US20180200497A1 - Catheters, catheter systems, and methods for puncturing through a tissue structure and ablating a tissue region - Google Patents

Abstract

A percutaneous catheter system for use within the human body and an ablation catheter for ablating a selected tissue region within the body of a subject. The percutaneous catheter system can include two catheters that are operatively coupled to one another by magnetic coupling through a tissue structure. The ablation catheter can include electrodes positioned within a central portion. The ablation catheter is positioned such that the central portion of a flexible shaft at least partially surrounds the selected tissue region. Each electrode of the ablation catheter can be activated independently to apply ablative energy to the selected tissue region. The ablation catheter can employ high impedance structures to change the current density at specific points. Methods of puncturing through a tissue structure using the percutaneous catheter system are disclosed. Also disclosed are methods for ablating a selected tissue region using the ablation catheter.

Description

CLAIM OF PRIORITY
• This application is a continuation of U.S. patent application Ser. No. 15/819,726, filed on Nov. 21, 2017, which is a continuation of U.S. patent application Ser. No. 14/400,455, filed on Nov. 11, 2014, now U.S. Pat. No. 9,861,802, which is a National Phase of PCT/US2013/031252, filed on Mar. 14, 2013 and claims benefit of Provisional Patent Application No. 61/681,552, filed on Aug. 9, 2012, which are all relied upon and incorporated herein in their entirety by reference.
FIELD
• This invention relates to percutaneous catheter systems and ablation catheters. More particularly, this invention relates to percutaneous catheter systems for puncturing through a tissue structure within the body of a subject and to ablation catheters for ablating a selected tissue region within the body of a subject.
BACKGROUND
• Atrial fibrillation can be treated by isolating portions of the atria. Such isolation of the atria can be done by open-heart surgery (e.g., a modified Maze procedure) or, most commonly, by a trans-venous catheter technique. In the majority of cases, the doctor cauterizes the left atrial muscle tissues using radiofrequency ablation techniques, with the ablation lesion targeting and/or circumscribing the pulmonary veins. Isolation of these anatomic portions of atria prevents the electrical propagation of the arrhythmia into the remainder of the atria. The operator places electrophysiologic catheters into the right heart. Under fluoroscopic guidance, a catheter is advanced adjacent to the atrial septum. In most cases, a puncture of the atrial septum (right to left) is made with a specialized needle catheter. A guide-wire is then advanced into the left atrium.
• The trans-septal catheter is removed and a guide catheter is delivered over the wire into the left atrium. An ablation catheter is then advanced into the left atrium under fluoroscopic guidance. Typically, electrophysiologists use additional imaging and mapping technology to improve safety and efficacy of the procedure, such as intercardiac ultrasound, cardiac CT, or non-contact mapping systems. Once the ablation/mapping catheters are in the left atrium, the operator delivers radiofrequency energy to the target sites. The operator moves the ablation catheter in a point-by-point fashion connecting the lesions to effectively electrically isolate the pulmonary veins from the rest of the atrium.
• These known procedures typically take 3-6 hours to complete. The procedural success varies between operators and patient selection (success rate is between 50-85% for a single attempt). A substantial minority of patients requires subsequent ablation procedures to “touch up” the prior ablation site. The cost of these procedures is highly variable and increases substantially with duration of procedure and the addition of adjuvant imaging/mapping technology. The current procedures are associated with a 5-6% risk of procedural complications, including a 1/200 risk of stroke due to the need to instrument (i.e., place one or more medical devices into) the left atrium. Other concerning complications include cardiac perforation, tamponade, pulmonary vein stenosis, and atrial-esophageal fistula. Despite attempts to simplify and streamline the procedure, the anatomic variations of the left atrium and pulmonary veins have limited the utility of alternative ablation techniques.
• Known epicardial techniques for atrial fibrillation also have various limitations. For example, most current epicardial ablation strategies require the operator to blindly navigate recesses of the pericardial space with an ablation catheter, and reflections of the pericardial anatomy pose an obstacle to delivery of a singlecontiguous lesion30 using these techniques. (See the broken line inFIG. 1.) Thus, the pericardial anatomy greatly limits the efficacy and technical ease of current pericardial/epicardial catheter-based procedures.
• Although the membranous reflections of the pericardial space that must be breached are very thin and relatively avascular, the angle, spatial limitations, and relative orientation of the surgical access point to the adjacent pericardial reflections do not facilitate simple puncture with a blunt catheter or a standard needle. Moreover, the large vessel and cardiac chambers adjacent to the pericardial reflections make the proposition of blind puncture with conventional catheters very risky.
• Currently known cardiac ablation catheters typically require frequent repositioning and/or advanced noncontact mapping techniques to identify incomplete segments in the ablation lesion. For epicardial techniques performed from the pericardial space, such manipulation is fraught with danger and technical limitations. Standard unipolar applications require an externalized grounding pad that results in a diffuse or spherical virtual electrode. Current bipolar ablation techniques utilize electrode pairs that are in close proximity, require the use of cumbersome equipment, and often require entry into both the pericardium and the left atrial blood pool.
• Accordingly, there is a need in the pertinent art for devices, systems, and methods for efficiently and reliably locating and puncturing pericardial reflections. There is a further need in the pertinent art for devices, systems, and methods for delivering a single contiguous lesion within the pericardial space without the need for repositioning of equipment.
SUMMARY
• Described herein is a percutaneous catheter system including first and second catheters. Each catheter can include a longitudinal axis, a longitudinal length, a proximal portion, and a distal portion. The distal portion of each catheter defines a distal end of its respective catheter. Each catheter defines at least one lumen extending from an opening of the distal end of the catheter toward the proximal portion of the catheter along the longitudinal length of the catheter. Each catheter has a magnet assembly positioned proximate the distal end of the catheter and operatively coupled to the distal portion of the catheter. Optionally, the magnet assembly of each respective catheter can be permanently and/or fixedly attached to a flexible extension mounted within a lumen of the catheter. The magnet assembly of the first catheter is configured for magnetic coupling to the magnet assembly of the second catheter such that the longitudinal axis of the first catheter is substantially axially aligned with the longitudinal axis of the second catheter. The magnet assemblies of the first and second catheters can be configured for magnetic coupling to one another through a tissue structure, such as, for example, a pericardial reflection.
• Methods of puncturing through a tissue structure are also described. In exemplary methods, the percutaneous catheter system can permit an operator to deliver a guidewire around target structures, thereby facilitating the deployment of an over-the-wire ablation catheter system. The catheter systems provide means for delivering a single isolating lesion around the pulmonary veins using a subxiphoid pericardial access point. The circumscribing lesion can be produced by any currently known energy sources, including radiofrequency (RF), cryoablation, electroporation, microwave, laser, and ultrasound energy sources. However, the circumscribing lesion can also be produced by a non-energetic ablation.
• In exemplary methods, extended bipolar application of high voltage ultra short direct current impulses (HVUS-DCI) are used. These impulses produce brief but extremely strong electric fields within the tissue leading to irreversible electroporation (IE), cell death, and injury. However, it should be noted that the total energy applied is relatively low averaging (estimated range 0.025J to 45J per pulse). At these energy levels there is very little tissue heating. Thus the mechanism of tissue injury is non-thermal; this is in contrast to RF ablation, which produces thermal tissue ablation through resistive heating.
• Also described herein is an ablation catheter for ablating a selected tissue region. The ablation catheter can have a flexible elongate shaft and a plurality of electrodes spaced along a longitudinal length of the flexible elongate shaft. The flexible elongate shaft has a longitudinal axis, a longitudinal length, a proximal portion, a central portion, and a distal portion, with the central portion being positioned between the proximal portion and the distal portion along the longitudinal length of the flexible elongate shaft. The elongate shaft can also define a primary lumen (and, optionally, one or more secondary lumens) of the ablation catheter. The plurality of electrodes can be positioned exclusively within the central portion of the elongate shaft. The electrodes can be separated by high impedance structures. The flexible elongate shaft can be selectively positioned within the body of a subject such that the central portion of the elongate shaft at least partially surrounds the selected tissue region and the proximal and distal portions of the elongate shaft are positioned external to the body of the subject. Upon positioning of the elongate shaft in this manner, each electrode of the plurality of electrodes is configured for selective, independent activation to apply ablative energy to the selected tissue region. Each of the high impedance structures is configured for selective, independent activation to intersect the theoretic field lines created by surrounding electrodes. An ablation catheter system including an ablation catheter, one or more signal generators, and a routing console is also described.
• Further described herein are methods of ablating the selected tissue region. In exemplary methods, the ablation catheter can be deployed into the pericardial space with both the proximal and distal portions of the catheter outside the body. The ablation catheter can be more flexible than other clinically available catheter-based ablation devices to thereby permit tissue contact around the left atrial structures. The electrodes of the ablation catheter can be capable of monitoring and/or delivering RF energy, electroporation impulses, and programmed cardiac pacing and/or neuro-stimulus. Unlike other known ablation catheters, the electrodes of the described ablation catheter also can have the capability of delivering extended bipolar high voltage, ultra-short impulses. The feature of individualizing the activation of each extended bipolar electrode can take advantage of the natural geometry inside the pericardial space to deliver energy to a series of electrodes arranged around the target structure and control the vector of the electrical current.
• Once the ablation catheter is deployed, a linear lesion can be created without repositioning the catheter, thereby increasing efficiency and effectiveness (when compared to standard point-by-point techniques). This ablation catheter can provide a stable and contiguous array of electrodes along the target path that can deliver ablation and can also be used to confirm electrophysiologic block using an extended bipolar electrocardiographic technique. The ablation catheter takes advantage of the natural contours of the left atrial epicardial surface to provide reliable and stable electrode contact. Additionally, the high-voltage, ultra-short duration impulses used in electroporation techniques do not require that the electrode be in direct contact with the ablation target.
• Moreover, the epicardial positioning can have mechanical advantages over endocardial multi-electrode arrays. Indeed, the positioning of the described ablation catheter can be varied with little effort to provide full circumferential coverage around a target structure. The flexibility of the ablation catheter provides a mechanism for ensuring secure tissue contact and/or tissue proximity around complex anatomic geometry. The natural spatial limitation of the pericardial space can provide a natural mechanism to assure electrode approximation. In addition, high impedance structures (e.g., insulators) found along the ablation catheter can change the contour of the current moving between electrodes. Such changes to the contour can lead to an increased current density at the farthest point along the flow of current and the electrodes.
• The risks of performing ablation from the epicardial surface can place the electrodes of the ablation catheter closer to some important bystander structures. However, the electrodes of the ablation catheter can be configured to deliver ablative energy with programmed directional vectors. With RF energy, extended bipolar ablation can result in a 40-50% deeper lesion in the direction of the programmed vector. With electroporation, the potential for creating a preferential directional injury vector is greater. In exemplary methods, extended bipolar irreversible electroporation (which cause no thermal injury) can be delivered.
• These and other objects and advantages of the invention will become apparent from the following detailed description of the preferred embodiment of the invention.
