cross-sectional view of a spherical or olive tip in accordance with one embodiment of the present description;

fig. 25A illustrates a longitudinal perspective view and a lateral perspective view of a dual balloon cardiac ablation catheter, according to some embodiments of the present description;

fig. 25B illustrates a longitudinal cross-sectional view and an enlarged view of a portion of the catheter of fig. 25A, according to some embodiments of the present description;

fig. 25C illustrates a transverse cross-sectional view of the elongate body of the catheter of fig. 25A, according to some embodiments of the present description;

fig. 25D illustrates a transverse cross-sectional view, a longitudinal cross-sectional view, and a perspective view of an outer catheter of the catheter of fig. 25A, according to some embodiments of the present description;

fig. 25E illustrates a transverse cross-sectional view and a longitudinal cross-sectional view of the inner catheter of the catheter of fig. 25A, according to some embodiments of the present description;

Fig. 25F illustrates a transverse cross-sectional view and a longitudinal cross-sectional view of a cooling tube of the catheter of fig. 25A, according to some embodiments of the present description;

fig. 25G illustrates a lateral perspective view and various perspective views of the outer balloon of the catheter of fig. 25A, according to some embodiments of the present description;

fig. 25H illustrates a lateral perspective view and various perspective views of the inner balloon of the catheter of fig. 25A, according to some embodiments of the present description;

FIG. 25I illustrates an angled perspective view, a side perspective view, and a longitudinal cross-sectional view of a spherical or olive tip in accordance with one embodiment of the present description;

fig. 25J illustrates bringing the inner balloon into contact with a desired portion or region of the outer balloon when the inner balloon is inflated with steam, and the outer balloon is in contact with a hot or ablated region/region that includes the targeted heart tissue, according to some embodiments of the present description;

fig. 25K illustrates an exemplary double balloon embodiment with an insulating region according to some embodiments of the present description;

fig. 25L illustrates an exemplary double balloon embodiment with an insulating region according to some embodiments of the present description;

fig. 25M illustrates an exemplary embodiment of a dual balloon configuration, according to some embodiments of the present description, wherein the outer balloon has thicker regions along the insulating regions and is relatively thinner along the ablation regions where heat transfer is desired, so as to create a relative degree of insulation;

FIG. 25N illustrates a dual balloon embodiment according to the present description, wherein at least one of the two balloons includes a plurality of discrete channels extending around its perimeter;

fig. 25O is a flow diagram illustrating an exemplary protocol for inflating a dual balloon ablation device according to some embodiments of the present description;

fig. 26A illustrates a substantially pear-shaped outer balloon of a dual balloon cardiac ablation catheter according to some embodiments of the present description;

fig. 26B illustrates a perspective view of a dual balloon cardiac ablation catheter having a substantially pear-shaped outer balloon and a substantially spherical inner balloon according to some embodiments of the present description;

fig. 26C illustrates another perspective view of the catheter of fig. 26B, according to some embodiments of the present description;

fig. 26D illustrates a plurality of perspective views of the catheter of fig. 26B, according to some embodiments of the present description;

fig. 26E illustrates another perspective view of the catheter of fig. 26B, according to some embodiments of the present description;

fig. 26F illustrates a longitudinal cross-sectional view of the catheter of fig. 26B, according to some embodiments of the present description;

fig. 26G illustrates a plurality of perspective views of the catheter of fig. 26B, wherein the inner balloon is substantially ovoid, according to some embodiments of the present description;

Fig. 26H illustrates another perspective view of the catheter of fig. 26B, wherein the inner balloon is substantially ovoid, according to some embodiments of the present description;

fig. 26I illustrates a longitudinal cross-sectional view of the catheter of fig. 26B, wherein the inner balloon is substantially ovoid, according to some embodiments of the present description;

fig. 26J illustrates a plurality of perspective views of the catheter of fig. 26B, wherein the inner balloon is substantially conical, according to some embodiments of the present description;

fig. 26K illustrates another perspective view of the catheter of fig. 26B, wherein the inner balloon is substantially conical, according to some embodiments of the present description;

fig. 26L illustrates a longitudinal cross-sectional view of the catheter of fig. 26B, wherein the inner balloon is substantially conical, according to some embodiments of the present description;

fig. 26M illustrates proximal and distal constraining elements in the outer balloon of the catheter of fig. 26B, according to some embodiments of the present description;

fig. 26N illustrates a transverse cross-sectional view of the elongate body of the catheter of fig. 26B, according to some embodiments of the present description;

fig. 26O illustrates another transverse cross-sectional view of the elongate body of the catheter of fig. 26B, according to some embodiments of the present description;

Fig. 26P illustrates a transverse cross-sectional view of an outer catheter of the catheter of fig. 26B, according to some embodiments of the present description;

fig. 26Q illustrates a transverse cross-sectional view of an inner catheter of the catheter of fig. 26B, according to some embodiments of the present description;

fig. 26R illustrates a plurality of exemplary shapes of the inner balloon of the catheter of fig. 26B, according to some embodiments of the present description;

fig. 26S illustrates an outer expandable member for replacing an outer balloon according to some embodiments of the present description;

fig. 26T shows a cross-sectional view of another embodiment of an ablation catheter according to the present description;

fig. 26U illustrates concentrically positioned channels between the outer circumference and the outer shaft of the ablation catheter of fig. 26T, according to some embodiments of the present description;

fig. 26V illustrates a cross-sectional view of another embodiment of an ablation catheter in accordance with the present description;

fig. 26W illustrates a distal end of an ablation catheter depicting an inner balloon positioned within an outer balloon, according to some embodiments of the present description;

fig. 26X is a flow chart listing steps in a method of ablating cardiac tissue according to some embodiments of the present description;

fig. 26Y illustrates a system for ablating cardiac tissue according to an embodiment of the present description;

FIG. 27 illustrates a first plurality of dual balloon configurations according to some embodiments of the present description;

fig. 28 illustrates a second plurality of dual balloon configurations according to some embodiments of the present description;

fig. 29 illustrates a number of exemplary shapes of the outer balloon or the inner balloon of a dual balloon catheter according to some embodiments of the present description;

fig. 30 illustrates a plurality of exemplary balloon ends or corners according to some embodiments of the present description;

fig. 31 illustrates a plurality of balloon shapes having at least one substantially tapered or conical end, according to some embodiments of the present description;

FIG. 32 illustrates a dual balloon catheter with an inflatable dilation balloon according to one embodiment of the present description;

fig. 33 illustrates a balloon catheter for measuring the geometry (shape and size) of a body lumen according to some embodiments of the present description;

fig. 34 illustrates relative flow paths of cooling fluid and ablation fluid in an ablation catheter according to some embodiments of the present description;

fig. 35A illustrates a dual-angle cardiac ablation catheter in accordance with some embodiments of the present description;

fig. 35B illustrates a plurality of patterns of ablation fluid channels defined in a multilayer balloon of an ablation catheter according to various embodiments of the present description;

Fig. 36A is a flow chart of exemplary steps for inflating a balloon of a cardiac ablation catheter and managing pressure within the balloon during an ablation procedure, according to one embodiment of the present description;

fig. 36B is a flowchart of exemplary steps of a method of performing atrial fibrillation ablation in accordance with some embodiments of the present description;

fig. 36C is a flowchart of exemplary steps of another method of performing atrial fibrillation ablation in accordance with some embodiments of the present description;

fig. 36D is a flow chart of exemplary steps of a method of performing left atrial appendage ablation according to some embodiments of the present description;

fig. 36E is a flowchart of exemplary steps of another method of performing left atrial appendage ablation, in accordance with some embodiments of the present description;

fig. 36F is a flow chart of exemplary steps of a method of performing vascular or bronchial ablation according to some embodiments of the present description;

fig. 36G is a flow chart illustrating exemplary steps under each of these tasks that may be performed to implement a process using a dual balloon cardiac ablation catheter in accordance with various embodiments of the present description;

fig. 36H depicts a tri-balloon configuration with multiple marker bands according to various embodiments of the present description for left atrial appendage ablation;

FIG. 36I shows the left atrium depicting the left atrial appendage in the wall of the left atrium;

fig. 36J illustrates a plurality of left atrial appendages depicting left atrial appendages of various shapes;

fig. 37A illustrates a first perspective view of a dual balloon test catheter for performing ablation in a pig heart according to some embodiments of the present description;

figure 37B illustrates a second perspective view of the test catheter of figure 37A according to some embodiments of the present description;

figure 37C illustrates a third perspective view of the test catheter of figure 37A according to some embodiments of the present description;

fig. 37D illustrates ablation in a frozen pig heart using the test catheter of fig. 37A, according to some embodiments of the present description;

fig. 37E illustrates circumferentially ablated tissue resulting from ablation therapy using the test catheter of fig. 37A, according to some embodiments of the present description;

fig. 38 shows another test catheter for performing ablation in a pig heart according to some embodiments of the present description;

fig. 39 illustrates a catheter according to some embodiments of the present description;

fig. 40 illustrates a trans-arterial steam ablation catheter according to some embodiments of the present description;

fig. 41A is a flow chart of exemplary steps of a method of performing transarterial steam ablation of a tumor, according to some embodiments of the present description;

Fig. 41B illustrates a trans-arterial steam ablation tumor performed in the liver according to some embodiments of the present description;

fig. 42A illustrates a mapping member in a looped configuration according to some embodiments of the present description;

fig. 42B illustrates a flexible annular mapping member extending from the distal end of a dual balloon catheter in accordance with some embodiments of the present description;

fig. 42C illustrates a flexible mapping member having vertical rings and horizontal rings with multiple electrodes according to some embodiments of the present description;

fig. 42D illustrates a flexible mapping member having vertical loops and horizontal loops with a plurality of electrodes extending from the distal end of a double balloon catheter, according to some embodiments of the present description; and

fig. 42E illustrates a flexible mapping member having vertical and horizontal rings with a plurality of electrodes pulled down onto the distal end of a dual balloon catheter, according to some embodiments of the present description.

Detailed Description

In various embodiments, the ablation devices and catheters described in this specification are used in conjunction with any one or more of the heating systems described in U.S. patent application No. 14/594,444 entitled "method and apparatus for tissue ablation" filed on 12.1.2015, which was issued on 7.2.2017 under U.S. patent No. 9,561,068, the entire contents of which are incorporated herein by reference.

"treating", "treatment", and variations thereof, refer to any reduction in the degree, frequency, or severity of one or more symptoms or signs associated with a disorder.

"duration" and variations thereof refer to the time course of a prescribed treatment, from beginning to end, whether the treatment is ended because the condition is resolved or whether the treatment is suspended for any reason. During treatment, a plurality of treatment time periods may be prescribed during which one or more prescribed stimuli are administered to the subject.

"period" refers to the time at which a "dose" of stimulus is administered to a subject as part of a prescribed treatment plan.

The term "and/or" refers to one or all of the listed elements, or a combination of any two or more of the listed elements.

In the description and claims of this application, the words "comprise", "comprising" and "have", and forms thereof, are not necessarily each limited to the members of the list with which they may be associated. The term "comprising" and its variants do not have a limiting meaning when these terms appear in the description and claims. It is noted herein that any feature or element described in connection with a particular embodiment may be used and practiced with any other embodiment, unless specifically stated otherwise.

Unless otherwise specified, "a," "an," "the," "one or more," and "at least one" are used interchangeably and mean one or more than one.

The term "controller" refers to an integrated hardware and software system defined by a plurality of processing elements, such as integrated circuits, application specific integrated circuits, and/or field programmable gate arrays, in data communication with memory elements, such as random access memories or read only memories, wherein one or more of the processing elements are configured to execute program instructions stored in the one or more memory elements.

The term "steam generation system" refers to any or all of the heaters or induction-based methods described herein that generate steam from water.

The terms "coolant," "coolant," and "insulator" may be used interchangeably and may refer to air, water, or CO₂。

The term "cardiac tissue" refers to a portion of a pulmonary vein, the ostium of a pulmonary vein, the junction between the left atrium and a pulmonary vein, the atrium, the left atrial appendage, tissue adjacent thereto, or other portions of the heart and adjacent tissue.

For any of the methods disclosed herein that include discrete steps, the steps may be performed in any order that is practicable. Also, any combination of two or more steps may be performed simultaneously, as appropriate.

Also herein, the recitation of numerical ranges by endpoints includes all numbers subsumed within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.). Unless otherwise indicated, all numbers expressing quantities of ingredients, molecular weights, and so forth, used in the specification and claims are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and claims are approximations that may vary depending upon the desired properties sought to be obtained by the present specification. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the specification are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. All numerical values, however, inherently contain a range necessarily resulting from the standard deviation found in their respective testing measurements.

The devices and methods of the present description may be used to cause controlled focal or circumferential ablation of target tissue to different depths in a manner that complete healing of re-epithelialization may occur. In addition, the vapor may be used to treat/ablate benign and malignant tissue growth, resulting in destruction, liquefaction and absorption of ablated tissue. The dose and manner of treatment may be adjusted based on the type of tissue and the desired ablation depth. The ablation device may be used to treat cardiac arrhythmias, atrial fibrillation, ventricular fibrillation, atrial appendage narrowing or closure, hypertension, diabetes, nonalcoholic steatohepatitis/nonalcoholic fatty liver disease (NASH/NAFLD), asthma, and to treat any mucosal, submucosal, or peripheral lesion, such as inflammatory lesions, tumors, polyps, and vascular lesions. The ablation device may also be used to treat lesions or circumferential mucosal or submucosal lesions of any hollow organ or hollow body passageway in the body. The hollow organ may be one of the vascular structures, such as a blood vessel, a cardiac tissue, a pulmonary artery or vein, a pulmonary vein ostium, the left atrium, a ventricular tissue, the left atrial appendage, a renal artery/vein/nerve, a hepatic artery/vein/nerve or a portal vein and a bronchial or bronchial nerve. The ablation device may be placed endoscopically, radioactively, surgically, or directly. In various embodiments, a wireless endoscope or a single fiber optic endoscope may be incorporated as part of the device. In another embodiment, magnetic or stereotactic navigation may be used to navigate the catheter to a desired location. Radiopaque or acoustically transparent materials may be incorporated into the body of the catheter for radiologic localization. Ferromagnetic materials or ferromagnetic materials may be incorporated into the catheter to aid in magnetic navigation.

Such as water vapor, heated gas, or a cryogen (e.g., without limitation, liquid nitrogen and liquid CO)₂) The ablative agent of (a), is inexpensive and readily available and is directed onto tissue via the injection port, held at a fixed and consistent distance, as a target for ablation. This allows for an even distribution of the ablative agent on the target tissue. For purposes of this specification, a preferred ablative agent is a hot vapor generated from a source of saline or carbonated water. In some embodiments, the ablative agent includes electrical energy delivered as a radio frequency or as an electrical pulse to effect electroporation.

The flow of the ablative agent is controlled by the microprocessor according to a predetermined method based on the characteristics of the tissue to be ablated, the desired ablation depth and the distance of the port from the tissue. The microprocessor may use temperature, pressure, electrical or other sensed data to control the flow of the ablative agent. Additionally, one or more suction ports are provided to suction ablative agent from the vicinity of the target tissue. The targeted portion may be treated by continuous infusion of the ablative agent or via cycles of infusion and removal of the ablative agent as determined and controlled by the microprocessor.

It should be understood that the apparatus and embodiments described herein are implemented with a controller that includes a microprocessor that executes control instructions. The controller may be in the form of any computing device, including desktop, laptop, and mobile devices, and may transmit control signals to the ablation device in a wired or wireless fashion.

The present invention relates to various embodiments. The following disclosure is provided to enable one of ordinary skill in the art to practice the invention. The language used in the specification should not be construed as a general disavowal of any one specific embodiment nor should it be used to limit the claims to the meanings of the terms used therein. The general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present invention. Also, the phraseology and terminology used are for the purpose of describing the exemplary embodiments and should not be regarded as limiting. Thus, the present invention is to be accorded the widest scope encompassing numerous alternatives, modifications and equivalents consistent with the principles and features disclosed. For the purpose of clarity, details relating to technical material that is known in the technical fields related to the invention have not been described in detail so that the invention is not unnecessarily obscured.

Ablation controller for delivering fluid to a catheter and heating the fluid therein

Fig. 1 illustrates an ablation device according to one embodiment of the present description. The ablation device includes acatheter 10 having a distal centering or positioning appendage, and an ablative agent control appendage, which is preferably aninflatable balloon 11. Thecatheter 10 is made of or covered with an insulating material to prevent ablation energy from escaping from the catheter body. The ablation device includes one ormore injection ports 12 for injecting an ablative agent and one ormore aspiration ports 13 for removing the ablative agent. In one embodiment, theinjection port 12 and theaspiration port 13 are identical. In one embodiment, theinjection port 12 may direct the ablative agent at different angles. In one embodiment, theinjection port 12 remains within theinflatable balloon 11.

The ablative agent is stored in areservoir 14 connected to thecatheter 10. Delivery of the ablative agent is controlled by acontroller 15. In various embodiments,controller 15 comprises a machine that controllably delivers a flow of fluid tocatheter 10. Anoptional sensor 17 monitors changes in or near the ablated tissue to direct the flow of the ablative agent. In one embodiment, theoptional sensor 17 further comprises a temperature sensor. An optional infrared, electromagnetic, acoustic or radio frequency energy emitter andsensor 18 measures the dimensions of the hollow organ. In one embodiment, the ablative agent is saline, which is converted to steam along the length of thecatheter 10.

In one embodiment, the user interface included withcontroller 15 allows the physician to define devices, organs, and conditions, which in turn create default settings for temperature, cycling, volume (sound), and standard RF settings. In one embodiment, these default values may be further modified by the physician. The user interface also includes a standard display of all key variables, and a warning if the value exceeds or falls below certain levels.

The ablation device also includes safety mechanisms to prevent the user from being burned while manipulating the catheter, including insulation, and optionally, cold/room temperature air or fluid irrigation, cold/room temperature water irrigation, and alarms/tones indicating the start and stop of treatment.

Universal ablation catheter and method

Fig. 2 is a flow chart listing the steps involved in hollow tissue or organ ablation using an ablation device, according to one embodiment of the present description. Atstep 202, an endoscope is inserted into a patient. Atstep 204, an ablation device including a catheter according to one embodiment of the present description is advanced through a working channel of an endoscope and to a target tissue. Atstep 206, the distal end or tip of the catheter is inserted into the targeted hollow tissue or organ. Suction is then applied at the proximal end of the catheter to remove the natural contents of the hollow tissue or organ atstep 208. The conductive medium is then injected into the hollow tissue or organ via at least one port on the distal end of the catheter atstep 210. Atstep 212, an ablative agent is delivered into the conductive medium for ablation of the target tissue. Atstep 214, the remaining contents of the tissue, including the conductive medium and the ablative agent, are removed via aspiration using a catheter. In another embodiment,step 214 is optional and the remaining contents of the hollow tissue or organ are resorbed by the body. In another embodiment, removal of the natural contents of the hollow tissue or organ atstep 208 is optional, and the process moves directly to injecting a conductive medium atstep 210 to avoid accessing the target tissue with a catheter atstep 206. Alternatively, in some embodiments, the natural contents of the hollow organ may be used as a conductive medium.

In various embodiments, the ablation therapy provided by the steam ablation system of the present description is delivered to achieve the following general therapy endpoints: maintaining the tissue temperature between 45 ℃ and 100 ℃ for a period of time longer than 1 second; maintaining the tissue temperature at 100 ℃ or less to cause coagulation of intracellular proteins without carbonizing intracellular sugars; applying a pressure on the tissue to be ablated that is equal to or less than 125% of the pre-treatment pressure of the tissue; and applying a pressure on the tissue to be ablated that is less than the mean arterial pressure of the patient so as not to impede injection into the tissue.

Fig. 3 shows agraph 30005 illustrating latent heat of vaporization and melting of water according to an embodiment of the present description. Thegraph 30005 shows the heat energy input or added on the X-axis and the corresponding increase in water temperature on the Y-axis.Graph 30005 shows various phase changes as thermal energy is added to the ice phase of water through the water vapor phase. Thefirst stage 30010 corresponds to ice below 0 degrees celsius, which is heated to reach a temperature of 0 degrees celsius. Thesecond stage 30015 corresponds to the melting of ice at 0 degrees celsius without any temperature change. The latent heat of fusion added in thesecond stage 30015 was 79.7 calories/gram or 334 kJ/kg. Thethird stage 30020 corresponds to an increase in water temperature from 0 ℃ to 100 ℃. The amount of heat required in thethird stage 30020 is 100 calories/gram or 418.6 kJ/kg. The fifth stage 30025 corresponds to boiling water at 100 degrees celsius to convert to water vapor at 100 degrees celsius without any temperature change. The latent heat of vaporization added in the fifth stage 30025 is 539 calories/gram or 2260 kJ/kg. According to one aspect of the present description, ablation using water vapor or steam utilizes the greater latent heat of vaporization stored in the water vapor.

Fig. 4A illustrates amulti-lumen ablation catheter 400 according to one embodiment of the present description. Thecatheter 400 includes anelongated body 405 having a proximal end and a distal end.Catheter 400 includes at least one positioning element near its distal end. In various embodiments, the positioning element is a balloon. In some embodiments, the catheter includes more than one positioning element.

In the embodiment shown in fig. 4A,catheter 400 includes two

positioning balloons

410, 412 near its distal end, withmultiple injection ports 415 located between the two

balloons

410, 412 onbody 405. Afluid delivery port 427 and asuction port 432 are located at the distal end of thebody 405. Thebody 405 includes afirst lumen 420 in fluid communication with the plurality ofinfusion ports 415, asecond lumen 425 in fluid communication with thefluid delivery port 427, and athird lumen 430 in fluid communication with theaspiration port 432. The first, second, and

third lumens

420, 425, 430 extend along the length of thebody 405 through thehandle 435 at the proximal end to the distal end. Anablative agent 421 is introduced into thefirst lumen 420 at an ablativeagent input port 401 at the proximal end of thecatheter 400 and exits through aninjection port 415 for ablation. In one embodiment, theablative agent 421 is steam or water vapor.

Fluid 426 is introduced into thesecond lumen 425 at thefluid input port 402 at the proximal end of thecatheter 400 and exits through thefluid delivery port 427. In one embodiment,fluid 426 is a coolant. In one embodiment, the coolant is water and the temperature range is 0 ℃ to 60 ℃. Negative pressure is applied to thethird lumen 430 at theaspiration input port 403 at the proximal end of thecatheter 400 using a pump to enable aspiration of fluid delivered from thefluid delivery port 427 and theinfusion port 415, respectively, via theaspiration port 432. In various embodiments, thefluid delivery port 427 and theaspiration port 432 can be located at various locations along the length of thecatheter 400 distal to thepositioning balloon 412 or proximal to thepositioning balloon 410.

Fig. 4B is a flow chart illustrating basic process steps for using theablation catheter 400 of fig. 4A according to one embodiment of the present description. Referring now to fig. 4A and 4B, atstep 462, thebody 405 of theablation catheter 400 is inserted into the organ to be ablated. For example, to perform ablation in the barrett's esophagus of a patient, a catheter is inserted into the barrett's esophagus via the patient's esophagus.

Instep 464, the positioning elements or

balloons

410, 412 are deployed such that the plurality ofinjection ports 415 are proximal to the tissue to be ablated, while thefluid delivery ports 427 andaspiration ports 432 are positioned at a site distal to the ablation region. Then, atstep 466, an ablative agent (e.g., water vapor) is delivered through the first lumen via theinjection port 415 to the target tissue to be ablated while fluid is delivered through the second lumen via thefluid delivery port 427 at a site remote from the ablated tissue such that the delivery of the fluid does not significantly interfere with the delivery of the ablative agent. According to some embodiments, the fluid is delivered at a temperature ranging from 0 ℃ to 60 ℃. Also, at the same time, the delivered fluid is aspirated from the site distal to the ablated tissue through theaspiration port 432 and thethird lumen 430, such that aspiration of the fluid does not result in aspiration of the delivered ablative agent. According to an alternative embodiment, instep 468, fluid is alternately delivered and aspirated through thefluid delivery port 427 and thesecond lumen 425, respectively. In another embodiment, atstep 469, fluid is allowed to passively escape through theaspiration port 432.

In one embodiment,first positioning balloon 410 is withinsecond positioning balloon 412 andvapor delivery port 415 is withinfirst positioning balloon 410 while coolingfluid delivery port 427 and coolingfluid aspiration port 432 are withinsecond positioning balloon 412.

Fig. 5A is a first graph illustrating a process of ablating tissue according to one embodiment. As shown in fig. 5A, an ablative agent, such as steam, is delivered to the target tissue for a first period oftime 570, with the result that the temperature of the target tissue is raised to afirst temperature 576. The target tissue temperature is maintained at thefirst temperature 576 for the first period oftime 570. After the first period oftime 570 is complete, delivery of the vapor is turned off and the target tissue temperature is allowed to cool to thebase temperature 575. After thesecond period 572, delivery of the vapor to the target tissue is resumed, and the ablation process cycle is repeated. Fig. 5B is a second graph illustrating a process of ablating tissue according to another embodiment. As shown in fig. 5B, an ablative agent, such as steam, is delivered to the target tissue for athird time period 580, with the result that the temperature of the target tissue is raised tosecond temperature 586. Target tissue temperature remains atsecond temperature 586 forthird time period 580. After thethird time period 580 is complete, delivery of the vapor is turned off and the target tissue temperature is allowed to cool to thebase temperature 585. After thefourth time period 582, delivery of steam to the target tissue is resumed, if necessary, and the ablation process cycle is repeated. In various embodiments, thefirst time period 570 and thesecond time period 572 may or may not be equal. Similarly, in various embodiments, thethird time period 580 and thefourth time period 582 may or may not be equal. In further embodiments,first time period 570 andthird time period 580 are not equal, andsecond time period 572 andfourth time period 582 are also not equal.

In various embodiments, the first and

third time periods

570, 580 are in a range from 1 to 1800 seconds, while the second and

fourth time periods

572, 582 are in a range from 0 to 1800 seconds. Also, in various embodiments,

base temperatures

575, 585 are in a range from 37 ℃ to 45 ℃, whilefirst temperature 576 andsecond temperature 586 are in a range from 60 ℃ to 110 ℃.

Fig. 5C is a flow chart illustrating a number of steps associated with the ablation process of fig. 5A and 5B. Instep 592, an ablation catheter is inserted into the organ such that the vapor delivery port is positioned proximate the target tissue for ablation. Instep 594, steam is delivered to the target tissue for a heating period ranging from 1 to 1800 seconds, with the result that the target tissue temperature is raised in the range of 60 ℃ to 110 ℃. Instep 596, steam delivery is turned off for a cooling period ranging from 1 to 1800 seconds, with the result that the target tissue temperature is reduced to within the range of 37 ℃ to 45 ℃. After the cooling period is complete, steps 592 and 594 are repeated.

Fig. 6 is a flow chart illustrating an ablation method for cardiac tissue according to some embodiments of the present description. Instep 602, a cardiac ablation catheter in accordance with embodiments of the present description is introduced into the left atrium of a patient by transseptal puncture. Instep 604, the uninflated outer balloon of the catheter is positioned in the pulmonary vein. Instep 606, the outer balloon is inflated with a cooling fluid such that the outer balloon, once deployed, contacts cardiac tissue proximate the pulmonary veins and blocks blood flow from the pulmonary veins into the left atrium. Optionally, instep 608, a staining study is used to confirm occlusion of blood flow. Instep 610, an inner balloon of a cardiac ablation catheter is inflated with steam such that a portion of the inner balloon, once deployed, contacts a portion of the deployed outer balloon to create a hot zone near a central region of both balloons, wherein thermal energy from the hot zone is transferred to the cardiac tissue to ablate the cardiac tissue. Delivery of the steam is terminated atstep 612 to allow the inner balloon to contract due to condensation of the steam and the outer balloon to contract. Optionally, instep 614, pacing of the pulmonary veins and/or the left atrium is performed to confirm completion of the ablation. In one embodiment, the inner balloon is inflated with air or CO₂Pre-expansion. In embodiments, a hot zone (ablation zone) is left on the distal hemisphere of both balloons.

Fig. 7A is an illustration of a water-cooled or brine-cooledconduit 700 according to one embodiment of the present description, and fig. 7B is a cross-sectional view of the shaft of the water-cooled conduit of fig. 7A. Thecatheter 700 includes anelongated body 705 having a proximal end and a distal end. The distal end includes a plurality ofinjection ports 715 for delivery of anablative agent 716, such as water vapor or steam for tissue ablation. Asheath 710 comprising cooling channels extends along thebody 705 of thecatheter 700. In some embodiments, thesheath 710 extends along thecatheter body 705 to a point distal or proximal to theport 715. In these embodiments, thesheath 710 is positioned such that it does not cover theport 715, thereby allowing theablative agent 716 to exit thecatheter 700 through theport 715, as shown in fig. 7B. In other embodiments, the sheath extends along the catheter body to a point proximal to the port. During use,water 720 from awater source 722 is circulated through thesheath 710 to cool thecatheter 700.Water 710 for cooling is then fed into thechamber 721 where it is heated to becomesteam 716 for delivery through theelongate body 705 and through theinjection port 715.Steam 716 for ablation andwater 720 for cooling are supplied to thecatheter 700 at the proximal end of the catheter.Arrows 723 show the path ofwater 710 through the sheath and intochamber 721.Arrows 724 illustrate the path of thevapor 716 through theelongated body 705 and out of theinjection port 715. In an embodiment, thechamber 721 is located anywhere along the length of theconduit 700.

Fig. 8A shows anablation catheter 805 according to one embodiment of the present description, while fig. 8B is a cross-sectional view of an elongate body orshaft 807 of thecatheter 805. The elongate body orshaft 807 has a distal end, a proximal end, and includes anouter lumen 809 and a coaxialinner lumen 811. According to one aspect,coolant 813, such as but not limited to air, CO₂Water or saline enters theouter lumen 809 from the proximal end of the body orshaft 807 and is expelled through the distal end of the body orshaft 807. Similarly,steam 815 enters theinner lumen 811 from the proximal end of the body orshaft 807 to emanate from the distal end of the body orshaft 807 while the body orshaft 807 is kept cool by circulatingcoolant 813.

Fig. 9A shows anablation catheter 905 according to one embodiment of the present description, while fig. 9B is a cross-sectional view of an elongate body orshaft 907 of thecatheter 905. The elongate body orshaft 907 has a distal end, a proximal end, and includes first and second

outer lumens

909a, 909b and a coaxialinner lumen 911. According to one aspect, acoolant 913, such as, but not limited to, air, CO₂Water or saline enters firstouter lumen 909a from the proximal end of body orshaft 907 and, after having circulated through body orshaft 907, is also expelled through secondouter lumen 909b at the proximal end of body orshaft 907.Steam 915 enters theinner lumen 911 from the proximal end of the body orshaft 907 to emanate from the distal end of the body orshaft 907 while the body orshaft 907 is kept cooled by the recirculatedcoolant 913. Where thecoolant 913 is air or CO₂In embodiments of (1), air or CO₂May be released or vented via a handle attached at the proximal end of body orshaft 907, thereby coolingBut the handle. In embodiments wherecoolant 913 is water or saline, water entersshaft 907 through firstouter lumen 909a and is fed through secondouter lumen 909b into a heating chamber enclosed within a handle attached at the proximal end of body orshaft 907 or placed anywhere along the length ofcatheter 905. The water supplied into the heating chamber is converted to steam 915, which then enters theinner lumen 911.

Fig. 10A shows anablation catheter 1005 according to one embodiment of the present description, while fig. 10B is a cross-sectional view of an elongate body orshaft 1007 of thecatheter 1005. The elongate body orshaft 1007 has a distal end, a proximal end, and includes first and second

outer lumens

1009a, 1009b and a coaxialinner lumen 1011. At least oneballoon 1025 is attached at the distal end of the body orshaft 1007 and is in fluid communication with the firstouter lumen 1009a and the secondouter lumen 1009 b. In some embodiments, the elongated body orshaft 1007 optionally includes one or more additional outer lumens 1027 (fig. 10B) to serve as auxiliary channels, for example, for various sensors. According to one aspect, thecoolant 1013, preferably air or CO₂Firstouter lumen 1009a is accessed from the proximal end of body orshaft 1007 and maintains air or CO in body orshaft 1007 whileballoon 1025 has been inflated to a desired pressure₂Cycling to maintain the shaft temperature below 60 degrees celsius, preferably below 45 degrees celsius, also exits through the secondouter lumen 1009b at the proximal end of the body orshaft 1007. The desired pressure within theballoon 1025 is maintained by a pressure valve (or electronic valve controlled by a microcontroller) positioned at the proximal end of the secondouter lumen 1009b, wherein the pressure valve maintains air flow and opens when the desired pressure is reached. Similarly, thesteam 1015 enters theinner lumen 1011 from the proximal end of the body orshaft 1007 to emanate from the distal end of the body orshaft 1007 while the body orshaft 1007 is kept cooled by the circulatingcoolant 1013. It will be appreciated that in some embodiments, theinner lumen 1011 is in fluid communication with another balloon positioned within theballoon 1025 and freely movable therein, and delivers steam into the second balloon. In another embodiment, the inner lumen is in fluid communication with another balloon positioned distal toballoon 1025 and free to move, and delivers steam to the first balloonIn the two saccules.

Thus, according to one aspect, a coolant, such as water, is circulated within the outer lumen of the elongate body and then supplied into the heating chamber for conversion to steam, as described with reference to fig. 9A, 9B. According to another aspect, a coolant, such as air, is circulated back and forth through the outer lumen of the elongate body in the balloon to cool the elongate body or shaft as described with reference to fig. 10A, 10B. In various embodiments, the heating chamber is positioned at any location along the length of the conduit. In one embodiment, a portion of the heating chamber is located at the distal tip within balloon 125. In various embodiments, additional cooling fluid is delivered to the exterior of the catheter body along the length of the catheter for therapeutic cooling purposes.