• Both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the invention as claimed. The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute part of this specification, illustrate several embodiments of the invention, and together with the description serve to explain the principles of the invention.
BRIEF DESCRIPTION OF THE FIGURES
• These and other features of the preferred embodiments of the invention will become more apparent in the detailed description in which reference is made to the appended drawings wherein:
• FIG. 1 depicts the posterior pericardial anatomy with a membranous reflection illustrating a hypothetical lesion delivered to the left atria (note: heart is absent from the illustration).
• FIG. 2 is a perspective view of a percutaneous catheter system according to an aspect.
• FIG. 3 is a schematic plane view of a percutaneous catheter system according to an aspect.
• FIG. 4 is a cross sectional view of a catheter of the system ofFIG. 3 along line4-4.
• FIGS. 5a-eare a series of cross sectional views of a portion of the catheter of the system ofFIG. 3.
• FIG. 6 is a cross sectional view of a portion of a catheter of the system ofFIG. 3.
• FIGS. 7a-bare cross sectional views of the assembly of a portion of a catheter of systemFIG. 3.
• FIG. 8 is a cross sectional view of the portion of the catheter of assembled inFIGS. 7a-b.
• FIG. 9 is a perspective view of a needle of the percutaneous catheter system ofFIG. 2.
• FIG. 10 is a schematic plane view of a needle of the percutaneous catheter system ofFIG. 3.
• FIG. 11 is a cross sectional view of a portion of a catheter of the percutaneous catheter system ofFIG. 3.
• FIG. 12 is a schematic view of a needle of the percutaneous catheter system ofFIG. 3.
• FIG. 13 is a schematic plane view of docked catheters of percutaneous catheter system ofFIG. 3.
• FIG. 14 is a cross-sectional schematic view of the “docked” catheter system ofFIG. 13.
• FIG. 15 is a depiction of a process to puncture a tissue structure using a percutaneous catheter system according to an aspect.
• FIGS. 16-23 are illustrations of the placement and use of a percutaneous catheter system according to an aspect.
• FIG. 24 is a depiction of a process to puncture a tissue structure using percutaneous catheter system according to an aspect.
• FIG. 25 is a schematic representation of the entry site for the process shown inFIG. 15.
• FIG. 26 is a depiction of a process to position a percutaneous catheter system according to an aspect.
• FIG. 27 depicts an exemplary ablation catheter according to an aspect.
• FIG. 28 is a schematic representation of an ablation catheter according to an aspect.
• FIG. 29 is a partial close-up view of a central portion the ablation catheter ofFIG. 27.
• FIG. 30 is a schematic cross-sectional view of a proximal end of an ablation catheter according to an aspect.
• FIG. 31 is a schematic cross-sectional view of a distal end of an ablation catheter according to an aspect.
• FIG. 32 is a partial close-up view of the central portion of the ablation catheter ofFIG. 27.
• FIG. 33 depicts the positioning of an ablation catheter during an exemplary ablation procedure as described herein.
• FIG. 34 is a schematic representation of an ablation catheter positioned around the heart according to an aspect.
• FIG. 35 is a depiction of a process to position and use an ablation catheter according to an aspect.
• FIGS. 36-38 are illustrations of the placement and use of an ablation catheter according to an aspect.
• FIG. 39 is a block diagram of an exemplary ablation catheter system according to an aspect.
• FIG. 40 is a schematic front plane view of a routing console according to an aspect.
• FIG. 41 is a block diagram of a routing console ofFIG. 40.
• FIG. 42 is a schematic front plane view of a signal generator according to an aspect.
• FIG. 43 is a block diagram of a signal generator ofFIG. 42.
• FIG. 44 is a block diagram of an exemplary computer system according to an aspect.
• FIG. 45 is an illustration of a graphic representation of a high-voltage impulse window according to an aspect.
• FIG. 46 is a depiction of a process to position and use an ablation catheter according to an aspect.
• FIG. 47 are schematic representations of epicardial ablation techniques.
• FIG. 48 is a schematic representation of an ablation catheter with electrodes according to an aspect.
• FIG. 49 is a schematic representation of an ablation catheter with electrodes and a high impedance structure according to an aspect.
• FIGS. 50-51 are schematic representations of a cross section of the ablation catheter according to an aspect.
• FIGS. 52a-cis a schematic representation of an ablation catheter with electrodes and a high impedance structure according to an aspect.
• FIGS. 53a-ddisplay exemplary electrode assignments according to an embodiment.
DETAILED DESCRIPTION
• The present invention can be understood more readily by reference to the following detailed description, examples, drawings, and claims, and their previous and following description. However, before the present devices, systems, and/or methods are disclosed and described, it is to be understood that this invention is not limited to the specific devices, systems, and/or methods disclosed unless otherwise specified, and, as such, can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.
• The following description of the invention is provided as an enabling teaching of the invention in its best, currently known embodiment. To this end, those skilled in the relevant art will recognize and appreciate that many changes can be made to the various aspects of the invention described herein, while still obtaining the beneficial results of the present invention. It will also be apparent that some of the desired benefits of the present invention can be obtained by selecting some of the features of the present invention without utilizing other features. Accordingly, those who work in the art will recognize that many modifications and adaptations to the present invention are possible and can even be desirable in certain circumstances and are a part of the present invention. Thus, the following description is provided as illustrative of the principles of the present invention and not in limitation thereof.
• As used throughout, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a delivery conduit” can include two or more such delivery conduits unless the context indicates otherwise.
• As used herein, the terms “optional” or “optionally” mean that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.
• The word “or” as used herein means any one member of a particular list and also includes any combination of members of that list.
• It is contemplated that the disclosed devices and systems can comprise elements of the devices and systems described in U.S. Pat. No. 6,314,963, the disclosure of which is incorporated herein by reference in their entireties.
• It is contemplated that thepercutaneous catheter system10 andablation catheter20 of the present invention can allow an operator to deliver a single isolating lesion around the pulmonary veins of a subject using a subxiphoid pericardial access point. The circumscribing lesion can be produced by any of the currently available energy sources, including, for example and without limitation, HVUS-DCI, RF, cryoablation, electroporation, microwave, laser, biologics, radiation, small molecule chemicals (e.g., ethanol ablation) and ultrasound. However, it is contemplated that the circumscribing lesion can be produced by any ablative energy source. In use, it is contemplated that, once an operator achieves a stable catheter position for theablation catheter20, delivery of a single circumscribinglesion30 around the pulmonary veins (as shown inFIG. 1) of the subject can become much simpler. The atrial fibrillation ablation technique described herein can require fewer steps, catheters, time, and equipment than conventional atrial fibrillation ablation techniques. Further, it is contemplated that the describedpercutaneous catheter system10 can minimize or avoid the need for expensive advanced mapping and imaging equipment; instead, the describedpercutaneous catheter system10 can permit usage of a purely anatomic approach. Consequently, it is contemplated that the described percutaneous catheter system can minimize the expense of atrial fibrillation ablation, thereby making atrial fibrillation ablation to a larger population of patients.
Catheter System for Puncturing Through a Tissue Structure
• With reference toFIGS. 2-24, disclosed herein, is apercutaneous catheter system10 for use within the body of a subject. In one aspect, thepercutaneous catheter system10 comprises afirst catheter100 and asecond catheter200. Thefirst catheter100 can be referred to as themale catheter100 and thesecond catheter200 can be referred to as thefemale catheter200. In this aspect, thefirst catheter100 and thesecond catheter200 can each have respectivelongitudinal axes102,202,longitudinal lengths104,204, proximal portions106,206, and distal portions,108,208. In exemplary aspects, the first andsecond catheters100,200 can each have alongitudinal length104,204 ranging from about 20 cm to about 50 cm. In another exemplary aspect, thelongitudinal length104,204 of thefirst catheter100 and thesecond catheter200 are approximately the same. While the length of thecatheters100,200 in relation to one another is not critical in many aspects, it is important that thecatheters100,200 are configured to work as a pair. However, the lengths of thecatheters100,200 collectively need to have a combined length that is long enough to reach the key areas of the anatomy for which thecatheter system10 is being used. In these aspects, it is contemplated, following magnetic coupling between thefirst catheter100 and thesecond catheter200, the total length of thefirst catheter100 and thesecond catheter200 can range from about 40 cm to about 100 cm.
• In other exemplary aspects, at least one of thefirst catheter100 and thesecond catheter200 can be flexible. In other exemplary aspects, both thefirst catheter100 and thesecond catheter200 can be flexible. Thecatheters100,200 should be comprised of a material that is also kink resistant. In an aspect, thecatheters100,200 can be comprised of kink resistant material such as expanded PTFE and/or more standard biocompatible materials (coil reinforced silicon, PFA, Pebax, and/or PVC). The construction can utilize expanded PTFE with progressively decreasing density distally, however other construction techniques could be employed. The stiffer proximal segment provides necessary column strength and transmission of torsional force for navigation. In an aspect, the distal portions106 (which can range between 10-20 cm) are more flexible to permit a-traumatic manipulation and navigation by over the wire techniques through tortuous anatomy. In some embodiments, in order to prevent kinking, braided reinforcement, as well as other types of reinforcement, can be utilized.
• In an exemplary aspect, the first andsecond catheters100,200 are configured to be flexible enough so that thecatheters100,200 can permit a 180° turn around a 1.5 cm obstacle. However, thecatheters100,200 can be made to perform to other standards (e.g., perform 180° turns around various sized obstacles) in other exemplary embodiments.
• In another aspect, thedistal portion108 of thefirst catheter100 can define adistal end110 of thefirst catheter100. In an aspect, thedistal end110 can have a nominal outer diameter between 1 mm to 5 mm to accommodate amagnet assembly120. In this aspect, thedistal end110 of thefirst catheter100 can define anopening112. In an aspect, the end of the proximal portion106 is configured to be larger than thedistal end110 in order to facilitate the manipulation of thecatheter100 at thehandle140, discussed in more detail below.
• In an additional aspect, thefirst catheter100 can define at least onelumen116,118 extending from theopening112 of thedistal end108 toward the proximal portion106 of thefirst catheter100 along at least a portion of thelongitudinal length104 of thefirst catheter100. The lumen can be defined by anouter shaft115 of thecatheter100. In a further aspect, thefirst catheter100 can comprise afirst magnet assembly120 positioned proximate thedistal end110 of thefirst catheter100 and operatively coupled to thedistal portion108 of thefirst catheter100.
• In another aspect, thedistal portion208 of thesecond catheter200 can define adistal end210 of thesecond catheter200. In an aspect, thedistal end210 can have a nominal outer diameter between 1 mm to 5 mm to accommodate amagnet assembly220. In an aspect, thedistal end210 of thesecond catheter200 can define anopening212. In an aspect, the end of the proximal portion206 is configured to be larger than thedistal end210 in order to facilitate the manipulation of thesecond catheter200 through the use of ahandle240, discussed in more detail below.