Referring now to fig. 8B, 9B and 10B, according to one aspect of the present description, the

inner layer

830, 930, 1030 of the

catheter shaft

807, 907, 1007 is thicker than the

outer layer

832, 932, 1032 to prevent heat loss or minimize energy transfer from the interior to the exterior of the catheter. This is in contrast to prior art cooling shaft ducts where the objective is to maximize the transfer of cold temperatures from the duct interior to the duct exterior.

Fig. 11 illustrates anablation catheter 1120 in accordance with an embodiment of the present description. Thecatheter 1120 includes anelongate body 1121 having a proximal end and a distal end. In one embodiment, thecatheter body 1121 includes aninner lumen 1122, a firstouter lumen 1123a, and a secondouter lumen 1123 b.Inner lumen 1122 is separated from

outer lumens

1123a, 1123b by asemi-permeable wall 1124 that allows a portion of the thermal energy to be transferred frominner lumen 1122 to

outer lumens

1123a, 1123 b. The catheter also includes at least one positioning element or balloon at its distal end. In the embodiment shown in fig. 11, thecatheter 1120 includes two

positioning balloons

1125, 1126 at its distal end, with a plurality ofdelivery ports 1127 located between the two

balloons

1125, 1126 on thecatheter body 1121.Delivery port 1127 is in fluid communication withinner lumen 1122. Anablative agent 1128 is introduced intoinner lumen 1122 at the proximal end ofcatheter 1120 and exits throughdelivery port 1127 into an organ such as the esophagus for ablation. In one implementation In this manner, theablative agent 1128 is water vapor. Such as air or CO₂Is introduced into the firstouter lumen 1123a at the proximal end of thecatheter 1120 and enters the

balloons

1125, 1126 through theinflation port 1130a to inflate said

balloons

1125, 1126, then exits the

balloons

1125, 1126 via theexit port 1130b into the secondouter lumen 1123b, and finally exits at the proximal end of the catheter, allowing air orCO₂1129 circulate along the length of thecatheter 1120 and through one or

more balloons

1125, 1126. In one embodiment, air or CO₂Circulates through thefirst balloon 1125, and releases the ablative agent into thesecond balloon 1126.

Figure 12 illustrates a connection between asyringe 12020 and acatheter 12010 according to one embodiment. As shown in fig. 12, the proximal end of thecatheter 12010 is configured to receive the distal end of theconnector component 12015 so that a fluid-tight seal is formed when the distal end of theconnector component 12015 is inserted into the proximal end of thecatheter 12010. Asyringe 12020 is coupled to the proximal end of theconnector component 12015 to supply water or saline to thecatheter 12010 through theconnector component 12015 coupled to thecatheter 12010. In various embodiments, a radiofrequency identification component 12025 is included at the proximal end of thecatheter 12010 to communicate a successful fluid connection between thecatheter 12010 and thesyringe 12020.

In various embodiments, the connectors described in this specification are composed of thermoplastics including ABS, acetal, nylon (polyamide), and Polyetheretherketone (PEEK) and fluoropolymers including polyvinylidene fluoride (PVDF). In various embodiments, the O-ring is composed of Fluorocarbon (FKM) or silicone.

Heating chamber

Fig. 13A is a transversecross-sectional view 1321 of aflexible heating chamber 1330 configured to be incorporated at or into a distal portion or tip of a catheter, according to one embodiment of the present description. Figure 13B illustrates a transversecross-sectional view 1322a and a longitudinal cross-sectional view 1322B of afirst electrode array 1336 and a transversecross-sectional view 1323a and a longitudinal cross-sectional view 1323B of asecond electrode array 1338 for a flexible heating chamber of a catheter, according to one embodiment of the present description. Fig. 13C and 13D are a transversesectional view 1324 and a longitudinal sectional view 1325, respectively, of theheating chamber 1330 including the assembled first and

second electrodes

1336 and 1338.

Referring now to fig. 13A, 13B, 13C and 13D simultaneously,heating chamber 1330 includesouter shroud 1332 and coaxialinner core 1334. A plurality of electrodes configured as afirst electrode array 1336 and asecond electrode array 1338 are disposed between theouter shroud 1332 and theinner core 1334. In some embodiments, thefirst electrode array 1336 and thesecond electrode array 1338 include a

metallic ring

1342, 1344, respectively, from which a plurality of electrode tabs or elements 1336', 1338' extend radially into the space between theouter shroud 1332 and the inner core 1334 (see

views

1322a, 1323 a). The electrode tabs or elements 1336', 1338' also extend longitudinally along alongitudinal axis 1350 of the heating chamber 1330 (see

views

1322b, 1323 b). In other words, each electrode tab 1336', 1338' has a first dimension along a radius of theheating chamber 1330 and a second dimension along alongitudinal axis 1350 of theheating chamber 1330. The electrode tabs or elements 1336', 1338' define a plurality ofsegmented spaces 1340 therebetween through which the brine/water flows and evaporates into water vapor. Electrical current is supplied to the

electrodes

1336, 1338, which causes the fins or elements 1336', 1338' to generate heat, which is then transferred to the brine/water to convert the brine/water into water vapor. The first and second dimensions enable the

electrodes

1336, 1338 to have an increased surface area for heating the saline/water flowing in thespace 1340. According to one embodiment, thefirst electrode 1336 has a first polarity and thesecond electrode 1338 has a second polarity opposite to the first polarity. In one embodiment, the first polarity is negative (cathode) and the second polarity is positive (anode).

In embodiments, theouter shroud 1332 and theinner core 1334 are constructed of silicone, teflon, ceramic, or any other suitable thermoplastic elastomer known to those of ordinary skill in the art. Theinner core 1334,outer cover 1332,electrodes 1336, 1338 (including

rings

1342, 1344 and tabs or members 1336', 1338') are all flexible to allow bending of the distal portion or tip of the catheter to provide better positioning of the catheter during an ablation procedure. In an embodiment, theinner core 1334 stabilizes the

electrodes

1336, 1338 and maintains the spacing orgap 1340 between the

electrodes

1336, 1338 while the tip of the catheter flexes or bends during use.

As shown in fig. 13C and 13D, when theheating chamber 1330 is assembled, the electrode tabs or elements 1336', 1338' are interleaved or interlocked with each other (similar to the fingers of two grasping hands) such that a cathode element is followed by an anode element, which is followed by a cathode element, which is followed by an anode element, and so on, with aspace 1340 separating each cathode and anode element. In various embodiments, eachspace 1340 has a distance ranging from 0.01mm to 1mm from the cathode element to the anode element. In some embodiments, thefirst electrode array 1336 has in the range of 1 to 50 electrode tabs 1336', preferably 8 electrode tabs 1336' in number, and thesecond electrode array 1338 has in the range of 1 to 50 electrode tabs 1338', preferably 8 electrode tabs 1338' in number. In various embodiments, theheating chamber 1330 has a width w in the range of 1 to 5mm and a length l in the range of 1 to 150 mm.

According to one aspect of the present description, a plurality ofheating chambers 1330 may be disposed in the catheter tip. Fig. 13E and 13F are longitudinal cross-sectional views of aconduit tip 1355 in which twoheating chambers 1330 are arranged in series, according to one embodiment of the present description. Referring to fig. 13E and 13I, the twoheating chambers 1330 are arranged in series such that thespace 1360 between the twoheating chambers 1330 serves as a region of lower stiffness, thereby imparting increased flexibility to theconduit tip 1355 to allow it to bend. The twoheating chambers 1330 include first and

second electrode arrays

1336 and 1338, respectively, that are staggered. The use of multiple (e.g., two)heating chambers 1330 enables further increases in the surface area of the

electrodes

1336, 1338 while maintaining the flexibility of thecatheter tip 1355.

Referring now to fig. 13A-13F, to generate steam, fluid is delivered from a reservoir to theheating chamber 1330 by a pump or any other pressurizing device. In embodiments, the fluid is sterile saline or water delivered at a constant or variable fluid flow rate. An RF generator connected toheating chamber 1330 provides power tofirst electrode array 1336 andsecond electrode array 1338. As shown in fig. 13D, during steam generation, as the fluid flows through thespace 1340 in theheating chamber 1330 and power is applied to the

electrodes

1336, 1338 causing the electrodes to heat, the fluid is heated in a firstproximal region 1370 of theheating chamber 1330. When the fluid is heated to a sufficient temperature, for example 100 degrees celsius at atmospheric pressure, the fluid begins to convert to steam or water vapor in the secondintermediate region 1375. All of the fluid is converted to steam as it reaches the thirddistal region 1380, after which it may exit thedistal end 1333 of theheating chamber 1330 and exit theconduit tip 1355. If the pressure in the heating chamber is greater than atmospheric pressure, a higher temperature will be required, and if it is less than atmospheric pressure, a lower temperature will produce steam.

A standard circular or rectangular electrode located in the catheter tip may have dimensions that prevent the catheter tip from effectively bending. Specifically, the electrode was printed on Kapton (polyimide) and then rolled into a cylinder, thereby making it rigid. Embodiments of catheter tips according to the present description have a bend radius in the range of 3 to 0.15 inches, and preferably in the range of 1 to 0.5 inches. Another design of the electrode is required in order to incorporate an electrode length that is larger than the bend radius.

Due to the bending radius at the tip, the size of the electrode becomes significant. The electrode needs to be less than or equal to 2.5 inches, preferably less than or equal to 1 inch, in order to allow the required bend radius. In one embodiment, the bend radius of the introducer sheath is 180 degrees around a 1 inch radius. In one embodiment, the maximum length of the continuous electrodes is equal to the bend radius. Figure 13G shows

discontinuous electrodes

1366 and 1368 such that they may be longer than the bend radius but flexible at the point of discontinuity according to one embodiment of the present description. Thus, in one embodiment, thethermal fluid channel 1370 includes two or

more electrode segments

1372 and 1374, wherein each electrode segment is separated by aspace 1376, and wherein each electrode segment is no longer than the bend radius of the conduit, or wherein the length of each electrode segment is equal to or less than 2.5 inches, preferably 1 inch.

For optimal positioning of the electrodes, the main requirement is that the electrodes are positioned close to the output of the thermal fluid channel into the inner balloon. At the same time, it is desirable that the electrodes are not too close because the water vapor quality (the amount of condensed water in the water vapor) decreases. In some embodiments, the electrode is positioned within the inner balloon. In some embodiments, the electrodes are positioned at a distance in the range of 0mm to 500mm near the outlet of the thermal fluid channel into the inner balloon. In some embodiments, the electrodes are positioned at a distance in the range of 1mm to 150mm near the outlet of the thermal fluid channel into the inner balloon.

In some embodiments, the electrodes are made of multiple segments that are electrically connected to each other and housed in a flexible segment of the catheter body at a desired bend radius, wherein the length of each segment of the electrode is less than four times the bend radius of the catheter, thereby providing sufficient length coverage.

Fig. 13H illustrates another embodiment of an arrangement ofelectrodes 1336 ", 1338" according to one embodiment of the present description that may be configured within a flexible heating chamber to be incorporated at or into the distal portion or tip of a catheter. Theelectrodes 1336 "and 1338" represent two poles (the ends of the

electrodes

1336 and 1338 seen in fig. 13A-13F), which are rectangular and arranged in a double helix structure. The use of a double helix structure enhances the flexibility of the catheter tip and enables easy bending of the catheter tip. In some embodiments, theelectrodes 1336 "and 1338" have a radial dimension in the range of 0.5mm to 5mm and an axial dimension in the range of 5mm to 150 mm.

Additionally, in some embodiments, the electrodes are fabricated using nitinol-based materials, thereby ensuring a simple installation process.

Fig. 13I illustrates another embodiment of a saw-tooth configuration ofelectrodes 1378 according to one embodiment of the present description, which may be configured within a flexible heating chamber to be incorporated at or into a distal portion or tip of a catheter. Theelectrode 1378 is designed with serrated edges and is arranged longitudinally around the circumference around the catheter tip. The zigzag pattern of the electrodes results in a high current density at the edges of the electrodes, resulting in increased heating or increased edge effects. This increases the power efficiency of the system by requiring less power generation to produce the steam required for treatment. In one embodiment, the electrode has a perimeter that is greater than 2 x (length + width) of the electrode.

In another embodiment, the electrodes are configured in a flat configuration. The flat electrode configuration includes an elongated linear member having a first side and an opposing second side that are both planar. The flat electrode configuration may include a bipolar array defined by a plurality of printed or deposited electrode tabs. The saline is configured to flow equally on the top and bottom surfaces of the flat electrode configuration. In an embodiment, the catheter lumen housing the flat electrode configuration has an elliptical geometry that concentrates the electrode configuration within the larger radius of the elliptical lumen in order to ensure consistent water vapor quality on both sides of the electrode configuration.

During steam generation, a signal may be sensed to determine whether the fluid has completely developed into steam before exiting the distal end of the heating chamber. In some embodiments, the signal is sensed by a controller. Sensing whether steam is fully developed is particularly useful for many surgical applications, such as in ablation of various tissues, where delivering high quality fully developed steam results in more effective treatment. In some embodiments, the heating chamber includes at least onesensor 1337. In various embodiments, the at least onesensor 1337 comprises an impedance, temperature, pressure, or flow sensor. In one embodiment, the electrical impedance of the

electrode arrays

1336, 1338 may be sensed. In other embodiments, the temperature of the fluid, the temperature of the electrode array, the fluid flow rate, the pressure, or the like may be sensed.

It should be understood that any ablation catheter or system of the present specification for ablating tissue in an organ may be used with a controller configured to limit the pressure generated by an ablation fluid, such as water vapor/steam, within the organ to less than 5atm or 100 psi.

Cardiac ablation catheter and method

In various embodiments, a cardiac ablation catheter having one or more inflatable balloons is disclosed. In various embodiments, the one or more balloons are of the following types and specifications, as described in detail in table 1 below:

TABLE 1

The following are some definitions of reference balloon types and specifications:

balloon diameter — refers to the nominal inflated balloon diameter measured at a specified pressure.

Balloon length-generally refers to the working length or length of the straight body segment.

Burst pressure-refers to the average pressure required to rupture the balloon; usually at body temperature.

Nominal burst pressure-refers to the maximum statistically guaranteed pressure to which the balloon can be inflated without failure. For PTCA and PTA catheters, this is typically a 95% confidence/99.9% guarantee.

Balloon profile-refers to the maximum diameter of the balloon when it is mounted on a catheter in its deflated and wrapped state, or the smallest hole through which a deflated wrapped balloon catheter can pass.

Balloon compliance-refers to the change in balloon diameter as a function of inflation pressure.

In various embodiments, when inflated, the one or more balloons can have a shape such as, but not limited to, conical, square, spherical, elliptical, conical-square, long conical-square, conical-spherical, long spherical, tapered, dog bone, stepped, offset, and conical offset.

Further, in various embodiments, the ends (distal and/or proximal) of the one or more balloons can have shapes such as, but not limited to, tapered sharp corners, tapered rounded corners, square ends, spherical ends, and offset necks.

Table 2 provides a comparison of a number of balloons made from various materials:

TABLE 2

Maximum rated pressure based on practical limits and uses

The material of the balloon is an important factor. If the softening temperature (Tg) of the balloon material is too low, the balloon may deform when exposed to water vapor during use. For example, the Tg of PET is 75 ℃. This means that after only one use, the PET balloon may be deformed and may not be used for additional ablation imaging of a given PV or other PVs in a patient. Therefore, it is desirable to work with materials having a Tg greater than 100 ℃. In an embodiment, there are two balloons, wherein each balloon has a different Tg value. In embodiments, the Tg value of each balloon is in the range of 60 ℃ to about 200 ℃. In some embodiments, the Tg is 80 ℃. In some embodiments, the Tg is l50 ℃. Outer balloon is composed of

(thermoplastic polyurethane).

It is also desirable to use materials that have a sufficiently wide range of elasticity at various operating temperatures. If the elastic range is too low, the yield point is exceeded during operation and the balloon deforms such that the ablation region may not be properly positioned during operation.

In embodiments, the material of the inner balloon is non-compliant to semi-compliant, meaning that the material eliminates any folds that may have been present during packaging, and conforms to the atrial anatomy for better contact. The compliant balloon may have a fixed volume at a fixed pressure. It is desirable that the material of the inner balloon be harder than the material of the outer balloon in order to maintain a certain shape. Some semi-compliant balloon materials, such as the PEBA series, face mechanical and thermal challenges when introducing water vapor. Thus, a preferred balloon material is a copolymer known as Arnitel. Arnitel is also relatively semi-compliant, but has higher softening and melting temperatures than standard PEBA polymers. According to embodiments of the present description, materials such as Arnitel may be used to fabricate the inner balloon, outer balloon and shaft applications. The advantage of using it as a shaft material is that it can be thermally bonded to the inner balloon currently made using PET, thereby eliminating the need to use an adhesive bonding process.

The ablation catheter needs to be covered and uncovered, especially if the ablation catheter is only 1fr or less than the guiding sheath. In some embodiments, a hydrophilic coating on the ablation catheter is used to enable easy coating. The coating also enables efficient energy transfer to the outer balloon surface and protects the outer balloon surface from charring. In embodiments, the balloon is pleated in a specific direction, for example in the right direction, to allow for easy coating/recoating.

In some embodiments, the guide sheath is braided and has a higher stiffness than the ablation catheter. A guidewire is typically positioned within the catheter or outer catheter sheath liner to assist in bending the sides. The distal opening of the introducer sheath is positioned orthogonal to the ostium (opening) of the pulmonary vein. In some embodiments, two guide sheaths are provided, wherein the two guide sheaths have two different radii and have different deflection characteristics. In one embodiment, one pull wire for the first sheath creates a radius in the range of 0.1 inches to 0.75 inches. In one embodiment, the second pull line to the second sheath creates a radius in the range of 0.5 inches to 10 inches. In some embodiments, catheter deflection is performed via a handle actuator. Each pull wire is attached to a knob or lever in the handle. The user will twist the knob or pull the rod to apply tension to the tip and deflect it. The radius is determined by the catheter structure. In embodiments, each half of the catheter has a separate and unique configuration, allowing for two unique radii.

Fig. 14A shows acardiac ablation catheter 1442 according to an embodiment of the present description, and fig. 14B shows acardiac ablation catheter 1442 The cardiac ablation performed by thecardiac ablation catheter 1442 of fig. 14A.Cardiac ablation catheter 1442 may be used to ablate cardiac tissue to treat cardiac arrhythmias, such as atrial fibrillation. Theconduit 1442 includes an elongatedinner shaft 1443 covered by anouter shaft 1444.Inner shaft 1443 includes aninflatable balloon 1445 near its distal end. The inflatable balloon is in fluid communication with an air/steam passage 1434 that extends from theballoon 1445 through theinner shaft 1443 to an air source or first pump 1433 that is in data communication with and controlled by thecontroller 1430. Air source 1433 draws air from the external environment throughoptional filter 1438 to fillballoon 1445. In one embodiment, air source or first pump 1433 is reversible, allowing air to be pumped into or out ofballoon 1445 as needed and as commanded bycontroller 1430. In another embodiment, CO is used₂Instead of air for expansion and contraction.

In some embodiments, the entire surface ofconduit 1442 is coated with heparin.

Amapping member 1446, which may be a radial extension, a catheter, or any substrate including a plurality of sensors, detectors, or electrodes, is attached to the distal end of theinner shaft 1443 distal to theballoon 1445. The mapping means 1446 maps (map) the region of cardiac tissue that is causing the arrhythmia. In some embodiments, themapping member 1446 comprises an extension of the catheter and has a length of up to 75 mm. In some embodiments, the mapping member is pre-shaped into an annular shape perpendicular to the catheter body axis. In some embodiments, themapping member 1446 is pre-shaped into a pigtail shape to allow wall contact. In embodiments, the pigtail or loop has a diameter between 5mm and 25 mm. In some embodiments,mapping member 1446 includes 1 to 8 electrodes configured to record signals from or pacing in the pulmonary vein.

The distal end ofouter shaft 1444 terminates a distance proximal toballoon 1445 such that a portion ofinner shaft 1443 betweenballoon 1445 andouter shaft 1444 is exposed.Water 1447 may be pumped fromsterile water reservoir 1431 viasecond pump 1432 throughfirst water lumen 1435 inouter shaft 1444 where it exits from the proximal side ofballoon 1445 to cool the space proximal toballoon 1445.Water 1437 can also be pumped from thesterile water reservoir 1431 via asecond pump 1432 through a secondwater tube lumen 1436 in theinner shaft 1443 where it exits from the distal side of theballoon 1445 and approaches themapping member 1446 to cool the space distal to theballoon 1445. Thefirst water lumen 1435 extends within theouter shaft 1444 from thesecond pump 1432 to the distal end of theouter shaft 1444. The secondwater line lumen 1436 extends from thesecond pump 1432 within theinner shaft 1443 to the distal end of theinner shaft 1443. Thecontroller 1430 is in data communication with and controls thesecond pump 1432, wherein thesecond pump 1432 is configured to transfer

water

1447, 1437 from thesterile water reservoir 1431 into the first and/or

second water lumens

1435, 1436 of the outer and

inner shafts

1444, 1443, respectively. Theballoon 1445 comprises an ablation orhot zone 1448 near its equator, and a first cold zone in itstop hemisphere 1449, cooled bywater 1437 pumped through theinner shaft 1443, and a second cold zone in itsbottom hemisphere 1450, cooled bywater 1447 pumped through theouter shaft 1444. The temperature of the ablated orhot zone 1448 is typically between 60-110 deg.C and the temperature of the

cold zone

1449, 1450 is typically between 35-60 deg.C, with the temperature of the

cold zone

1449, 1450 decreasing as the

cold zone

1449, 1450 extends away from thehot zone 1448. The equatorialhot zone 1448 remains heated by the steam used to heat the interior of theballoon 1445 and is far enough away from the

water

1437, 1447 pumped through the inner and

outer shafts

1443, 1444 that it does not get cold.

Referring to fig. 14B, theballoon 1445 of thecatheter 1442 has been positioned in theheart 1451 proximate to thepulmonary vein 1452. Heat supplied to theballoon 1445 by the steam is transferred from thehot zone 1448 to the targetedcardiac tissue 1453 to ablate thetissue 1453 and treat the arrhythmia. Thehot zone 1448 is defined by the portion of the balloon that contacts the targetedcardiac tissue 1453 where the water used for cooling does not contact the balloon surface, while the

cold zones

1449, 1450 are defined by the portion of the balloon that does not contact the targetedcardiac tissue 1453, allowing the water to contact and cool the balloon surface. In some embodiments, the two temperature zones may also be defined by constructing the balloon from two different materials having different thermal conductivities. In one embodiment, the hot zone is located more towards the distal hemisphere of the balloon facing the Pulmonary Vein (PV) ostium.

Fig. 14C is a flow chart illustrating the steps involved in one embodiment of a method of ablating cardiac tissue using the catheter of fig. 14A. Atstep 1454, a region of the heart prone to arrhythmia is mapped using a mapping catheter. Atstep 1455, the balloon is inflated with air to a first pressure (P1) to cause the balloon to contact the target arrhythmic tissue. Instep 1456, water is injected to cool the catheter and optionally the top and bottom hemispheres of the balloon. In some embodiments,step 1456 occurs before, concurrently with, or afterstep 1455. In some embodiments, the blood helps to cool the top and bottom hemispheres of the balloon. Instep 1457, water vapor or steam is injected into the balloon to heat the interior of the balloon while removing air from the balloon to maintain a second pressure (P2) equal to P1 +/-25%. The amount of steam delivered to the balloon may also be adjusted (without removing air) to maintain the second pressure (P2) equal to P1 +/-25%. Instep 1458, a hot zone is created on the balloon by the injected water vapor, wherein the hot zone contacts the cardiac tissue, resulting in ablation.

Fig. 14D illustrates acardiac ablation catheter 1460 according to another embodiment of the present description.Catheter 1460 includes anelongate body 1461, a proximal end and a distal end with an air/water lumen 1462 and asteam lumen 1463 at its proximal end supplied by a port. The air/water lumen 1462 is in fluid communication with aballoon 1464 attached to the distal end of thecatheter 1460.

Balloon 1464 includes a plurality ofoptional mapping electrodes 1466 within or attached to the outer surface of its wall. In an embodiment,mapping electrode 1466 is a glued metal electrode or a printed electrode, within or attached to the outer surface of its wall midway along its length axis, that is circularly configured to record cardiac signals to map regions of cardiac tissue responsible for cardiac arrhythmias. In some embodiments,mapping balloon 1464 includes up to 24 mapping electrodes.

Steam lumen 1463 is in fluid communication with anablation balloon 1465 attached to the distal end ofcatheter 1460 and positioned withinballoon 1464. Once both

balloons

1464, 1465 are inflated, the length of theballoon 1464 is greater than the length of theablation balloon 1465, and the diameter of theablation balloon 1465 approximates the diameter of theballoon 1464.

In some embodiments, the entire surface ofcatheter 1460 is coated with heparin. In some embodiments, theablation balloon 1465 can be moved along and within the entire length of theballoon 1464 along the longitudinal axis of the

balloon

1464, 1465 using a guide wire mechanism in the handle at the proximal end of thecatheter 1460 to better position the ablation balloon within theballoon 1464.

In an embodiment, at least one dimension ofablation balloon 1465 differs fromballoon 1466 by at least 10%. In some embodiments, the dimension is the length of theablation balloon 1465. In an embodiment, the shape ofablation balloon 1465 is different than the shape ofballoon 1466. In an embodiment, the intersection of the shapes ofablation balloon 1465 andballoon 1466 determines the shape and/or size ofablation region 1467.

During use, with water or air or CO₂Theballoon 1464 is inflated and theablation balloon 1466 is inflated with steam such that theablation balloon 1465 is in contact with theballoon 1464 and theballoon 1464 is in contact with target heart tissue near the equator of the two

balloons

1464, 1465. This creates a hot zone orablation zone 1467 near the equator of theballoon 1464. Thecold zone 1471 is located on theballoon 1464 with theinflated ablation balloon 1465 not in contact with theinflated balloon 1464. Heat is transferred from the interior of theablation balloon 1465 through theballoon 1464 and into the heart tissue to ablate the tissue and treat the arrhythmia.

Fig. 14E shows aballoon 1464 with anoptional mapping electrode 1466 of thecatheter 1460 of fig. 14D. Fig. 14F shows a cross-sectional view of the intermediate shaft portion of thecatheter 1460 of fig. 14D. Thecatheter 1460 includes a spacedouter wall 1468 that includes an air/water lumen 1462 and aguidewire 1469 for mapping electrodes.Catheter 1460 also includes avapor lumen 1463 and, in one embodiment, aguidewire lumen 1470. Fig. 14G shows a cross-sectional view of the distal tip portion of thecatheter 1460 of fig. 14D.Catheter 1460 includes a plurality ofmapping electrodes 1466 built into its outer wall (or in one embodiment, into the wall of a mapping balloon), asteam lumen 1463, and aguidewire lumen 1470.

FIG. 14H is an embodiment of a method of ablating cardiac tissue using the catheter of FIG. 14DA flow chart of the steps involved in the embodiments. Atstep 1472, the mapping balloon is inflated to a first pressure (P1). Atstep 1473, the arrhythmia region is mapped using a mapping balloon. Atstep 1474, the catalyst is treated with or without air or CO₂The steam of (a) inflates the ablation balloon to a second pressure (P2) greater than P1 to contact the mapping balloon. Instep 1475, a hot zone is created on the surface of the mapping balloon, wherein the ablation balloon contacts the mapping balloon, and wherein the mapping balloon contacts the cardiac tissue to ablate the cardiac tissue, while a cold zone is present, wherein the ablation balloon does not contact the mapping balloon. Atstep 1476, electrical activity is monitored during and after the ablation process to record complete ablation of the arrhythmic lesion. Optionally, atstep 1477, the mapping electrodes monitor tissue impedance and tissue temperature to guide ablation. Optionally, atstep 1478, pacing distal to the balloon is performed to check the adequacy of ablation. Pressure may be applied to the catheter shaft to deform the shape of the outer balloon by pressing it against the heart tissue, which in turn changes the shape, size, or surface area of the contact region between the inner and outer balloons to in turn change the shape, size, or surface area of the ablation region.

Fig. 14I illustrates acardiac ablation catheter 1480 according to another embodiment of the present description. Fig. 14J shows a cross-sectional view of a middle portion of theelongate body 1481 of thecatheter 1480 of fig. 14I, and fig. 14K shows cardiac ablation performed by thecardiac ablation catheter 1480 of fig. 14I. Referring now to fig. 14I-14K concurrently, thecatheter 1480 includes anelongate body 1481, a proximal end and a distal end with an air/water lumen 1482 and asteam lumen 1483 supplied by the ports at the proximal end thereof. The air/water lumen 1482 is in fluid communication with aballoon 1484 attached to the distal end of thecatheter 1480. Air/water lumen 1482 optionally includes a plurality of sub-channels or lumens (along the length of elongate body 1481) to allow air/water to enter andexit lumen 1482 at the proximal end ofconduit 1480.

Balloon 1484 includes a plurality ofoptional mapping electrodes 1486 within or attached to the outer surface of its wall. In an embodiment,mapping electrodes 1486 are glued metal or printed electrodes within or attached to the outer surface of their walls midway along their length axis that are circularly configured to record cardiac signals to map regions of cardiac tissue responsible for cardiac arrhythmias. In some embodiments,mapping balloon 1484 includes up to 24 mapping electrodes.

Thevapor lumen 1483 is in fluid communication with anablation balloon 1485 attached to the distal end of thecatheter 1480, is positioned within theballoon 1484, and is freely movable inline along a longitudinal axis within theballoon 1484 and along its entire length to be positioned at a plurality of locations along thelongitudinal axis 1488. In some embodiments, thecatheter 1480 includes aguidewire mechanism 1459 operable by a user at a handle of thecatheter 1480 for moving theablation balloon 1485 within theballoon 1484. According to one exemplary embodiment, thecatheter 1480 shows theablation balloon 1485 being moved along alongitudinal axis 1488 from afirst position 1489a to asecond position 1489 b.

In some embodiments, the entire surface of thecatheter 1480 is coated with heparin (heparin).

In an embodiment, at least one dimension of theablation balloon 1485 differs from theballoon 1484 by at least 10%. In some embodiments, the dimension is the length of theablation balloon 1485. In an embodiment, the shape of theablation balloon 1485 is different than the shape of theballoon 1484. In an embodiment, the intersection of the shape ofablation balloon 1485 and the shape ofballoon 1484 determines the shape and/or size ofablation region 1487 a. Once both

balloons

1484, 1485 are inflated, the length of the balloon 1484 (along the longitudinal axis 1488) is greater than the length of the ablation balloon 1485 (along the longitudinal axis 1488), and the diameter of theablation balloon 1485 approximates the diameter of theballoon 1484. During use, with CO₂Or air, inflates theballoon 1484 and inflates theablation balloon 1485 with steam and places it at thefirst location 1489a (within the balloon 1484) such that theablation balloon 1485 is in contact with theballoon 1484 and theballoon 1484 is in contact with target cardiac tissue proximate thefirst location 1489a in theheart 1401 proximate thepulmonary vein 1402. This creates a hot orablation region 1487a near thefirst location 1489 a. Heat is transferred from the interior of theablation balloon 1485 through theballoon 1484 and into the heart tissue to ablate the tissue at thefirst location 1489 a. Theablation balloon 1485 is then moved to asecond position 1489b (within the balloon 1484) such thatThe ablation balloon contacts theballoon 1484 and theballoon 1484 contacts the target cardiac tissue near thesecond location 1489b within thepulmonary vein 1402. This creates a hot zone orablation region 1487b near thesecond location 1489 b. Heat is now transferred from the interior of theablation balloon 1485, through theballoon 1484 and into the heart tissue to ablate the tissue at thesecond location 1489 b. Thecold zone 1490 is located on theballoon 1484 where theinflated ablation balloon 1485 is not in contact with theinflated balloon 1484. It should be understood that theballoon 1484 and theablation balloon 1485 may have to be differentially inflated at thefirst location 1489a and thesecond location 1489b in order to conform to the space within the pulmonary vein 1402 (associated with thefirst location 1489a and thesecond location 1489 b).

According to one aspect, theballoon 1484 is more flexible (as compared to the ablation balloon 1485) and may be freely shaped or conformable to fit the shape of anatomical structures, such as the lumen of thepulmonary vein 1402, in order to create sufficient contact for electrical contact between theelectrodes 1486 and cardiac tissue. Theablation balloon 1485 is more secure and is intended to exert a firm contact at points of its axial contact with the target tissue (e.g., those points corresponding to the first and

second locations

1489a, 1489 b) in order to desirably deliver thermal energy to the target cardiac tissue.

FIG. 14L is a flow chart illustrating the steps involved in one embodiment of a method of ablating cardiac tissue using the catheter of FIG. 14I. Instep 1410, the outer balloon with optional mapping electrodes uses air or CO₂Is expanded to a first pressure (P1). Instep 1411, first and second locations corresponding to the first and second areas of cardiac arrhythmia are mapped using an outer balloon. Instep 1412, the ablation balloon is inflated with steam to a second pressure greater than or equal to P1 (P2) to contact the outer balloon at the first location. According to one embodiment, the air or CO circulated into the outer balloon₂Maintaining a temperature of less than 60 degrees celsius while maintaining a pressure in the outer balloon between 0.5

xp

1 and 1xp 2. Instep 1413, at a first location where the inner ablation balloon contacts the outer balloon and the outer balloon contacts the first cardiac tissue to ablate the first cardiac tissue, a hot zone is created on a surface of the outer balloon while the inner ablation balloon does not contact the outer balloon There is a cold zone at the location. Instep 1414, electrical activity is monitored during and after the ablation procedure to record a complete ablation of the first cardiac arrhythmia lesion. Optionally, instep 1415, the mapping electrodes monitor tissue impedance and tissue temperature to guide ablation. Once ablation at the first location is complete, instep 1416, the inner ablation balloon is moved to create a hot zone on a surface of the outer balloon at the second location, wherein the ablation balloon has been moved to contact the outer balloon, and wherein the balloon contacts the second cardiac tissue to ablate the second cardiac tissue.

Steps

1414 and 1415 are repeated at the second location for the ablation process. It will be appreciated that in various embodiments, the ablation balloon may be moved to multiple locations, thus creating multiple thermal zones on the surface of the outer balloon to ablate cardiac tissue corresponding to the multiple locations. In embodiments, the mapping electrodes and ablation regions are positioned on a distal surface of the outer balloon facing the cardiac tissue to be ablated.

Fig. 14M illustrates acardiac ablation catheter 1400 including at least oneflexible heating chamber 1330 of fig. 13A-13D according to one embodiment of the present description. Thecatheter 1400 includes anelongated body 1491 having proximal and distal ends with anair lumen 1492 and a water/steam lumen 1493 in fluid communication with anair pump 1494 and awater pump 1495 at the proximal end of thecatheter 1400. Theair lumen 1492 is in fluid communication with anouter balloon 1496 attached to the distal end of thecatheter 1400.

Theouter balloon 1496 can include a plurality of optional mapping electrodes within or attached to the outer surface of its wall. The mapping electrodes map regions of cardiac tissue that cause arrhythmias. In an embodiment, the mapping electrodes are glued metal electrodes or printed electrodes, within or attached to the outer surface of their walls, midway of their length axis, which are circularly configured to record cardiac signals to map regions of cardiac tissue responsible for cardiac arrhythmias. In some embodiments, theouter balloon 1496 includes up to 24 mapping electrodes.

The water/steam lumen 1493 is in fluid communication with anablation balloon 1497 attached to the distal end of thecatheter 1400 and positioned within theouter balloon 1496. A plurality ofinjection ports 1499 are included in a portion of the distal end in which theablation balloon 1497 is attached.

In some embodiments, the entire surface of thecatheter 1400 is coated with heparin. In some embodiments, theablation balloon 1497 is movable within theouter balloon 1496 along the longitudinal axis of the

balloons

1496, 1497 and along the entire length thereof to better position the inner ablation balloon within the outer balloon using a guide wire mechanism in the handle at the proximal end of thecatheter 1400.

In an embodiment,inner ablation balloon 1497 has at least one dimension that differs fromouter balloon 1496 by at least 10%. In some embodiments, the dimension is the length of theablation balloon 1497. In an embodiment, the shape of theablation balloon 1497 is different than the shape of theouter balloon 1496. In an embodiment, the intersection of the shapes of theablation balloon 1497 and theouter balloon 1496 determines the shape and/or size of theablation region 1417.

In some embodiments, amapping member 1499m, which may be a distal extension, catheter, or any substrate including a plurality of sensors, detectors, or electrodes, is attached to the distal end of thebody 1491 distal to theouter balloon 1496. Themapping member 1499m maps regions of cardiac tissue that cause arrhythmias. In some embodiments, themapping member 1499m has a length of up to 75 mm. In some embodiments, themapping members 1499m are pre-shaped into a pigtail shape to allow wall contact. In an embodiment, the pigtail has a diameter between 5mm and 25 mm. In some embodiments, themapping member 1499m includes 1-8 electrodes configured to record signals from or pacing in the pulmonary veins. In some embodiments, the mapping member is a separate catheter that can be inserted or withdrawn through a lumen in thecatheter 1400.

Once both

balloons

1496, 1497 are inflated, the length of theouter balloon 1496 is greater than the length of theinner ablation balloon 1497, and the diameter of theablation balloon 1497 is similar to the diameter of theouter balloon 1496. Thecatheter 1400 further includes at least one flexible heating chamber 1330 (described with reference to fig. 13A-13D) near the proximal end of themapping balloon 1496. In one embodiment, as shown in fig. 14M, twoheating chambers 1330 are arranged in series in thebody 1491. AnRF generator 1498 is coupled to a plurality of electrodes (e.g.,

electrodes

1336, 1338 of fig. 13B) included in theheating chamber 1330.

During use, theair pump 1494 supplies air or CO via theair lumen 1492₂Or another cooling/insulating fluid, causing theouter balloon 1496 to expand, thewater pump 1495 supplies water/saline to the proximal end of theheating chamber 1330 via the water/steam lumen 1493 while theRF generator 1498 supplies electrical current to the electrodes, causing it to heat and evaporate the water/saline flowing through theheating chamber 1330. The generated vapor exits through theinjection ports 1499, inflating theinner ablation balloon 1497 so that theablation balloon 1497 is in contact with theouter balloon 1496 and theouter balloon 1496 is in contact with the target heart tissue near the equator of the two

balloons

1496, 1497. This creates a hot zone or ablated 1417 near the equator of theouter balloon 1496. Thecold zone 1418 is located on theouter balloon 1496 where theinflated ablation balloon 1497 is not in contact with the inflatedouter balloon 1496. Heat is transferred from the interior of theinner ablation balloon 1497 through theouter balloon 1496 at thehot zone 1417 and into the heart tissue to ablate the tissue and treat the arrhythmia. Theflexible heating chamber 1330 imparts improved flexibility and maneuverability to thecatheter 1400, allowing a physician to better position thecatheter 1400 when performing cardiac ablation procedures, such as ablating arrhythmic lesions in a patient's heart.

Fig. 14N is a flow chart illustrating the steps involved in one embodiment of a method of ablating cardiac tissue using the catheter of fig. 14M. Atstep 1472n, the outer balloon with the optional mapping electrodes is inflated to a first pressure by operating the air pump (P1). Atstep 1473n, the arrhythmia region is optionally mapped using an outer balloon. Atstep 1474n, water/brine is provided to the at least one heating chamber by operating the water pump. Atstep 1475n, a current is provided to the electrodes of the heating chamber using the RF generator to convert the water/saline into steam exiting the injection port to inflate the ablation balloon to a second pressure greater than or equal to P1 (P2), causing the inner ablation balloon to contact the outer balloon. Atstep 1476n, a hot zone is created on the anterior or distal surface of the outer balloon, where the ablation balloon contacts the outer balloon and the outer balloon contacts the cardiac tissue to ablate the cardiac tissue, while a cold zone exists where the ablation balloon does not contact the outer balloon. Atstep 1477n, electrical activity is monitored, optionally during and after an ablation procedureMove to record complete ablation of the arrhythmic lesion. Optionally, atstep 1478n, the mapping electrodes monitor tissue impedance and tissue temperature to guide ablation. Optionally, atstep 1479n, pacing distal to the balloon is performed to check the adequacy of ablation. The inner balloon may optionally be CO before it is inflated with steam₂Or the air is pre-expanded to a pressure less than or equal to P2.

Fig. 15 shows asteam ablation catheter 1501 introduced into the left atrium of aheart 1502 via a transseptal access in accordance with one embodiment of the present description. In one embodiment, a flexible tipped guidewire (not shown) is introduced through the lumen of thesteam ablation catheter 1501 and directed into the targeted pulmonary vein. A 20mm to 50mm steam ablation balloon is positioned at the tip of the guidewire, which is then inflated in the chamber of the left atrium and guided through the guidewire to the chamber of the targeted pulmonary vein. Amapping catheter 1503 is also introduced at the site to guide ablation.

Fig. 16A shows acardiac ablation catheter 1601 according to one embodiment of the present description. The catheter includes ahandle 1604. Thecatheter 1601 includes anelongated body 1602, a proximal end and a distal end, with an air, water orsaline lumen 1609 and asteam lumen 1606 supplied by ports at its proximal end. In some embodiments, air/water or preferablysaline 1607 is circulated insaline lumen 1609 to coolbody 1602 whilevapor 1608 is injected intolumen 1606. The distal end ofbody 1602 has a distal accessory, such as aretractable needle 1605 in fluid communication with avapor lumen 1606.Retractable needle 1605 has at least one opening or injection port at its distal end to allowvapor 1608 to escape therefrom to ablate targeted heart tissue whilebody 1602 is cooled bysaline 1607 circulating insaline lumen 1609. In various embodiments, thecatheter 1601 includes a plurality of sensors, such as electrical sensors at the distal end of thecatheter 1601, for monitoring electrical activity and measuring tissue impedance during and after an ablation procedure to record complete ablation of the target cardiac tissue; a pressure sensor for measuring the pressure invapor lumen 1606 and shutting off vapor delivery when a predetermined threshold pressure is reached; and a temperature sensor for monitoring tissue temperature to guide ablation.

It will be appreciated that in various embodiments, the shape and size of the distal appendage is varied to accommodate the particular anatomy to be treated by ablation. For example, fig. 16B shows another embodiment of acardiac ablation catheter 1615 in which the distal attachment is aretractable disc 1616 covered in a thermal barrier film and attached to the distal end of theelongate body 1602. The catheter includes ahandle 1604. During use,vapor 1608 is delivered todisc 1616 throughvapor lumen 1606 whilesaline 1607 is circulated throughsaline lumen 1609 to keep the outer surfaces ofelongate body 1602 anddisc 1616 cool.Vapor 1608 is injected from at least one injection port or opening at the distal surface ofretractable disc 1616 to ablate the target tissue. In various embodiments, thecatheter 1615 includes a plurality of sensors, such as electrical sensors at the distal end of thecatheter 1615, for monitoring electrical activity and measuring tissue impedance during and after an ablation procedure to record complete ablation of the targeted cardiac tissue; a pressure sensor for measuring the pressure invapor lumen 1606 and shutting off vapor delivery once a predetermined threshold pressure is reached; and a temperature sensor for monitoring tissue temperature to guide ablation.

In some embodiments, the entire surface of thecatheter 1615 is coated with heparin.

Fig. 16C shows yet another embodiment of acardiac ablation catheter 1620, in which the distal attachment includes aninner balloon 1622 located within anouter balloon 1624 at the distal end of thecatheter 1620. The catheter includes ahandle 1604.Outer balloon 1624 and air/CO₂Thelumen 1609 is in fluid communication, while theinner balloon 1622 is in fluid communication with the saline/vapor lumen 1606. In some embodiments, the entire surface ofcatheter 1620 is coated with heparin.

In an embodiment, theinner balloon 1622 has at least one dimension that differs from theouter balloon 1624 by at least 10%. In some embodiments, this dimension is the length of theinner balloon 1622. In an embodiment, the shape of theinner balloon 1622 is different than the shape of theouter balloon 1624. In an embodiment, the intersection of the shapes of the inner and

outer balloons

1622, 1624 determines the shape and/or size of the ablation zone.

During use, theouter balloon 1624 is inflated with saline 1607 (or alternatively air/water) to enable theouter balloon 1624 to contact an ablation region including target tissue to be ablated. Thevapor 1608 enters theinner balloon 1622 to inflate theinner balloon 1622 to contact theouter balloon 1624 near the ablation region. In various embodiments, the contact area between theinner balloon 1622 and theouter balloon 1624 is between 5% and 95%, and is located at the distal or top end of theouter balloon 1624.

In an embodiment, theinner balloon 1622 may move within theouter balloon 1624, thus contacting theouter balloon 1624 at different circumferential regions. In some embodiments, using a guide wire mechanism within thehandle 1604, theinner balloon 1622 may be moved along the longitudinal axis of the

balloons

1622, 1624 within theouter balloon 1624 and along the entire length of theouter balloon 1624 to better position the inner balloon within the outer balloon. A hot zone is created at the contact area between theinner balloon 1622 and theouter balloon 1624 such that thermal energy from theinner balloon 1622 passes through theouter balloon 1624 to an ablation region near the distal end or tip of theouter balloon 1624. Theelongated body 1602 and theouter balloon 1624 are heated by circulating air or CO in portions other than the hot zone₂Or another cooling/insulating fluid 607.

In various embodiments, thecatheter 1620 comprises a plurality of sensors, e.g., electrical sensors, at the distal end of thecatheter 1620 for measuring tissue impedance for mapping the target tissue and monitoring electrical activity during and after the ablation process to record complete ablation of the target tissue; a pressure sensor for measuring the pressure invapor lumen 1606 and shutting off vapor delivery once a predetermined threshold pressure is reached; and a temperature sensor for monitoring tissue temperature to guide ablation.

In some embodiments, a mapping member, which may be a distal extension, a catheter, or any substrate including a plurality of sensors, detectors, or electrodes, is attached to the distal end of the catheter distal to theouter balloon 1624. The mapping member maps regions of cardiac tissue that cause arrhythmias. In some embodiments, the mapping member has a length of up to 75 mm. In some embodiments, the mapping member is pre-shaped into a pigtail shape to allow wall contact. In an embodiment, the pigtail has a diameter between 5mm and 25 mm. In some embodiments, the mapping member includes 1 to 8 electrodes configured to record signals from or pacing in the pulmonary vein.

In some embodiments, theouter balloon 1624 includes a plurality of mapping electrodes, which are either glued metal electrodes or printed electrodes, within or attached to the outer surface of its wall midway along its length axis that are circularly configured to record cardiac signals to map regions of cardiac tissue responsible for cardiac arrhythmias. In some embodiments, theouter balloon 1624 includes up to 24 mapping electrodes.

It should be noted that in various embodiments, brine, air, CO₂Or other cooling/insulatingfluid 1607 enters thesaline lumen 1609 at the proximal end of the catheter and exits from the proximal end of the catheter after circulating through theouter balloon 1624. In some embodiments, the cooling/insulatingfluid 1607 enters and exits thesaline lumen 1609 through the same opening. In other embodiments, the cooling/insulatingfluid 1607 enters thesaline lumen 1609 via a first opening and exits the saline lumen through a second, separate opening that is different from the first opening.

Fig. 17 illustrates one embodiment of acardiac ablation catheter 1701 traversing theleft atrium 1702 of the heart and entering thepulmonary veins 1703 according to one embodiment of the present description. In one embodiment, the catheter is encased in a steerableouter sheath 1704. At the distal end of the catheter is air or CO₂Circulating through theouter balloon 1705. Inside the outer balloon is aninner balloon 1706 filled with water vapor. It is understood that theablation region 1709 here includes a tissue-balloon interface. Amapping catheter 1707 is coupled to the balloon by atip 1708.

In some embodiments, the entire surface ofcatheter 1701 is coated with heparin.

In some embodiments, theinner balloon 1706 may be moved within theouter balloon 1705 along the longitudinal axis of the

balloons

1705, 1706 and along its entire length to better position the inner balloon within the outer balloon using a guide wire mechanism in the handle at the proximal end of thecatheter 1701. In some embodiments, pressure is applied to the outer balloon using a steerable outer sheath to press the outer balloon against the cardiac tissue to be ablated, changing the size, shape or dimension of the intersection between the two balloons, and thus the size, shape or dimension of the ablation region.

In an embodiment, theinner balloon 1706 differs from theouter balloon 1705 in at least one dimension by at least 10%. In some embodiments, the dimension is the length of theinner balloon 1706. In an embodiment, theinner balloon 1706 has a shape that is different from the shape of theouter balloon 1705. In an embodiment, the intersection of the shapes of theinner balloon 1706 and theouter balloon 1705 determines the shape and/or size of the ablation region.

In some embodiments, a mapping member, which may be a distal extension, catheter, or any substrate including a plurality of sensors, detectors, or electrodes, is attached to the distal end of thecatheter 1701 distal to theouter balloon 1705. The mapping member maps regions of cardiac tissue that cause arrhythmias. In some embodiments, the mapping member has a length of up to 50 mm. In some embodiments, the mapping member is pre-shaped into a pigtail shape to allow wall contact. In an embodiment, the pigtail has a diameter between 5mm and 25 mm. In some embodiments, the mapping member includes 1 to 8 electrodes configured to record signals from or pacing in the pulmonary vein.

In some embodiments,outer balloon 1705 includes a plurality of mapping electrodes, which are either glued metal electrodes or printed electrodes, within or attached to the outer surface of its wall midway along its length axis, which are circularly configured to record cardiac signals to map regions of cardiac tissue responsible for cardiac arrhythmias. In some embodiments, theouter balloon 1705 includes up to 24 mapping electrodes.

Fig. 18A is a flow chart listing the steps involved in one embodiment of a cardiac ablation method. The ablation device used is similar to that described with reference to fig. 17. Instep 1801, a 10-50mm vapor ablation balloon is introduced into the left atrium via a transseptal approach. Next, instep 1802, a flexible tipped guidewire is introduced through the lumen of the steam ablation catheter and is guided into the target pulmonary vein. Then, instep 1803, the outer balloon is inflated in the chamber of the left atrium and guided over a guidewire to the targetThe chamber of the pulmonary vein. Next, instep 1804, steam in the range of 99 to 115 ℃ is pumped into the inner balloon and converted to water upon contact with the balloon surface due to temperature changes at the balloon/tissue interface. This conversion of steam to water is an exothermic reaction that delivers heat to the tissue, causing the balloon/tissue interface to become extremely hot, for example between 60 ℃ and 115 ℃. The extreme heat temperature at the balloon/tissue interface causes irreversible damage to the pulmonary vein/atrial tissue, thereby ablating the tissue. Air or CO₂Or cooling/insulating fluid is circulated through the outer balloon, separating the outer balloon from the inner balloon except at the desired inner balloon/outer balloon tissue interface, the remainder of the surface of the inner balloon is insulated from contact with surrounding tissue or blood instep 1805.

Fig. 18B and 18C illustrate a dual ballooncardiac ablation catheter 1810 according to one embodiment of the present description. Thecardiac ablation catheter 1810 may be used to ablate cardiac tissue to treat cardiac arrhythmias, such as atrial fibrillation. Thecatheter 1810 includes anelongate body 1812, aproximal end 1812p and adistal end 1812d having at least one air lumen and a steam lumen supplied by a port at its proximal end. The at least one air lumen is in fluid communication with an inflatableouter balloon 1815 attached to the distal end of thecatheter 1810. The at least one air lumen extends from theouter balloon 1815 to an air pump that is in data communication with and controlled by the controller. The air pump draws air (cooling fluid) from the external environment through an optional filter to fillouter balloon 1815. In one embodiment, the air pump is reversible, allowing air to be pumped into or out ofballoon 1815 as needed and on command by the controller. In another embodiment,body 1812 includes a first lumen in fluid communication withouter balloon 1815 and configured to carry air toouter balloon 1815, and a second lumen also in fluid communication withouter balloon 1815 and configured to carry air away fromouter balloon 1815. In one embodiment, CO₂Or other cooling/insulating fluids may be used in place of air.

The steam lumen is in fluid communication with an inflatableinner balloon 1816 attached to the distal end of thecatheter 1810 and positioned within theouter balloon 1815. The steam lumen extends from theinner balloon 1816 to a water/steam pump, which is also in data communication with and controlled by the controller. Water is pumped from the sterile water reservoir through the water/steam lumen via the water/steam pump. In some embodiments,inner balloon 1816 may be moved along the longitudinal axis of

balloons

1815, 1816 withinouter balloon 1815 and along the entire length ofouter balloon 1815, using a guide wire mechanism in the handle at the proximal end ofcatheter 1810, to better position the inner balloon within the outer balloon. For example, fig. 18C showsinner balloon 1816 moved to near the distal end ofouter balloon 1815.

In some embodiments, at least one flexible heating chamber 1820 (such as those described with reference to fig. 13A-13D) is positioned in-line within the steam lumen of theelongate body 1812 adjacent to and proximate to the

balloons

1815, 1816. It is to be understood that in various embodiments, thecatheter 1810 does not include a heating chamber within the steam lumen, and that any heating chamber of the present description may be used with thecatheter 1810 to generate steam for ablation. During operation, the at least oneflexible heating chamber 1820 or any other heating chamber herein converts water flowing proximally into steam that exits through a plurality ofports 1822 located on a portion of thebody 1812 within theinner balloon 1816, thereby inflating theinner balloon 1816.

In an embodiment,inner balloon 1816 has at least one dimension that differs fromouter balloon 1815 by at least 10%. In some embodiments, the dimension is the length ofinner balloon 1816. In some embodiments, once both

balloons

1815, 1816 are inflated, the length ofouter balloon 1815 is greater than the length ofinner balloon 1816, and the diameter ofinner balloon 1816 is similar to the diameter ofouter balloon 1815. In various embodiments,outer balloon 1815 andinner balloon 1816 have any of a spherical, conical, elliptical, square, or stepped shape when inflated. In an embodiment, the shape ofinner balloon 1816 is different from the shape ofouter balloon 1815. In an embodiment, the intersection of the shapes ofinner balloon 1816 andouter balloon 1815 determines the shape and/or size ofablation region 1809, which is defined as the contact area of the two

balloons

1815, 1816.

In some embodiments, amapping member 1818, which may be a distal extension, catheter, or any substrate including a plurality of sensors, detectors, or electrodes, is attached to the distal end of thebody 1812 distal of theouter balloon 1815. Themapping member 1818 maps regions of cardiac tissue that cause arrhythmias. In some embodiments, themapping member 1818 has a length of up to 50 mm. In some embodiments, themapping members 1818 are pre-shaped to a pigtail shape to allow wall contact. In an embodiment, the pigtail has a diameter between 5mm and 25 mm. In some embodiments,mapping member 1818 includes 1-8 electrodes configured to record signals from or pacing in the pulmonary vein.

In some embodiments,outer balloon 1815 includes a plurality of mapping electrodes, which are either glued metal electrodes or printed electrodes, within or attached to the outer surface of its wall midway along its length axis, which are circularly configured to record cardiac signals to map regions of cardiac tissue responsible for cardiac arrhythmias. In some embodiments,outer balloon 1815 includes up to 24 mapping electrodes. In an embodiment, the mapping electrodes measure cardiac electrical activity to assess at least one treatment endpoint.

In some embodiments, the entire surface ofcatheter 1810 including

balloons

1815, 1816, mapping electrodes, andmapping members 1818 is coated with heparin.

Fig. 18D showsblood flow 1825 through thepulmonary veins 1826 to theleft atrium 1827. During operation, thecardiac ablation catheter 1810 is introduced into theleft atrium 1827 of the heart by transseptal puncture and the outer balloon is advanced to thepulmonary vein 1826. Next, as shown in fig. 18E,outer balloon 1815 is inflated with air to blockblood flow 1825 frompulmonary vein 1826 to leftatrium 1827. In some embodiments, the blockage ofblood flow 1825 is confirmed with a staining study. Then, as shown in fig. 18F and 18H,inner balloon 1816 is inflated with steam such thatinner balloon 1816 contacts a desired portion or area ofouter balloon 1815, andouter balloon 1815 contacts a hot or ablated region/area 1830 that includes the targeted cardiac tissue. The obstructedblood flow 1825 is also shown in fig. 18F and 18H. In some embodiments, as shown in fig. 18F, athermal zone 1830 is formed near the equator of both

balloons

1815, 1816. In some embodiments, as shown in fig. 18H, athermal zone 1830 is formed near the distal end ofouter balloon 1815. A cold zone orcold area 1850 is located onouter balloon 1815 with the inflatedinner balloon 1816 not in contact with the inflatedouter balloon 1815. Thus, thermal energy is transferred from the interior ofinner balloon 1816 throughouter balloon 1815 atablation region 1830 and into the cardiac tissue to ablate the tissue and treat the arrhythmia.

The non-contact orcold region 1850 between the inner and outer balloons is filled with air or CO acting as aninsulator₂1835. In some embodiments, the distal cold zone and theproximal cold zone 1850 are connected by a passage to equalize pressure. In one embodiment, the passage is a lumen in the catheter or integrated into the outer surface of the inner balloon, fluidly connecting thedistal cold zone 1850 and theproximal cold zone 1850. Optionally, air or CO inouter balloon 1815₂1835 are circulated out of thecatheter 1810 to actively cool theouter balloon 1815 or to move heated air in theouter balloon 1815 out through thecatheter 1810 to prevent accidental injury to cardiac tissue near the non-contact surface of theouter balloon 1815. The thermal energy is delivered for a desired duration, after which timeouter balloon 1815 contracts andinner balloon 1816 self-contracts due to condensation of the steam. Thecatheter 1810 is removed and, as shown in fig. 18G,circumferential ablations 1837 are created in the pulmonary veins 1826 (or in some embodiments, theleft atrium 1827, if desired) to treat atrial arrhythmias. Optionally, the pulmonary veins 1826 (or in some embodiments, theleft atrium 1827 if needed) are paced with a pacing catheter to confirm completion of the circumferential ablation.

In some embodiments,outer balloon 1815 includes thermocouples in predetermined areas to detect contact ofinner balloon 1816 withouter balloon 1815. In some embodiments,outer balloon 1815 includes thermocouples in predetermined areas to monitor the delivery of thermal energy to the targeted cardiac tissue. In some embodiments,outer balloon 1815 includes thermocouples outside of the predetermined area ofouter balloon 1815 to measure the temperature inouter balloon 1815 and maintain the temperature away from the predetermined area (hot zone) at less than 60 degrees celsius. In some embodiments,inner balloon 1816 includes a pressure sensor for measuring pressure insideinner balloon 1816. In some embodiments, the inner balloon includes a temperature sensor for monitoring proper water vapor production. In various embodiments, the inner and outer balloons are connected to pressure valves to maintain a constant pressure within the inner and outer balloons.

Fig. 18I is a flow diagram illustrating steps of a method of ablating cardiac tissue to treat an arrhythmia using a cardiac ablation catheter, according to one embodiment of the present description. Instep 1840, the catheter and balloon are positioned in a pulmonary vein or left atrium of a patient's heart. Instep 1841, the outer balloon is inflated to a first pressure (Pl) to block the flow of blood from the pulmonary vein to the left atrium, wherein the pressure is greater than the mean pulmonary vein pressure and less than 5 atm. Optionally, instep 1842, a diagnostic study, such as, but not limited to, a staining study, is used to confirm completion of the blood flow occlusion. Instep 1843, steam begins to flow into the inner balloon, which in turn inflates the inner balloon and raises the temperature inside the inner balloon to greater than 100 degrees celsius. Optionally, a pressure sensor measures the pressure inside the inner balloon. Optionally, the inner balloon is connected to a pressure valve having a predetermined pressure rating to maintain a constant maximum pressure inside the inner balloon. Optionally, in some embodiments, the inner balloon may be moved along the length of the catheter inside the outer balloon to better position the inner balloon inside the outer balloon. Atstep 1844, inflation of the inner balloon and/or heating of the air in the outer balloon will cause the pressure in the outer balloon to rise, thus initiating suction of air from the inner balloon to maintain the pressure P1 of the outer balloon. In some embodiments, the outer balloon is connected to a pressure valve having a predetermined pressure rating to maintain a constant maximum pressure within the outer balloon.

Instep 1845, the fully inflated inner balloon is contacted with a predetermined region of the outer balloon (also referred to as a hot zone or ablation zone), and thermal energy is transferred from the interior of the inner balloon through the outer balloon into the surrounding cardiac tissue in contact with the predetermined region of the outer balloon to cause thermal damage to the cardiac tissue in a circumferential pattern. Optionally, at least one electrode on the outer surface of the outer balloon contacts cardiac tissue to measure cardiac electrical activity to assess one of the plurality of treatment endpoints. Optionally, a thermocouple positioned in a predetermined area of the outer balloon is used to detect contact of the inner balloon with the outer balloon. Optionally, a thermocouple positioned in a predetermined region of the outer balloon is used to monitor the delivery of thermal energy to the cardiac tissue.

Optionally, instep 1846, air or CO₂Circulating air into and out of the outer balloon to cool air inside the outer balloon to maintain a portion of the outer balloon at a temperature below 60 degrees celsius. Optionally, a thermocouple positioned at a predetermined region of the outer balloon is used to measure the temperature in the outer balloon and maintain the temperature away from the predetermined region below 60 degrees celsius.

Instep 1847, delivery of the steam to the inner balloon is stopped after a predetermined time, allowing the inner balloon to contract, thereby removing the contact area between the inner balloon and the outer balloon, and stopping the delivery of thermal energy from the interior of the inner balloon through the outer balloon into the surrounding heart tissue. Optionally, additional suction is applied to the inner balloon to further deflate the balloon. Contraction of the inner balloon will cause a reduction in pressure in the outer balloon, which in turn may break the seal between the outer balloon and the pulmonary veins, thereby allowing blood to begin to flow through the ablated cardiac tissue, further cooling the cardiac tissue. At the controller level, automatic pressure control of the fluid in the outer balloon in relation to the fluid in the pump may counteract this contraction.

Instep 1848, the outer balloon is deflated by aspirating air and the catheter is removed after ablation is complete or for therapeutic purposes. In some embodiments, the inner balloon self-contracts after the outer balloon contracts due to condensation of the vapor. Optionally, prior to removal of the catheter atstep 1848, the pulmonary vein is electrically paced to check if the therapeutic objectives have been met.

Fig. 19A shows a side cutaway view of one embodiment of acardiac ablation catheter 1902 in which the distal attachment includes aninner balloon 1904 located within anouter balloon 1903 at the distal end of thecatheter 1902. The cooling fluid circulates through theouter balloon 1903, while theinner balloon 1904 is inflated with steam or water vapor. In one embodiment, theouter balloon 1903 is made of a harder material, such as PET, and theinner balloon 1904 is made of a softer material, such as latex. At theproximal end 1902b of thecatheter 1902 is ahandle 1907 having a channel orlumen 1908 extending therethrough for carrying water vapor and cooling water.

In some embodiments, the entire surface of thecatheter 1902 is coated with heparin.

In some embodiments, theinner balloon 1904 may be moved within theouter balloon 1903 along the longitudinal axis of the

balloons

1903, 1904 and along its entire length using a guide wire mechanism in thehandle 1907 at the proximal end of thecatheter 1902 to better position the inner balloon within the outer balloon.

In an embodiment, theinner balloon 1904 has at least one dimension that differs from theouter balloon 1903 by at least 10%. In some embodiments, the dimension is the length of theinner balloon 1904. In an embodiment, the shape of theinner balloon 1904 is different from the shape of theouter balloon 1903. In an embodiment, the intersection of the shapes of theinner balloon 1904 and theouter balloon 1903 determines the shape and/or size of theablation region 1909.

In some embodiments, amapping member 1952, which may be a distal extension, catheter, or any substrate including a plurality of sensors, detectors, or electrodes, is attached to the distal end of thecatheter 1902 distal to theouter balloon 1903. Themapping member 1952 maps regions of cardiac tissue that cause arrhythmias. In some embodiments, themapping member 1952 has a length of up to 75 mm. In some embodiments, themapping member 1952 is pre-shaped into a pigtail shape to allow wall contact. In an embodiment, the pigtail has a diameter between 5mm and 25 mm. In some embodiments, themapping member 1952 includes 1-8 electrodes configured to record signals from or pacing in the pulmonary vein. In another embodiment, themapping member 1952 includes up to 64 electrodes.

In some embodiments, theouter balloon 1903 includes a plurality of mapping electrodes, which are either glued metal electrodes or printed electrodes, within or attached to the outer surface of its wall midway along its length axis, which are circularly configured to record cardiac signals to map regions of cardiac tissue responsible for cardiac arrhythmias. In some embodiments, theouter balloon 1903 includes up to 24 mapping electrodes. In other embodiments, theouter balloon 1903 includes up to 64 mapping electrodes.

During operation, water vapor/steam at a temperature of about 100-. This allows theinner balloon 1904 to expand and contact theouter balloon 1903 near the ablation region. An ablation orhot zone 1909 is created at the contact area between theinner balloon 1904 and theouter balloon 1903, such that heat energy passes from theinner balloon 1904 through theouter balloon 1903 to the ablation area. The elongated body and portions of theouter balloon 1903 other than thehot zone 1909 remain cooled due to the circulating water. In some embodiments, saline is input from theluer connector 1910 and carried via thecatheter 1902 to an in-line heating member 1999 at the distal end of the catheter near the outer balloon, which generates water vapor/steam at a temperature of about 100-.

As described above, channels are provided in theconduit 1902 for carrying cooling or insulating fluids and water vapor. The cooling or insulating fluid enters thecatheter 1902 from atube 1911 at the proximal end of the catheter and exits from anothertube 1912 at the proximal end of the catheter after circulating through theouter balloon 1903.Luer connectors 1913 are used to enable cooling fluid to be supplied to and removed from

tubes

1911 and 1912, respectively. In one embodiment,luer connector 1910 at the inlet of water vapor is a pressure resistant luer lock. In one embodiment, the cooling fluid is water. In another embodiment, the cooling fluid is air or CO₂. In one embodiment, the temperature of the cooling fluid is between 0 ℃ and 40 ℃. In another embodiment, the cooling fluid is at room temperature.

In one embodiment, the length of thecatheter 1902 between itsdistal end 1902a andproximal end 1902b is about 1800mm, with a margin of ± 500 mm. In one embodiment, theouter balloon 1902 is substantially cylindrically shaped, having tapered ends, while theinner balloon 1904 is substantially spherically shaped. In another embodiment, the outer balloon is pear-shaped. In one embodiment, theouter balloon 1903 has an overall length between its two ends of about 83mm, while the cylindrical portion has a length of about 60mm with a margin of + -25 mm, and a width of about 24mm with a margin of + -15 mm. In one embodiment, theinner balloon 1904 is about 25mm in diameter with a margin of ± 15 mm. In another embodiment, the length of the outer balloon is 45mm with a margin of ± 25 mm.