• In an additional aspect, thesecond catheter200 can define at least onelumen216,218 extending from theopening212 of thedistal end210 toward the proximal portion206 of thesecond catheter200 along at least a portion of thelongitudinal length204 of thesecond catheter200. Thelumen216,218 can be defined by an outer shaft215 of thesecond catheter200. In a further aspect, thesecond catheter200 can comprise asecond magnet assembly220 positioned proximate thedistal end210 of thesecond catheter200 and operatively coupled to thedistal portion208 of thesecond catheter200.
• In an exemplary aspect, thefirst catheter100 and thesecond catheter200 can have a nominal outer diameter of 1 to 5 mm and in other respects the geometry ofcatheter100 and200 will be similar to provide a symmetric and complementary magnetic coupling surface for themagnet assemblies120,220. However, in other aspects, the outer diameter of thecatheters100,200 can vary. In an exemplary aspect, the first andsecond catheters100,200 can have an inner diameter configured to accommodate aneedle tube130 discussed in more details below. In an exemplary aspect, inner diameter of the first andsecond catheters100,200 can be configured to accommodate aneedle tube130 of approximately 1.473 mm in diameter. However, in other aspects, the inner diameter of thecatheters100,200, as well as the diameter of theneedle tube130, can vary. In other aspects, when magnetic coupling and guide wire transfer are the only desired functions, thecatheters100/200 may not have a needle component.
• In an exemplary aspect, the firstmagnetic assembly120 of thefirst catheter100 is configured for magnetic coupling to thesecond magnet assembly220 of thesecond catheter200. In this aspect, it is contemplated that the firstmagnetic assembly120 can be configured for magnetic coupling to thesecond magnet assembly220 such that thelongitudinal axis102 of thefirst catheter100 is substantially axially aligned with thelongitudinal axis202 of thesecond catheter200. It is further contemplated that thefirst magnet assembly120 can be configured for magnetic coupling to thesecond magnet assembly220 through a tissue structure within the body of the subject, discussed further below.
• It is contemplated that the at least one lumen of thefirst catheter100 can comprise aprimary lumen116. Similarly, it is contemplated that the at least one lumen of thesecond catheter200 can comprise aprimary lumen216. Optionally, in another exemplary aspect, the at least one lumen of thefirst catheter100 can further comprise one or moreauxiliary lumens118. Similarly, it is contemplated that the at least one lumen of thesecond catheter200 optionally can further comprise one or moreauxiliary lumens218. In an aspect, theprimary lumen116,216 and theauxiliary lumen118,218 can be separate by aninner shaft117,217 in eachcatheter100,200, with theprimary lumen116,216 being contained within theinner shaft117,217, and theauxiliary lumen118,218 being contained between theinner shaft117,217 and theouter shaft115,215. Theprimary lumen116,216 can be configured to receive theneedle tube130. In some aspects, theinner shaft117,217 can move up and down theouter shaft115,215 of thecatheters100,200 respectively.
• Optionally, it is contemplated that the one or moreauxiliary lumens118 of the first catheter100 can be configured for delivery of one or more fluids to theopening112 of thedistal end110 of thefirst catheter100, while the one or moreauxiliary lumens218 of thesecond catheter200 can be configured for delivery of one or more fluids to theopening212 of thedistal end210 of thesecond catheter200. Optionally, it is further contemplated that the one or moreauxiliary lumens118 of thefirst catheter100 can be configured for application of suction to theopening112 of thedistal end110 of thefirst catheter100, while the one or moreauxiliary lumens218 of thesecond catheter200 can be configured for application of suction to theopening212 of thedistal end210 of thesecond catheter200.
• In another aspect, theauxiliary lumens118,218 can perform the delivery of fluids and the application of suction through irrigation ports/side openings/side holes119,219 approximate theopenings112,212 of the distal ends110,210 of thecatheters100,200. In one optional exemplary aspect, the at least one lumen of thefirst catheter100 and/orsecond catheter200 can comprise aprimary lumen116,216 and anauxiliary lumen118,218, with theauxiliary lumen118,218 radially surrounding theprimary lumen116,216.
• In one aspect, thefirst catheter100 can further comprise aneedle130 operatively positioned within theprimary lumen116 of thefirst catheter100, as shown inFIGS. 5e,9-12 and14. Theneedle130 can further comprise a flexibletubular needle130. In an exemplary aspect, the flexibletubular needle130 can comprise a modified hypodermic needle spirally cut circumferentially around a shaft132 of theneedle130. Theneedle130 can have a progressive pitch to the coil providing increasing flexibility at adistal tip134. Theneedle130 can be made of materials that include, but are not limited to, metal, plastic, or other suitable compounds. In an aspect, theneedle130 can be a composite with a coating to improve mechanical and/or functional characteristics (examples include, but are not limited to, a lubricious polymer, insulator, electrical components, and/or biocompatible metals). A proximal portion of theneedle130 can connect to a mounting hub, theinner shaft117, and/or other elements to provide a method of fixation within thecatheter100 and/or a deployment mechanism146 in thecatheter handle140. In an exemplary aspect, theneedle130 is mounted to theinner shaft117 of thefirst catheter100. In other aspects, theneedle130 can extend the length of thecatheter100. In additional aspects, theneedle130 can be connected to the inner wall of theouter shaft115 of thecatheter100.
• In an exemplary embodiment, thetubular needle130 can have a flexibility to accommodate a 1.5 cm turn radius. However, in other aspects, the flexibility of theneedle130 can vary depending on the needs of the application. In one exemplary aspect, it is contemplated that theneedle130 of thefirst catheter100 can have adistal puncturing surface134 and be configured for selective axial movement relative to thelongitudinal axis102 of thefirst catheter100.
• In an aspect, thedistal tip134 is configured to serve as a puncturingsurface134. In an exemplary aspect, the puncturingsurface134 can be flared at a 45° angle and OD 2.5 mm. However, in other aspects, the puncturingsurface134 can be configured differently. It is still further contemplated that thedistal puncturing surface134 of theneedle130 of thefirst catheter100 can be configured to puncture through a tissue structure within the body of the subject positioned between the distal ends110,210 of the first andsecond catheters100,200 respectively when the ends110,210 are magnetically coupled, discussed below.
• Optionally, in one aspect, theneedle130 of thefirst catheter100 can be retractably secured within theprimary lumen116 of thefirst catheter100. In this aspect, theneedle130 of thefirst catheter100 can define adelivery lumen138. In this aspect, thedelivery lumen138 of theneedle130 of thefirst catheter100 can be configured to receive a guide wire300 (shown inFIG. 3). Theguide wire300 can be utilized before and after the placement of thecatheters100,200. In this aspect, upon receipt of at least aportion134 of theneedle130 of thefirst catheter100 within theopening212 of thedistal end210 of the second catheter200 (as shown inFIG. 14), thedelivery lumen138 of theneedle130 of thefirst catheter100 can be configured to permit transfer of aguide wire300 from thefirst catheter100 to thesecond catheter200.
• In an aspect, as illustrated inFIGS. 3 and 6, thehandles140,240 are found approximate the proximal ends106,206 of thecatheters100,200. Thehandles140,240 can be made of a rigid material, such as, but not limited to, machined aluminum, carbon fiber, and the like. Thehandles140,240 provide the means of manual manipulation of thecatheters100,200 when in use. Thehandles140,240 provide a place to apply force to advance, withdrawal, and apply rotational torsion tocatheters100,200.
• As shown inFIG. 6, thehandle140 of the male catheter100 (i.e., thecatheter100 operating the needle130) can include a proximal chamber142 and a distal chamber144. In an aspect, the proximal chamber142 can contain a stylus/integrated lever146 that is connected to theinner shaft117 of thecatheter100. The stylus/integrated lever146 allows for the independent manipulation of theneedle130 within theouter shaft115 of thecatheter100. In an aspect, the stylus146 allows for the independent manipulation of theinner catheter117 to manipulate theneedle130 within theouter shaft115 of thecatheter100. In a further aspect the control of theinner shaft117 by the integrated lever146 provides a means to transmit force distally and deploy theneedle130 through the central bore122 of themagnetic assembly120. The stylus/integrated lever146 can include acompression spring148 that ensures that theneedle130 is not deployed until actually called on by the user. In an aspect, thespring148 prevents the stylus/integrated lever146 from theinner shaft117 from deploying the needle until called upon.
• In an aspect, the integrated lever146 includes arigid tube150 connected to the proximal end of thespring148. Therigid tube150 is hollow, and allows passage of theguidewire300 and other components to thedistal end110 of thecatheter100. A projection152 extends from therigid tube150 through a slot154 found on the outer portion of thehandle140. The projection152 allows the user to activate the integrated lever/stylus146, compressing thespring148 and pushing theneedle130 distally along thecatheter100. Lastly, thehandle140 can include a guidewire entry point156. In an aspect, theinner shaft117 passes through afluid hub168 found in the distal chamber144.
• In an aspect, thehandle240 of thefemale catheter200 can include all of the same components of as described above for themale catheter100, but it is not necessary. For example, when afemale catheter200 is used that does not employ aneedle230, thehandle240 does not need to have a integrated lever and the associated components to control the needle andinner shaft217. In another aspect, thecatheter pair100/200 can be constructed without aninner needle130/230, and be equipped to form magnetic coupling with central lumen for the passage of a guide wire. In other aspects, thefemale catheter200 can have a proximal chamber242 and a distal chamber244, with the proximal chamber242 providing aguidewire entry point256 to receive aguide wire300 to pass through to theprimary lumen216 and the distal chamber244 including a fluid hub268.
• In an aspect, thehandles140,240 can include a hemostasis/fluid management system. The fluid management systems include proximal valves (not shown) that prevent unwanted fluid leakage through the primary lumens116,216 of the respectivemale catheter100 andfemale catheter200. In addition, the proximal valves prevent the introduction of unwanted air through the centers lumen116,216. In an aspect, a second fluid valve (166 inFIG. 6) can be used to provide a seal of theauxiliary lumens118,218. Both the first and second fluid valves can include silicon o-rings and various other seal-creating mechanisms.
• Fluid hubs168,268 can be found within thehandles140,240 near the proximal ends106,206 of themale catheter100 andfemale catheter200 respectively. Thefluid hub168,268 of eachcatheter100,200 can be in communication with their respectiveauxiliary lumen118,218.Fluid ports170,270 provide access to thefluid hubs168,268. In an aspect, the combination of thefluid ports170,270,fluid hubs168,268,auxiliary lumen118,218 andside openings119,219 create the fluid management system. The fluid management system provides for the delivery of radio contrast agents for intra-pericardial navigation under x-ray fluoroscopic guidance. In addition, the fluid management systems provide a means to inject and suck moderate volumes of fluid through thelumen118,218 quickly. This is specifically used to inject and withdraw radio contrast agents and/or other fluids (including but not limited to saline, medications, etc.) within the pericardial space; thus accentuating anatomic boundaries. The system, through theside openings119,219 can also be used to manage and/or drain a pericardial effusion.