Fig. 19B shows a detailed internal view of acatheter 1902 having various lumens. Referring to fig. 19B, a central lumen 1901 is used to carry water vapor into theinner balloon 1904. A firstouter lumen 1914 is used to carry cooling fluid from thetube 1911 into theouter balloon 1903, and a secondouter lumen 1915 of the catheter is used to carry cooling fluid back from the outer balloon and out through thetube 1912. All lumens are encased in another tube or handle 1905 for reinforcement.

In one embodiment, as shown in fig. 19B, the channel or lumen of thecatheter 1902 is designed with openings at appropriate locations to ensure proper flow of fluid-water vapor into the inner balloon and proper flow of cooling fluid into and out of the outer balloon. Fig. 19C illustrates the flow mechanism of thecatheter 1902 as it passes through theinner balloon 1904 and theouter balloon 1903. Referring to fig. 19C, cross-sectional views of the catheter lumen at

locations

1920, 1930, and 1940 are shown as 1921, 1931, and 1941. Details of the cross-sectional views can be seen in 1922, 1932 and 1942. As can be seen in 1922, there areopenings 1922a in the tube to allow cooling fluid to enter the channels from the outer balloon. This cooling fluid is carried by the lumen to the outlet (test tube 1912 in fig. 19B). As can be seen in 1942, there is anopening 1942a in the tube to allow cooling fluid to exit the channel into the outer balloon. This cooling fluid is supplied by tube 1911 (shown in fig. 19B) and carried by the channel to the outer balloon. In 1932, two

openings

1932a and 1932b in the channel can be seen through which water vapor is supplied from thecentral lumen 1932c to the inner balloon. In some embodiments, the cooling fluid is air, CO₂Or water.

Fig. 20A shows a side cross-sectional 2001 andperspective view 2002 of the inner balloon (shown as 1904 in fig. 19A, 19B, and 19C) when the balloon is in an undeployed state, i.e., the balloon is not inflated with water vapor. Referring to fig. 20A, in one embodiment, theballoon 2003 in its unexpanded form has a substantially cylindrical shape and tapers at both ends 2004 and 2005. The ends extend into the

tubular structures

2006 and 2007, which help to hold the catheter in place as it passes through the balloon, as shown in fig. 19A. In one embodiment, the overall length of the balloon in the undeployed state is about 28mm with a margin of ± 15mm, while the length ofcylindrical section 2009 is about 13.2mm with a margin of ± 10 mm. The length of each

tubular section

2006, 2007 is approximately 4.9mm, while the length of the tapered

portions

2004, 2005 on each side is 2.5 mm. In one embodiment, the inner diameter of each tubular section is about 2.9mm and the outer diameter is 3.7 mm. The widest portion of theballoon 2009 is approximately 5.6mm wide with a margin of ± 2.5 mm.

Fig. 20B shows a side cross-sectional 2011 and aperspective view 2012 of the inner balloon (shown as 1904 in fig. 19A, 19B and 19C) when the balloon is in an expanded state, i.e., the balloon is inflated with steam. Referring to fig. 20B, in one embodiment, theballoon 2013 in a deployed form has the shape of an elongated spheroid.

Tubular structures

2016 and 2017 extend from two opposing sides in the balloon, which help to hold the catheter in place as it passes through the balloon, as shown in fig. 19A. In one embodiment, the total length of the balloon in the deployed state, including the

tubular segments

2016, 2017, is about 28mm with a margin of ± 15mm, while the length of each individual tubular segment is about 4.8mm with a margin of ± 2.0 mm. In one embodiment, the inner diameter of each tubular section is about 2.9mm and the outer diameter is 3.3mm with a margin of ± 2.0mm when theballoon 2013 is in the deployed state. In one embodiment, the length of themajor axis 2019 of the balloon in the shape of an elongated sphere is about 23.8mm with a margin of ± 15mm when the balloon is inflated.

Fig. 21A shows aside cutaway 2101 andperspective view 2102 of the outer balloon (shown in fig. 19A as 1903) in a deployed state. Referring to fig. 21A, in one embodiment,balloon 2103 has a substantially cylindrical shape and is substantially tapered or conical at both ends 2104 and 2105. The ends extend into tubular structures or

necks

2106 and 2107, which help hold the catheter in place as it passes through the outer balloon, as shown in fig. 19A. In one embodiment, the overall length of the balloon including the tubular neck or

structure

2106, 2107 is about 113 ± 35mm, while the length of thecylindrical portion 2109 is about 60 ± 25 mm. The length of each

tubular section

2106, 2107 is about 15mm with a margin of + -15 mm, while the length of the tapered

portions

2104, 2105 is 12mm on each side with a margin of + -10 mm. In one embodiment, the diameter of each tubular section is about 3 mm. The width of the cylindrical portion ofballoon 2109 is about 24mm with a margin of ± 15mm, while the thickness of the balloon material is about 0.10 mm.

Fig. 21B shows a sidecross-sectional view 2110 of the outer balloon (shown in fig. 19A as 1903) in a deployed state, according to another embodiment of the present description. Theballoon 2115 has a substantially cylindrical shape and is substantially tapered or conical at both ends 2120 and 2125. The ends extend into tubular structures or

necks

2130 and 2135, which help to hold the catheter in place as it passes through the outer balloon, as shown in fig. 19A. In one embodiment, the overall length of the balloon including the tapered or conical ends 2120, 2125 is about 120mm, while the length of thecylindrical portion 2122 is about 80 ± 4 mm. In one embodiment, the inner diameter of each tubular section is about 3.52 ± 0.1mm and the outer diameter of each tubular section is about 4.06 mm. The width of the cylindrical portion of theballoon 2115 is about 34mm with a margin of + -or-0.5 mm.

Fig. 22 shows aside view 2201, a sidecross-sectional view 2202, and aperspective view 2203 of the pressureresistant luer lock 2200 shown as 1910 at the proximal end of the catheter in fig. 19A. Referring to fig. 22, in one embodiment, theluer lock 2203 includes ahandle 2204 at the center for manipulating thelock 2203, amale connector 2203 at itsdistal end 2209, and afemale connector 2206 at its proximal end 2210. Themale connector 2203 includes atapered end 2208 and is configured to securely attach to the proximal end of thehandle 1907 in fig. 19A to form a luer lock for the water vapor inlet in the catheter.Female connector 2206 includes an opening 2211 for receiving a water vapor source tube and agroove 2207 for securing the water vapor source tube.Handle 2204 is used to manipulatelock 2200 when the lock is attached to a water vapor source. In one embodiment, the overall length of thelock 2200 is about 21.9 mm. Atfemale connector 2206, the outer diameter is about 7.5mm and the inner diameter is about 4.2 mm. In one embodiment, the width of thefemale connector 2206 is about 4 mm. In one embodiment, thegroove 2207 is etched on thefemale connector 2206, which has a uniform width of about 0.6 mm. The diameter of themale connector 2203 just prior to its tapering is about 4mm, while the diameter decreases to 3.3mm at thedistal end 2209. In one embodiment,lock 2200 has a standard taper of 6%.

In one embodiment, thehandle 2204 of theluer lock 2200 has a width of about 7mm and a diameter of about 11 mm.

Fig. 23A illustrates longitudinal and transverse cross-sectional views of a dual ballooncardiac ablation catheter 2310, fig. 23B and 23C illustrate various views of the outer and inner balloons of thecatheter 2310, respectively, and fig. 23D illustrates longitudinal and transverse cross-sectional views of theelongate body 2312 of thecatheter 2310, according to some embodiments of the present description. Referring also to fig. 23A-23D, unless otherwise specifically noted, theelongate body 2312 has a proximal end, a distal end, and a plurality of lumens.

Referring now to longitudinal and transverse

cross-sectional views

2380, 2385 of fig. 23A and 23D, in one embodiment, theelongate body 2312 includes a first coolingfluid injection lumen 2320 and a second cooling fluid aspiration lumen 2322 (in some embodiments, located diametrically opposite relative to the first cooling fluid injection lumen 2320) in fluid communication with an inflatableouter balloon 2360 attached to the distal end of thecatheter 2310. In embodiments, the cooling fluid is water, air or carbon dioxide. During operation, cooling fluid enters the first coolingfluid injection lumen 2320 from the proximal end of the catheter and exits from the proximal end of the catheter through the second coolingfluid aspiration lumen 2322 after circulating through theouter balloon 2360. Cooling fluid is circulated throughcatheter 2310 andouter balloon 2360 using a cooling fluid pump in data communication with and controlled by the controller.

In one embodiment, theelongate body 2312 further comprises a central water/steam lumen 2317 in fluid communication with an inflatableinner balloon 2365 attached to the distal end of thecatheter 2310 and positioned within theouter balloon 2360 via a plurality ofsteam injection ports 2368. In some embodiments, the plurality ofsteam injection ports 2368 are positioned along a portion of water/steam lumen 2317 located withininner balloon 2365. Theelongate body 2312 also includes athird lumen 2370 and a fourth lumen 2371 (located diametrically opposite one another).

In some embodiments, theelongate body 2312 has a length of 1800mm, an outer diameter of 2.9mm, and an inner diameter of 2.6 mm. In some embodiments, the thickness of the material of the elongated body 2312 (e.g., without limitation, PET) is 0.15 mm. In some embodiments, central water/steam lumen 2317 has an inner diameter of 0.9 mm.

In some embodiments, at least one flexible heating chamber comprising a plurality of electrodes (such as those described with reference to fig. 19A-19D) is disposed inline within the central water/steam lumen 2317. In some embodiments, the at least one flexible heating chamber is disposed in-line within the central water/steam lumen such that the plurality of electrodes are at least partially within theinner balloon 2365. During operation, the water/steam pump, which is also in data communication with and controlled by the controller, pumps water from the sterile water reservoir through the water/steam lumen 2317 to enter the proximal end of the at least one flexible heating chamber. The at least one flexible heating chamber converts water to steam that exits through at least onesteam injection port 2368 to inflateinner balloon 2365 and contactouter balloon 2360 near the ablation area. An ablation or thermal zone is created at the contact area between theinner balloon 2365 and theouter balloon 2360 such that thermal energy from theinner balloon 2365 passes through theouter balloon 2360 to the ablation area. Theelongated body 2312 and portions of theouter balloon 2360 other than the hot zones remain cooled due to the circulating cooling fluid.

Referring to fig. 23B, in one embodiment,outer balloon 2360 has a compound shape (when in a fully expanded state) that includes a substantially cylindrical portion 2360B having a substantially tapered or conicalproximal end 2360a and adistal end 2360c (shown in side perspective views 2340, 2342 ofouter balloon 2360 in fig. 23A, 23B, respectively). The ends extend into

tubular structures

2361 and 2362 which help hold the catheter in place as it passes through the balloon. In one embodiment, theouter balloon 2360 has a length of 130mm between the substantially tapered or conicalproximal end 2360a anddistal end 2360c, the substantiallycylindrical portion 2360b has a length of 90mm and an outer diameter of 30mm, and each of the

tubular structures

2361, 2362 has a length of 10mm and an inner diameter of 4mm (also shown inenlarged view 2352 of one tubular structure). In one embodiment, theouter balloon 2360 is made of a harder material relative to the inner balloon, such as PET, which has a thickness of 0.1 mm.

Referring to fig. 23C, in one embodiment, theinner balloon 2365 has a compound shape (when in a fully expanded state) that includes a substantiallycylindrical portion 2365b having a substantially tapered or conicalproximal end 2365a and a distal end 2365C (also shown in aside perspective view 2344 of the inner balloon 2365). The ends extend into

tubular structures

2366 and 2367 which help hold the catheter in place as it passes through the balloon. In one embodiment, theinner balloon 2365 has a length of 86mm between the substantially tapered or conical proximal and

distal ends

2365a, 2365c, each of the substantially tapered or conical proximal and

distal ends

2365a, 2365c has a length of 17mm, the substantiallycylindrical portion 2365b has a length of 55mm and an outer diameter of 20mm, and each of the

tubular structures

2366, 2367 has a length of 10mm and an inner diameter of 2.9mm (shown inenlarged view 2353 of one tubular structure). In one embodiment, theinner balloon 2365 is made of a softer material, such as latex, relative to the outer balloon.

In some embodiments, theinner balloon 2365 may be moved within theouter balloon 2360 along a portion of theelongate body 2312 using a guide wire mechanism in the handle at the proximal end of thecatheter 2310 to better position the inner balloon within the outer balloon and ensure proper contact of the inner balloon with the outer balloon.

In some embodiments, a mapping member, which may be a distal extension, catheter, or any substrate including a plurality of sensors, detectors, or electrodes, is attached to the distal end of thebody 2312 distal to theouter balloon 2360. The mapping member maps regions of cardiac tissue that cause arrhythmias. In some embodiments, the mapping member has a length of at most 75 mm. In some embodiments, the mapping member is pre-shaped into a pigtail shape or a lasso ring shape to allow wall contact. In an embodiment, the pigtail has a diameter between 5mm and 25 mm. In some embodiments, the mapping member includes 1 to 8 electrodes configured to record signals from or pacing in the pulmonary vein.

In some embodiments, theouter balloon 2360 includes a plurality of mapping electrodes, which are either glued metal electrodes or printed electrodes, within or attached to the outer surface of its wall midway along its length axis, which are circularly configured to record cardiac signals to map areas of cardiac tissue responsible for arrhythmia. In some embodiments, theouter balloon 1903 includes up to 24 mapping electrodes. In other embodiments, the mapping electrodes measure cardiac electrical activity to assess at least one treatment endpoint.

In some embodiments, the entire surface ofcatheter 2310, including

balloons

2360, 2365, mapping electrodes, and mapping members, are coated with heparin.

According to some embodiments of the present description, fig. 24A shows a longitudinal perspective view and a lateral perspective view of a dual ballooncardiac ablation catheter 2410, fig. 24B shows a longitudinal cross-sectional view and an enlarged view of a portion of thecatheter 2410, and fig. 24C shows a lateral cross-sectional view of theelongated body 2412 of the catheter. Referring to fig. 24A, 24B, and 24C concurrently, unless specifically indicated otherwise, theelongate body 2412 has a proximal end, a distal end, and a plurality of lumens.

In one embodiment, theelongate body 2412 includes anouter conduit 2415 having a lumen and aninner conduit 2416 having a water/steam lumen 2417. Theinner catheter 2416 is positioned within the lumen of theouter catheter 2415 so as to form an annular coolingfluid aspiration lumen 2422 between the two

catheters

2415, 2416. According to one embodiment, the two

conduits

2415, 2416 are coaxial. The annular coolingfluid aspiration lumen 2422 houses first and second coolingfluid injection tubes 2420.

The first and second coolingfluid injection tubes 2420 and the annular coolingfluid aspiration lumen 2422 are in fluid communication with an expandableouter balloon 2460 attached to the distal end of thecatheter 2410. In an embodiment, the distal end of theouter catheter 2415 and the distal ends of the first and second coolingfluid injection tubes 2420 are located or terminate at the proximal end of theouter balloon 2460, while the distal end of theinner catheter 2416 extends beyond the distal end of theouter balloon 2460. In embodiments, the cooling fluid is water, air or carbon dioxide. During operation, cooling fluid enters the first and second coolingfluid injection tubes 2420 from the proximal end of the catheter and exits from the proximal end of the catheter through the annular coolingfluid suction lumen 2422 after circulating through theouter balloon 2460. Cooling fluid is circulated through theconduit 2410 and theouter balloon 2460 using a cooling fluid pump that is in data communication with and controlled by the controller.

The water/steam lumen 2417 is in fluid communication with an inflatableinner balloon 2465 attached to the distal end of thecatheter 2410 and positioned within theouter balloon 2460 via a plurality ofsteam injection ports 2468. In some embodiments, the plurality ofsteam injection ports 2468 are located along a portion of theinner conduit 2416 that is located within theinner balloon 2465.

As shown in the transverse cross-sectional, longitudinal cross-sectional, and perspective views of fig. 24D, in some embodiments, theouter conduit 2415 has a length of 1800mm, an inner diameter of 2.2mm, and an outer diameter of 2.5 mm. As shown in the transverse and longitudinal cross-sectional views of fig. 24E, theinner conduit 2416 has a length of 1960mm, an inner diameter of 1mm, and an outer diameter of 1.3 mm. In some embodiments, sevensteam injection ports 2468 are located on the inner conduit 2416 (and in communication with the water/steam lumen 2417), wherein eachport 2468 has a diameter of 0.5 mm. In some embodiments, theproximal port 2468a is located at a distance of 1850mm from the proximal end 1850mm of theinner catheter 2416 and at a distance of 110mm from the distal end of theinner catheter 2416. In some embodiments, as also shown in theenlarged view 2480 of fig. 24B, the plurality ofsteam injection ports 2468 are spaced apart from each other by a distance of 10 mm. As shown in the transverse and longitudinal cross-sectional views of fig. 24F, in some embodiments, each of the first and second coolingfluid injection pipes 2420 has a length of 1800mm, an inner diameter of 0.3mm, and an outer diameter of 0.4 mm.

In some embodiments, at least one flexible heating chamber comprising a plurality of electrodes (such as those described with reference to fig. 19A-19D) is positioned inline within the central water/steam lumen 2417. In some embodiments, the at least one flexible heating chamber is positioned in-line within the central water/steam lumen 2417 such that the plurality of electrodes are at least partially within theinner balloon 2465. During operation, the water/steam pump, which is also in data communication with and controlled by the controller, pumps water from the sterile water reservoir through the water/steam lumen 2417 to enter the proximal end of the at least one flexible heating chamber. The at least one flexible heating chamber converts the water to steam, which exits through the plurality ofsteam injection ports 2468 to inflate theinner balloon 2465 and contact theouter balloon 2460 near the ablation region. An ablation or hot zone is created at the contact area between theinner balloon 2465 and theouter balloon 2460 such that heat energy from theinner balloon 2465 passes through theouter balloon 2460 to the ablation area. Theelongated body 2412 and the portion of theouter balloon 2460 other than the hot zone remain cooled due to the circulating cooling fluid.

Referring to the lateral view and various perspective views of fig. 24G, in one embodiment, theouter balloon 2460 has a compound shape (when in the fully expanded state) that includes a substantiallycylindrical portion 2460b having a substantially tapered or conicalproximal end 2460a and adistal end 2460 c. The ends extend into the

tubular structures

2461 and 2462, which help to hold the catheter in place as it passes through the balloon. In one embodiment, theouter balloon 2460 has a length of 123mm between the

tubular structures

2461 and 2462, the substantiallycylindrical portion 2460b has a length of 75mm and an outer diameter of 30mm, each of the

tubular structures

2461, 2462 has a length of 7mm and an inner diameter of 2.5mm, and each of the substantially tapered or

conical ends

2460a, 2460c has a length of 18.8 mm. In one embodiment, theouter balloon 2460 is made of a harder material relative to the inner balloon, such as PET, which has a thickness of 0.15 mm.

Referring to fig. 24H, in one embodiment, theinner balloon 2465 has a compound shape (when in a fully inflated state) that includes a substantiallycylindrical portion 2465b (also shown in aside perspective view 2444 of the inner balloon 2465) having a substantially tapered or conicalproximal end 2465a and adistal end 2465 c. The ends extend into the

tubular structures

2466 and 2467, which help to hold the catheter in place as it passes through the balloon. In one embodiment, theinner balloon 2465 has a length of 114mm between the

tubular structures

2466 and 2467, the substantiallycylindrical portion 2465b has a length of 55mm and a diameter of 20mm, each of the

tubular structures

2466, 2467 has a length of 15mm and a diameter of 1.4mm, and each of the substantially tapered or

conical ends

2465a, 2465c has a length of 17 mm. In one embodiment, theinner balloon 2465 is made of a softer material relative to the outer balloon, such as latex.

In some embodiments, theinner balloon 2465 can be moved within theouter balloon 2460 along a portion of theinner catheter 2416 using a guide wire mechanism in the handle at the proximal end of thecatheter 2410 to better position the inner balloon within the outer balloon and ensure proper contact of the inner and outer balloons.

In one embodiment, the distal end of theelongate body 2412 has a bulbous (bulbus)tip 2470, which may have an elliptical or olive tip (olive tip), so that when thecatheter 2410 is introduced into a body lumen, the distal end is relatively atraumatic to the tissue. Fig. 24I illustrates acorner perspective view 2471, aside perspective view 2473, and a longitudinalcross-sectional view 2475 of a bulbous or olive-shapedtip 2470 according to one embodiment of the present description. Thetip 2470 has a proximal substantiallycylindrical portion 2472 that leads to a substantially oval or olive-shapeddistal portion 2474. Thecylindrical portion 2472 has anopening 2476 at a proximal end that leads to acylindrical passage 2477 that receives a portion of the distal end of the catheter 2410 (i.e., the distal end of the inner catheter 2416) when thetip 2470 is mounted on the distal end of thecatheter 2410.

In one embodiment, the overall length of the elliptical or olive shapedtip 2470 is 5 mm. In one embodiment, the proximal substantiallycylindrical portion 2472 has an outer diameter of 1.8mm and a length of 2 mm. In one embodiment,opening 2476 has a diameter of 1.3mm andcylindrical passage 2477 has a length of 3.5 mm. In one embodiment, the substantially elliptical or olive-shapeddistal portion 2474 has a width of 2.5mm and a radius of 1.3 mm.

In some embodiments, a mapping member, which may be a distal extension, catheter, or any substrate including a plurality of sensors, detectors, or electrodes, is attached to the distal end of thebody 2412 distal to theouter balloon 2460. The mapping member maps regions of cardiac tissue that cause arrhythmias. In some embodiments, the mapping member has a length of at most 75 mm. In some embodiments, the mapping member is pre-shaped into a pigtail shape or a lasso ring shape to allow wall contact. In an embodiment, the pigtail has a diameter between 5mm and 25 mm. In some embodiments, the mapping member includes 1 to 8 electrodes configured to record signals from or pacing in the pulmonary vein.

In some embodiments, theouter balloon 2460 includes a plurality of mapping electrodes, which are either glued metal electrodes or printed electrodes, within or attached to the outer surface of its wall midway along its length axis, which are circularly configured to record cardiac signals to map regions of cardiac tissue responsible for arrhythmias. In some embodiments, theouter balloon 2460 includes up to 24 mapping electrodes. In an embodiment, the mapping electrodes measure cardiac electrical activity to assess at least one treatment endpoint.

In some embodiments, the entire surface of thecatheter 2410, including the

balloons

2460, 2465, the elliptical or olive-shapedtip 2470, the mapping electrodes, and the mapping members, are coated with heparin.

According to some embodiments of the present description, fig. 25A shows a longitudinal perspective view and a lateral perspective view of a dual ballooncardiac ablation catheter 2510, fig. 25B shows a longitudinal cross-sectional view and an enlarged view of a portion of thecatheter 2510, and fig. 25C shows a lateral cross-sectional view of theelongated body 2512 of the catheter. Referring to fig. 25A, 25B, and 25C concurrently, unless specifically indicated otherwise, theelongate body 2512 has a proximal end, a distal end, and a plurality of lumens.

In one embodiment, theelongated body 2512 includes anouter catheter 2515 having a lumen and aninner catheter 2516 having a first water/steam injection lumen 2517a and a secondsteam suction lumen 2517 b. In some embodiments, first and

second steam lumens

2517a and 2517b are diametrically opposed to each other. Theinner catheter 2516 is positioned within the lumen of theouter catheter 2515 so as to form a coolingfluid pumping channel 2522 between the two

catheters

2515, 2516. The coolingfluid pumping channel 2522 houses a first cooling fluid injection tube and a second coolingfluid injection tube 2520.

The first and second coolingfluid injection tubes 2520 and the coolingfluid aspiration passageway 2522 are in fluid communication with an expandableouter balloon 2560 attached to the distal end of thecatheter 2510. In an embodiment, the distal end of theouter catheter 2515 and the distal ends of the first and second coolingfluid injection tubes 2520 are located or terminated at the proximal end of theouter balloon 2560, while the distal end of theinner catheter 2516 extends beyond the distal end of theouter balloon 2560. In embodiments, the cooling fluid is water, air or carbon dioxide. During operation, cooling fluid enters the first and second coolingfluid injection tubes 2520 from the proximal end of thecatheter 2510 and exits the proximal end of thecatheter 2510 through the coolingfluid suction pathway 2522 after circulating through theouter balloon 2560. Cooling fluid is circulated through theconduit 2510 and theouter balloon 2560 using a cooling fluid pump in data communication with and controlled by the controller.

First water/steam injection lumen 2517a is in fluid communication with an inflatableinner balloon 2565 attached to the distal end ofcatheter 2510 and positioned withinouter balloon 2560 via a plurality ofsteam injection ports 2568 a. Secondvapor suction lumen 2517b is also in fluid communication with inflatableinner balloon 2565 via a plurality ofvapor suction ports 2568 b. In some embodiments, the suction ofvapor suction port 2568b is controlled by an external pump controlled by a pressure sensor or by a self-opening pressure valve. In some embodiments, the plurality ofsteam injection ports 2568a andsuction ports 2568b are positioned along a portion of theinner catheter 2516 located within theinner balloon 2565.

As shown in the transverse cross-sectional, longitudinal cross-sectional, and perspective views of fig. 25D, in some embodiments, theouter catheter 2515 has a length of 1800mm, an inner diameter of 2.6mm, and an outer diameter of 2.9 mm. In some embodiments, as shown in transversecross-sectional view 2585 of fig. 25E,inner catheter 2516 has an outer diameter of 1.8mm, the centers of first and

second steam lumens

2517a and 2517b are separated by a distance of 0.9mm, and the inner diameter of each of first andsecond steam lumens 2517a and 25l7b is 0.7 mm. In some embodiments, as shown in longitudinalcross-sectional view 2586 of fig. 25E, theinner catheter 2516 has a length of 1910.4 mm.

In some embodiments, sevensteam injection ports 2568a are located oninner catheter 2516 along first water/steam injection lumen 2517a, wherein eachport 2568a has a diameter of 0.8 mm. In some embodiments, theproximal port 2568a' is located at a distance of 1800mm from the proximal end of theinner catheter 2516 and at a distance of 110.4mm from the distal end of theinner catheter 2516. In some embodiments, as also shown inenlarged view 2580 of fig. 25B, the plurality ofsteam injection ports 2568a are spaced apart from each other by a distance of 10 mm. In some embodiments, sixsteam suction ports 2568b are located oninner catheter 2516 along secondsteam suction lumen 2517b, wherein eachport 2568b has a diameter of 0.8 mm. In some embodiments, as also shown inenlarged view 2580 of fig. 25B, the plurality ofsteam injection ports 2568a are spaced apart from each other by a distance of 10mm, and the plurality of steam suction ports 2568B are also spaced apart from each other by a distance of 10 mm. Also, in some embodiments, each ofsteam suction ports 2568b is located at a distance of 5mm from the immediately preceding and immediately succeedingsteam injection ports 2568 a.

As shown in the transverse cross-sectional view and the longitudinal cross-sectional view of fig. 25F, in some embodiments, each of the first cooling fluid injection tube and the second coolingfluid injection tube 2520 has a length of 1800mm, an inner diameter of 0.4mm, and an outer diameter of 0.5 mm.

In some embodiments, at least one flexible heating chamber comprising a plurality of electrodes (such as those described with reference to fig. 19A-19D) is positioned in-line within the first water/steam injection lumen 2517 a. In some embodiments, the at least one flexible heating chamber is positioned in-line within first water/steam injection lumen 2517a such that the plurality of electrodes are at least partially withininner balloon 2565. During operation, the water/steam pump, which is also in data communication with and controlled by the controller, pumps water from the sterile water reservoir through the water/steam lumen 2517a to enter the proximal end of the at least one flexible heating chamber. The at least one flexible heating chamber converts the water into steam, which exits through the plurality ofsteam injection ports 2568a to inflate theinner balloon 2565 and contact theouter balloon 2560 near the ablation region. An ablation or hot zone is created at the contact region between theinner balloon 2565 and theouter balloon 2560 such that thermal energy from theinner balloon 2565 passes through theouter balloon 2560 to the ablation region. Theelongated body 2512 and portions of theouter balloon 2560 other than the hot zones remain cool due to the circulating cooling fluid. To deflate, steam is drawn frominner balloon 2565 through the plurality ofsteam suction ports 2568b and via secondsteam suction lumen 2517 b.

Referring to the side perspective view and various perspective views of fig. 25G, in one embodiment, theouter balloon 2560 has a compound shape (when in a fully expanded state) that includes a substantiallycylindrical portion 2560b (shown in theside perspective view 2542 of theouter balloon 2560 in fig. 25G) having a substantially tapered or conicalproximal end 2560a and adistal end 2560 c. The ends extend into the

tubular structures

2561 and 2562, which help to hold the catheter in place as it passes through the balloon. In one embodiment,outer balloon 2560 has a length of 123mm between

tubular structures

2561 and 2562, substantiallycylindrical portion 2560b has a length of 75mm and an outer diameter of 30mm, each of

tubular structures

2561, 2562 has a length of 7mm and an inner diameter of 3mm, and each of substantially tapered or

conical ends

2560a, 2560c has a length of 7 mm. In one embodiment, theouter balloon 2560 is made of a harder material relative to the inner balloon, such as PET, which has a thickness of 0.15 mm.

Referring to the side perspective view and various perspective views of fig. 25H, in one embodiment, theinner balloon 2565 has a compound shape (when in a fully expanded state) that includes a substantiallycylindrical portion 2565b (also shown in theside perspective view 2544 of the inner balloon 2565) having a substantially tapered or conicalproximal end 2565a and adistal end 2565 c. The ends extend into

tubular structures

2566 and 2567, which help to hold the catheter in place as it passes through the balloon. In one embodiment,inner balloon 2565 has a length of 114mm between

tubular structures

2566 and 2567, substantiallycylindrical portion 2565b has a length of 55mm and a diameter of 20mm, each of

tubular structures

2566, 2567 has a length of 15mm and a diameter of 1.7mm, and each of substantially tapered or

conical ends

2565a, 2565c has a length of 17 mm. In one embodiment, theinner balloon 2565 is made of a softer material relative to the outer balloon, such as latex.

In some embodiments, theinner balloon 2565 can be moved within theouter balloon 2560 along a portion of theinner catheter 2516 using a guide wire mechanism in the handle at the proximal end of thecatheter 2510 to better position the inner balloon within the outer balloon and ensure proper contact of the inner and outer balloons.

In one embodiment, the distal end of theelongate body 2512 has abulbous tip 2570, which may have an elliptical or olive-shaped tip (olive-shaped tip) so that when thecatheter 2510 is introduced into a body lumen, the distal end is relatively atraumatic to the tissue. FIG. 25I illustrates aperspective view 2571, aside perspective view 2573, and a longitudinalcross-sectional view 2575 of a bulbous or olive-shapedtip 2570 according to one embodiment of the present description.Tip 2570 has a proximal substantiallycylindrical portion 2572 leading to a substantially oval or olive shapeddistal portion 2574. Thecylindrical portion 2572 has anopening 2576 at a proximal end that leads to a cylindrical passageway 2577 that receives a portion of the distal end of the catheter 2510 (i.e., the distal end of the inner catheter 2516) when thetip 2570 is mounted on the distal end of thecatheter 2510.

In one embodiment, the overall length of the elliptical or olive shapedtip 2570 is 5 mm. In one embodiment, proximal substantiallycylindrical portion 2572 has a length of 2 mm. In one embodiment,opening 2576 has a diameter of 1.8mm and cylindrical passage 2577 has a length of 3.5 mm. In one embodiment, the substantially elliptical or olive shapeddistal portion 2574 has a width of 2.9mm and a radius of 1.5 mm.

In some embodiments, a mapping member, which may be a distal extension, a catheter, or any substrate including a plurality of sensors, detectors, or electrodes, is attached to the distal end of thebody 2512 distal of theouter balloon 2560. The mapping member maps regions of cardiac tissue that cause arrhythmias. In some embodiments, the mapping member has a length of at most 75 mm. In some embodiments, the mapping member is pre-shaped into a pigtail shape or a lasso ring shape to allow wall contact. In an embodiment, the pigtail has a diameter between 5mm and 25 mm. In some embodiments, the mapping member includes 1 to 8 electrodes configured to record signals from or pacing in the pulmonary vein.

In some embodiments, theouter balloon 2560 includes a plurality of mapping electrodes, which are either glued metal electrodes or printed electrodes, within or attached to the outer surface of its wall midway along its length axis, which are circularly configured to record cardiac signals to map regions of cardiac tissue responsible for cardiac arrhythmias. In some embodiments, theouter balloon 2560 includes up to 24 mapping electrodes. In an embodiment, the mapping electrodes measure cardiac electrical activity to assess at least one treatment endpoint. In one embodiment, eight equally spaced mapping electrodes are positioned in a circle surrounding theouter balloon 2560, forming a ring having a diameter of 20 mm.

In some embodiments, the entire surface of thecatheter 2510, including the

balloon

2560, 2565, the elliptical or olive-shapedtip 2570, the mapping electrode, and the mapping member, is coated with heparin.

It is one goal of embodiments of the present description to create different ablation regions, the size of which is preferably variable depending on the anatomy of the patient. Another objective is to create "transition" or "exclusion" regions at the proximal and distal ends of the ablation region. Fig. 25J shows theinner balloon 2565 being brought into contact with a desired portion or region of theouter balloon 2560 as the inner balloon is inflated with steam to form a hot zone/region or ablation zone/region 2580 for ablating targeted cardiac tissue. Since the configuration of theouter balloon 2560 changes based on the way it is pressed into the patient's pulmonary vein, the configuration of theprecise ablation region 2580 also changes, molding itself into the patient's pulmonary vein and pulmonary vein ostial anatomy. More specifically, according to embodiments herein, theouter balloon 2560 deforms to optimally contact the pulmonary veins, and based on this deformation, theinner balloon 2565 contacts theouter balloon 2560 primarily at the point of deformation, which is the location where ablation is desired. This is because ablation with steam requires that the heating be confined to a specific anatomical region so that heat does not enter adjacent structures or blood causing complications. This concept creates a dynamic ablation zone that can be customized to the individual patient's anatomy.