• In another aspect, it is contemplated that thefirst magnet assembly120 of thefirst catheter100 can be positioned within theprimary lumen116 of thefirst catheter100, as shown inFIG. 5. In this aspect, it is further contemplated that thesecond magnet assembly220 can be positioned within theprimary lumen216 of thesecond catheter200. It is still further contemplated that thefirst magnet assembly120 of thefirst catheter100 can define a central bore122 configured to receive theneedle130 of thefirst catheter100. Similarly, it is contemplated that thesecond magnet assembly220 of thesecond catheter200 can define a central bore222 configured to receive theneedle130 of thefirst catheter100.
• In an aspect, as shown inFIGS. 7a-band8, themagnet assemblies120,220 can be coupled to the distal ends110,210 ofrespective catheters100,200 through the use of a flexible needle guide124,224. The flexible needle guides124,224 include adistal portion125,225 and a proximal portion126,226. The flexible needle guides124,224 can include central lumen127,227 that extend the length of the guides124,224 and are configured to receive theneedle130,230. Thedistal portions125,225 of the needle guides124,224 are secured within central bores122,222 of themagnet assemblies120,220, with the proximal portions being secured within theprimary lumens116,216 at thedistal portions108,208 of thecatheters100,200. The needle guide124,224 can be attached coaxially through adhesive or by mounting over a thin walled rigid tube that has been affixed to the magnetic assembly and extends proximally from themagnet120,220.
• The needle guides124,224 provide a means to maintain central alignment of the inner and outer shafts of thecatheters100,200 while allowing independent degrees of lengthwise movement. In an aspect, the flexible needle guides124,224 can provide a way to introduce a fixed and/or adjustable angle at the distal ends110,210 of thecatheters100,200. In the cases where thedistal portions110,210 andmagnet assemblies120,220 of thecatheters100,200 meet curved portions, the flexible needle guide124,224 provides a flexible curved angle between the mostdistal portion125,225 and proximal portions126,226, as shown inFIG. 8. Further, the guides124,224 prevent theneedle130 from exiting theopening112,212 when thedistal end110,210 encounters a curve, preventing accidental punctures. In an aspect, a rigid tube guide124,224 can be utilized. In such an aspect, the segment of the needle guide124,224 extending proximally from the magnet may be aligned with thelong axis102,202 of theinner lumen116,216 or the rigid component may bend providing a means to introduce a fixed curve into the tip of the assembled catheter. The variations in performance requirements and mounting techniques will influencemagnet assembly120,220 and needle guide124,224 dimensions and shape.
• It is still contemplated that thefirst magnet assembly120 can have a distal surface128 substantially flush with thedistal end110 of thefirst catheter100. Similarly, it is contemplated that thesecond magnet assembly220 of thesecond catheter200 can have adistal surface228 substantially flush with thedistal end210 of thesecond catheter200. In exemplary aspects, thefirst magnet assembly120 can be permanently fixedly secured to thefirst catheter100. Similarly, it is contemplated that thesecond magnet assembly220 can be permanently fixedly secured to thesecond catheter200. However, in other aspects, the first and second magnet assemblies can be removably coupled to the first andsecond catheters100,200 respectively.
• In an aspect, themagnet assembly120 of thefirst catheter100 and themagnet assembly220 of thesecond catheter200 are configured to be magnetically attracted to one another. In an exemplary aspect, it is desired that themagnet assemblies120,220 are strong enough to automatically magnetically couple to one another when themagnet assemblies120,220 come within approximately 1 cm of each other. In the exemplary catheter we found magnetic field strength between 0.5 kG to 1.5 kG was ample to provide the desired coupling characteristics. However, in all aspects, the strength of the magnetic attraction has to be strong enough to magnetically couple themagnet assemblies120,220 and hold them together magnetically on opposite sides of human tissue. In an aspect, the magnetic attraction can occur automatically. In another aspect, the magnetic attraction between the twomagnet assemblies120,220 can be manually controlled.
• It is contemplated that, upon magnetic coupling between thefirst magnet assembly120 of thefirst catheter100 and thesecond magnet220 assembly of thesecond catheter200 such that thelongitudinal axis102 of thefirst catheter100 is substantially axially aligned with thelongitudinal axis202 of thesecond catheter200, theneedle130 can be configured for axial movement relative to thelongitudinal axis102 of thefirst catheter100 such that at least aportion134 of theneedle130 exits theopening112 of thedistal end110 of thefirst catheter100 and is received within theopening212 of thedistal end210 of thesecond catheter200.
• Similarly, in another optional aspect, thesecond catheter200 can further comprise aneedle230 operatively positioned within theprimary lumen216 of thesecond catheter200. In this aspect, theneedle230 of thesecond catheter200 can be configured for selective axial movement relative to thelongitudinal axis202 of thesecond catheter200. It is further contemplated that, upon magnetic coupling between themagnet assemblies120,220 of the first andsecond catheters100,200 such that thelongitudinal axis102 of thefirst catheter100 is substantially axially aligned with thelongitudinal axis202 of thesecond catheter200, theneedle230 of thesecond catheter200 can be configured for axial movement relative to thelongitudinal axis202 of thesecond catheter200 such that at least a portion232 of theneedle230 exits theopening212 of thedistal end210 of thesecond catheter200 and is received within theopening212 of thedistal end210 of thefirst catheter100. Theneedle230 can also include a delivery lumen238.
• In use, the disclosedpercutaneous catheter system10 can be incorporated into methods of puncturing through a tissue structure within the body of a subject (method1000), as shown inFIG. 15. In one aspect, an exemplary method of puncturing through a tissue structure within the body of a subject can comprise positioning thedistal end110 of thefirst catheter100 proximate a first side of the tissue structure (step1100). In another aspect, the exemplary method can comprise positioning adistal end210 of asecond catheter200 proximate a second side of the tissue structure (step1200). In an additional aspect, the exemplary method can comprise magnetically coupling thefirst magnet assembly120 of thefirst catheter100 to thesecond magnet assembly220 of thesecond catheter200 through the tissue structure such that thelongitudinal axis102 of thefirst catheter100 is substantially axially aligned with thelongitudinal axis202 of the second catheter202 (step1300). In a further aspect, the exemplary method can comprise selectively advancing aneedle130 through the at least one lumen114 (e.g., theprimary lumen116 in the exemplary aspect) of thefirst catheter100 such that at least a portion132 of theneedle130 exits theopening112 of thedistal end110 of thefirst catheter100 and is received within theopening212 of thedistal end210 of thesecond catheter200, piercing the tissue structure40 (step1400), as shown inFIG. 14. In exemplary aspects, the tissue structure can comprise an anatomical pericardial reflection adjacent to the heart of the subject. In these aspects and others, bothcatheters100,200 can employ aguide wire300 to reach their positions incrementally, with the operator using standard over-the-wire maneuvering techniques to advance thecatheters100,200.
• In an exemplary aspect of the method (1000) discussed above, thedistal end110 of thefirst catheter100 being positioned in the transverse sinus (step1100), as illustrated inFIG. 16. Thedistal end210 of thefemale catheter200 can be introduced over the anterior/superior aspect of the ventricle (FIG. 17), and then advanced toward the right pericardial “gutter” by way of the posterior/inferior cardiac border (FIG. 18) to be proximate the first catheter100 (step1200). When in place, themagnet assemblies120,220 of the male andfemale catheters100,200 can then be magnetically coupled (Step1300), as illustrated inFIG. 19. Theneedle130 can then exit thedistal end110 of themale catheter100 to be received within the bore222 of themagnet assembly220 of the female catheter (step1400), as shown inFIG. 14.
• In addition, steps of the method as discussed above can be repeated during certain procedures. Referring back to the exemplary aspect discuss above, afterstep1400 has been completed, thesecond catheter200 can be withdrawn into the obtuse sinus (step1100), as shown inFIG. 20. Themale catheter100 can be positioned adjacent the second catheter200 (step1200) (FIG. 21) and couple the targeted pericardial reflection sandwiched in between (steps1300), as shown inFIG. 22. Theneedle130 can then puncture the tissue (step1400). After theneedle130 has punctured the tissue, theguidewire300 can be advanced from the proximal male catheter across the magnetic coupled ends and out the proximal end of thefemale catheter200. Thecatheters100,200 can be removed, leaving theguidewire300 in place, as shown inFIG. 23. In additional aspects, it is contemplated that thepercutaneous catheter system10 can be used to cross and/or puncture through other anatomic boundaries within the body of a subject. For example, it is contemplated that thepercutaneous catheter system10 can be used to cross and/or puncture through the pericardium and plural space (to create a pericardial window). In another exemplary aspect, it is contemplated that thepercutaneous catheter system10 can be used to create access between various organ structures in a controlled manner (e.g., between the bladder and the perineum or between ventricles in a brain (for drainage or placement of electrodes)). In yet another exemplary aspect, it is contemplated that the percutaneous catheter system can be used intravascularly to create an AV fistula in a dialysis patient. In still another exemplary aspect, it is contemplated that thepercutaneous catheter system10 can be used to accomplish trans-venous delivery of electrodes, such as electrodes used in pacemakers and/or nerve stimulators, when an electrical generator is positioned remotely from an electrode target and surgical tunneling is not a desirable option.
• In exemplary applications, it is contemplated that thepercutaneous catheter system10 can safely perform punctures across membranous pericardial reflections. Thecatheter system10 can be introduced into the pericardium by one of several common transcutaneous techniques.
• The following exemplary method (2000) can be employed following access to the pericardial space via a subxiphoid approach (step2100) as shown inFIG. 24; however, it is understood that the method described below can also be employed following other conventional approaches.FIG. 25 illustrates the sterile field2002 for percutaneous access into the pericardial space. Theentry site2004 is also shown. It is contemplated that the respectivelongitudinal lengths104,204 of the first andsecond catheters100,200 of thepercutaneous catheter system10 can be sufficiently long to permit advancement of the first andsecond catheters100,200 into the transverse sinus of the pericardium from the subxiphoid approach. Thus, it is contemplated that thelongitudinal length102,202 of eachrespective catheter100,200 can range from about 20 cm to about 50 cm.
• In exemplary aspects, the first andsecond catheters100,200 can be introduced into the pericardial space over a guide wire300 (step2200). Thecatheters100,200 can then be directed to opposite sides of the target pericardial reflection using standard over-the-wire steering techniques and/or fluoroscopic guidance (step2300). When the distal ends110,210 of thecatheters100,200 respectively are within close proximity, themagnet assemblies120,130 of the catheters will be drawn together magnetically, magnetically coupling the distal ends110,210 of the first andsecond catheters100,200 together (step2400). Under conditions where there is a thin intervening tissue membrane, it is contemplated that the distal ends110,210 of thecatheters100,200 can “sandwich” the membrane orthogonally to theprimary lumens116,216, of the twocatheters100,200. It is further contemplated that the magnetic field created by themagnet assemblies120,220 of thecatheters100,200 can align theprimary lumen116 of thefirst catheter100 with the correspondingprimary lumen216 of thesecond catheter200, thereby facilitating longitudinal continuity. It is still further contemplated that the strength of themagnet assemblies120,220 and the size and flexibility of thecatheters100,200 can allow the distal ends110,210 of thecatheters100,200 to align when in close proximity.
• Using fluoroscopic guidance, the operator can position the twocomplementary catheters100,200 on opposite sides of a target pericardial reflection (method3000), as shown inFIG. 26. Visualization of key pericardial and cardiac landmarks can be facilitated by varying concentrations of radiopaque contrast injected and withdrawn through theirrigation ports119,219 of thecatheters100,200. Thecatheters100,200 can access the pericardial space via a subxiphoid approach (step3100). Referring to the exemplary pericardial reflection depicted inFIG. 1, it is contemplated that the male catheter100 (i.e., the catheter of the two in which the needle is advanced) can be placed at the membranous reflection of the superior vena cava from the transverse sinus (step3200), while the female catheter200 (i.e., the catheter receiving the needle) can be advanced to the same membranous reflection via the post-caval recess (step3300). Fluoroscopic navigation can be facilitated by delivery of 5-10 cc of one or more known radio-contrast agents that are injected into the pericardial space. It is contemplated that the first andsecond catheters100,200 can have a plurality of irrigation ports/side openings119,219 located at theirdistal ends110,910 to permit injection and suction of fluids, including, for example and without limitation, radio-contrast agents, saline, medications, and body fluids. It is further contemplated that the membranous reflection at this location can have a thickness ranging from about 0.25 mm to about 1 mm. After thecatheters100,200 are positioned in near proximity (e.g., within about 1-2 cm of one another), the magnet assemblies attract and align the distal ends of the catheters in a “docking” orientation (step3400). Proper “docking” orientation can be confirmed by fluoroscopic imaging (step3500).
• In exemplary aspects, both male andfemale catheters100,200 can have acentral lumen116,216 to accommodate astandard guide wire300. In these aspects, it is contemplated that thestandard guide wire400 can be withdrawn once thecatheters100,200 are positioned at a desired site and orientation. It is further contemplated that, through the use of fluoroscopic guidance, the position of the male andfemale catheters100,200 can be confirmed by injection and/or suction of one or more radio-contrast agents into or from the pericardial space. It is still further contemplated that themale catheter100 can have aretractable puncture needle130 that can extend and “dock” with thefemale catheter200 when the twodistal ends110,210 are aligned.
• Once thecatheters100,200 are magnetically attached and aligned, with the target membrane sandwiched in between the distal ends110,210 of thecatheters100,200, the operator can advance a stylus146 (i.e., the elongate member) of themale catheter100 until theneedle130 punctures through the target membrane and “docks” with thefemale catheter200. The operator can then advance theguide wire300 from themale catheter100 into theprimary lumen216 of thefemale catheter200. Theneedle130 can then be retracted, and thecatheters100,200 can be withdrawn, leaving theguide wire300 in place. It is contemplated that the previously described steps can be repeated as necessary to create a path for circumnavigating the left atrial target structures. For example, it is contemplated that the above-described method can be used to create a puncture across the pericardial reflection between the superior vena cava and the right superior pulmonary vein located at the rightward terminus of the transverse sinus and a second pericardial reflection puncture located between the inferior vena cava and the right inferior pulmonary vein traversing from the rightward aspect of the pericardial space into the oblique sinus. Following removal of thecatheters100,200 from the body of the subject, one ormore ablation catheters20 can be delivered and positioned over theguide wire300.
• It is contemplated that thepercutaneous catheter system10 can perform the puncture methods described herein without the need for direct visualization and/or mechanically advantageous positioning, as is required for more conventional puncture techniques. Typically, the restrictions of space and geometric boundaries of the pericardial space constrain over-the-wire catheter design. However, the disclosedcatheters100,200 of thepercutaneous catheter system10 can be flexible enough to navigate multiple turns while maintaining rotational rigidity for “steer-ability” and direct of the guide wire. Additionally, the distal ends110,210 of thecatheters100,200 can be blunt and/or rounded, thereby reducing the risk of inadvertent puncture of surrounding vascular structures. With the magnetic “docking” capabilities of thecatheters100,200 through their respectivemagnetic assemblies120,220 it is contemplated that theneedle130 can be deployed when the target membrane is the only structure in jeopardy; otherwise, theneedle130 will be housed within alumen116 of thecatheter system10 such that there is no risk of inadvertent puncture. While the exemplary aspects of thepercutaneous catheter system10 have been disclosed in relation tofirst catheter100 as being the male catheter, and thesecond catheter200 being the female catheter, either assignments can differ based upon which ever catheter is configured to control the advancement of the needle. For example, in an exemplary aspect, thesecond catheter200 can include aneed230 with a lumen238 and a sharp edge234 that is longitudinally controlled along theprimary lumen216 by a stylus246.
• In additional exemplary applications, it is contemplated that thepercutaneous catheter system10 can be applied anywhere precision catheter-based puncture between two adjacent anatomic spaces (as described above) is desired. For example, it is contemplated that a dialysis fistula can be performed by advancing opposing catheters of apercutaneous catheter system10 to a site of adjacent artery and vein to make a controlled perforation and shunt. In another exemplary application, it is contemplated that a controlled trans-cardiac puncture can be performed across the atrial wall into the pericardial space of a subject to accomplish epicardial pacemaker lead implantation. Where a trans-vascular puncture site is remote, it is contemplated that other biosensor and/or stimulator lead placement could be performed using the disclosedpercutaneous catheter system10. In still further exemplary aspects, it is contemplated that thepercutaneous catheter system10 can be used for shunt placement between internal cavities, such as the plural space and parental space, for chronic plural effusions, or for creating a fistula between the bladder and a drain. It is further contemplated that the disclosedpercutaneous catheter system10 can be modified as necessary to permit usage of the catheter system in percutaneous procedures where special and anatomic restrictions do not facilitate precise puncture of a tissue structure and/or guide-wire manipulation.
Ablation Catheter
• With reference toFIGS. 27-34, described herein is anablation catheter20 for ablating a selected tissue region within the body of a subject. In exemplary aspects, theablation catheter20 is an over-the-wiremulti-electrode ablation catheter20 that can create a linear circumferential ablation lesion using one or more of radiofrequency (RF) energy, irreversible electroporation (IE) impulses, and other hybrid electro cautery techniques. Theablation catheter20 is designed to apply high-voltage, ultra-short direct current pulses to tissue that causes tissue injury, cell death, and in some instances, only cell function disruption.
• However, it is contemplated that other ablative techniques such as cooling, microwave, ultrasound, light, and/or chemical ablation techniques could also be used as alternative and/or as adjuvant to the ablation approaches described herein. For example, aspects of theablation catheter20 can apply HVUS-DCI, RF, cryoablation, electroporation, microwave, laser, biologics, radiation, and small molecule chemicals. These impulses produce brief but extremely strong electric fields within the tissue leading to irreversible electroporation (IE), cell death, and injury. However, in an aspect, the total energy applied is relatively low averaging (estimated range 0.025J to 45J per pulse).
• In additional exemplary aspects, theablation catheter20 can be used in conjunction with thepercutaneous catheter system10 described above. In these aspects, thepercutaneous catheter system10 can be used to place aguide wire300 within the heart of a subject, and theablation catheter20 can be advanced within the heart over the guide wire. Following placement of theablation catheter20, ablative energy can be selectively applied within the heart of the subject. In exemplary aspects, the entire ablation procedure can be performed without administration of anesthesia.
• In one aspect, as illustrated inFIGS. 27-32, theablation catheter20 comprises a flexibleelongate shaft500 having a longitudinal axis502, a longitudinal length504, aproximal portion506, acentral portion508, and adistal portion510. In this aspect, theelongate shaft500 can define a primary lumen512. In this aspect, it is contemplated that the primary lumen512 can be configured to receive theguide wire300. While theablation catheter20 can be comprised of many different materials, the material should flexible. In exemplary aspects, theablation catheter20 can be highly flexible such that, upon deployment, the flexibleelongate shaft500 of thecatheter20 can conform to the natural contours of the anatomy. In these aspects, the flexibility of theablation catheter20 can facilitate positioning ofelectrodes530 around the outside of asymmetric and/or complex contours.
• In another aspect, theablation catheter20 further comprises a plurality ofelectrodes530 spaced along the longitudinal length504 of thecentral portion508 of the flexibleelongate shaft500. In this aspect, it is contemplated that the plurality ofelectrodes530 can be integrally formed with theelongate shaft500. Each of theelectrodes530 is configured to be connected to a signal source through an independent wire518 (shown inFIG. 28) that is connected by pins519 to the signal source. Theelectrodes530 are configured to apply a signal to the targeted area to perform an ablation.Individual electrodes530 can be assigned polarity and function in real time to optimize direction of current vectors during ablation. In an aspect, theelectrodes530 can be capable of monitoring and/or delivering RF energy, electroporation impulses, and programmed cardiac pacing and/or neuro-stimulus. Unlike other known ablation catheters, theelectrodes530 of the describedablation catheter20 also can have the capability of delivering extended bipolar high voltage, ultra-short impulses.
• In an aspect, in addition to being configured to apply a signal, theelectrodes530 are configured to be capable to selectively record signals. In this aspect, the signals can be described by an impulse strength, a duration, a duty cycle, and a timing. When theelectrode530 is configured to record the signals, theelectrode530 can record the above described characteristics of the signal(s) applied. Theelectrode530 can capture this information, and send it to a console, described in more detail below. In an aspect, anelectrode530 that is not applying a signal can act as arecording electrode530. In another aspect, theelectrodes530 of theablation catheter20 can be configured to act as a recording electrode andsignal delivering electrode530 at the same time.
• In another aspect, theelectrodes530 can be configured to monitor the vital signals of the subject. For example, theelectrodes530 can receive the electronic signals produce by the subject's heart to which theelectrode530 is in contact. In an aspect, theelectrode530 can act like an EKG. In another aspect, theelectrode530 can monitor the atrial pacing (including the atria refractory period), the ventricular pacing (including the ventricular refractory period), the cycle length, the QT interval, and the QRS interval of the subject's heart. The information can be passed along to other components discussed in more detail below.
• In exemplary aspects, the plurality ofelectrodes530 can be spaced to provide adequate coverage for creating a contiguouslinear ablation lesion40. In these aspects, it is contemplated that the ratio of the spacing532 betweenconsecutive electrodes530 to the longitudinal length of each electrode can be less than about 3:1 and, more preferably, less than about 2:1. In additional exemplary aspects, it is contemplated that the plurality ofelectrodes530 can comprise between about 20 to about 40independent electrodes530. In an example, theablation catheter200 can have 30 independent electrodes (e.g.,FIG. 34). In further exemplary aspects, it is contemplated that the plurality ofelectrodes530 can be spaced along a sufficient length of the elongate shaft500 (e.g., ranging from about 15 cm to about 30 cm) to create a circumscribinglesion30 around a left atrial target and pulmonary veins. It is contemplated that the plurality ofelectrodes530 can be positioned centrally along the longitudinal length504 of theablation catheter20 so that the proximal portion504 anddistal portion510 of theelongate shaft500 are of sufficient length such that at least a portion of the proximal portion504 and thedistal portion510 are positioned external to the body when thecentral portion506 of the elongate shaft500 (including the plurality of electrodes530) is deployed around the left atrial target structures. It is contemplated that the ratio between the longitudinal length of theproximal portion506 to the longitudinal length of thecentral portion508 and the ratio between the longitudinal length of thedistal portion510 and the longitudinal length of thecentral portion508 can each range from about 1.5:1 to about 2:1. It is further contemplated that theproximal portion506 and thedistal portion510 of theelongate shaft500 can each have a longitudinal length ranging from about 40 cm to about 60 cm.