Fig. 25K and 25L illustrate an exemplary dual balloon embodiment with an insulated region identified asablation region 2580 defined by contact regions 2580a and 2580 b.Ablation region 2580 may have a circumference corresponding to the anatomical size and shape of the patient's pulmonary veins. The ablation zone may vary based on the anatomy of the patient. The non-contact or cold region between theinner balloon 2565 and theouter balloon 2560 is filled with air, which acts as aninsulating region 2582a proximal to theouter balloon 2560 and as aninsulating region 2582b distal to theouter balloon 2560. In some embodiments, the isolation region extends a width of about 0.1mm around the perimeter of the region betweeninner balloon 2565 andouter balloon 2560. Furthermore, in embodiments,

exclusion regions

2582a and 2582b extend a length of 1mm to 20 mm. In some embodiments,ablation region 2580 covers an area ranging from 1% to 99% of the outer balloon surface, with a corresponding reduction in the exclusion area from 99% to 1%. In some embodiments,ablation region 2580 covers an area ranging from 5% to 95% of the outer balloon surface, with the exclusion area correspondingly reduced from 95% to 5%.

Theablation region 2580 defined by the contact area of the inflatedinner balloon 2565 with theouter balloon 2560, and thus the area of theouter balloon 2560 in contact with the patient's tissue, is an area where blood cannot flow. In some embodiments,ablation region 2580 extends over a width of 1mm to 20 mm. The temperature of the outer surfaces of the

exclusion regions

2582a and 2582b is lower than the temperature of theablation region 2580. According to various embodiments herein,variable ablation region 2580 is implemented and surrounded by

exclusion regions

2582a and 2582 b. Thevariable ablation region 2580 provides a better cross-sectional fit within the anatomy of different patients.Variable ablation region 2580 also results in

variable isolation regions

2582a and 2582 b. This variability is a result of the variable shape, size, and stiffness of the two

balloons

2560 and 2565. As a result, theinner balloon 2565 is less compliant and maintains a relatively rigid shape, while the outer balloon is more compliant and shaped to the patient's atrial and pulmonary vein anatomy. The interaction between the heart tissue, the compliant and easily deformable outer balloon and the semi-compliant and rigid inner balloon results in a dynamic/variable ablation zone. Thus, the degree of compliance of the inner balloon is less than the degree of compliance of the outer balloon.

Optionally, theinner balloon 2565 "floats" within the outer balloon, and the user can apply an axial force through the guide sheath, further deforming the outer balloon and pushing theinner balloon 2565 in any orientation, and creating tissue contact with theablation region 2580 formed by the intersection of the outer and inner balloons. The width of theablation region 2580 can be increased by increasing the axial force transmitted to the outer and inner balloons through the guide sheath. Additionally, the inner balloon may float relative to the outer balloon, and the guide sheath pressure may be used to move the inner balloon relative to the outer balloon.

Fig. 25L also shows acoated portion 2584 on theinner balloon 2565 that serves as insulation within the

insulation regions

2582a and 2582b, according to one embodiment of the present description. In some embodiments, the interior of theouter balloon 2560 is coated to provide insulation, rather than the exterior of theinner balloon 2565. In embodiments, the coating is a ceramic coating, such as parylene; or a gel coat. The coating is disposed in areas that may be

exclusion areas

2582a and 2582b, and is not present inablation area 2580.

In some embodiments, the membrane thickness of either or bothinner balloon 2565 andouter balloon 2560 is variable along its circumferential length along its longitudinal axis. Fig. 25M shows an exemplary embodiment of a dual balloon configuration in which theouter balloon 2563 has

thicker films

2584, 2587 along insulatingregions 2583a and 2583b, and is relatively thin along theablation region 2581 where heat transfer is desired, so as to create a relative degree of insulation.

Fig. 25N illustrates a dual balloon embodiment according to the present description, wherein at least one of the two balloons 2560' includes a plurality ofdiscrete channels 2588 extending around its circumference. The balloon 2560' is an inner balloon, such asballoon 2565, or an outer balloon, such asballoon 2560. Eachpassage 2588 is connected to a lumen through which steam passes. In some embodiments, thepassage 2588 is connected to the lumen through a valve. Once the balloon 2560' is positioned in the correct location,radiopaque markers 2590 are used around its surface to determine whichchannel 2588 is best in contact with the target surface for ablation. Once the optimal channel is identified, the appropriate valve can be opened to the identified channel and steam can be delivered through the channel to ablate the target surface.

In alternative embodiments, insulation such as

insulation regions

2582a and 2582b is created by various means. In one approach, the air gap is provided by adhering a repaired film or foam or any other material to the outer surface of theinner balloon 2565 or the inner surface of theouter balloon 2560. In another embodiment, insulation is facilitated by the use of an insulation bag on the surface of theinner balloon 2565.

Fig. 25O is a flow diagram illustrating an exemplary protocol for inflating a dual balloon ablation device according to some embodiments of the present description. First, at 2592, a small amount of carbon dioxide (CO) is used₂) Partially inflating an outer balloon, such asballoon 2560. In one embodiment, CO is used₂The outer balloon is inflated to a volume of about 30 cubic centimeters (cc). Then, at 2593, CO is used₂The inner balloon, such asballoon 2565, is partially inflated as part of its priming function. At 2594, water vapor is used to further inflate the inner balloon. In some embodiments, up to 15cc of saline is used to generate the water vapor. At 2595, inflating the inner balloon with steam automatically inflates the outer balloon. When the outer balloon is inflated, it serves to push blood proximally and distally out of the ablation region. In some embodiments, the outer balloon surface is inflated to a diameter in the range of 20mm to 100 mm.

The pressure in the inflated balloon is regulated using pressure valves in the outflow channel connected to the inner balloon and the outflow channel connected to the outer balloon. In embodiments, the pressure is maintained between 0psi and 50psi in both the outer balloon and the inner balloon. In some embodiments, a check valve (self-opening valve) is located in the outflow channel from the outer balloon and is set at a pound-force per square inch (psi) value in the range of 0 to 5 psi. In some embodiments, another check valve (self-opening valve) is located in the outflow channel from the inner balloon and is set at a psi value in the range of 0.5 to 10. In some embodiments, the outer balloon valve opens at a pressure between 0 and 1.0 psi. In some embodiments, the inner balloon pressure is released at above 2.0 to 3.0 psi. The volume ratio maintained by the inner and outer balloons is dynamic and is controlled by controlling the pressure in the balloons. In some embodiments, the outer balloon is first inflated to a maximum volume, the inner balloon is "primed", and then steam is generated. Due to the pressure valve control, the outer balloon volume does not change when water vapor is generated, while the inner balloon volume increases to 100% of its volume, which in some embodiments is equal to about 40% of the volume of the outer balloon. Check valves are used to automatically control the pressure in the balloon. In some embodiments, the pressure in the inner balloon is equal to or greater than the pressure in the outer balloon. Thus, the pressure remains within its predetermined range, otherwise the check valve opens. In an alternative embodiment, an active pressure management system, such as suction, is used to regulate the pressure.

To achieve optimal heat resistance, expansion and compliance, it is important to use the appropriate materials to make the outer and inner balloons. If the softening temperature (Tg) of the balloon material is too low, the balloon may deform when exposed to water vapor during use. For example, the Tg of PET is 75 ℃. This means that after only one use, the PET balloon may be deformed and may not be used for additional ablation imaging of a given PV or other PVs within the patient. Therefore, it is desirable to work with materials having a Tg greater than 100 ℃. In an embodiment, there are two balloons, wherein each balloon has a different Tg value. In some embodiments, the Tg value of each balloon is in the range of 60 ℃ to about 200 ℃, in some embodiments the Tg is 80 ℃. In some embodiments, the Tg is 150 ℃.

It is also desirable to use materials that have a sufficiently wide range of elasticity at various operating temperatures. If the elastic range is too low, the yield point is exceeded during operation and the balloon deforms such that the ablation region may not be properly positioned during operation. In embodiments, thermoplastic copolyester materials having a Tg of about 150 ℃, such as those provided by Arnitel, may be used.

In embodiments, the material of the inner balloon is semi-compliant, meaning that the material eliminates any wrinkles that may be present during packaging, and conforms to the atrial anatomy for better contact. The compliant balloon may have a fixed volume at a fixed pressure. It is desirable that the material of the inner balloon be harder than the material of the outer balloon in order to maintain a certain shape and not be easily deformed by pressing against heart tissue. Some semi-compliant balloon materials, such as the PEBA series, face mechanical and thermal challenges when introducing water vapor. Thus, one possible balloon material is a copolymer known as Arnitel. Arnitel is also relatively semi-compliant, but has a higher softening and melting temperature than standard PEBA polymers. According to embodiments of the present description, materials such as Arnitel may be used to fabricate the inner balloon and shaft applications. The advantage of using it as a shaft material is that it can be thermally bonded to the inner balloon currently made using PET, thereby eliminating the need to use an adhesive bonding process.

According to some embodiments of the present description, fig. 26A, 26B, 26C, 26D, 26E, 26G, 26H, 26J, and 26K illustrate perspective views of a dual ballooncardiac ablation catheter 2610, fig. 26F, 26I, 26L, and 26M illustrate longitudinal cross-sectional views of thecatheter 2610, fig. 26N and 26O illustrate transverse cross-sectional views of theelongate body 2612 of thecatheter 2610, and fig. 26P and 26Q illustrate transverse cross-sectional views of the outer and inner catheters of theelongate body 2612, respectively. In some embodiments, thecardiac ablation catheter 2610 may be used to ablate cardiac tissue to treat cardiac arrhythmias, such as atrial fibrillation.

Referring now to fig. 26A-26Q, theelongate body 2612 has a proximal end, a distal end, anouter catheter 2615 and an optional inner catheter orlumen 2650. One preferred embodiment does not have aninner catheter 2650, but only includes anouter catheter 2615 with an associated lumen, as described. A handle is disposed at the proximal end of thebody 2612. In some embodiments, the outer and inner catheters or

lumens

2615, 2650 are coaxial. In an alternative embodiment, the outer and inner catheters or

lumens

2615, 2650 are eccentric.

In one embodiment, the outer conduit 2615 (fig. 26N, 26O, 26P) includes acentral steam lumen 2617, which may be circular or elliptical, and a plurality of circumferentially positioned additional lumens, wherein each additional lumen is fluidly isolated from thecentral steam lumen 2617 and from each other along the length of the conduit. In an embodiment, each lumen has a diameter in the range of 25% to 300% of each of the other lumen diameters. The plurality of circumferentially positioned lumens include a coolingfluid injection lumen 2620, a cooling fluid aspiration lumen 2622 (in some embodiments, diametrically oppositely positioned relative to the injection lumen 2620), two fluid aspiration lumens 2625 (in some embodiments, diametrically oppositely positioned relative to each other), two lumens 2638 (in some embodiments, diametrically oppositely positioned relative to each other) to allow at least one steerable guidewire to be introduced therethrough to enable bi-directional maneuverability, and two sensor lumens 2640 (in some embodiments, diametrically oppositely positioned relative to each other) to allow one or more electrical leads from the handle to be connected to sensors, such as, but not limited to, thermocouples and pressure transducers. In various embodiments, the cooling fluid comprises air, water, or carbon dioxide.

In one embodiment, the inner catheter or lumen 2650 (fig. 26N, 26O, 26Q) includes a hollow core positioned coaxially within thesteam lumen 2617 of theouter catheter 2615. An inner catheter orlumen 2650 extends from the proximal end to the distal end of the catheter and is configured to pass a guidewire or sensing pacing guidewire through and inject irrigation fluid, coolant, or contrast. In some embodiments, the inner conduit is asolid structure 2650 and does not function as an actual conduit. In other embodiments, there is noinner catheter 2650, and only anouter catheter 2615 with a lumen as shown. At least one flexible heating chamber 2630 (such as those described with reference to fig. 19A-19D) positioned inline within the central water/steam lumen 2617 includes a plurality ofelectrodes 2655 disposed between theouter conduit 2615 and theinner conduit 2650. Electrical leads connect theelectrodes 2655 to a plug in the handle. In some embodiments, theinner catheter 2650 includes a plurality of circumferential projections or tabs 2652 (fig. 26O and 26Q) to provide a channel for saline flow between the outer surface of thecatheter 2650 and theelectrode 2655.

In an embodiment, two cooling

fluid lumens

2620, 2622 are in fluid communication with an inflatableouter balloon 2660 attached to the distal end of thecatheter 2610. Two cooling

fluid lumens

2620, 2622 extend from theouter balloon 2660 to a cooling fluid pump that is in data communication with and controlled by the controller. In some embodiments, the cooling

fluid lumens

2620, 2622 are pressure controlled or integrated in a cooling fluid pump and serve as a coupled conditioning fluid circuit. During operation, the cooling fluid pump pushes cooling fluid into the injection lumen 2620 (through an optional filter) to exit via the first andsecond injection ports 2662a and 2662B, as shown in fig. 26B, thereby inflating theouter balloon 2660. In one embodiment, the cooling fluid pump is reversible, allowing cooling fluid to be pumped out of theballoon 2660 through the coolingfluid aspiration lumen 2622 via the first and

second aspiration ports

2664a and 2664b as needed and as commanded by the controller. First and

second injection ports

2662a and 2662b are located at the distal and proximal ends, respectively, of anotherballoon 2660. Afirst suction port 2664a and asecond suction port 2664b are located at the distal and proximal ends, respectively, of theother balloon 2660. In some embodiments, the first and

second injection ports

2662a and 2662b have a diameter of 0.2 mm. In some embodiments, the first and

second suction ports

2664a and 2664b have a diameter of 0.2 mm.

Thesteam lumen 2617 is in fluid communication with an expandableinner balloon 2665 attached to the distal end of thecatheter 2610 and positioned within theouter balloon 2660. Asteam lumen 2617 extends from theinner balloon 2665 to a water/steam pump, which is also in data communication with and controlled by the controller. The proximal end of thesteam lumen 2617 has a luer lock connection to a sterile water/saline reservoir at the handle. Optionally, a Y-shaped adapter is included to allow the guidewire/mapping catheter to pass through while saline is injected into the steam lumen to convert to water vapor as it passes through the electrode at the distal tip. Water/saline is pumped from a sterile water/saline reservoir through the water/steam lumen 2617 via a water/steam pump to enter the proximal end of the at least one flexible heating chamber 2630 (as shown in fig. 26B). The at least oneflexible heating chamber 2630 converts water into steam, which exits through at least onesteam injection port 2668 positioned on a portion of themain body 2612 located within theinner balloon 2665 to inflate theinner balloon 2665. In some embodiments, theflexible heating chamber 2630 is attached to theinner balloon 2665. In some embodiments, theinner balloon 2665 is configured to expand only within predetermined locations within theouter balloon 2660. In some embodiments,outer balloon 2660 includes a retaining structure to ensure thatinner balloon 2665 expands within a predetermined position. In some embodiments,inner balloon 2665 is configured to withstand an operating temperature of at least 125 ℃, and in some embodiments,inner balloon 2665 is configured to have a burst pressure rating of at least 5atm at the rated temperature. In some embodiments,inner balloon 2665 is configured to withstand at least 50 ablation treatment cycles of 0 to 180 seconds using a power level of at least 30 watts. In some embodiments,outer balloon 2660 is configured to withstand an operating temperature of at least 110 ℃.

In some embodiments, as seen in fig. 26B, the at least onesteam injection port 2668 is positioned adjacent to the distal end of theinner balloon 2665. In some embodiments, the at least onesteam injection port 2668 has a diameter of 2.0 mm. At least twowater suction ports 2669 are positioned on a portion of themain body 2612 that is within theinner balloon 2665. In some embodiments, the at least twowater suction ports 2669 are positioned adjacent to the proximal end of theinner balloon 2665. When theinner balloon 2665 is filled with steam, some of the steam converts or condenses into water when in contact with the balloon surface. The water (condensed steam) is drawn from theinner balloon 2665 through at least twowater suction ports 2669 in fluid communication with the twowater suction lumens 2625, respectively.

In some embodiments, as shown in fig. 26N, 26O, and 26P, theouter conduit 2615 has an outer diameter of 3.5mm and an inner diameter of 2 to 2.5mm (i.e., the inner diameter of thecentral steam lumen 2617 is 2 to 2.5 mm). In some embodiments, as shown in fig. 26F, 26I, and 26L, theouter conduit 2615 has an outer diameter of 4.8 mm. In some embodiments, the maximum outer diameter of the outer catheter is 7.4 mm.

In some embodiments, as shown in fig. 26F, 26I, 26L, 26H, 26I, and 26K, theinner catheter 2650 including the plurality ofelectrode tabs 2652 has an outer diameter of 2 mm. In embodiments whereinner conduit 2650 is hollow,inner conduit 2650 has an inner diameter of 1mm +/-0.5 mm. However, it should be understood that theinner catheter 2650 is optional, and that preferred embodiments include only a single catheter (outer catheter 2615) having a central elliptical lumen and a plurality of additional lumens positioned circumferentially around the central lumen, wherein each of the plurality of additional lumens is fluidly isolated from the central elliptical lumen along the length of the catheter.

Fig. 26C illustrates across-sectional view 2695 showing a triple lumen flow mechanism of acatheter 2610, according to an alternative embodiment of the present description.Cross-sectional view 2695 showscatheter 2615c having a coaxialinner lumen 2650c with dimensions in the range of 2 to 9 french.Catheter 2615c has a first water/steam lumen 2696 in fluid communication withinner balloon 2665 to draw saline or water or steam frominner balloon 2665 and a second fluid infusion and/orsuction lumen 2697 in fluid communication withouter balloon 2660. The catheter has athird lumen 2698 that includes an in-line flexible heating element to convert water introduced from the proximal end into water vapor that enters theinner balloon 2665 via at least one vapor injection port.

Referring now to fig. 26A-26L, in some embodiments, the expandableouter balloon 2660 is pear-shaped (when expanded or deployed) that may be generally defined by a proximal hemisphericalfirst portion 2670 that transitions into a distal taperedsecond portion 2672 that tapers into a substantially rounded or sphericaldistal end 2673. In other words, when inflated, the outer balloon has a length, an axis extending along the length and through the center of the outer balloon, and a distance from the axis to the outer surface of the outer balloon. This distance varies along the length of the outer balloon and may be defined by four different distances D1, D2, D3, and D4 extending from the distal end of the axis to the outer surface of the outer balloon (D1) and moving sequentially proximally upward along the axis.

Specifically, referring to fig. 26W, starting from the distal end of the outer balloon, the distance D1 at a point between 0mm and 4mm (preferably 0mm) from the distal attachment point of the outer balloon to the catheter is in the range of 1mm to 20 mm. The distance D2, when moved proximally, is in the range of 15mm to 30mm at a point between 7mm and 14mm (preferably 10mm) from the point of distal attachment of the outer balloon to the catheter. The distance D3, when moved proximally, is in the range of 20mm to 50mm at a point between 25mm and 35mm (preferably 30mm) from the point of distal attachment of the outer balloon to the catheter. The distance D4, when moved proximally, is in the range of 1mm to 20mm at a point between 30mm and 45mm (preferably 33mm) from the point of distal attachment of the outer balloon to the catheter. Thus, D1 and D4 are preferably smaller than D3 or D2, and D3 is preferably larger than each of D1, D2, and D4.

In another embodiment, the maximum distance from the central axis of the outer balloon to the outer surface of the outer balloon (e.g., D3) is less than the length of the outer balloon, measured from the proximal attachment point of the outer balloon to the catheter to the distal attachment point of the outer balloon to the catheter. In another embodiment, the distance from the central axis to the outer surface of the outer balloon increases from a first minimum to a first maximum as one progresses distally along the length of the outer balloon. After reaching the first maximum, the distance decreases to a second minimum, where the second minimum is greater than the first minimum. The distance from the first maximum to the second minimum ranges from 2mm to 35 mm. After reaching the second minimum, the distance is again reduced to a third minimum, where the second minimum is greater than the third minimum. The distance from the second minimum to the third minimum ranges from 2mm to 25 mm.

In an embodiment, the pear shape of inflatableouter balloon 2660 is symmetric aboutlongitudinal axis 2674. In embodiments, the proximal and distal ends of theouter balloon 2660 extend into tubular structures or

necks

2681, 2682, which help to hold thecatheter 2610 in place as it passes through the balloon. In an alternative embodiment,outer balloon 2660 has a short cylindrical shape that is configured to be positioned or embedded in a pulmonary vein.

In some embodiments, as shown in fig. 26B-26F,inner balloon 2665 is spherically shaped. In some embodiments, as shown in fig. 26G, 26H, and 26I,inner balloon 2665 has a substantially oval shape. In some embodiments, as shown in fig. 26J, 26K, and 26L,inner balloon 2665 has a substantially conical shape. In various embodiments, the proximal and distal ends of theinner balloon 2665 extend into tubular structures or

necks

2666, 2667, which help to hold thecatheter 2610 in place as it passes through the balloon. In some embodiments, the space withininner balloon 2665 is divided into multiple compartments, wherein each compartment can be inflated with steam independently.

In other embodiments, the inflatableinner balloon 2665 has a shape such as, but not limited to, a disc, an oval, a rectangular prism, and a triangular prism. Fig. 26R illustrates a plurality of exemplary shapes ofinner balloon 2665 according to some embodiments of the present description.First view 2686a shows substantially sphericalinner balloon 2665a,second view 2686b shows hemisphericalinner balloon 2665b,third view 2686c shows conicalinner balloon 2665c such that the apex of the cone is located proximally and the base of the cone is located distally,fourth view 2686d shows another conicalinner balloon 2665d such that the apex of the cone is located distally and the base of the cone is located proximally, andfifth view 2686e shows ellipticalinner balloon 2665 e. In other embodiments, the hemispheric balloon may be derived from any of the full shaped balloons shown in

views

2686a, 2686c, 2686d, and 2686 e. In an embodiment, one quarter or 1/4^thIndividual balloons can be derived from any of the shaped balloons shown in

views

2686a, 2686c, 2686d, and 2686 e.

As shown in fig. 26B-26L, according to one aspect of the present description, when the outer and

inner balloons

2660, 2665 are fully inflated, the pear-shapedouter balloon 2660 is characterized by three regions, regions or zones-a) a distalfirst region 2675 that is a cooler region (because the outer and

inner balloons

2660, 2665 do not contact in this region) and sized and shaped to fit into the pulmonary veins, B) an intermediate second region 2676 (also referred to as a hot zone or ablation region) where theouter balloon 2660 contacts theinner balloon 2665 filled with steam, creating a hot zone or ablation region, and c) a proximalthird region 2677 that is positioned in the left atrium to provide a cooler left atrial surface (because the outer and

inner balloons

2660, 2665 do not contact in this region) so as not to scald the atrium. In various embodiments, the thermal zone or ablation zone shape is dependent on the shape of the inner and outer balloons, and in some embodiments, the shape is similar to the outer surface of the outer perimeter of the torus or ring, wherein the area of the outer surface, and thus the area of the ablation zone, is dependent on the physiology of the patient.

In some embodiments, theinner balloon 2665 is an annular tube positioned inside theouter balloon 2660 towards the hot orablation zone 2676. In some embodiments, theinner balloon 2665 has the shape of a ring or tube such that the outer rim of theinner balloon 2665 at the equator is attached to the inner side of theouter balloon 2660 at the equator.

In some embodiments, as shown in fig. 26B, when fully deployed, the proximal hemisphericalfirst portion 2670 of theouter balloon 2660 has a diameter of 32mm, while the length of theouter balloon 2660 along thelongitudinal axis 2674 is 36 mm. In some embodiments, theinner balloon 2665 is 28mm in diameter when fully deployed.

In some embodiments, as shown in fig. 26C, when fully deployed, the proximal hemisphericalfirst portion 2670 of theouter balloon 2660 has a diameter of 30mm, while the length of theouter balloon 2660 along thelongitudinal axis 2674 is 36 mm. In some embodiments, theinner balloon 2665 is 28mm in diameter when fully deployed.

In some embodiments, as shown in fig. 26E, 26H, and 26K, when fully deployed, the proximal hemisphericalfirst portion 2670 has a diameter in the range of 20mm to 60mm, the distal taperedsecond portion 2672 has a length (along the longitudinal axis 2674) in the range of 2mm to 50mm, and the length of each of the

necks

2681, 2682 is in the range of 1mm to 10 mm.

In some embodiments, as shown in fig. 26E, when fully deployed, theinner balloon 2665 assumes a spherical shape having a diameter "d" ranging from 15mm to 50 mm. In some embodiments, the contact orablation region 2676 has a width ranging from 1mm to 50 mm. In some embodiments, the gap or width "w" betweenouter balloon 2660 andinner balloon 2665 along diameter "d" ofinner balloon 2665 in the non-ablated region is in the range of 0.1mm to 50 mm.

In some embodiments, as shown in fig. 26H, when fully deployed, theinner balloon 2665 exhibits an oval shape with a horizontal axis 2674H along thelongitudinal axis 2674 and a vertical axis 2674H' substantially perpendicular to thelongitudinal axis 2674. In some embodiments, the first length along thehorizontal axis 2674h is in the range of 15mm to 45mm and the second length along thevertical axis 2674h' is in the range of 15mm to 50 mm. In some embodiments, the contact orablation region 2676 has a width ranging from 1mm to 50 mm. In some embodiments, the gap or width "w" betweenouter balloon 2660 andinner balloon 2665 alongvertical axis 2674h' in the non-ablated region is in the range of 0.1mm to 50 mm.

In some embodiments, as shown in fig. 26K, when fully deployed, theinner balloon 2665 exhibits a conical shape with a horizontal axis 2674K along thelongitudinal axis 2674 and a vertical axis 2674K' substantially perpendicular to thelongitudinal axis 2674. In some embodiments, the first length along thehorizontal axis 2674k is in the range of 15mm to 45mm and the second length along thevertical axis 2674k' is in the range of 15mm to 50 mm. In some embodiments, the contact orablation region 2676 has a width ranging from 1mm to 50 mm. In some embodiments, the gap or width "w" betweenouter balloon 2660 andinner balloon 2665 alongvertical axis 2674k' in the non-ablated region is in the range of 0.1mm to 50 mm.

In some embodiments, as shown in fig. 26D, 26E, 26J, and 26K, theinner balloon 2665 contacts theouter balloon 2660 more anteriorly than posteriorly at the contact orablation region 2676. In other words, the contact area between the inner and outer balloons is positioned such that more than 50% of the contact area is located within the proximal end of the outer balloon, wherein the distal or rear end is defined as the portion of the outer balloon that is half or more (farther) along the length of the outer balloon when the outer balloon is inflated, and the proximal or front end is defined as the portion of the outer balloon that is half or less (closer) along the length of the outer balloon when the outer balloon is inflated.

In some embodiments, the contact orablation area 2676 on theanterior surface 2676a of theouter balloon 2660 is at least 10% larger than the contact or ablation area on the posterior surface or end of theouter balloon 2660. In some embodiments, the contact orablation region 2676 ranges from 10% to 95% of theanterior surface 2676a of theouter balloon 2660. In some embodiments, the contact orablation region 2676 is greater than 25% of the circumference of theouter balloon 2660. In some embodiments, the contact orablation region 2676 ranges from 10% to 50% of the surface area of theouter balloon 2660.

In some embodiments, as shown in fig. 26D, 26E, 26J, 26H, 26J, and 26K, a firstcircumferential marker 2690 on theouter balloon 2660 indicates a contact orablation region 2676. In some embodiments, as shown in fig. 26D, a secondcircumferential marker 2691 onouter balloon 2660 is marked adjacent to the distal end ofouter balloon 2660. In various embodiments, the circumferential marker is radiopaque to provide radiographic visualization of the balloon to ensure proper placement during the ablation procedure.

In some embodiments, as shown in fig. 26F, 26I, and 26L, when fully deployed, the proximal hemisphericalfirst portion 2670 of theouter balloon 2660 has a diameter of 26mm, while the length of theouter balloon 2660 along thelongitudinal axis 2674 is 39 mm. The length of the taperedsecond portion 2672 along thelongitudinal axis 2674 is 7.5mm, while the width of the taperedsecond portion 2672 towards its distal end is 10 mm. In some embodiments, the diameter of each of the

necks

2681, 2682 is 5 mm. In some embodiments, theouter catheter 2615 has an outer diameter of 4.8mm and the inner catheter orlumen 2650 has an inner diameter of 1 mm.

In some embodiments, as shown in fig. 26F, theinner balloon 2665 is 28mm in diameter when fully deployed, wherein theballoon 2665 is spherical. In some embodiments, as shown in fig. 26I, the diameter of theinner balloon 2665 when fully deployed (along vertical axis 2674I) is 28mm, wherein theballoon 2665 is oval-shaped. In some embodiments, as shown in fig. 26L, the diameter of theinner balloon 2665 when fully deployed (along vertical axis 2674L) is 28mm, wherein theballoon 2665 is conically shaped.

In some embodiments,outer balloon 2660 is more compliant thaninner balloon 2665. In some embodiments, the outer balloon has a radial expansion in the range of 10% to 25% at 1 atmosphere. In an embodiment,inner balloon 2665 is semi-compliant and may have a radial expansion of less than 10% at 1 atmosphere. In some embodiments,inner balloon 2665 is coated or compounded with a hydrophilic coating, or with barium, gold, platinum, or other radiopaque material for radiographic visualization. In other embodiments, the outer surface of the balloon is spotted with silver or gold paint dots for radiographic visualization. In some embodiments, up to 25 dots are coated on each balloon.

In some embodiments, the at least oneflexible heating chamber 2630 is positioned in-line within the central water/steam lumen 2617 such that the plurality ofelectrodes 2655 are at least partially inside theinner balloon 2665. In one embodiment, as shown in fig. 26B, theflexible heating chamber 2630 is positioned such that the distal end of thechamber 2630 is located within theinner balloon 2665 at a distance of 30mm from the proximal end of theouter balloon 2660.

In some embodiments, theinner balloon 2665 can be moved along thelongitudinal axis 2674 within or along a portion of the length of theouter balloon 2660 using a guide wire mechanism in the handle at the proximal end of thecatheter 2610 to better position the inner balloon within the outer balloon and ensure proper contact of the inner balloon with the outer balloon.

In some embodiments, as shown in fig. 26M, the proximal and distal constrainingelements 2680a and 2680b are positioned inside theouter balloon 2660 such that theinner balloon 2665 is constrained to expand or deploy between the proximal and distal constrainingelements 2680a and 2680 b. In embodiments, proximal and distal constrainingelements 2680a and 2680b are desired wheninner balloon 2665 is semi-compliant or compliant. In accordance with aspects of the present description, the proximal and distal constrainingelements 2680a and 2680b control or change the shape of the deployedinner balloon 2665 so as to preferably allow theinner balloon 2665 to contact theouter balloon 2660 at a predetermined target intermediate orablation region 2676. Theproximal elements 2680a ensure that theinner balloon 2665 does not move proximally away from the desired intermediate orablation region 2676 during operation. In an embodiment, the proximal and distal constrainingelements 2680a and 2680b are permeable to allow a cooling fluid, such as air or carbon dioxide, to flow into theouter balloon 2660 to fully inflate it but to mechanically constrain the deployment or inflation of theinner balloon 2665 such that theinner balloon 2665 just fills the space between the proximal and distal constrainingelements 2680a and 2680 b. In some embodiments, proximal and distal constrainingelements 2680a and 2680b are meshes or nets. In some embodiments, theouter balloon 2660 is separated using strips or ribbons of the same material as theouter catheter 2615.

In accordance with one aspect of the present description,outer balloon 2660 is held under pressure and never under vacuum during ablation. In some embodiments,outer balloon 2660 is at a first pressure andinner balloon 2665 is at a second pressure. In some embodiments, the first pressure is equal to or less than the second pressure. In some embodiments, the pressurization differential betweenouter balloon 2660 andinner balloon 2665 is less than 20 psi. In some embodiments, there is a minimum desired volume difference betweenouter balloon 2660 andinner balloon 2665. In some embodiments,outer balloon 2660 has a volume that is at least 10% greater than the volume ofinner balloon 2665 during operation. In some embodiments, at least a 10% volume difference is distributed between thefirst region 2675 and thethird region 2677. In some embodiments,outer balloon 2660 has a volume that is at least 5% greater than the volume ofinner balloon 2665 during operation. In some embodiments, at least a 5% volume difference is distributed between thefirst region 2675 and thethird region 2677.

In some embodiments, amapping member 2685, which may be a distal extension, a catheter, or any substrate including a plurality of sensors, detectors, or electrodes, is attached to the distal end of thebody 2612 distal to theouter balloon 2660. Themapping member 2685 maps regions of cardiac tissue that cause arrhythmias. In some embodiments, themapping member 2685 has a length of up to 75 mm. In some embodiments, themapping member 2685 is pre-shaped into a pigtail shape to allow wall contact. In an embodiment, the pigtail has a diameter between 5mm and 35 mm. In some embodiments, themapping member 2685 includes 1-32 electrodes configured to record signals from or pacing in the pulmonary vein. In some embodiments, the catheter body further comprises a lumen for advancing the mapping member. In some embodiments, the lumen used to advance the mapping member has a diameter in the range of 0.5 to 1.5 mm. In some embodiments, the lumen used to advance the mapping member has a diameter of 1.0 mm.

In some embodiments, theouter balloon 2660 includes a plurality of mapping electrodes, which are either glued metal electrodes or printed electrodes, within or attached to the outer surface of its wall midway along its length axis that are circularly configured to record cardiac signals to map regions of cardiac tissue responsible for cardiac arrhythmias. In some embodiments, theouter balloon 2660 includes up to 24 mapping electrodes. In an embodiment, the mapping electrodes measure cardiac electrical activity to assess at least one treatment endpoint.

In some embodiments, the entire surface of thecatheter 2610, including the

balloons

2660, 2665, mapping electrodes, andmapping members 2685, is coated with heparin or a hydrophilic coating.

During operation, thecardiac ablation catheter 2610 is introduced into the left atrium by transseptal puncture and the outer balloon is advanced to the pulmonary vein of the heart. Next, theouter balloon 2660 is inflated with a cooling/insulating fluid, such as air or carbon dioxide, to occlude blood flow from the pulmonary veins to the left atrium. In some embodiments, staining studies are used to confirm occlusion of blood flow. Theinner balloon 2665 is then inflated with steam such that theinner balloon 2665 contacts a desired portion or region of the outer balloon 2660 (i.e., the mid-hot zone 2676) and theouter balloon 2660 remains in contact with the ablation region including the target cardiac tissue. Cold zones or

areas

2675, 2677 are located onouter balloon 2660 where the inflatedinner balloon 2665 does not contact the inflatedouter balloon 2660. Thus, thermal energy is transferred from the interior of theinner balloon 2665 through theouter balloon 2660 at the mid-thermal zone 2676 (ablation region) and into the heart tissue to ablate the tissue and treat arrhythmias.

The non-contact or

cold regions

2675, 2677 between the inner and outer balloons are filled with a cooling/insulating fluid that acts as an insulator. The thermal energy is delivered for a desired duration, after which theinner balloon 2665 self-contracts due to condensation of the vapor and theouter balloon 2660 contracts. Thecatheter 2610 is removed and circumferential ablation is created in the pulmonary vein (or left atrium, if desired, in some embodiments) to treat atrial arrhythmias. Optionally, the pulmonary veins (or left atrium, if desired, in some embodiments) are paced to confirm completion of the circumferential ablation.

In some embodiments,outer balloon 2660 includes thermocouples in predetermined areas to detect contact ofinner balloon 2665 withouter balloon 2660. In some embodiments,outer balloon 2660 includes thermocouples in predetermined areas to monitor the delivery of thermal energy to the target cardiac tissue. In some embodiments, theouter balloon 2660 includes thermocouples outside of predetermined regions of theouter balloon 2660 to measure the temperature in theouter balloon 2660 and to control the temperature outside of the predetermined regions to remain at less than 60 degrees celsius, and desirably less than 54 degrees celsius. In some embodiments,inner balloon 2665 includes a pressure sensor for measuring the pressure insideinner balloon 2665. In some embodiments, a thermocouple and/or pressure sensor is introduced through bothsensor lumens 2640.

Fig. 26S shows an outerexpandable member 2671 to be used in place of an outer balloon according to some embodiments of the present description. In some embodiments, the catheter of the present description includes an outerexpandable member 2671 instead of an outer balloon, and an inner balloon is positioned within the outerexpandable member 2671. In some embodiments, the outerexpandable member 2671 has a tapered shape with an elongated body that tapers toward itsdistal end 2671 d. The outerexpandable member 2671 is constructed of aflexible material 2678 and includes ashape memory wire 2679 extending along a body thereof. In some embodiments,flexible material 2678 includes silicone. In some embodiments, theshape memory wire 2679 comprises nitinol. In some embodiments, similar to the deflated outer balloon, the outerexpandable member 2671 is compressed for delivery and the catheter is advanced to the left atrium of the patient.Distal end 2671d is positioned in the pulmonary vein of the patient. Theshape memory wire 2679 changes to its post-deployment shape upon delivery, e.g., in response to a patient' S body temperature, causing the outerexpandable member 2671 to expand to its expanded shape, as shown in fig. 26S. In contrast to the dual balloon catheter embodiment of the present description, the outerexpandable member 2671 expands passively due to its shape memory properties, rather than actively via gas or liquid insufflation as with the outer balloon. After the outerexpandable member 2671 has changed to its post-deployment shape, the inner balloon is inflated with an ablative agent (e.g., water vapor) and brought into contact with a portion of the outerexpandable member 2671 at the hot zone. Thermal energy is transferred from this thermal zone to the cardiac tissue in contact therewith for ablation. In some embodiments, portions of the outerexpandable member 2671 distal and proximal to the thermal zone are in contact with the cardiac tissue. These portions serve both to prevent blood from contacting the hot zone surfaces and coagulating, and as an outer insulator for the heart tissue proximal and distal to the hot zone.

Fig. 26T illustrates a cross-sectional view of another embodiment of anablation catheter 26102 according to the present description. In one embodiment,conduit 26102 is fabricated using a copolymer such as Arnitel or Pebax (nylon elastomer). In an embodiment, theconduit 26102 is a multi-lumen extruded (MLE) conduit that includes achannel 26104, achannel 26106, and at least two diametricallyopposed channels 26108. In some embodiments, the diameter of theablation catheter 26102 is in the range of 2mm to 10 mm. The

channels

26104, 26106, and 26108 are located in the center of theablation catheter 26102.Channel 26104 is used to position the electrodes and to pass saline therethrough. Passage 26014 leads to an inner balloon, such asinner balloon 2665. Thechannel 26104 is circular and configured to allow at least 0.07mm of an electrode pin to pass therethrough, and thus thechannel 26104 is configured to have a diameter in the range of 0.072 to 0.078 mm. A wall of about 0.010mm separateschannel 26104 from the

other channels

26106 and 26108. The circular shape of the channels 12104 enables an optimal fit of the electrode without space around the perimeter of the electrode. If space is present, the saline will pass behind the electrodes without being heated. In some embodiments, the inner perimeter ofchannel 26104 is coated with a hydrophilic coating to attract fluid. In some embodiments, thechannel 26104 is eliminated into the inner balloon at a point distal to the output of thechannel 26104, thereby providing additional space for the folded/pleated balloon material. This further allows for a reduction in the size of the ablation catheter and better handling due to the reduced stiffness.

Thechannel 26106 is configured to receive at least one of a guidewire, a mapping catheter, and a pacing catheter. In addition,channel 26108 leads to the inner balloon and receives hot fluid that flows out of the inner balloon. In an embodiment, a valve between the inner balloon and thechannel 26108 ensures that the thermal fluid only flows out when the pressure in the balloon exceeds a threshold or when the valve opens to empty the inner balloon.

Fig. 26U illustrates a concentrically positionedchannel 26110 between the outer circumference of anablation catheter 26102 and the outer shaft according to some embodiments of the present description. In an embodiment,channel 26110 is used to channel CO₂By inflating and deflating an outer balloon (e.g., outer balloon 2660). In an embodiment,channel 26110 is connected to the outer balloon by a valve.

Fig. 26V illustrates a cross-sectional view of another embodiment of anablation catheter 2692 according to the present description.Catheter 2692 includes multiple separate lumens for balloon infusion, guidewire advancement, for accommodating electrode/water vapor generation (water vapor ingress), and for vapor egress. In one embodiment,catheter 2692 includes afirst lumen 2693 configured to allow steam to be released or aspirated fromcatheter 2692 after ablation.First lumen 2693 is positioned within the catheter, bounded bycatheter wall 2643. The first elongate tubular member 2644 is positioned within thefirst lumen 2693 and includes asecond lumen 2694 configured to receive a push/pull wire. In some embodiments, the first elongated tubular member 2644 has a circular cross-section. The secondtubular elongate member 2649 is also positioned within thefirst lumen 2693 and includes athird lumen 2699 configured to receive an electrode and receive a first fluid to be converted to steam (incoming water vapor) and expand the inner balloon. In some embodiments, CO₂May first be delivered to thethird lumen 2699 to partially inflate the inner balloon. In some embodiments, the secondelongated tubular member 2699 has an elliptical cross-section. Theelongated portion 2642 of thecatheter wall 2643 extends inward into thefirst lumen 2693 along the entire length of the catheter, creating afourth lumen 2647 configured to receive a second fluid for inflating the outer balloon and releasing or withdrawing the outer balloonA second fluid is drawn to deflate the outer balloon.

Fig. 26W illustrates the distal end of theablation catheter 2600, depicting theinner balloon 2601 positioned within theouter balloon 2602, according to some embodiments of the present description. Theelongate tubular member 2603 extends within a lumen of thecatheter body 2604 and is configured to receive a push/pull guidewire.

Fig. 26X is a flow chart listing steps in a method of ablating cardiac tissue according to some embodiments of the present description. Instep 2601, a catheter is positioned near cardiac tissue of a patient. In an embodiment, a catheter includes an elongated body having a lumen, a proximal end, and a distal end, and an outer balloon and an inner balloon positioned at the distal end such that the inner balloon is positioned within the outer balloon. In various embodiments, the cardiac tissue is a pulmonary vein, a portion of a pulmonary vein, a pulmonary vein ostium, an atrium, tissue near a pulmonary vein ventricle, or a left atrial appendage. In some embodiments, the method further comprises recording the extent of pulmonary vein occlusion achieved by inflating the outer balloon. Atstep 2602, the outer balloon is inflated with a first fluid to increase the pressure of the outer balloon to a first outer balloon pressure. In some embodiments, the first fluid is air or CO₂. In some embodiments, the first outer balloon pressure is between 0.01atm and 5atm, and preferably between 0.1atm and 5atm, or any range or increment therein.

Instep 2603, heated steam is injected into the inner balloon to increase the pressure of the inner balloon to a first inner balloon pressure, wherein injecting the heated steam into the inner balloon creates an ablation region, and wherein a surface area of the ablation region is defined by a portion of the inner balloon that contacts a portion of the outer balloon, thereby allowing heat to transfer from the heated steam in the inner balloon to the heart tissue through the ablation region. In some embodiments, the heated steam comprises water steam, and the temperature of the heated steam is at least 100 ℃. In some embodiments, the method further comprises inflating the inner balloon with a second fluid prior to injecting the heated steam into the inner balloon. In an embodiment, the second fluid is air or CO₂. Instep 2604, the first inner balloon pressure is maintained at a first pressureFor a predetermined period of time to ablate cardiac tissue to a predetermined degree. In some embodiments, the first predetermined period of time is between 1 second and 5 minutes. In some embodiments, the first outer balloon pressure is maintained for a first predetermined period of time. Instep 2605, the injection of the heating steam is stopped, wherein the stopping of the injection of the heating steam causes the pressure of the inner balloon to decrease to a second inner balloon pressure. Instep 2606, the outer balloon is deflated to a second outer balloon pressure.

In some embodiments, the surface area of the ablation region is a function of the surface area of tissue positioned at the junction between the pulmonary veins of the patient and the left atrium of the patient. In some embodiments, the method further comprises removing fluid resulting from condensation of the heated steam in the inner balloon, wherein the removal of fluid reduces the pressure of the inner balloon to a third inner balloon pressure that is less than or equal to the first inner balloon pressure. In some embodiments, the catheter includes a plurality of electrodes positioned proximate to the distal end of the catheter and the heated vapor is generated by directing saline through the lumen and past the plurality of electrodes. In some embodiments, the method further comprises recording the extent of removal of the occlusion of the pulmonary vein after deflating the outer balloon.

In some embodiments, the method further comprises placing a guidewire or pacing catheter in the heart of the patient, and placing the catheter over the guidewire or pacing catheter. In an embodiment, the method further comprises sensing or stimulating the pulmonary vein using a guidewire or pacing catheter to determine the degree of pulmonary vein isolation. In some embodiments, the distal tip of the catheter is configured to deflect from a linear configuration to a curved configuration, wherein the curved configuration is defined by the distal tip adapted to bend up to 150 degrees through a radius ranging from 0.5 to 2.5 inches.

In some embodiments, the inflated outer balloon contacts a portion of the pulmonary vein ostium and occludes at least a portion of the pulmonary vein 2mm to 15mm distal to the pulmonary vein ostium. In some embodiments, the ablation region has a width of 2mm to 15mm and has a curved length defined at least in part by a degree of contact between the inflated outer balloon and the surface of the cardiac tissue. In some embodiments, the distance between the outer surface of the inflated outer balloon and the outer surface of the uninflated inner balloon is in the range of 1mm to 25 mm.

In some embodiments, the method further comprises determining a degree of contact between at least two of the inner balloon, the outer balloon, and the cardiac tissue using at least one of fluoroscopy, three-dimensional mapping, or endoscopic surgery.

In some embodiments, the catheter further comprises at least one sensor. In embodiments, the sensor is configured to monitor contact of the inner balloon with the outer balloon, or to monitor temperature or pressure of the outer balloon or temperature or pressure of the inner balloon.

In some embodiments, further comprising introducing a catheter through a venipuncture in a femoral vein of the patient and advancing the catheter into a left atrium of the patient and into a pulmonary vein or left atrial appendage through a transseptal puncture.

In some embodiments, the ablation zone is positioned no more than 100mm away from the source of generation of the heating vapor. In some embodiments, the ablation zone is only generated when the pressure against the surface of the outer balloon is greater than 0.1 psi.

In some embodiments, the method further comprises repeating the steps to ablate the cardiac tissue for a second predetermined period of time, wherein the second predetermined period of time is equal to 50% to 250% of the first predetermined period of time.

In some embodiments, ablation is performed to treat atrial fibrillation or to ablate the left atrial appendage in a patient.

In some embodiments, upon inflation, the outer balloon has a pear-shaped configuration, wherein the pear-shaped configuration includes a proximal body that narrows to a tapered distal end.

In some embodiments, upon inflation, the shape of the outer balloon is defined by a curve of the surface of the outer balloon, the curve further defined by a plane intersecting the entire length of the catheter, wherein the curve is characterized by a first point, a second point, and a third point located sequentially and extending along the length of the catheter between a proximal point and a distal point, wherein a first slope between the proximal point and the first point has a first value, a second slope between the first point and the second point has a second value, a third slope between the second point and the third point has a third value, a fourth slope between the third point and the distal point has a fourth value, and wherein the absolute value of the first value is greater than the absolute value of the second value, greater than the absolute value of the third value, or the absolute value of the fourth value, greater than the absolute value of the third value; and wherein, when inflated, the inner balloon has the shape of an oblate spheroid with a minor or major axis coincident with the longitudinal axis of the catheter and a major or major axis perpendicular to the catheter.

In some embodiments, upon inflation, the shape of the outer balloon may be defined by a first distance from a central axis of the outer balloon to a first proximal point on the outer surface of the outer balloon, a second distance from the central axis to a second proximal point on the outer surface of the outer balloon, a third distance from the central axis to a third point on the outer surface of the outer balloon, a fourth distance from the central axis to a first distal point on the outer surface of the outer balloon, and a fifth distance from the central axis to a second distal point on the outer surface of the outer balloon, wherein each of the first proximal point, the second proximal point, the third point, the first distal point, and the second distal point are sequentially located and extend distally from a proximal location along a length of the central axis, wherein the second distance is greater than the first distance, the third distance, and the fifth distance, and wherein the fourth distance is greater than the first distance, the second distance, the third distance, a second distance, a third distance, and a fifth distance.

In some embodiments, the ablation region has a width and a curved length defined by a degree of contact between the outer balloon and a portion of the cardiac tissue when the inner and outer balloons are inflated.

Fig. 26Y illustrates asystem 26200 for ablating cardiac tissue according to an embodiment of the present description. Thesystem 26200 includes: acatheter 26201 adapted to be positioned adjacent cardiac tissue of a patient, wherein the catheter comprises: adistal end 26202; aproximal end 26203; afirst lumen 26204; asecond lumen 26205 including aheating element 26206; aninner balloon 26207 positioned at thedistal end 26202 of thecatheter 26201 and in fluid communication with thesecond lumen 26204; and anouter balloon 26208 positioned at thedistal end 26204 of thecatheter 26201 and surrounding theinner balloon 26207, wherein theouter balloon 26208 is in fluid communication with a firstfluid source 26209 via afirst lumen 26204, and wherein anablation region 26210 is formed at a contact region of theinner balloon 26207 with theouter balloon 26208 when theouter balloon 26208 is inflated with the first fluid and theinner balloon 26207 is inflated with heated steam; and acontroller 26211, whereincontroller 26211 includes program instructions that when executed result in: injecting a first fluid into the outer balloon; and directing a second fluid through the second lumen and into contact with the heating element to form a heated vapor.

In some embodiments,outer balloon 26208 is not fixedly attached toinner balloon 26207 in the contact areas. In some embodiments, the contour of the surface area of theablation region 26210 is a function of, and depends on, a portion of the pulmonary veins of the patient. In some embodiments,ablation region 26210 is defined by a surface area, and the size of the surface area ranges from 5% to 95% of the surface area of at least one ofinner balloon 26207 orouter balloon 26208. In some embodiments, theablation region 26210 has a width in the range of 1mm to 20 mm. In some embodiments, the first fluid is air or CO₂. In some embodiments, the second fluid is brine or carbonate, the heated steam is water vapor, and the heated steam has a temperature of at least 100 ℃. In some embodiments, theheating element 26206 is flexible and includes a plurality ofelectrodes 26212 positioned within thesecond lumen 26205 and configured to receive electrical current activated by a controller. In some embodiments, each of the plurality ofelectrodes 26212 includes at least one edge adapted to be exposed to fluid present in the second lumen. In some embodiments, theheating element 26206 is defined by a distal end, and the distal end is positioned at a distance in the range of 0mm to 80mm from the proximal end of theouter balloon 26208.

In some embodiments,system 26200 further comprises one ormore isolation regions 26213, wherein each of the one ormore isolation regions 26213 is defined by a surface region ofouter balloon 26208 proximal or distal toablation region 26210, and wherein an average temperature of each of the one ormore isolation regions 26213 is less than an average temperature ofablation region 26210. In some embodiments, each of the one or moreinsulating regions 26213 has a width of at least 0.1mm and extends along a curved length in the range of 1mm to the entire circumference of the outer balloon, or any increment therein.

In some embodiments, theinner balloon 26207 is configured to be movable within theouter balloon 26208 along a horizontal longitudinal axis, and thecatheter 26201 further includes amechanism 26214 configured to move theinner balloon 26207 within theouter balloon 26208.

In some embodiments,controller 26211 further includes program instructions that, when executed, causeouter balloon 26208 to inflate to a first pressure and remain at the first pressure during ablation. In some embodiments, thecontroller 26211 further includes program instructions that, when executed, cause theinner balloon 26207 to inflate to a second pressure during ablation, wherein the first pressure is equal to or less than the second pressure. In some embodiments, the first pressure is between 0.01atm and 5atm, preferably between 0.1atm and 5atm, or any range or increment therein.

In some embodiments,system 26200 further includes one ormore pressure valves 26215 in fluid communication withfirst lumen 26204, wherein each of the one ormore pressure valves 26215 is configured to control the movement of fluid into or out ofouter balloon 26208 based on a predetermined pressure level.

In some embodiments, thecontroller 26200 further includes program instructions that, when executed, cause theablation region 26210 to remain for a period of time between 1 second and 5 minutes.

In some embodiments, the system further includes amapping member 26216 positioned at thedistal end 26202 of thecatheter 26201 and configured to map a region of cardiac tissue causing an arrhythmia, wherein themapping member 26216 includes a plurality of sensors, detectors, orelectrodes 26217. In some embodiments, themapping member 26216 includes a range of 1 to 64 electrodes configured to record signals from or pacing in the pulmonary vein.

In some embodiments, the system further comprises at least onesensor 26218, wherein the at least onesensor 26218 is positioned at thedistal end 26202 of thecatheter 26201 or at theproximal end 26203 of thecatheter 26201. In some embodiments, thesensor 26218 includes a temperature sensor configured to monitor the delivery of thermal energy to the cardiac tissue. In some embodiments,sensor 26218 includes a pressure sensor configured to measure pressure within the inner balloon.

In some embodiments, theouter balloon 26208 is defined by a pear shape and is configured to be positioned in a pulmonary vein of a patient to occlude the pulmonary vein.

In some embodiments,outer balloon 26208 has an axis extending along the length ofouter balloon 26208 and through the center ofouter balloon 26208 that varies in distance along the length when inflated.

In some embodiments, the shape ofouter balloon 26208 is defined by the curve of the surface ofouter balloon 26208, which is further defined by a plane that intersects the entire length oftubing 26201, wherein the curve is characterized by a first point, a second point, and a third point, which are sequentially positioned and extend along the length of thecatheter 26201 between the proximal point and the distal point, wherein a first slope between the proximal point and the first point has a first value, a second slope between the first point and the second point has a second value, a third slope between the second point and the third point has a third value, a fourth slope between the third point and the distal point has a fourth value, and wherein the absolute value of the first value is greater than the absolute value of the second value, greater than the absolute value of the third value, or the absolute value of the fourth value, greater than the absolute value of the third value; and wherein, when inflated, the inner balloon has the shape of an oblate spheroid with a minor or major axis coincident with the longitudinal axis of thecatheter 26201 and a major or major axis perpendicular to thecatheter 26201.

In some embodiments, upon inflation, the shape ofouter balloon 26208 may be defined by a first distance from the central axis ofouter balloon 26208 to a first proximal point on the outer surface ofouter balloon 26208, a second distance from the central axis to a second proximal point on the outer surface ofouter balloon 26208, a third distance from the central axis to a third point on the outer surface ofouter balloon 26208, a fourth distance from the central axis to a first distal point on the outer surface ofouter balloon 26208, and a fifth distance from the central axis to a second distal point on the outer surface ofouter balloon 26208, wherein each of the first proximal point, the second proximal point, the third point, the first distal point, and the second distal point are sequentially located and extend distally from the proximal location along the length of the central axis, wherein the second distance is greater than the first distance, the third distance, and the fifth distance, and wherein, the fourth distance is greater than the first distance, the second distance, the third distance, and the fifth distance.

In some embodiments, theinner balloon 26207 has a spherical, oval, conical, disc-shaped, elliptical, rectangular prism, or triangular prism shape.

In some embodiments, theouter balloon 26208 is characterized by at least one first radial length when inflated that extends from a center point on an axis extending longitudinally along thecatheter 26201 and through theouter balloon 26208 to a point on the surface of theouter balloon 26208, wherein theinner balloon 26207 is characterized by at least one second radial length when inflated that extends from a center point on an axis extending longitudinally along thecatheter 26201 and through theinner balloon 26207 to a point on the surface of theinner balloon 26207, and wherein the at least one first radial length is different than the at least one second radial length. In some embodiments, the at least one first radial length is any amount or at least 10% greater than the at least one second radial length.

In some embodiments, theablation region 26210 has a width and a curved length defined by the degree of contact between theouter balloon 26208 and the heart tissue when theinner balloon 26207 and theouter balloon 26208 are inflated.

Fig. 27 illustrates a plurality of dual balloon configurations according to some embodiments of the present description. Fig. 27 shows a firstdual balloon catheter 2705, a seconddual balloon catheter 2710, a thirddual balloon catheter 2715, a fourthdual balloon catheter 2720, and a fifthdual balloon catheter 2725. Thefirst catheter 2705 shows a substantially ellipticalouter balloon 2706 attached to the distal tip of thecatheter 2705. A double-taperedinner balloon 2707 is attached to the distal tip of thecatheter 2705 inside theouter balloon 2706. According to one embodiment, the double-taperedinner balloon 2707 comprises a first taperedportion 2707a and a second taperedportion 2707b coupled at the bases thereof. In one embodiment, the height of the first taperedportion 2707a is greater than the height of the second taperedportion 2707 b.

Thethird catheter 2715 also shows a substantially ovalouter balloon 2716 attached to the distal tip of thecatheter 2715. A double truncated coneinner balloon 2717 is attached to the distal tip of thecatheter 2715 within theouter balloon 2716. According to one embodiment, the double truncated coneinner balloon 2717 includes first and second truncated cone (or frustum)

portions

2717a, 2717b coupled at their bases. In one embodiment, the height of the firstfrustoconical portion 2707a is greater than the height of the secondfrustoconical portion 2707 b.

Thesecond catheter 2710 shows a substantially sphericalouter balloon 2711 attached to the distal tip of thecatheter 2710. A taperedinner balloon 2712 is attached to the distal tip of thecatheter 2710 within theouter balloon 2711. According to one embodiment, the apex or apex of the taperedinner balloon 2712 faces the distal end of theouter balloon 2711, while the base of the taperedinner balloon 2712 faces the proximal end of theouter balloon 2711.

Thefifth catheter 2725 also shows a substantially sphericalouter balloon 2726 attached to the distal tip of thecatheter 2725. A taperedinner balloon 2727 is attached to the distal tip of thecatheter 2725 within theouter balloon 2726. According to one embodiment and in contrast to thesecond catheter 2710, the apex or apex of the taperedinner balloon 2727 faces the proximal end of theouter balloon 2726, while the base of the taperedinner balloon 2727 faces the proximal end of theouter balloon 2726.

Thefourth catheter 2720 shows a substantially double-taperedouter balloon 2721 attached to the distal tip of thecatheter 2720. According to one embodiment, the double-taperedouter balloon 2721 includes a first taperedportion 2721a and a second taperedportion 2721b coupled at a base thereof. In one embodiment, the height of the first taperedportion 2721a is substantially equal to the height of the second taperedportion 2721 b. A substantially ellipticalinner balloon 2722 is attached to the distal tip of thecatheter 2720 within theouter balloon 2721.

For each of

catheters

2705, 2710, 2715, 2720, and 2725, the volume of the inner balloon is less than the volume of the outer balloon. In some embodiments, the volume of the outer balloon is at least 10% greater than the volume of the inner balloon when both balloons are fully inflated. In various embodiments, the contact surface area between the inner balloon and the outer balloon in the fully inflated state is less than 90%.

Each of the firstdual balloon catheter 2705, the seconddual balloon catheter 2710, the thirddual balloon catheter 2715, the fourthdual balloon catheter 2720, and the fifthdual balloon catheter 2725 has a handle attached to its respective proximal end. Fig. 27 shows anexemplary handle 2730 that includes afirst inlet port 2702 through which a cooling fluid, such as, for example, air or carbon dioxide, is pumped to inflate the outer balloon and asecond inlet port 2703 through which an ablative agent, such as, for example, steam, is pumped to inflate the inner balloon. In various embodiments, handle 2730 is configured to be operated by a single operator.

Fig. 28 illustrates a plurality of dual balloon configurations according to some embodiments of the present description. Fig. 28 shows the firstdual balloon configuration 2805, the seconddual balloon configuration 2810, the thirddual balloon configuration 2815, the fourthdual balloon configuration 2820, the fifthdual balloon configuration 2825, the sixthdual balloon configuration 2830, and the seventhdual balloon configuration 2835 in a fully deployed state.First configuration 2805 illustratesouter balloon 2806 having a compound shape that includes a substantially sphericalproximal portion 2806a that transitions into a substantially ellipticaldistal portion 2806 b. Theinner balloon 2807 is substantially spherical. In one embodiment, theouter balloon 2806 and/or theinner balloon 2807 includeradiopaque markers 2808 that identify areas of ablation or heat, where theinner balloon 2807 contacts theouter balloon 2806 when both the inner and

outer balloons

2807, 2806 are in a fully expanded state.

Second configuration 2810 showsouter balloon 2811 having a composite shape that includes a short substantially sphericalproximal portion 2811a, a substantially cylindricalmiddle portion 2811b, and a short substantially conical or tapereddistal portion 2811 c.Inner balloon 2812 has a substantially tear-drop or droplet shape with an apex or apex 2812a pointing toward the proximal end ofconstruct 2810. In one embodiment,outer balloon 2811 and/orinner balloon 2812 includeradiopaque markers 2813 that identify areas of ablation or heat, whereinner balloon 2811 contactsouter balloon 2812 when both inner and

outer balloons

2811 and 2812 are in a fully expanded state.

Thethird configuration 2815 shows theouter balloon 2816 having a substantially teardrop or droplet shape such that the apex orapex 2816a forms a distal end and thebulbous end 2816b forms a proximal end of theouter balloon 2816.Inner balloon 2817 also has a substantially teardrop or droplet shape such that apex orapex 2817a points proximally andbulbous end 2817b points distally ofouter balloon 2816. In one embodiment,outer balloon 2816 and/orinner balloon 2817 includeradiopaque markers 2818 that identify areas of ablation or heat, whereinner balloon 2817 contactsouter balloon 2816 when both inner and

outer balloons

2817 and 2816 are in a fully expanded state.

Thefourth configuration 2820 illustrates theouter balloon 2821 having a substantially tear-or droplet-like shape, such that the apex or top 2821a forms the distal end, and thebulbous end 2821b forms the proximal end of theouter balloon 2821. Theinner balloon 2822 also has a substantially tear-drop or droplet shape, such that the apex or apex 2822a is directed proximally and thebulbous end 2822b is directed distally of theouter balloon 2821. Theouter balloon 2821 and theinner balloon 2822 are shown attached to the distal end of theelongate body 2823. When both theinner balloon 2822 and theouter balloon 2821 are in a fully expanded state, an ablation orhot zone 2824 is formed where they meet. In some embodiments, theinner balloon 2822 occupies a smaller area of the interior of theouter balloon 2821 of thefourth configuration 2820 when compared to the

balloons

2816, 2817 shown in thethird configuration 2815.

Thefifth configuration 2825 illustrates theouter balloon 2826 having a substantially ellipticalproximal portion 2826a that transitions to a relatively smaller substantially ellipticaldistal portion 2826 b. Theinner balloon 2827 has a substantially tear-drop or droplet shape with an apex orvertex 2827a pointing toward the proximal end of theouter balloon 2826. Theouter balloon 2826 and theinner balloon 2827 are shown attached to the distal end of theelongate body 2828. When both theinner balloon 2827 and theouter balloon 2826 are in a fully expanded state, an ablation orhot zone 2829 is formed where they meet. In some embodiments, the ellipticaldistal portion 2826b includes a third balloon that operates independently of the separate ellipticalproximal balloon 2826a and may be inflated with a coolant/insulating fluid or an ablative agent such as water vapor.

Thesixth configuration 2830 illustrates theouter balloon 2831 having a substantially tear-or drop-like shape, such that the apex or apex 2831a forms the distal end, and thebulbous end 2831b forms the proximal end of theouter balloon 2831. Theinner balloon 2832 has a substantially spherical shape. Theouter balloon 2831 and theinner balloon 2832 are shown attached to the distal end of theelongate body 2833. When both theinner balloon 2831 and theouter balloon 2832 are in a fully expanded state, an ablation orhot zone 2834 is formed where they meet.

Theseventh configuration 2835 illustrates anouter balloon 2836 having a compound shape that includes a substantially sphericalproximal portion 2836a that transitions to a relatively smaller substantially sphericaldistal portion 2836 b. Theinner balloon 2837 has a substantially oval shape such that thelong axis 2837a of theinner balloon 2837 is substantially orthogonal to thelongitudinal axis 2838a of theconstruction 2835. Theouter balloon 2836 and theinner balloon 2837 are shown attached to the distal end of theelongate body 2838. When both theinner balloon 2836 and theouter balloon 2835 are in a fully expanded state, an ablation orhot zone 2839 is formed where they contact. In some embodiments, the sphericaldistal portion 2836b includes a third balloon that operates independently of the separate sphericalproximal balloon 2836a and may be inflated with a coolant/insulating fluid or an ablative agent such as water vapor.

Fig. 29 illustrates a number of exemplary shapes of the outer balloon or the inner balloon of a dual balloon catheter according to some embodiments of the present description.First view 2905 shows a tapered or double-taperedballoon 2906 that includes a first taperedportion 2906a and a second taperedportion 2906b coupled at their bases. The proximal and distal ends of theballoon 2906 extend into a tubular structure orneck 2907, which helps to hold the catheter in place as it passes through the balloon.

Second view 2910 shows asquare balloon 2911. It should be understood that the modifier "square" refers to a substantially right angle or square end or corner ofballoon 2911. The proximal and distal ends ofballoon 2911 extend into a tubular structure orneck 2912, which helps to hold the catheter in place as it passes through the balloon.Third view 2915 showsspherical balloon 2916. The proximal and distal ends ofballoon 2916 extend into a tubular structure or neck 2917, which helps to hold the catheter in place as it passes through the balloon.

Fourth view 2920 shows a cone-cylinder (short)balloon 2921 that includes a cone-shapedfirst portion 2921a coupled at its base to a short cylinder-shapedsecond portion 2921b, the short cylinder-shapedsecond portion 2921b having substantially right or square ends or corners (similar to square balloon 2911). The length of thesecond portion 2921b is much shorter than the length of thefirst portion 2921 a. The proximal and distal ends of theballoon 2921 extend into a tubular structure orneck 2922, which helps to hold the catheter in place as it passes through the balloon. It should be understood that the modifier "short" indicates that thesecond portion 2921b is short or short.

Fifth view 2925 shows a cone-cylindrical (long)balloon 2926 that includes a cone-shapedfirst portion 2926a coupled at its base to a long cylindricalfirst portion 2926b, the long cylindricalfirst portion 2926b having substantially right or square ends or corners (similar to square balloon 2911). The length of the cylindricalsecond portion 2926b is substantially longer than the length of the conicalfirst portion 2926 a. The proximal and distal ends of theballoon 2926 extend into a tubular structure orneck 2927, which helps to hold the catheter in place as it passes through the balloon. It should be understood that the modifier "long" indicates that thesecond portion 2931b is elongated.

Asixth view 2930 shows a cone-cylinder (long)balloon 2931 that includes a cone-shapedfirst portion 2931a coupled at its base to a long-cylinder-shapedsecond portion 2931b having substantially spherical or rounded ends or corners. The length of thesecond portion 2931b is much longer than the length of thefirst portion 2931 a. The proximal and distal ends of theballoon 2931 extend into a tubular structure orneck 2932, which helps to hold the catheter in place as it passes through the balloon. It should be understood that the modifier "long" indicates that thesecond portion 2931b is elongated.