• In exemplary aspects, the flexibleelongate shaft500 can be configured for selective positioning within the body of the subject such that thecentral portion508 of theelongate shaft500 at least partially surrounds the selected tissue region (shown inFIGS. 33-34) and the proximal506 anddistal portions510 of theelongate shaft500 are positioned external to the body of the subject. In these aspects, it is contemplated that, upon positioning of theelongate shaft500 such that thecentral portion508 of theelongate shaft500 at least partially surrounds the selected tissue region, eachelectrode530 of the plurality ofelectrodes530 is configured for selective, independent activation to apply ablative energy to the selected tissue region.
• Optionally, in one aspect, the flexibleelongate shaft500 can further comprise one or moresecondary lumens514 defined by the flexibleelongate shaft500 and/or positioned within the primary lumen512. In an aspect, at least onesecondary lumen514 of the one or moresecondary lumens514 or the primary lumen512 of the flexibleelongate shaft500 can be configured to receive theguide wire300. In such an aspect, theother lumen512,514 that are not for use with theguide wire300 can be configured to receive a flexible stylus and/or other mechanical support. Further, such lumens can be configured to carry and/or deliver a cooling fluid, an irrigation fluid, small molecules, peptides, and/or DNA/RNA to improve ablation characteristics. It is further contemplated that theelongate shaft500 can be configured for deployment within the body of the subject over theguide wire300. However, it is contemplated that theablation catheter20 can optionally be deployed within the body of a subject in a manual fashion (without a guide wire).
• In an aspect, theproximal end506 of thecatheter20 can include a luer lock516 andopening518 to receive aguidewire300 in the primary lumen512 orsecondary lumen514, as shown inFIG. 30. Thedistal end510 can include an opening520 that continues to thesecondary lumen514, allowing aguidewire300 to exit, as shown inFIG. 31. Further, thedistal end510 can have a tapered shape as well.
• In an aspect, theablation catheter20 can include acatheter noose524, as shown inFIGS. 27 and 32. Thecatheter noose524 is configured to apply tension to theelongated body500 of thecatheter20 when thecatheter20 is positioned around the targeted sight. In an aspect, and discussed in further details below, thecentral portion508 of thecatheter20 is positioned around the targeted area within the body, with the proximal506 and distal510 ends positioned outside of the body. Thecatheter noose524 is then used to tighten the loop formed by thecenter portion508 of thecatheter20 around the targeted area. In an aspect, thecatheter noose524 can include two lumens (not shown). The first lumen can be configured to receive theproximal end506 of thecatheter20. The second lumen can be configured to receive thedistal end510 of thecatheter20 after thecatheter20, and more specifically thecentral portion508, has been positioned around the targeted area within the body and thedistal end510 andproximal end506 are positioned outside the body. Thecatheter noose524 can then be advanced along the proximal anddistal portions506,510 until thecentral portion508 is fully secured, as shown inFIGS. 33-34.
• In use, theablation catheter20 can be employed in a method for ablating a selected tissue region within the body of a subject. In one aspect, the method for ablating the selected tissue region (4000), as shown inFIG. 35, can comprise selectively positioning the flexible elongate shaft of the ablation catheter within the body of the subject such that the central portion of the elongate shaft at least partially surrounds the selected tissue region (step4100). In this aspect, theproximal portion506 and thedistal portion510 of theelongate shaft500 of theablation catheter20 can optionally be positioned external to the body of the subject (step4200). In another aspect, the method for ablating the selected tissue region can comprise selectively, independently activating eachelectrode530 of the plurality ofelectrodes530 of theablation catheter20 to apply ablative energy to the selected tissue region (step4300).
• In an exemplary aspect of the method4000 described above, thedistal end510 of thecatheter20 can be advanced along theguidewire300 to be positioned around the left atrial target structures, with thedistal end510 being deployed to cross the pericardial reflection into the transverse sinus and through until thecentral portion508 is positioned correctly (step4100), as shown inFIGS. 36-37. Theproximal portion506 anddistal portion510 can be placed outside of body (step4200), as shown inFIG. 37. Once in place, thecatheter noose524 can be advanced to cinch the loop, as shown inFIG. 38. In cases where the circumference is less than the length504 of thecatheter20 along the central portion508 (i.e., the multi-electrode530 array), excessproximal electrodes530 are deactivated and pulled proximally into thecatheter noose524 before applying ablative energy (step4300). If the circumference of the targeted area is greater than the length504 along thecentral portion508, thecentral portion508 will require an additional repositioning after applying the ablative energy (step4300).
• In exemplary aspects, it is contemplated that theablation catheter20 can be included in anablation catheter system600 for ablating a selected tissue region within the body of a subject, as shown inFIGS. 39-44. In an aspect, theablation catheter system600 can include arouting console610, a recording console650, asignal generator700, and a computer800. Therouting console610 is electrically coupled to the plurality ofelectrodes530 of theablation catheter20. More specifically, therouting console610 is connected to each pin519 of eachindependent wire518 from eachelectrode530. Therouting console610 can carry signals from thesignal generator700 to theelectrodes530, as well as assign polarity and function in real time to optimize the direction of current vectors during ablation, discussed in more detail below.
• As shown inFIGS. 40-41, therouting console610 includescatheter connectors612 to receive the pins519 of theablation catheter20. Anexemplary routing console610 can include two 16 pin connecters used to accommodate thirty (30)independent electrodes230 on theexemplary ablation catheter200. However, the total number of catheter connectors can be adjusted to accommodate any range of electrode arrays. The routing console also includes pacinginputs614, which can receive monitoring information from devices (EKG, etc.) used to monitor the function of the subjects' vital parts, including the heart. Therouting console610 can includesignal inputs616. Thesignal inputs616 receive the signal(s) from thesignal generator700. In an aspect, thesignal inputs616 can includehigh voltage inputs616. In other aspects, the signal inputs can accept RF and/or any electrical ablation energy source generated by thesignal generator700. The pacinginputs614 andsignal inputs616 feed into theinput signal relay618, which passes along all the information and signals to the various other components of theablation catheter system600, including thesignal generator700, recording console650 and computer800, as well as other components of therouting console610.
• Theinput signal relay618 is connected tologic controllers620 and arelay bank622. Thelogic controllers620 andrelay bank622 work in tandem to send signals to aspecific electrode530 based upon the information and commands received from other components, including thesignal generator700, the computer800, and the pacinginputs612. Therelay bank622 can pass signal information, as well as other information, to anotherrelay bank624 which is connected to an I/O interface626. The I/O interface626 can be in communication with thesignal generator700 through a signal generator output628. Thefirst relay bank622 can also pass along any information related to the signals that are being monitored by anelectrode530 to sensingoutputs630, which can be connected to the recording console650. The routing console can also include a timing relay632 which works with thecontrollers620 to control the delivery of the signals to theelectrodes530. The timing relay632 is connected to asynchronization trigger634, which is in communication with thesignal generator700.
• In an aspect, thesynchronization trigger634 ensures that when signals are sent to theelectrodes530 for ablation, the signals are applied in synchronization with the cardiac cycle, discussed in more detail below. Thesynchronization trigger634 can receive monitoring information monitoring devices through the pacinginputs614 or throughelectrodes530 that are assigned to a monitoring function. Thesynchronization trigger634 can monitor the EKG results, the atrial pacing (including the atria refractory period), the ventricular pacing (including the ventricular refractory period), the cycle length, the QT interval, and the QRS interval of the subject's heart to indicate when a signal should be delivered to theelectrodes530. For example, as shown inFIG. 45, thesynchronization trigger634 can determine the impulse window900 (i.e., when to apply the signal) by identifying when the ventricularrefractory period902 and the atria refractory period904 overlap. Thesynchronization trigger634 can then alert therouting console610 and thesignal generator700 of the window900 to apply the signal.
• 31 Therouting console610 includes afire button636. The fire button activates thesignal generator700 to generate a signal to deliver a signal to therouting console610. Therouting console610 will then deliver the signal to the desiredelectrodes530. The computer800 can direct therouting console610 as to whichelectrodes230 to deliver the signal.
• Therouting console610 is electrically coupled to thesignal generator700. In an aspect, thesignal generator700 can comprise one ormore signal generators700. It is contemplated that eachsignal generator700 of the one ormore signal generators700 can be configured to selectively generate one or more electrical signals. Thesignal generator700 can create several types of signals, including, but not limited to, radio-frequency (RF), high voltage ultra-short direct current (DC) impulses (as used in electroporation), stimulus range impulses, and/or hybrid electrical impulses. In addition, thesignal generator700 can vary at least one of the impulse strength, duration, duty cycle, and timing of the signals that thesignal generator700 generates.
• In an aspect, as illustrated inFIGS. 42-43, thesignal generator700 includes pulse/high voltage outputs702 that are configured to connect with the pulse/high voltage inputs616 of therouting console610. The outputs702 deliver the signal to therouting console610. Thesignal generator700 can include acontrol circuit704 that controls the characteristics of the signal that it generates, discussed in more detail below. Thecontrol circuit704 can also be connected to a voltage level controller705. The pulse outputs702 receive the signal from a capacitor706. In an aspect, the capacitor706 can comprise a bank of capacitors706. Apower supply708 can provide the power needed to the capacitor(s)706 to generate a signal. In an aspect, the capacitor706 can pass along the signal to a transistor710. In an aspect thetransistor708 can include an insulated-gate bi-polar transistor710. Thesignal generator700 also includes a commercially available pulse capacitor charger711 which provides a high voltage source for the capacitor bank and a feedback control to adjust peak voltage charge.
• In an aspect, thesignal generator700 can also include various inputs to reference information and commands. For example, thesignal generator700 can be connected to the computer800 and therouting console610 through an input/output connection712. The input/output connection can comprise a plurality of input/output connections712. In addition, the signal generator can be connected to the fire button through a separate input714. Parameters/commands from the computer800 and information from therouting console610, including thesynchronization trigger634 and activation of thefire button636, are received by thecontrol circuit704. Based upon the information received, thecontrol circuit704 controls the generation of the signal. For example, thecontrol circuit704 can control the pulse duration, the number of pulses within a burst, the burst pulse spacing, the voltage of the signal, and other signal parameters. In another aspect, thecontrol circuit704 can initiate the signal upon receiving a response from the fire button. In another aspect, thecontrol circuit704 can control when the signal is generated based upon information received from thesynchronization trigger634 in order to deliver a signal within the pulse window900.