Seventh view 2935 shows a longcylindrical balloon 2936 having substantially spherical or rounded ends or corners. The proximal and distal ends of theballoon 2931 extend into a tubular structure orneck 2937, which helps to hold the catheter in place as it passes through the balloon. It should be understood that the modifier "long" indicates that theballoon 2936 is elongated.

Aneighth view 2940 shows atapered balloon 2941 that includes a first tapered orconical end 2941a and a second tapered orconical end 2941b of a taperedcylindrical portion 2941 c. The proximal and distal ends of theballoon 2941 extend into a tubular structure orneck 2942, which helps to hold the catheter in place as it passes through the balloon.

Aninth view 2945 shows adog bone balloon 2946.Balloon 2946 has a compound shape resembling a dog's biscuit or dog-bone toy, with first 2946a, second 2946b, and third 2946c cylindrical portions, such that intermediate/second 2946b has a smaller diameter than first 2946a and third 2946c cylindrical portions that form the ends of intermediate/second 2946 b. Each of the first and third

cylindrical portions

2946a and 2946c has a tapered orconical end 2947. The proximal and distal ends of theballoon 2946 extend into the tubular structure orneck 2948, which helps to hold the catheter in place as it passes through the balloon.

Tenth view 2950 shows a steppedballoon 2951 including a firstcylindrical portion 2951a, a secondcylindrical portion 2951b, and a thirdcylindrical portion 2951c, where the diameter ofsecond portion 2951b is greater than the diameter offirst portion 2951a, and the diameter ofthird portion 2951c is greater than the diameter ofsecond portion 2951 b. Theballoon 2950 has tapered or conical proximal and distal ends 2952. A tapered orconical portion 2953 is included betweenfirst portion 2951a andsecond portion 2951b, and betweensecond portion 2951b andthird portion 2951 c. The proximal anddistal ends 2952 of theballoon 2946 extend into a tubular structure orneck 2954, which helps to hold the catheter in place as it passes through the balloon.

Aneleventh view 2955 shows the offsetballoon 2956. The offset shape of theballoon 2956 comprises longitudinal halves of a compound shape having tapered or

conical ends

2956a, 2956c of a middlecylindrical portion 2956 b. The proximal and distal ends of theballoon 2956 extend into the tubular structure orneck 2957, which helps to hold the catheter in place as it passes through the balloon.

Atwelfth view 2960 shows a tapered offsetballoon 2961. Theballoon 2961 includes a fullcylindrical portion 2961b having a full tapered or taperedfirst end 2961a and a longitudinally halved tapered or taperedsecond end 2961 c. The proximal and distal ends of theballoon 2961 extend into a tubular structure orneck 2962, which helps to hold the catheter in place as it passes through the balloon.

Fig. 30 illustrates a plurality of exemplary balloon ends or corners according to some embodiments of the present description. Thefirst view 3005 shows anacute taper angle 3006 having a tapered or taperedportion 3006a, the tapered or taperedportion 3006a having abase 3006b with a square or acute angle. Thesecond view 3010 shows ataper radius corner 3011 having a tapered or taperedportion 3011a, the tapered or taperedportion 3011a having abase 3011b with a spherical or rounded corner. Thethird view 3015 shows a square end 3016 having a square or acute angle. Afourth view 3020 shows aspherical end 3021 having a spherical shape or rounded corners. Afifth view 3025 shows the offsetneck 3026 as a longitudinal half of the tapered orconical portion 3026 a.

Fig. 31 illustrates a plurality of balloon shapes having at least one substantially tapered or conical end according to some embodiments of the present description. The figures show afirst balloon 3105, asecond balloon 3110, athird balloon 3115 and afourth balloon 3120. Thefirst balloon 3105 has a compound shape including aproximal end 3105a and a tapered or conicaldistal end 3105c, with a substantially cylindricalmiddle portion 3105 b. Each of theproximal end 3105a and the tapered or conicaldistal end 3105c has a first taper angle. Thesecond balloon 3110 also has a compound shape including aproximal end 3110a and a tapered or conicaldistal end 3110c having a substantially cylindricalmiddle portion 3110 b. Each of theproximal end 3110a and the tapered or tapereddistal end 3110c has a second taper angle.Third balloon 3115 also has a compound shape including aproximal end 3115a and a tapered or conicaldistal end 3115c having a substantially cylindricalintermediate portion 3115 b. Each of theproximal end 3115a and the tapered or conicaldistal end 3115c has a third taper angle. Thefourth balloon 3110 also has a compound shape that includes a tapered or conicaldistal end 3120a and a substantially cylindricalproximal portion 3120 b. The tapered or conicaldistal end 3120a has a fourth cone angle.

In embodiments, the different first, second, third and fourth taper angles enable the respective balloons to meet different taper requirements.

Fig. 32 illustrates adual balloon catheter 3200 having aninflatable dilation balloon 3220 according to one embodiment of the present description.Catheter 3200 has anelongate body 3212. An outerinflatable balloon 3260 is attached near the distal end of theelongate body 3212. An inflatableinner balloon 3265 is also attached near the distal end of theelongate body 3212 such that theinner balloon 3265 is positioned within theouter balloon 3260. Aninflatable balloon 3220 is attached to the distal end of theelongate body 3212 such that theballoon 3220 is positioned distal of theouter balloon 3260.

During operation, a cooling fluid, such as, but not limited to, water or air, is injected into theballoon 3220 to inflate theballoon 3220 and expand or dilate openings or punctures made in, for example, the atrial septum. In one embodiment, thedilation balloon 3220 has a compound shape including aproximal end 3220a and a substantially tapered or conicaldistal end 3220c, and a substantially cylindricalintermediate portion 3220b when in a fully deployed state.

Oncecatheter 3200 is positioned adjacent the target tissue (e.g., in a pulmonary vein), fluid is circulated intoouter balloon 3260 while an ablative fluid (e.g., steam) is injected intoinner balloon 3265 to inflateouter balloon 3260 andinner balloon 3265, respectively. In one embodiment, theouter balloon 3260 is substantially elliptical in a fully deployed state. In one embodiment, when fully expanded, theinner balloon 3265 has a double-tapered shape including a first taperedportion 3265a and a second taperedportion 3265b coupled or fused at their bases.

Fig. 33 illustrates aballoon catheter 3310 for measuring the geometry of a body lumen according to some embodiments of the present description. Referring to fig. 3305, thecatheter 3310 includes anelongate body 3312 having an inflatablecompliant balloon 3360 mounted on the distal end of thebody 3312. Thebody 3312 has at least one lumen in fluid communication with theballoon 3360. Theballoon 3360 houses a plurality ofelectrode pairs 3315 spaced throughout the longitudinal length of theballoon 3360 for measuring voltages. Thecatheter 3310 uses these voltages to estimate diameters at multiple points (e.g., 16 points in one embodiment) along thebody lumen 3320. Optionally, a solid state pressure sensor may also be positioned at the distal end ofballoon 3360.

To estimate the shape and size (geometry) of thebody lumen 3320, thecatheter 3310 is positioned within thebody lumen 3320 and theballoon 3360 is inflated with a conductive solution. Thecatheter 3310 measures multiple (e.g., 16) lumen cross-sectional areas (thereby estimating shape and size) along thebody lumen 3320 and pressure during controlled volume deployment of theballoon 3360 within the body lumen.

In some embodiments, thecatheter 3310 uses an impedance area method to characterize the geometry (shape and size) of thebody lumen 3320. The impedance area method uses Alternating Current (AC) voltage measurements made between pairs of electrodes to estimate the diameter of the medium (conducting fluid) at a midpoint between the electrodes. Assuming that the voltage drop across the medium is produced by a constant alternating current source, the conductivity of the medium is constant, and given a given temperature, a voltage measurement can be obtained.

Referring now to view 3330, the inflation of aballoon 3360 with a conductive solution within abody cavity 3320 is shown. A pair ofelectrodes 3315 are shown separated by a fixed distance (L) and connected via wires to a voltmeter 3335. A constant current source 3340 is applied and an electric field (represented by a plurality of electric field lines 3345) is generated in a conductive medium contained in aninflated balloon 3360 constrained by awall 3322 of thebody lumen 3320.

Now, the resistance (R) or impedance can be determined by:

V/I＝R

＝L/(Aσ)

＝L/[Π(D_est/2)²·σ]

where R is the resistance (impedance), given by V/I, σ is the conductivity of the medium, L is the distance between the pair ofelectrodes 3315, A is the cylinder area, D_estIs the cylinder diameter. When the alternating current (I) is known and fixed, R, resistance (impedance) can be calculated and the alternating voltage (V) measured on the pair of electrodes. Since L is a fixed distance between the electrodes and the conductivity (σ) of the medium at a given temperature is known, D can be determined_est. Balloon or cylinder diameter (D) at a given electrode location_est) The estimate of (a) is derived from the measured cylinder area (a), assuming that theballoon 3360 is symmetrical about its longitudinal axis at this electrode location.

Thus, once theballoon 3360 is filled with the conductive solution, theimpedance measuring electrodes 3315 measure 16 intraluminal cross-sectional areas (CSAs) and the pressure sensors provide the corresponding intraballoon pressures. Diameter D_estAnd the intra-balloon pressure measurements are exported to a software application to generate and display atopographical map 3350. Fig. 3350 shows the calculated cross-sectional area (CSA) in cylinders of different diameters. The geometry of the body lumen may be used to direct the amount of ablative agent that needs to be delivered to achieve effective ablation.

Fig. 34 illustrates relative flow paths of cooling fluid and ablation fluid in an ablation catheter, according to some embodiments of the present description. As shown, in various ablation catheters of the present description, an ablation fluid (e.g., water vapor or steam) flows in afirst path 3405, while a second fluid (e.g., water, air, or carbon dioxide) flows in asecond path 3410.

In some embodiments, thefirst path 3405 is substantially linear, and thesecond path 3410 is substantially helical or spiral around thefirst path 3405.

In some embodiments, thefirst path 3405 is 1.1 to 10 times longer than thesecond path 3410. In some embodiments, the ratio between the lengths of thefirst path 3405 and thesecond path 3410 is pi.

Fig. 35A illustrates a dual-anglecardiac ablation catheter 3500 in accordance with some embodiments of the present description. Thecatheter 3500 has anelongate body 3512 having a proximal end and a distal end. Theelongate body 3512 is bifurcated at a distal end into afirst branch 3515 and asecond branch 3516. An inflatableouter balloon 3560 is attached to the distal end, and an inflatableinner balloon 3565 is also attached to the distal end and positioned within theouter balloon 3560.

According to one aspect, in the fully deployed state, theouter balloon 3560 has a compound shape that includes a substantially ellipticalproximal portion 3560a, and a first substantially spherical or elliptical distal corner orportion 3560b and a second substantially spherical or elliptical distal corner orportion 3560 c. In one embodiment, themajor axis 3520 of the substantially ellipticalproximal portion 3560a is substantially orthogonal to thelongitudinal axis 3525 of theelongate body 3512.First branch 3515 is directed into firstdistal angle 3560b ofouter balloon 3560 whilesecond branch 3516 is directed into seconddistal angle 3560c ofouter balloon 3560. In some embodiments, thefirst branch 3515 includes amapping member 3527 extending distally therefrom, and thesecond branch 3516 extends asecond mapping member 3526 extending distally therefrom.

In some embodiments, theelongate body 3512 includes a first cooling fluid injection lumen and a second cooling fluid aspiration lumen, both of which are in fluid communication with theouter balloon 3560, which includes

corners

3560b, 3560 c. During operation, a cooling fluid pump in data communication with and controlled by the controller enables pumping of cooling fluid into theouter balloon 3560 through the cooling fluid injection lumen and allows pumping of cooling fluid out of theouter balloon 3560 through the cooling fluid suction lumen.

In some embodiments,elongate body 3512 further comprises a water/steam lumen in fluid communication withinner balloon 3565 via a plurality of steam injection ports. In some embodiments, at least one flexible heating chamber (such as those described with reference to fig. 19A-19D) comprising a plurality of electrodes is positioned inline within the water/steam tube cavity. In some embodiments, the at least one flexible heating chamber is positioned in-line within the central water/steam tube lumen such that the plurality of electrodes are at least partially within theinner balloon 3565. During operation, a water/steam pump, also in data communication with and controlled by the controller, pumps water from the sterile water reservoir through the water/steam lumen into the proximal end of the at least one flexible heating chamber. The at least one flexible heating chamber converts water to steam, which exits through the plurality of steam injection ports to inflateinner balloon 3565 and contactouter balloon 3560 near the ablation area.

An ablation orhot zone 3530 is created at the contact region between theinner balloon 3565 and theouter balloon 3560 such that thermal energy from theinner balloon 3565 passes through theouter balloon 3560 to the ablation region. Portions ofelongate body 3512 and outer balloon 3560 (excluding the hot zone) remain cool due to the circulating cooling fluid.

According to one embodiment, an ablation orthermal zone 3530 forms an ablation orlesion region 3535 that is generally in the form of an "8" shape, as shown inview 3540. During operation (e.g., during a pulmonary vein isolation procedure of view 3540),catheter 3500 is guided into the left atrium such thatfirst corner 3560b andsecond corner 3560c are located in firstpulmonary vein 3542a and secondpulmonary vein 3542b or thirdpulmonary vein 3543a and fourthpulmonary vein 3543b, respectively. The left atrium between the two

pulmonary veins

3542a, 3542b or 3543a, 3543b prevents theballoon 3560 from sliding into the pulmonary veins. Thus, ablation may be performed simultaneously at both

pulmonary veins

3542a, 3542b or 3543a, 3543b using thedual angle catheter 3500, resulting in an ablation orlesion region 3535 similar to the figure "8". In an embodiment, simultaneous ablation of two pulmonary veins using thedual angle catheter 3500 may reduce ablation time by 50%.

According to one aspect, the inflatable ablation balloon of a balloon cardiac ablation catheter (e.g.,catheter 1442 of fig. 14A) is multi-layered, comprising an outer balloon layer and an inner balloon layer fused together. A plurality of ablation fluid channels or pathways are defined and sandwiched between the outer and inner layers. During operation, the balloon is inflated to contact the target tissue and water vapor/steam is allowed to circulate through the plurality of ablation fluid channels to create deep burns in the target tissue without causing adjacent circumferential scarring. This results in thermal energy spreading in a controlled manner non-continuously over the tissue region and can be cycled without causing adjacent circumferential scarring and thus stenosis.

In various embodiments, the plurality of ablation fluid channels are configured in a plurality of patterns or profiles (e.g., without limitation, waves, a series of lines, sine waves, square waves) such that the circulating water vapor/steam produces ablation in the vicinity of the channel region without any ablation in the remaining regions of the balloon (i.e., the regions without channels). In an exemplary application of PV (pulmonary vein) ablation, the plurality of channels create an ablation pattern in the PV sufficient to block conduction of electrical activity from the PV to the Left Atrium (LA) without causing a significant stenosis in the PV, wherein a length of the circumferential pattern of ablation is greater than a circumference of the PV in a vicinity of the ablation. In some embodiments, the circumferential pattern of ablation has a length or width that is 1.2 times the circumferential width of the PV or another organ being ablated near the ablation. Thus, in one embodiment, if the width of the PV perimeter is 10mm, the width of the ablation perimeter will be 12mm or greater. In some embodiments, the distance between two adjacent circumferential ablation patterns is greater than twice the thickness of the PV or the wall or parietal layer of the ablated organ.

Fig. 35B illustrates a plurality of patterns of ablation fluid channels orpathways 3570 defined in a multi-layer balloon of an ablation catheter in accordance with various embodiments of the present description. The figure shows a firstexemplary pattern 3575, a secondexemplary pattern 3576, a thirdexemplary pattern 3577, a fourthexemplary pattern 3578, and a fifthexemplary pattern 3579. The pattern ofchannels 3570 defines an ablation profile or pattern.

In various embodiments, balloon pressures of the inner and outer balloons of the ablation catheter of the present description are managed as water vapor is generated. In some embodiments, the catheter includes a plurality of ports at the proximal end for delivery and removal of the bulking agent and the ablative agent. In some embodiments, the ablation catheter includes at least one ablation agent "input" port, at least one ablation agent "output" port, at least one bulking agent "input" port, and at least one bulking agent "output" port. In various embodiments, the ablative agent is steam and the bulking agent is CO₂. Each port is in fluid communication with a corresponding lumen within the catheter.

In some embodiments of the present invention, the substrate is,each port-steam in, steam out, CO₂Input, CO₂Output-is actively managed by a controller that also actively manages the water vapor/steam generator. In some embodiments, each port may be opened or closed in response to instructions from the controller. Controlling the open and closed state of the port may prevent leakage and ensure that the outlet port will be closed and/or controlled during vapor delivery. In some embodiments, the outflow of steam or water vapor is controlled by a column of fluid that is back-loaded into a water vapor or steam "output" lumen. The liquid level is controlled by an input pump and an output pump controlled by pressure and volume at the proximal end of the conduit. In various embodiments, actively managing the ports includes sensing pressure and temperature at each port and then varying the input at each port based on a desired range of values. In various embodiments, each port includes a valve configured to be opened or closed by a controller.

In various embodiments, the catheter is configured to deliver and/or remove/aspirate fluid in any direction. The air in the balloon lumen will, at least initially, cause the balloon to deploy. Only once the temperature in the balloon has been reached>Steam can expand at 100 c and the condensation of water vapor stops. The pressure in the outer balloon will increase as the inner balloon inflates. In some embodiments, the outer balloon is actively deflated to maintain a constant pressure as the inner balloon is inflated with heated steam. In some embodiments, the amount of pre-existing air in the catheter lumen expands due to heat from the delivered steam or water vapor and results in some expansion of the inner balloon. In some embodiments, the inner balloon is partially inflated with carbon dioxide prior to inflation with water vapor while the inner balloon is maintained at a constant pressure. In some embodiments, the conduit includes a single injection port for CO alone₂To assist in the inflation of the inner balloon. In another embodiment, CO₂Mixed with saline (carbonated water) and released as the saline evaporates, assisting in inflation of the inner balloon.

In some embodiments, the inner and outer balloons are inflated according to a specific protocol to ensure proper operation of the ablation catheter. In some embodiments, the expansion protocol comprises: inflating the outer balloon to a first pressure level in the range of 0.5 to 100psi, first with CO₂Inflating the inner balloon to a second pressure level or volume at least 5% lower than the first pressure level, inflating the inner balloon to a third pressure level or volume higher than the first and second pressure levels with steam, and monitoring the pressure level of the outer balloon, removing or adding CO₂To maintain this level. In another embodiment, the inner balloon is inflated by allowing CO in the inner balloon₂Or steam escaping from the catheter to monitor and maintain a third pressure level of the inner balloon.

In various embodiments, the catheter body of the present description includes a squeeze shaft having a plurality of lumens therein. In other embodiments, the catheter body of the present description comprises a single lumen having a plurality of binding pads within the single lumen. The bundling liner is configured to serve as a separate lumen for various functions of the catheter, including inflation agent delivery and aspiration and ablation agent delivery and aspiration. In various embodiments, each of the plurality of tie-down pads has a different diameter. The individual lumens facilitate identification of each, the inner balloon has greater independence, and the air gap between the binding pads for isolation. In one embodiment, the vapor delivery lumen further comprises an insulating liner at a distal end thereof. In one embodiment, the insulating liner comprises a woven polyimide/Pebax axis.

In an embodiment, the ablation zone is created when the relative pressure to the outer balloon is greater than 0.1psi relative to the outer balloon. If the blood flow through a portion of the ablation region is greater than 1ml/min, no ablation region will be created. In some embodiments, an ablation zone is not created if blood flow through a portion of the ablation zone is greater than 10ml/min or greater than 100 ml/min. In embodiments, blood flow as referred to herein refers to the flow of blood between the outer surface of the outer balloon and the tissue to be ablated. In one embodiment, blood flows from the pulmonary veins to be ablated into the left atrium.

In an embodiment, the water vapor for ablation is generated within a range of distances from the tissue to be ablated. Thus, in some embodiments, the area contacting the tissue or ablation region is distant from the steam generation source at a distance in the range of 0mm to 100 mm. In some embodiments, the balloon is collapsible and may be deployed by a controller in the handle.

In some embodiments, the conduit is configured to have a temperature difference between an outer surface of the conduit and an inner surface of the lumen, wherein no less than 40 degrees celsius heating steam is generated. More specifically, the outer surface of the catheter should be less than 60 degrees celsius, preferably less than 45 degrees celsius. In some embodiments, the catheter shaft is insulated with an introducer sheath and a constant saline flow. This insulation prevents conduction from increasing the shaft temperature during water vapor generation.

In various embodiments, the outer balloon comprises silicone. In various embodiments, the inner balloon comprises medium durometer polyurethane, PET, or Pebax. In various embodiments, the inner balloon comprises a material configured to be semi-compliant while also having thermal resistance.

Fig. 36A is a flow chart of exemplary steps for inflating a balloon of a cardiac ablation catheter and managing pressure within the balloon during an ablation procedure, according to one embodiment of the present description. After the distal end of the cardiac ablation catheter according to embodiments herein has been advanced into the pulmonary vein of the patient, the outer balloon is inflated with fluid to a first pressure P1 atstep 3610. In various embodiments, P1 is in the range of 0.01 to 5 atm.

Instep 3612, pulmonary vein occlusion is recorded. In various embodiments, pulmonary vein occlusion is recorded radiologically, via ultrasound, or endoscopically. Optionally, no blockage is recorded at all. Unlike other treatment methods, if there is no occlusion, the ablation region will not have any effect, i.e., will not ablate tissue, because no backpressure is applied to the ablation region surface area. Without applying backpressure to the ablation zone surface, heat is transferred from the ablation zone surface area sufficiently that tissue ablation will not occur. Accordingly, in one embodiment, the present invention is directed to a method of ablating cardiac tissue, wherein without a backpressure exceeding a threshold on the ablation zone surface, heat transfer from the ablation zone surface area sufficient to cause ablation of the tissue will not occur.

Instep 3614, the inner balloon is inflated to a first volume V1. In various embodiments, air or CO is used₂Causing the inner balloon to expand. Steam is injected at 100 ℃ or higher to raise the temperature of the inner balloon to equal to or greater than 100 ℃, and instep 3616, the volume of the balloon is raised to a second volume V2. Then, instep 3618, the injection of steam is continued at 100 ℃ to raise the volume of the balloon to a third volume V3, wherein V3 is equal to or greater than V2, and V3 is maintained for a predetermined period of time T1, wherein T1 is sufficient to ablate a portion of the pulmonary vein, pulmonary vein ostium or atrium, or wherein T1 is between 1 second and 5 minutes. It will be appreciated that this step results in the formation of an ablation zone as described herein, as well as a transition zone located proximally and distally. The transition zone is a region at least partially defined by the surface of the outer balloon and adjacent (proximal, distal, or both) to the ablation zone, wherein the temperature of the surface region is equal to no greater than 95%, preferably no greater than 80%, even more preferably no greater than 60%, or any increment between 30% and 95% of the ablation zone temperature. An insulating region is a region at least partially defined by the surface of the outer balloon and adjacent (proximal, distal, or both) to the ablation region, where a material or fluid (including, but not limited to, gas, liquid, air, or CO)₂) Between the inner surface of the outer balloon and the outer surface of the inner balloon, resulting in a separation or gap between the heated surfaces of the inner and outer balloons. The gap or separation is the space enclosed by the outer balloon, defined by the distance between the inner surface of the outer balloon and the outer surface of the inner balloon, which is 0 in the ablation zone and greater than 0 outside the ablation zone.

Instep 3620, the pressure in the outer balloon is maintained between 0.01atm and 5 atm. Instep 3622, the flow of steam is stopped, allowing the steam to condense and the inner balloon to deflate to a volume V4, wherein V1 < V4 < V2/V3. Instep 3624, the fluid and water resulting from the condensation of the steam from the inner balloon are removed or aspirated to bring the volume of the inner balloon to the pre-inflation volume or < V1. The outer balloon is deflated to a pressure < P1 and instep 3626, reversal of pulmonary vein occlusion is optionally recorded. Instep 3628, the cycle is repeated in the same or separate pulmonary veins.

Fig. 36B is a flowchart of exemplary steps of a method of performing atrial fibrillation ablation, according to some embodiments of the present description. Instep 3630, a guidewire or pacing catheter is placed in the pulmonary vein of the patient. In various embodiments, the lumen of the pacing catheter or pacing guidewire is configured to eject contrast agent while the pacing catheter or guidewire occupies the lumen. In some embodiments, the pacing guidewire lumen has a diameter of 0.045 inches. Instep 3632, a double balloon catheter of the present description is placed in the pulmonary vein over a guidewire or pacing catheter. In various embodiments, a catheter is introduced and navigated to a treatment area via a femoral insertion site and includes a length sufficient to reach a pulmonary vein from the femoral insertion site. In some embodiments, the distal tip of the catheter has a specific angle from the left atrium to access the pulmonary veins. In various embodiments, the angle is in the range of 0 to 180 degrees. In some embodiments, the distal tip of the catheter is configured to deflect 180 degrees around a 1 inch radius. In another embodiment, the distal tip of the catheter is configured to deflect 180 degrees around a 2 inch radius. In some embodiments, the distal tip of the catheter is configured to deflect 150 degrees around a radius of 0.5 inches to 2.5 inches.

Now, instep 3634, the outer balloon of the dual balloon catheter is inflated with a barrier fluid such as carbon dioxide to occlude the pulmonary vein. In some embodiments, the inflated outer balloon is in physical contact with the entire pulmonary vein ostium. In other embodiments, the inflated outer balloon is in contact with a portion of the pulmonary vein ostium. In some embodiments, the pear-shaped balloon is configured to contact the pulmonary vein ostium. In some embodiments, the inflated outer balloon blocks at least a portion of the pulmonary vein 2-15mm distal to the pulmonary vein ostium. In some embodiments, the distance or physical gap between the inflated outer balloon and the uninflated inner balloon is in the range of 5-15mm before inflating the inner balloon. In some embodiments, there is a gap in the range of 0.1mm to 10mm between the proximal end of the inflated outer balloon and the uninflated inner balloon. In some embodiments, there is a gap of at least 5mm between the proximal end of the inflated outer balloon and the uninflated inner balloon.

Contrast is injected into the lumen to ensure that the outer balloon blocks the pulmonary veins. In one embodiment, pulmonary vein occlusion is recorded and confirmed radiologically. Then, instep 3636, the inner balloon of the double balloon catheter is inflated with steam or water vapor so that the inflated inner balloon contacts the inflated outer balloon at the ablation zone. In some embodiments, the inflated inner balloon contacts at least 2-15mm along the 360 degree circumference of the inflated outer balloon, wherein the outer balloon contacts the oral axial surface. In some embodiments, the contact between the inner balloon and the outer balloon is constant during treatment. In various embodiments, the inner balloon is disc-shaped or spherical. In some embodiments, the inner balloon is radiopaque. In some embodiments, the inner balloon comprises a barium coating. Subsequently, instep 3638, thermal energy is transferred from the inner balloon through the outer balloon to ablate the pulmonary vein, pulmonary vein ostia, or left atrium. Finally, instep 3640, the pulmonary veins are stimulated through the pacing catheter to record complete Pulmonary Vein Isolation (PVI). Instep 3641, after each treatment cycle, a sufficient amount of fluid is expelled from the inner balloon and the outer balloon is deflated to allow removal of the catheter.

Fig. 36C is a flow chart of exemplary steps of another method of performing atrial fibrillation ablation in accordance with some embodiments of the present description. Instep 3642, the right atrium of the patient's heart is accessed by venipuncture. Then, instep 3644, the left atrium of the patient's heart is accessed by transseptal puncture. Instep 3646, a guidewire or pacing catheter is placed in the pulmonary vein using fluoroscopic guidance. Instep 3648, a double balloon catheter of the present description is placed in the pulmonary vein over a guidewire or pacing catheter.

Now, instep 3650, the outer balloon of the dual balloon catheter is inflated with a barrier fluid such as carbon dioxide to occlude the pulmonary veins and expel blood in the left atrium out of the ablation site. In one embodiment, occlusion of the pulmonary vein is recorded and confirmed by a staining study. The pressure and volume of the inflated outer balloon are monitored. In one embodiment, the pressure of the inflated outer balloon is maintained below 5 atm.

Then, instep 3652, the inner balloon of the double balloon catheter is inflated with steam or water vapor so that the inflated inner balloon contacts the inflated outer balloon at the ablation zone. In some embodiments, contact of the inner and outer balloons at the ablation region is recorded and confirmed using fluoroscopy, 3D mapping, and/or endoscopy. In some embodiments, one or more sensors in the ablation zone are used to monitor contact of the inner and outer balloons. In embodiments, the temperature or pressure of the inner balloon is monitored.

Subsequently, instep 3654, thermal energy is transferred from the inner balloon through the outer balloon to ablate the pulmonary vein, pulmonary vein ostia, or left atrium. The temperature and pressure in the outer balloon are monitored to maintain the desired therapeutic value. Instep 3656, heat is delivered to the pulmonary vein, pulmonary vein ostium or left atrium for a first duration. In some embodiments, the first duration ranges from 5 seconds to 5 minutes.

Now, instep 3658, the pulmonary veins are stimulated through the pacing catheter to record the complete Pulmonary Vein Isolation (PVI). Optionally, instep 3660, theablating step 3656 is repeated (if needed), wherein heat is delivered for a second duration. In some embodiments, the second duration is in a range between 50% and 250% of the first duration.

Fig. 36D is a flow chart of exemplary steps of a method of performing left atrial appendage ablation according to some embodiments of the present description. Instep 3662, a guidewire or pacing catheter is placed in the left atrial appendage of the patient. Instep 3664, a double balloon catheter of the present description is placed in the left atrial appendage over a guidewire or pacing catheter.

Now, instep 3666, the outer balloon of the dual balloon catheter is inflated with a barrier fluid such as carbon dioxide to occlude the left atrial appendage. In one embodiment, occlusion of the left atrial appendage is recorded and confirmed radiologically. Then, instep 3668, the inner balloon of the double balloon catheter is inflated with steam or water vapor so that the inflated inner balloon contacts the inflated outer balloon at the ablation zone. Subsequently, instep 3670, thermal energy is transferred from the inner balloon through the outer balloon to ablate the left atrial appendage. Finally, instep 3672, the left atrial appendage is filled with a acellular matrix to promote cell growth and occlusion of the left atrial appendage. In one embodiment, the left atrial appendage is ablated using a third balloon distal to the double balloon. In another embodiment, a third balloon distal to the double balloon is inflated to expel blood out of the left atrial appendage. In yet another embodiment, the left atrial appendage is flushed with a fluid to drain blood from the left atrial appendage. In another embodiment, suction is applied into the occluded left atrial appendage to create a vacuum in order to better access the wall of the left atrial appendage with the ablation surface of the balloon.

Fig. 36E is a flow chart of exemplary steps of another method of performing left atrial appendage ablation according to some embodiments of the present description. Instep 3674, the right atrium of the patient's heart is accessed by venipuncture. Then, instep 3676, the left atrium of the patient's heart is accessed by transseptal puncture. Instep 3678, a guidewire or pacing catheter is placed in the left atrial appendage using fluoroscopic guidance. Instep 3680, a double balloon catheter of the present description is placed in the left atrial appendage over a guidewire or pacing catheter.

Now, instep 3682, the outer balloon of the dual balloon catheter is inflated with a barrier fluid, such as carbon dioxide, to occlude a portion of the left atrial appendage and to expel blood in the left atrial appendage from the ablation site. In one embodiment, occlusion of the left atrial appendage is recorded and confirmed radiologically by staining studies. The pressure and volume of the inflated outer balloon are monitored. In one embodiment, the pressure of the inflated outer balloon is maintained below 5 atm.

Then, instep 3684, the inner balloon of the double balloon catheter is inflated with steam or water vapor so that the inflated inner balloon contacts the inflated outer balloon at the ablation zone in the left atrial appendage. In some embodiments, contact of the inner and outer balloons at the ablation region is recorded and confirmed using fluoroscopy, 3D mapping, and/or endoscopy. In some embodiments, one or more sensors in the ablation zone are used to monitor contact of the inner and outer balloons. In an embodiment, the temperature of the inner balloon is monitored.

Subsequently, instep 3686, thermal energy is transferred from the inner balloon through the outer balloon to ablate the left atrial appendage. The temperature and pressure in the outer balloon are monitored to maintain the desired therapeutic value. Instep 3688, heat is delivered to the left atrial appendage for a first duration. In some embodiments, the first duration ranges from 5 seconds to 5 minutes.

Optionally, instep 3690, theablating step 3688 is repeated, wherein heat is delivered for a second duration. In some embodiments, the second duration is in a range between 50% and 250% of the first duration.

Now, instep 3692, the left atrial appendage is optionally filled with a acellular matrix. Finally, atstep 3694, tissue is allowed to grow inward into the acellular matrix to occlude the left atrial appendage. In another embodiment, a scaffold structure or scaffold is inserted into the left atrial appendage to promote re-epithelialization or tissue growth.

In some embodiments, the balloon catheter does not have an inner balloon, but rather includes a distal balloon for ablating the left atrial appendage, while a proximal balloon is used to occlude the ostium of the left atrial appendage. The distal and inner ablation balloons used for this application are compliant or semi-compliant balloons, comparable in stiffness to the outer balloon. In the double balloon configuration, a majority of the anterior hemisphere of the outer balloon occludes the left atrial appendage ostium.

Fig. 36F is a flow chart of exemplary steps of a method of performing vascular or bronchial ablation according to some embodiments of the present description. Instep 3695a, a guidewire is placed in a target vessel or organ (e.g., a pulmonary artery or lung) of the patient. Atstep 3695b, a balloon catheter of the present description is placed over the guidewire or endoscopically in the target organ.

Now, instep 3695c, the balloon of the balloon catheter is inflated with a barrier fluid, such as carbon dioxide, to obtain contact and occlusion with the target site. In one embodiment, occlusion of the target site is recorded and confirmed radiologically or by pressure monitoring in the balloon, wherein the pressure is maintained below 5 atm.

Then, instep 3695d, steam or water vapor is passed through the channels in the balloon wall to generate ablation in a desired pattern (such as those shown with reference to fig. 36A) in the target site or tissue. Optionally, in step 3695e, theablation step 3695d is repeated, if necessary.

Fig. 36I showsleft atrium 3601 depicting leftatrial appendage 3603 inwall 3605 ofleft atrium 3601. Fig. 36J illustrates a plurality of left

atrial appendages

3611, 3613, 3615, 3617 depicting various shapes of the left

atrial appendages

3611, 3613, 3615, 3617.

In various embodiments, blood is evacuated from the treatment area prior to beginning treatment with the ablation catheter of the present description to prevent coagulation of the blood. In some embodiments, during the ablation procedure, an amount of blood has been drained from the treatment region such that the treatment region defined as the region of cardiac tissue to be ablated is covered by less than 100mL of blood, preferably less than 75mL of blood, even more preferably less than 50mL of blood. In some embodiments, the treatment area has 25-100% of the blood removed prior to the ablation procedure.

In some embodiments, the ablation provided by the ablation catheter of the present description is configured to ablate a treatment region defined as having a width of 1 to 15mm, more preferably 5 to 10mm, and having a curved band shape extending around an inner surface of a pulmonary vein and including a pulmonary vein ostium.

In some embodiments, to manage the shape of the treatment region, the expandable member or outer balloon of the ablation catheters of the present description is configured to apply a pressure in the range of 0.01 to 5atm in the range of 0 to 10cm from the central axis of the catheter when fully expanded. In embodiments, where multiple balloons are provided, either balloon may be inflated first.

In an embodiment, the saline is delivered using a saline flow rate in the range of 1ml/min to 25 ml/min. In an embodiment, the power delivered to the electrodes to generate the steam is in the range of 10W to 800W. In an embodiment, the ablation is performed for a period of time in the range of 1 second to 600 seconds.

In an embodiment, at least 25% of the adjacent circumference of the pulmonary vein ostium or atrium surrounding the pulmonary vein is ablated, and at least 25% of the thickness of the left atrial wall or a portion of the pulmonary vein ostium or pulmonary vein is ablated.

Additionally, in various embodiments, the ablation catheters of the present description are configured to isolate non-target tissue and blood from excess heat. In some embodiments, during the procedure, tissue and/or blood outside the treatment area but within 5cm of the treatment area undergoes a temperature increase of no greater than 20 ℃, and tissue and/or blood at least 5cm from the treatment area undergoes a temperature increase of no greater than 10 ℃ for a duration of more than 10 seconds.

In various embodiments, the ablation therapy provided by the steam ablation system of the present description is delivered to achieve at least one of the following therapeutic goals or endpoints for cardiac ablation:

maintaining the tissue temperature at 1l0 ℃ or less;

Ablation of cardiac tissue without damage to esophageal tissue;

at least 10% of patients recover normal sinus rhythm for at least 1 week;

at least 10% of patients maintain normal sinus rhythm for at least 1 week;

a reduction in the number of atrial arrhythmia episodes by at least 5% relative to the number of atrial arrhythmia episodes prior to treatment;

a reduction in the number of supraventricular arrhythmia episodes by at least 5% relative to the number of supraventricular arrhythmia episodes treated;

a reduction in the number of ventricular arrhythmia episodes by at least 5% relative to the number of ventricular arrhythmia episodes prior to treatment;

an increase in esophageal mucosa temperature of less than 8 ℃ during or after treatment, or an esophageal mucosa temperature of less than 45 ℃ during or after treatment;

raising the temperature of a portion of cardiac tissue to greater than or equal to 60 degrees celsius along the circumference;

maintaining the epicardial temperature at or below 100 degrees celsius, the phrenic nerve temperature at or below 75 degrees celsius, and the esophageal temperature at or below 60 degrees celsius;

raising the temperature of 25% of the endocardium periphery to greater than or equal to 60 degrees celsius and maintaining the temperature for more than 10 seconds;

raising the temperature of 25% around the myocardium to greater than or equal to 60 degrees celsius and maintaining the temperature for more than 10 seconds;

In at least 25% of the treated patients, the number of arrhythmia episodes is reduced by at least 25% relative to the number of arrhythmia episodes prior to treatment;

a reduction in the need for a cardiac arrhythmia medication by at least 25% relative to the need for a cardiac arrhythmia medication prior to treatment by at least 25% of the treated patients;

at least 25% of treated patients recover normal sinus rhythm;

reducing the incidence of permanent phrenic nerve damage after ablation to less than or equal to 25%; and

reduce the incidence of permanent transesophageal injury to less than or equal to 25% after ablation;

ablating tissue to a depth of at least 25% of the adjacent perimeter and at least 25% of the adjacent thickness of the PV or left atrial wall.

Methods of using a dual balloon cardiac ablation catheter according to various embodiments of the present description can be broadly described under the tasks of positioning the catheter, occluding, pushing blood aside, creating an ablation zone, and finally monitoring with pacing. Fig. 36G is a flow chart illustrating exemplary steps under each of these tasks that may be performed to implement a process using a dual balloon cardiac ablation catheter in accordance with various embodiments of the present description. These steps are mentioned under each task and provide an exemplary method of use.

Positioning

Instep 36102, a contrast agent is injected intravenously to enhance real-time imaging of blood flow. Instep 36104, a guide, for example in the form of a wire, may be passed through the vascular system of the patient, into the heart, through the septum, and into the superior pulmonary vein. This wire serves as a guide for the subsequent catheter. Instep 36106, the sheath is guided through the rail. The purpose of the guide sheath is to provide a restricted path for the ablation catheter. The use of an introducer sheath may provide one dimension of steerability of the catheter and is therefore useful. The ablation catheter may be forced through the S-shaped path and, as it exits the other end, the distal tip may bend to provide steerability in a second dimension. Instep 36108, an ablation catheter is passed through the guide rail and into the guide sheath. When the distal tip of the ablation catheter is positioned within the chamber, just before the ostium of the Pulmonary Vein (PV) (and the guidewire is positioned within the PV), the guide sheath is retracted to expose the balloon.

Blocking of a vessel

Instep 36110, the outer balloon is inflated to a pressure in the range of 0.1 to 10psi, preferably 0.5 to 1 psi. Expansion above a given range may result in air or CO₂Back through the conduit via the outlet check valve. Instep 36112, the outer balloon is positioned into the ostium of the pulmonary vein by pushing using the guide sheath or guide shaft of the ablation catheter. Instep 36114, more contrast agent may be added to enhance real-time imaging. Contrast imaging may help determine whether the outer balloon is in the correct position and whether blood flow is effectively blocked. An image with a predefined color (e.g., white or black) may confirm the absence of blood. If there are radiopaque markers on the surface of the outer balloon or catheter according to some embodiments of the present description, visualization of the occlusion under fluoroscopy is allowed. The marker may be located anywhere. In some embodiments, the marker is located on a proximal portion of the catheter (where the balloon is attached proximally to the catheter), on a distal portion of the catheter (where the balloon is attached distally to the catheter), or along the length of the catheter between these two points and on the outside of the outer balloon. In one embodiment, the marker ring extends around a location where an ablation zone may be present. In one embodiment, occlusion of the pulmonary vein is recorded and confirmed by radiology.

Push blood away

Instep 36116, the guide rails are removed and replaced with a mapping catheter. The mapping (monitoring) catheter is an elongated wire with a loop at the end of the wire configured to sense electrically active cells. In some embodiments, a pacing catheter is used in place of a mapping catheter. The monitoring catheter passively detects the electrical signal. Pacing catheters provide electrical pulses (pacing pulses) and monitor how the signals propagate through the pulmonary veins. In both cases, the goal is to determine whether ablation successfully produced electrical insulation. In an alternative approach, the mapping/pacing electrodes are configured to be deployed from the tip of the ablation catheter. The guide rail can be moved through the ablation catheter tip and then retracted. While retracting the guide rail, the guide rail hooks the mapping/pacing electrode and causes it to deploy.

Creating an ablation zone

Once the guide sheath, ablation catheter, and mapping/pacing catheter are in place and the outer balloon is inflated, the inner balloon is inflated atstep 36118. The physician or any other person operating the system according to the present description may trigger inflation of the inner balloon by pressing a switch, button or pedal. In response, some amount of air or CO may be provided₂To partially inflate the inner and/or outer balloons. If both are expanded, they may be expanded simultaneously or sequentially. In some embodiments, the outer balloon is inflated to a pressure in the range of 0.1 to 10 psi. In some embodiments, the inner balloon is inflated to a pressure in the range of 0.5 to 20psi, preferably in the range of 2.5 to 3.5 psi. In embodiments, the pressure within the inner balloon is always greater than the pressure of the outer balloon during the ablation step. In an embodiment, the outer balloon is 3 to 75cc larger in volume than the inner balloon, and there are air gaps on the distal and proximal ends between the outer balloon and the inner balloon. The air gap provides an insulating zone distal and proximal to the ablation zone. In an embodiment, the distance of the exclusion zone is in the range of 0.01mm to 20 mm.

Once the inner balloon is inflated, the generator activates the pump, which pushes saline (0.9% saline) through the catheter and into the ablation catheter. The amount of saline pushed is sufficient to first wet the electrodes, but insufficient to fill the inner balloon. The RF electrode is then activated to heat the saline. Water vapor enters the inner balloon and passes the CO through the one-way check valve₂Pushing out the inner balloon. Due to the inflow of water vapor, the inner balloon inflates further and forms a particularly defined ablation zone with the outer balloon. The ablation zone being a surface area of the outer balloonA portion that, upon contact with tissue, reaches a temperature sufficient to cause ablation of the tissue. The temperature of the outer balloon surface outside the ablation zone may be in the range of 37 to 60 c, preferably in the range of 37 to 40 c, while the temperature in the ablation zone may be in the range of 80 to 150 c, preferably in the range of 90 to 110 c. In an embodiment, the ablation zone surface area is less than 50% of the outer balloon surface area and at least 5% of the outer balloon surface area. In some embodiments, at least 25% of the outer balloon surface area is within the ablation zone.

In step 13120, water vapor is generated for a predefined period of time. The time period may be predefined to be in the range from a few seconds to a few minutes. In some embodiments, the range is 15 seconds to 2 minutes. In one embodiment, the time period is defined as 20 seconds. After a predefined period of time, the system shuts down and stops the production and supply of water vapor. The therapeutic endpoint used to define the period of time for the emission of the vapor is the point at which the endothelium is raised above 85 ℃, or the temperature of a portion of the outer surface of the atrium is raised to 45 ℃ or greater, or pacing is interrupted for more than 2 seconds, preferably permanent pacing. For safety purposes, it is preferred that the temperature is raised to less than 10% above the esophageal temperature for no more than 1 minute. Once the therapeutic, safety or time endpoint is reached, the electrodes are first turned off, and then the saline is turned off. In some embodiments, the generator uses 60W of power to operate the steam and supply the brine. The wattage may be increased or modified depending on the electrode. In some embodiments, the temperature of the water vapor may be controlled based on the flow rate of the brine. As a result, if the brine flow rate is low, the energy level is adjusted and reduced to prevent low impedance faults.

The saline flow rate may also depend on the size of the electrode, including the length, width and periphery of the electrode; and the power supplied. The generation of water vapor causes thermal energy to be transferred from the inner balloon through the outer balloon to ablate the target tissue. In some embodiments, contact of the inner and outer balloons at the ablation region is recorded and confirmed using fluoroscopy, 3D mapping, and/or endoscopy. In some embodiments, one or more sensors in the ablation zone are used to monitor contact of the inner and outer balloons. In an embodiment, the temperature of the inner balloon is monitored. During and between ablations, the temperature and pressure in the outer balloon are monitored to maintain the desired therapeutic value.

Instep 36122, the electrodes/saline are turned off, causing the inner balloon to collapse almost instantaneously. In some embodiments, CO may be automatically injected at this point₂To maintain volume or pressure in the outer balloon. The volume of the outer balloon is maintained such that the ablation step (if needed) is repeated, wherein heat is delivered for a second duration. In some embodiments, the second duration is in a range between 50% and 250% of the first duration. In one embodiment, the inner balloon is configured to reduce in volume without applying negative pressure after terminating RF energy to the electrode and/or saline flow. In one embodiment, the outer balloon is configured to automatically receive fluid (e.g., CO) after termination of the electrode/saline₂) Without measuring pressure, temperature or volume changes.

Monitoring by pacing

In step 13224, ablation success is confirmed by mapping/pacing. The mapping catheter passively detects electrical signals. Pacing catheters provide electrical pulses (pacing pulses) and monitor how signals propagate through the pulmonary veins. In both cases, the objective is to determine whether ablation successfully produced electrical insulation.

In step 13226, the ablation catheter is recapped and positioned aside. The guide rails are then repositioned to different pulmonary veins so that the entire process is repeated as necessary.

In some embodiments, another balloon other than the two balloons (inner and outer) is used for ablation. Referring now to fig. 36H, theelongate catheter body 36212 has a proximal end, a distal end, anouter catheter 36215, and aninner catheter 36250. A handle is disposed at the proximal end ofbody 36212. In some embodiments, theouter conduit 36215 and theinner conduit 36250 are coaxial. In an alternative embodiment, theouter duct 36215 and theinner duct 36250 are eccentric. In another embodiment, theouter catheter 36215 and theinner catheter 36250 are replaced with MLEs. In one embodiment, the configuration of the different system components of fig. 36H are similar to those described in the context of fig. 26A-26O. For the sake of brevity, similar components are not described again here.

The configuration of fig. 36H has an additional element in the form of asecond balloon 36290 at thedistal end 36280 of thecatheter device 36210. Fig. 36D discusses a flowchart of various exemplary steps of a method of performing left atrial appendage ablation (LAA) according to some embodiments of the present description. The embodiment of fig. 36H is used in the process described in fig. 36D. In an embodiment, thesecond balloon 36290 is configured for ablation, similar to theinner balloon 36265. The two

balloons

36290, 36265 may be operated simultaneously or in any particular order. Thesecond ablation balloon 36290 is inflated to a pressure between 0.5 and 10psi and is an elongate balloon to fit the LAA anatomy. Thesecond ablation balloon 36290 is between 5mm and 25mm in diameter and between 20mm and 50mm in length. Thesecond ablation balloon 36290 may be operated using the same lumen as the inner balloon, or have a separate lumen to operate.Second balloon 36290 is a more compliant material thaninner balloon 36265. Thus, while the inner balloon may have a radial expansion of less than 10% at 1 atmosphere, thesecond balloon 36290 may have a radial expansion in the range of 10-25% at 1 atmosphere. In addition to the ablation performed by theinner balloon 36265 and theouter balloon 36260, thesecond balloon 36290 is inflated with an ablative agent to ablate a portion of the LAA. Which in combination with the ablation function may achieve a reduction in the size of the LAA lumen of greater than or equal to 5%. In various embodiments, up to a 10%, 20%, or 25% size reduction may be achieved by a combined ablation of the dual balloon arrangement and thesecond balloon 36290.

Example case study

In one exemplary pathology study, multiple ablative surgeries were performed on frozen swine hearts. The ablation procedure was performed using a dual balloon cardiacablation test catheter 3700, as shown in fig. 37A-37C. Referring now to fig. 37A-37C, acatheter 3700 includes anelongate body 3712 having aproximal end 3701, adistal end 3720, and a plurality of lumens.

The insufflation port 3720 (at the proximal end of the elongate body 3712) is in fluid communication with an inflatableouter balloon 3760 attached to the distal end of the elongate body via a cooling fluid injection lumen and a cooling fluid suction lumen. During operation, a cooling fluid pump in data communication with and controlled by the controller enables a cooling fluid (such as, but not limited to, water, air, or carbon dioxide) to be pumped into and out of theouter balloon 3760 through the cooling fluid infusion lumen and the cooling fluid suction lumen.

The steam port 3725 (at the proximal end of the elongate body 3712) is in fluid communication via a steam lumen with an inflatableinner balloon 3765 attached to the distal end of the elongate body and located within theouter balloon 3760. During operation, a steam pump, also in data communication with and controlled by the controller, enables steam to be injected into theinner balloon 3765 via a plurality of steam injection ports on theelongate body 3712 located within theinner balloon 3765, causing theinner balloon 3765 to inflate and contact the inflatedouter balloon 3760 adjacent the ablation region, creating a hot zone on theouter balloon 3760. Aguidewire 3730, as shown in fig. 37C, is inserted through the proximal opening of the guidewire lumen to enable positioning of the

balloons

3760, 3765 for ablation.

Fig. 37D shows ablation in afrozen pig heart 3740 using acatheter 3700. When both balloons 3760, 3765 are fully inflated, the hot zone on the surface of theouter balloon 3760 approaches a temperature in the range of 98 to 102 degrees celsius. Multiple atrial ablation treatments were performed due to the loss of pulmonary veins, with the following results:

a 20 second treatment results in a treatment depth of approximately 1mm (i.e., tissue ablation to a depth of 1 mm).

A 30 second treatment results in a treatment depth of about 1.75 mm.

Two 15 second treatments resulted in a treatment depth of approximately 1 mm.

Two 20 second treatments resulted in a treatment depth of approximately 2 mm.

During any ablation treatment, theouter balloon 3760 does not stick to the target tissue. Fig. 37E shows circumferential ablated tissue 3770 (lighter colored tissue) resulting from ablationtreatment using catheter 3700.

In another ablation treatment, the

inflated balloons

3760, 3765 are placed inside the atrial appendage to produce a 30 second ablation (until a white discoloration of the tissue can be seen). This results in full thickness ablation of the target tissue, stiffening of the wall, and collagen denaturation (at about 70 degrees celsius). During treatment, the surface temperature of theouter balloon 3760 is in the range of 85 to 100 degrees celsius.

In addition, a macroscopic evaluation of the ablated circle is performed on a plurality of animal source samples. In all cases, ablations were identified as greater than 75% of the circumference, with ablations of the remaining tissue greater than 50%. At least three defined tissue sections were used for microscopic evaluation. This assessment was scored by the following ablation-related degree of coagulation (necrosis/coagulation) according to the following scale shown in table 3, reflecting ablation success rate:

TABLE 3

0	Is absent from
		1	Affects up to 25% of RSPV/left atrial myocardium wall thickness;minimum size
2	Affects RSPV/left atrial myocardium wall thickness between 26% and 50%; is slight
		3	Affecting RSPV/left atrial myocardium wall thickness between 51% and 75%; moderate inquality
4	Affects over 76% of RSPV/left atrial myocardium wall thickness; is remarkable in

In the sampled animals, ablation success rates of 45 seconds and 60 seconds were found to be highest. Only one 45 second attempt has not been the most successful due to technical failure. The results are provided in table 4 provided below.

TABLE 4

The data collected in the above study showed that the ablated scars grew on the surviving animals for approximately 48 hours, indicating that the scores shown in table 4 would be closer to complete success in real life.

Fig. 38 shows anothertest catheter 3800 for performing ablation in a frozen porcine heart according to some embodiments of the present description. Thecatheter 3800 has an elongatedbody 3812 with a proximal end, a distal end, and a water/steam lumen 3815. Aninflated balloon 3860 is attached to the distal end of thebody 3812. Theballoon 3860 is in fluid communication with thelumen 3815 via a plurality of steam injection ports formed in a portion of thebody 3812 located within theballoon 3860.

At least one flexible heating chamber 3830 (such as those described with reference to fig. 19A-19D) including a plurality ofelectrodes 3835 is positioned inline within thelumen 3815. During operation, a water/steam pump in data communication with and controlled by the controller pumps water/saline from the sterile saline reservoir through thelumen 3815 into the proximal end of the at least oneflexible heating chamber 3830. The at least oneflexible heating chamber 3830 converts the water/saline to steam, which exits through the at least one steam injection port to inflate theballoon 3860. The steam inflatedballoon 3860 enables ablation of the target tissue in the vicinity of theballoon 3860.

Fig. 39 showscatheter 3900 according to some embodiments of the present description.Catheter 3900 has anelongate body 3912, a proximal end, and a distal end. The proximal end of thebody 3912 has aninlet 3930 for awater vapor conduit 3925. The distal end of thebody 3912 has anoutlet 3935 for water/saline. Aninflatable balloon 3960 is mounted near the distal end of thebody 3912. Thebody 3912 has alumen 3920 and a plurality ofports 3925 within theballoon 3960. Awater vapor conduit 3925 is introduced intolumen 3920 viainlet 3930.

Transarterial steam ablation

Fig. 40 illustrates a trans-arterialsteam ablation catheter 4000 according to some embodiments of the present description. Thecatheter 4000 has an elongatedbody 4012 having a proximal end and a distal end.Cable 4050 provides electrical power athandle 4025 at the proximal end ofmain body 4012. A positioning or occlusion element (e.g., inflatable balloon 4060) is attached near the distal end of theelongate body 4012. Theinflatable balloon 4060 is in fluid communication with the balloon inflation/deflation port 4020 at thehandle 4025 via a first lumen. During operation, a fluid pump in data communication with and controlled by the controller enables fluid (such as, but not limited to, water, air, or carbon dioxide) to be pumped into and out ofballoon 4060 through the first lumen.

At least onevapor delivery port 4030 is located at the distal end of themain body 4012 and the distal end of theballoon 4060. Thevapor delivery port 4030 is in fluid communication with thesaline port 4035 at thehandle 4025 via a second lumen. In some embodiments, at least one flexible heating chamber 4040 (such as those described with reference to fig. 19A-19D) including a plurality ofelectrodes 4042 is positioned in-line within the second lumen. During operation, the water/steam pump, which is also in data communication with and controlled by the controller, pumps water/saline from the sterile saline reservoir through the second lumen into the proximal end of the at least oneflexible heating chamber 4040. The at least oneflexible heating chamber 4040 converts the water/saline to steam, which exits through thesteam delivery port 4030 to ablate the target tissue in the vicinity of theport 4030.

In some embodiments, the at least oneflexible heating chamber 4040 is positioned in-line within the second lumen such that the proximal end of theheating chamber 4040 is proximal to the proximal end of theballoon 4060 and the distal end of theheating chamber 4040 is distal to the distal end of theballoon 4060. In other words, in some embodiments, the proximal and distal ends of theheating chamber 4040 extend beyond the respective proximal and distal ends of theballoon 4060. In some embodiments, the at least oneflexible heating chamber 4040 is positioned in-line within the second lumen such that the plurality ofelectrodes 4042 are at least partially within theballoon 4060.

Fig. 41A is a flow chart of exemplary steps of a method of performing trans-arterial steam ablation of a tumor, according to some embodiments of the present description. Instep 4105, a trans-arterial steam ablation catheter, such ascatheter 4000 of fig. 40, is placed in an artery supplying blood to the tumor. Fig. 41B illustrates deployment of a catheter 4000 (of fig. 40) into anartery 4106 supplying blood to atumor 4107 in aliver 4108 according to one embodiment of the present description.

Instep 4110,balloon 4060 ofcatheter 4000 is inflated to occlude blood flow intoartery 4106. Optionally, instep 4115, a radiopharmaceutical dye is injected to obtain an arterial map to check for accurate placement of the catheter, to obtain a perfusion scan of thetumor 4107 and to highlight tumor vessels. Instep 4120, steam is administered to ablate thearteries 4106 supplying blood to thetumor 4107 and the adequacy of the ablation is determined by measuring the degree of washout of the radiopharmaceutical dye from the tumor vessels. Optionally, instep 4125, a radiopharmaceutical dye is injected to obtain an arteriography or perfusion scan to check for adequacy of ablation. The steam ablation ofstep 4120 is repeated if necessary.

Optionally, instep 4130, chemotherapy, embolization, or radioactive agents are administered in conjunction with steam ablation. Optionally, instep 4135, the pressure inartery 4106 is maintained below 5 atm. In one embodiment, the liquid CO is blown in before the steam is blown in₂To replace the blood. In another embodiment, the carbonate water is used to produce steam and CO simultaneously₂To ablate the artery. The above-described devices and methods may be used to ablate arteries, veins, or cardiac stenoses such as the left atrial appendage.

Fig. 42A illustrates amapping member 4200 in a looped configuration according to some embodiments of the present description. Themapping member 4200 includes a semi-flexible, elongated guide wire orcatheter 4201 having a plurality ofelectrodes 420 located on the guide wire orcatheter 4201. Themapping member 4200 is configured in a ring or lasso ring shape.

Fig. 42B illustrates a flexibleannular mapping member 4210 extending from the distal end of adual balloon catheter 4215, according to some embodiments of the present description. Themapping member 4210 includes a flexible guidewire orcatheter 4211 having a plurality ofelectrodes 4212 and extends distally away from an outer surface of theouter balloon 4217.

Due to the short length of excitable tissue in the pulmonary vein, the distance of the mapping member from the ablation zone is too large, possibly resulting in difficulty in pacing or sensing while ablating. Thus, in some embodiments, the mapping member is configured to be positioned such that the pace/sense electrodes are closer to the ablation zone, near the upper hemisphere of the outer balloon. Fig. 42C illustrates aflexible mapping member 4230 according to some embodiments of the present description, including a flexible guidewire orcatheter 4231 havingvertical rings 4233 andhorizontal rings 4234 with a plurality ofelectrodes 4232 on the guidewire orcatheter 4231. In an embodiment, theelectrodes 4232 are positioned on thehorizontal ring 4234. The vertical ring has a first diameter D1, which in some embodiments ranges from 5mm to 20 mm. The horizontal ring has a second diameter D2, which in some embodiments ranges from 10mm to 40 mm. In some embodiments, diameter D1 is equal to about half of diameter D2. The configuration of themapping members 4230 allows a user to pull thehorizontal ring 4234 over the upper hemisphere of the outer balloon (or "anterior" of the catheter) to enable pacing and sensing near the ablation region.

Fig. 42D illustrates aflexible mapping member 4240 according to some embodiments of the present description, including a flexible guidewire orcatheter 4241 havingvertical rings 4243 andhorizontal rings 4244 with a plurality ofelectrodes 4242 on the guidewire orcatheter 4241 extending from the distal end of adouble balloon catheter 4245. In an embodiment, theelectrodes 4242 are positioned on thehorizontal ring 4244. In an embodiment, the mapping member is slowly retracted to pull thehorizontal ring 4234 over the "anterior" of thecatheter 4245 or upper hemisphere of theouter balloon 4247, thereby accessing theablation zone 4249. Theouter balloon 4247 has a spherical shape.

Fig. 42E illustrates aflexible mapping member 4250 according to some embodiments of the present description, comprising a flexible guidewire orcatheter 4251 having avertical ring 4253 and ahorizontal ring 4254 with a plurality ofelectrodes 4252 on the guidewire orcatheter 4251, pulled down onto the distal end of adual balloon catheter 4255. In an embodiment, theelectrodes 4252 are located on thehorizontal ring 4254. In an embodiment, the mapping member is slowly retracted to pull thehorizontal ring 4254 over the "anterior" of thecatheter 4255 or upper hemisphere of theouter balloon 4257 to access theablation zone 4259. Theouter balloon 4257 has a pear shape, allowing theelectrodes 4252 of the horizontal ring 2554 to approach theablation zone 4259.

The above examples are merely illustrative of many applications of the system of the present invention. Although only a few embodiments of the present invention have been described herein, it should be understood that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the present invention. Accordingly, the present examples and embodiments are to be considered as illustrative and not restrictive, and the invention may be modified within the scope of the appended claims.

Claims

1. A system for ablating cardiac tissue, comprising:

a catheter adapted to be positioned adjacent cardiac tissue of a patient, wherein the catheter comprises:

a distal end;

a proximal end;

a first lumen;

a second lumen comprising a heating element;

an inner balloon positioned at the distal end of the catheter and in fluid communication with the second lumen; and

an outer balloon positioned at the distal end of the catheter and surrounding the inner balloon, wherein the outer balloon is in fluid communication with a first fluid source via the first lumen, and wherein an ablation region is formed at a contact area of the inner balloon and the outer balloon when the outer balloon is inflated with a first fluid and the inner balloon is inflated with heated steam; and

A controller, wherein the controller comprises program instructions that when executed result in:

the first fluid is to be injected into the outer balloon; and

a second fluid will be directed through the second lumen and placed in contact with the heating element to form a heated vapor.

2. The system of claim 1, wherein the outer balloon is not fixedly attached to the inner balloon in the contact area.

3. The system of claim 1, wherein a contour of the surface region of the ablation region is a function of and dependent on a portion of a pulmonary vein of the patient.

4. The system of claim 1, wherein the ablation region is defined by a surface area, and wherein the surface area ranges in size from 5% to 95% of the surface area of at least one of the inner balloon or the outer balloon.

5. The system of claim 1, wherein the ablation region has a width in a range of 1mm to 20 mm.

6. The system of claim 1, wherein the first fluid is air or CO₂。

7. The system of claim 1, wherein the second fluid is brine or carbonate, the heated steam is water steam, and the heated steam has a temperature of at least 100 ℃.

8. The system of claim 1, wherein the heating element is flexible and comprises a plurality of electrodes positioned within the second lumen.

9. The system of claim 8, wherein the heating element is defined by a distal end, and wherein the distal end is positioned at a distance in the range of 0mm to 80mm from the proximal end of the outer balloon.

10. The system of claim 1, wherein the heating element comprises a plurality of electrodes configured to receive an electrical current activated by the controller.

11. The system of claim 10, wherein each electrode of the plurality of electrodes comprises at least one edge adapted to be exposed to fluid present in the second lumen.

12. The system of claim 1, further comprising one or more insulating regions, wherein each of the one or more insulating regions is defined by a surface area of the outer balloon proximal or distal to the ablation region, and wherein an average temperature of each of the one or more insulating regions is less than an average temperature of the ablation region.

13. The system of claim 12, wherein each of the one or more insulating regions has a width of at least 0.1mm and extends along a curved length in a range of 1mm to a circumference of the outer balloon.

14. The system of claim 1, wherein the inner balloon is configured to be movable within the outer balloon along a horizontal longitudinal axis, and the catheter further comprises a mechanism configured to move the inner balloon within the outer balloon.

15. The system of claim 1, wherein the controller further comprises program instructions that, when executed, cause the outer balloon to be inflated to a first pressure and maintained at the first pressure during ablation.

16. The system of claim 15, wherein the controller further comprises program instructions that, when executed, cause the inner balloon to be inflated to a second pressure during ablation, wherein the first pressure is equal to or less than the second pressure.

17. The system of claim 15, wherein the first pressure is between 0.01atm and 5atm, preferably between 0.1atm and 5atm, or any range or increment therein.

18. The system of claim 1, further comprising one or more pressure valves in fluid communication with the first lumen, wherein each of the one or more pressure valves is configured to control movement of fluid into or out of the outer balloon based on a predetermined pressure level.

19. The system of claim 1, wherein the controller further comprises program instructions that, when executed, cause the ablation zone to remain for a period of between 1 second and 5 minutes.

20. The system of claim 1, further comprising a mapping member positioned at the distal end of the catheter and configured to map an area of cardiac tissue responsible for an arrhythmia, wherein the mapping member comprises a plurality of sensors, detectors, or electrodes.

21. The system of claim 20, wherein the mapping member includes a range of 1 to 64 electrodes configured to record signals from or pacing in a pulmonary vein.

22. The system of claim 1, further comprising at least one sensor, wherein the at least one sensor is positioned at the distal end of the catheter or the proximal end of the catheter.

23. The system of claim 22, wherein the sensor comprises a temperature sensor configured to monitor delivery of thermal energy to cardiac tissue.

24. The system of claim 22, wherein the sensor comprises a pressure sensor configured to measure a pressure inside the inner balloon.

25. The system of claim 1, wherein the outer balloon is defined by a pear shape and is configured to be positioned in a pulmonary vein of a patient to occlude the pulmonary vein.

26. The system of claim 1, wherein the outer balloon has an axis that extends along a length of the outer balloon and through a center of the outer balloon when inflated, and wherein a distance from the axis to an outer surface of the outer balloon varies along the length.

27. The system of claim 1, wherein, upon inflation, the shape of the outer balloon is definable by a first distance from a central axis of the outer balloon to a first proximal point on an outer surface of the outer balloon, a second distance from the central axis to a second proximal point on the outer surface of the outer balloon, a third distance from the central axis to a third point on the outer surface of the outer balloon, a fourth distance from the central axis to a first distal point on the outer surface of the outer balloon, and a fifth distance from the central axis to a second distal point on the outer surface of the outer balloon, wherein each of the first proximal point, the second proximal point, the third point, the first distal point, and the second distal point are sequentially located and extend distally along a length of the central axis from a proximal location, wherein the second distance is greater than the first, third, and fifth distances, and wherein the fourth distance is greater than the first, second, third, and fifth distances.

28. The system of claim 1, wherein the inner balloon has a spherical, oval, conical, disc, elliptical, rectangular prism, or triangular prism shape.

29. The system of claim 1, wherein the outer balloon is characterized by at least one first radial length when inflated extending from a center point on an axis extending longitudinally along the catheter and through the outer balloon to a point on a surface of the outer balloon, wherein the inner balloon is characterized by at least one second radial length when inflated extending from a center point on an axis extending longitudinally along the catheter and through the inner balloon to a point on a surface of the inner balloon, and wherein the at least one first radial length is different than the at least one second radial length.

30. The system of claim 1, wherein the ablation region has a width and a curved length defined by a degree of contact between the outer balloon and cardiac tissue when the inner and outer balloons are inflated.