• In an aspect, the recording console650 can receive and record all the information that is collected by the various other components of thesystem600. For example, the recording console650 can record the pacing information that therouting console610 receives from monitoring devices associated with the subject. In addition, the recording console650 can receive monitoring information from theelectrodes530 monitoring the subject. In an aspect, the recording console650 can also receive the signal information from therecording electrodes530. In another aspect, the recording console650 can receive other information from thesignal generator700 regarding the timing and strength of the signals generated, as well as other information. In an aspect, the recording console650 can be a separate component from the computer800 androuting console610. It can be a display device that immediately displays conditions to the users of thesystem600. In other aspects, the recording console650 can be an application within the computer800. The physical characteristics of the recording console650 are not important, nor whether it is a separate entity from the other components of theablation system600.
• In an aspect, the computer (shown inFIG. 44) can include ablation control software806 that controls the overall function of theablation system600. The ablation control software806 can use the other components of thesystem600 to retrieve information (gathering signal information from thesignal generator700/electrodes230, and pacing information from therouting console610/electrodes530) in order to initiate and maintain the ablation treatment. In other aspects, the ablation control software806 can also control thesynchronization trigger634, or supply thesynchronization trigger634 with the needed information to apply the signal during the window900.
• In these aspects, therouting console610 can be configured to receive the one or more electrical signals from the one ormore signal generators700. It is contemplated that therouting console610 can be further configured to selectively activate the plurality ofelectrodes530 by delivery of the one or more electrical signals from thesignal generators700. In an aspect, therouting console610 can be configured to selectively activate at least oneelectrode530 of the plurality ofelectrodes530 of theablation catheter20 such that the at least oneelectrode530 has a first polarity that is different from a polarity of at least oneother electrode530 of the plurality ofelectrodes530, which, in turn, can provide means for customizing the ablation vector for eachelectrode530 individually and/or delivering pacing and/or ablation impulses in quick succession.
• In exemplary aspects, theablation catheter system600 can be employed in a method for ablating a selected tissue region within the body of a subject5000, as shown inFIG. 46. In one aspect, themethod5000 for ablating a selected tissue region can comprise selectively positioning the flexibleelongate shaft500 of theablation catheter20 within the body of the subject such that acentral portion508 of theelongate shaft500 at least partially surrounds the selected tissue region (step5100) and aproximal portion506 and adistal portion510 of theelongate shaft500 are positioned external to the body of the subject (step5200). In another aspect, the method for ablating the selected tissue region can comprise selectively generating one or more electrical signals using the one or more signal generators610 (step5300). In an additional aspect, the method for ablating the selected tissue region can comprise, through therouting console620, receiving the one or more electrical signals from the one or more signal generators610 (step5400). In a further aspect, the method for ablating the selected tissue region can comprise, through therouting console620, delivering the one or more electrical signals to the plurality ofelectrodes530 of theablation catheter20 such that eachelectrode530 of the plurality ofelectrodes530 is selectively, independently activated to apply ablative energy to the selected tissue region (step5500). In an exemplary aspect, the method for ablating the selected tissue region can further comprise, through the plurality ofelectrodes530, selectively recording one or more electrical signals within the body of the subject (step5600). In another exemplary aspect, the method for ablating the selected tissue region can further comprise, through the one ormore signal generators610, selectively varying at least one of the impulse strength, the duration, the duty cycle, and the timing of the one or more electrical signals generated by the one ormore signal generators610 based upon the one or more electrical signals recorded by the plurality of electrodes530 (step5700). In a further exemplary aspect, it is contemplated that the step of, through the routing console, delivering the one or more electrical signals to the plurality ofelectrodes530 can comprise selectively activating at least oneelectrode530 of the plurality ofelectrodes530 such that the at least oneelectrode530 has a first polarity that is different from a polarity of at least one other electrode of the plurality ofelectrodes530, as discussed above.
• In exemplary aspects, theablation catheter20 can be highly flexible such that, upon deployment, the flexibleelongate shaft500 of thecatheter20 can conform to the natural contours of the anatomy. In these aspects, the flexibility of theablation catheter20 can facilitate positioning ofelectrodes530 around the outside of asymmetric and/or complex contours.
• It is contemplated that theablation catheter20 can be configured to deliver both radio frequency (RF) and/or high intensity ultra short duration electrical impulses/irreversible electroporation (IE) to ablate adjacent tissue. RF ablation in the closed pericardial space has some important limitations. First, RF ablation can produce tissue injury through resistive heating. The lesion depth resulting from RF ablation can be limited by the energy and thermodynamics of the tissue environment. For example, a unipolar RF lesion created from the epicardium can require greater energy to create a transmural lesion than the same lesion delivered form an endocardial approach; this is because the endocardium is cooled by the blood pool and there is often a layer of epicardial fat that adds thickness. (SeeFIG. 47.) Using an extended bipolar electrode arrangement, it is contemplated that approximately 50% more directional penetration can be achieved (using RF techniques).
• FIG. 47 shows the potential advantages of an extended bipolar ablation arrangement for epicardial ablation techniques. Panel (A) depicts a virtual electrode from a standard unipolar RF ablation on an endocardial surface. As shown, the field of the unipolar signal extends substantially only along the myocardium (a) and epicardial fat (b). Panel (B) shows unipolar RF ablation from an epicardial approach, with the field of the unipolar signal extends into the epicardial fat (b), pericardial space (c), and parietal pericardium (d). However, the field also extends to a bystander vulnerable structure (f). Panel (C) illustrates the distortion of the virtual electrode by using an extended bipolar orientation. As shown, the bipolar orientation leads the field to extend into the ventricular myocardium (a), epicardial fat (b), pericardial space (c), and parietal pericardium (d) without impacting the bystander vulnerable structure (f).
• It is contemplated that the use of high-voltage, ultra-short impulses (irreversible elecroporation) can substantially increase the directionality of the ablation vector. In a closed pericardial space, the thermal conduction can continue to be problematic, causing undesirable collateral damage and/or accumulation of proteinaceous material on the electrodes, which can require device removal, cleaning, and/or reinsertion. However, despite these limitations, it is contemplated that RF techniques may be preferred for ablation targets that are epicardial structures, such as autonomic ganglia.
• The selected polarity of eachelectrode530 of the plurality ofelectrodes530 can be assigned based upon the geometric orientation of eachrespective electrode530 toward the ablation target. Optionally, the assignment of polarity to eachrespective electrode530 can be performed in real time using therouting console610 attached to thecatheter530 outside the body. In an aspect, the polarity assignment for eachrespective electrode530 can be adjusted to tailor the intended vectors of ablation current. It another aspect, the polarity assignment can optionally be performed in connection with a remote electrode located within or external to the body. In these aspects, the vector of current between any two electrodes of the plurality of electrodes can be directed toward the intended ablation target by choosing anelectrode530 combination that optimizes the intended vector and away from bystander structures (seeFIG. 47). In another aspect, the electrode combination can comprise two ormore electrodes530 of thecentral portion508 of theablation catheter50.
• In another aspect, ahigh impedance structure540 can be positioned between theelectrodes530. Thehigh impedance structure540 is configured to change and/or direct the current path between selectedelectrodes530, as illustrated inFIGS. 48-52(a-c). In an aspect, theablation catheter20 can use a plurality ofhigh impedance structures540. Thehigh impedance structures540 are configured to intersect the theoretic field lines550 (seeFIGS. 48-49) created by twobipolar electrodes530 by creating an obstacle to a baseline current flow. For example, in a homogeneous conductor such as seawater or blood plasma, the predicted current path will follow the shortest path (i.e., the current will follow the path of least resistance), as shown inFIG. 48. By placing ahigh impedance structure540 betweenadjacent electrodes530, the current contour550, as shown inFIG. 49, can be distorted by the contours of thehigh impedance structure540, with the current density decreasing linearly between theelectrodes530 but increasing orthogonally along the surface of thehigh impedance structure540.FIGS. 50-51 show an axial perspective of the change of the location of thecurrent density544 of a coaxiallycylindrical insulator540 relative to the insulator circumference. As shown inFIG. 50, when the circumference of the insulator/high impedance structure540 is small, thecurrent density544 is approximate the surface of theelectrode530. However, as thehigh impedance structure540 expands, thecurrent density544 becomes located further from the surface of theelectrode530.
• In exemplary aspects, the shape, and more specifically the height of thehigh impedance structure540 relative to the axis502 of theablation catheter20, is adjustable. For example, thehigh impedance structure540 comprises aninflatable balloon540 made of a suitable nonporous material with high dielectric constantan (i.e., effectively an electric insulator). Theinflatable balloon540 is coaxially situated between twoelectrodes530, as shown inFIG. 52a-c.As theinflatable balloon540 is inflated, thecurrent density544 along the surface of the balloon will decrease linearly while the relativecurrent density544 at an arbitrary point between theelectrodes510 and orthogonally remote from the axis502 of theablation catheter20 increases. The adjustment of theinflatable balloon540 provides a way to project and or direct the electric field along an orthogonal/radial vector to increase thecurrent density544. While the exemplary aspect utilizes aballoon540 to provide low profile delivery, other articulated, fixed and/or mechanicalhigh impedance structures540, including a wide variety of insulators, can be employed. Further, it is preferable that thehigh impedance structures540 are controllably adjustable, for the reasons discussed below.
• The current density at the surface of the cylindrical insulator symmetrical positioned between two ring electrodes is geometrically related to the radius of the cylinder. In such an exemplary aspect can be determined by the following formula:
• 
  J=J_i(Πr²* 1_ii)_i/((Πr²*1_i)₂−(Πr²*1_i)_i)
• where J is the resulting density, J_iis the initial density, (Π r²*1_i)_iis the initial area of the high impedance structure before activation, and (Π r²*1_i)₂is the area of the high impedance structure after activation.
• In our exemplary aspect, the electrical conductivity ranges 50-100 S/M (conductivity σ is defined as the ratio of the current density J to the electric field strength E). (J=Sigma.E). The predicted electric field strength at the surface of the insulator balloon540 (represented by A inFIGS. 48-49) will be related to the current density/conductivity of the environment.
• Positioning of the high impedance structure orinsulator540 between the dipole formed fromadjacent electrodes530 will change the contour of the current path and increase the relative electric field strength at point A, as shown inFIGS. 48-49. The shape of thehigh impedance structure540 can be varied to project/amplify the relative the current orthogonal to the axis502 of theablation catheter20. Other shapes and materials can be uses as high in combination with high impedance structures/insulators540 to focus the current asymmetrically or to isolate the current source form the target tissue. In an aspect, the high impedance structure orinsulator540 can comprise aninsulator balloon540 configured to expand off center to provide a preferential path for current ipsilateral to the shorter axis's.
• In other aspects, the high impedance structure orinsulator540 can be constructed to geometrically isolate current from onesource electrode530 from untargeted nearby structures but allow the current to travel through a fenestration or other geometrically oriented opening, there by changing the current density. In a simple example, a balloon when expanded would partially cover theelectrodes530 while creating a prescribed tunnel for the current to travel through. In an aspect, anasymmetrical balloon530 can focus current along the path of least resistance (generally the shortest linear distance). In another aspect, an expanding meshhigh impedance structure530 can surround theelectrode530 to safely increase current at thatelectrode530 with less risk of unwanted collateral damage by simply maintaining a prescribed distance from soft tissues. Such a high impedance structure allows an increase current density at one end of a bipole near an ablation target while protecting structures at the counterpoint. The use of geometric high impedance structures orinsulators540 to contour the current path of a current created betweendipole electrodes530 within a conductive media such as tissue could be used to precisely deliver electrical ablation or stimulus energy to targeted tissues adjacent to thehigh impedance structure540.
• While the combination of theelectrodes530 and thehigh impedance structures540 are directed to deliver high voltage ultra short ablation impulses in the pericardial/epicardial space for the purpose of treating cardiac arrhythmia, there is an immediate implication for other ablation procedures using theelectrode530/high impedance structures540 for contouring ablation energy to vascular walls (in stent restenosis) and/or contour thevirtual electrode530 in ablation procedures targeting solid tumors and/or prostatic hypertrophy. While balloon catheters are known in the art for the purpose of providing mechanical force, geometric stabilization, and or the delivery of ablation energy such a laser light or ultrasound, the combination ofelectrodes530 andhigh impedance structures540 oriented on aablation catheter20 is fundamentally distinct as theablation catheter20 uses thehigh impedance structures540 to shape the electric current used in an in vivo therapy.
• It is contemplated that theindependent electrodes530 can be assigned polarity individually or in groups. Depending on these polarity assignments, it is contemplated that the relative orientation of the electrical impulses and the virtual electrode properties (e.g., the surface area and thus control current density) of theelectrodes530 can be selectively adjusted. In exemplary aspects, the plurality ofelectrodes530 of theablation catheter20 can be connected to a routing console/switchboard610 outside the body where theelectrodes530 can be assigned a role as a recording electrode, an active pacing, and/or an ablation electrode, as discussed above. Theconsole610, in turn, can be operatively coupled to a computer-controlledsignal generator700 and recording console650. In an aspect, the electrode polarity assignments can be changed as needed to achieve one or more desired effects. By changing the relative polarity assignments of theelectrodes530, at least one of the virtual electrode shape and the current density can be selectively varied.
• In another aspect, the ablation energy can be delivered to asingle electrode530 or tomultiple electrodes530 simultaneously. In an aspect,FIGS. 53a-ddisplay an array of dexemplary electrode530 assignments.FIG. 53aillustrates an extended bipolar arrangement with equal current density betweenelectrodes8 and23. The selectedelectrodes8 and23 can deliver an ablation impulse for every cardiac cycle, changing the active bipoles with every cardiac cycle in a step-wise manner. In an example, if the heart is paced at a 500 ms cycle length the circumferential linear lesion will be delivered in 7.5 seconds.
• FIG. 53billustrates an extended bipolar arrangement with asymmetric current density, wherein electrode8 is assigned a different polarity thanelectrodes22,23, and24. This assignment decreases the current density at one of the bipoles to reduce injury to bystander structures near the pole.
• FIG. 53cillustrates an extended bipolar arrangement with equal current density but activated as a simultaneous array. As illustrated, electrodes9-13 are assigned one polarity, whereas electrodes24-28 are assigned another. Theelectrodes530 are activated simultaneously to form complimentary arrays. This could be employed in cases where sub straight accommodated more rapid ablation sequencing (2-3 cycle lengths).
• An extended bipolar arrangement with asymmetric current density is illustrated inFIG. 53d. As shown,electrodes11,12,17, and18 are assigned a polarity different fromelectrode30, which creates an extended bipolar arrangement with a gap in the complementary electrode array. Such an arrangement can be used to avoid inadvertent ablation of a vulnerable bystander structures, including the phrenic nerve.
• It is still further contemplated that the impulses can be delivered in a programmed manner, triggered by feedback from a bio-potential or physiologic signal (such as respirations, nerve impulses, fluctuations in blood pressure, and/or the cardiac action potential) or an outside event.
• In exemplary applications, as described above, theablation catheter20 can be deployed such that both theproximal portion506 anddistal portion510 of theelongate shaft500 are external to the body (thecentral portion508 of the catheter with the multi-electrode array remains internal). However, in additional applications, it is contemplated that theablation catheter20 can be customized to take advantage of target anatomy; in some cases, thedistal portion510 of theablation catheter20 can remain in the body, and a remote electrode can be used to complete the ablation procedure.
• In exemplary applications, theablation catheter20 can be employed in a catheter-based epicardial atrial fibrillation ablation procedure performed in a closed pericardium. In this atrial fibrillation ablation procedure, theablation catheter20 can be advanced over aguide wire300 that has already been positioned around the epicardial left atrial structures. Thus, theablation catheter20 can be deployed into the pericardial space from a subxiphoid or apical percutaneous approach, as discussed above.
• It is contemplated that theguide wire300 can be delivered around the left atrium by using thepercutaneous catheter system10 described herein to puncture through two key anatomic obstacles (pericardial reflections near the vena cava and the right pulmonary veins). Using this method, theguide wire300 can enter the pericardium and then travel under the inferior-lateral left ventricle, along the lateral left atria, into the transvers sinus, along the roof of the left atria, between the right superior pulmonary vein and superior vena cava (SVC) through a pericardial puncture site. Then, theguide wire300 can travel along the right lateral aspect of the left ventricle, between the right inferior pulmonary vein and inferior vena cava (IVC), traveling through the second pericardial puncture into the obtuse sinus under the posterior left atria. Theguide wire300 can then extend under the ventricle and out of the pericardium such that both ends of theguide wire300 are outside the body. Once theguide wire300 has been positioned, theablation catheter20 can be advanced along theguide wire300. From this advantageous position, the ablation energy can be delivered directly to the key left atrial ablation targets, thereby creating a circumferential lesion without the need for repositioning theablation catheter20 or entering the left atrial blood pool. However, theablation catheter20 can be repositioned to perform other targeted epicardial ablations, including, for example and without limitation, ablation of autonomic ganglia or creation of additional linear ablation lesions.
• In an aspect a goal of the disclosed ablation procedure can be the electrophysiological isolation/decoupling of key segments of the heart (e.g., the left atrium and the ostia of the pulmonary veins) that are thought to be involved in the genesis and/or maintenance of atrial fibrillation. The disclosedpercutaneous catheter system10 andablation catheter20, and the associatedablation catheter system600, can provide means for creating a “box” lesion around ostia of the pulmonary veins without the need to enter the arterial blood pool. In use, after theablation catheter20 is deployed over theguide wire300, one ormore electrodes530 of the plurality ofelectrodes530 of theablation catheter20 can be used to measure local electrograms and/or deliver mapping stimuli. Using an extended bipolar arrangement of theelectrodes530, the directional electrograms adjacent to theelectrodes530 can be assessed to permit identification of changes in the substrate and local conduction block. As further described herein, theablation catheter20 can be connected to one ormore impulse generators700 and arouting console610. It is contemplated that the operator can select an electrode configuration to optimize the vector of current for each segment of the lesion. In exemplary aspects, the procedure can be at least partially computer-automated while requiring at least some input from the operator to identify a preferred current vector. Theimpulse generator700 can then deliver ablative energy to theelectrodes530 of the ablation catheter.
• In exemplary applications, theablation catheter20 can be configured to deliver high intensity ultra-short duration impulses/IE to produce a transmural lesion. In an aspect, the IE impulses can be delivered by theelectrodes530 in synchrony with the cardiac cycle (e.g., from about 200 ms to about 300 ms after detection of a QRS complex) to reduce the chance of inducing arrhythmias. In an aspect, the impulse strength, duration, duty cycle and timing of the IE impulses can be selectively adjusted to tailor the ablation characteristics in real time. In such an aspect, the real-time adjustments can be required to address changes in tissue conductance as the lesion evolves. In exemplary aspects, the power can be adjusted to maintain a constant current density in the virtual electrode, thereby reducing the tissue conductance. In such aspects, the tissue conductance can be measured between impulses and integrated into an automated feedback circuit. In such aspects, the impulse strength can be adjusted to electroporation impulses using a standard unipolar configuration or an extended bipolar configuration.
• Irreversible electroporation (IE) is a non-thermal ablation technique that can be advantageously used within the pericardial space. IE works by delivery on ultra-short (nano-seconds) high voltage (100-10,000V) impulses that cause very brief disruption in the membrane of cells. The disruption in the lipid bilayer leads to cell death through necrosis or apoptosis, depending on the field strength involved. In exemplary aspects, theablation catheter20 can permit customization of the direction of ablation energy within the pericardium. When compared to RF ablation, IE ablation can produce a lesion that follows a geometric pattern more closely approximating the contours of thevirtual electrode530. In such an aspect, theablation catheter20 can take advantage of these electrophysiologic properties to create a more focal lesion that directs the vector of current toward the target and also reduces the risk of unintended collateral injury. Although RF ablation using the same extended bipolar technique shows directionality, local tissue heating can reduce the current vector effect. (SeeFIG. 26). Additionally, the IE ablation can leave the intracellular matrix of tissue relatively undistorted, thereby reducing the risk of structural tissue instability, rupture, and fistula formation; there is typically limited or no opportunity for “char” formation on the electrode, so it generally will not need to be removed, cleaned, or redeployed. Because nerve fibers are particularly resistant to injury from IE techniques, IE ablation can reduce the risk of damage to nearby phrenic nerves. IE ablation can produce effective lesions in a fraction of the time required to create a transmural lesion by RF techniques. In exemplary aspects, IE impulses can be delivered via theablation catheter20 through theelectrodes530 in an automated fashion in a variety of extended bipolar orientations to create the complete linear circumscribing lesion in less than 1/10th the time it would take to produce the same lesion set using RF ablation techniques. IE ablation techniques are not dependent on tissue thermodynamics, thereby improving the chance of creating a full thickness lesion. Thermal techniques such as resistive heating from RF energy can be less effective because conductive cooling properties of the blood pool can protect the endocardium. In an aspect, IE ablation techniques can be selectively tuned to create lesions by apoptosis (as opposed to necrosis), leaving a very clean scar with less local inflammation.
• In exemplary configurations, theablation catheter system600 can comprise theablation catheter20 and arouting console610 that is linked to a commerciallyavailable signal generator700 which is capable of arbitrary electrical waveform generation, including simple DC stimulus, radiofrequency monophasic and biphasic impulse generation, and high voltage ultra short impulse generation.
• In use, after an operator has positioned aguide wire300 around the left atrium, theablation catheter20 can be advanced over theguide wire300 so that the array of electrodes530 (located at thecentral portion508 of the elongate shaft500) now surrounds the left atrium. Thedistal portion510 of theablation catheter20 can extend outside the body of the subject and be passed through the means for applying tension524 (e.g., a loop tensioner524), as further described herein. Theloop tensioner524 can then be advanced over theproximate portion506 anddistal portion510 of theablation catheter500 to provide lateral tension and create a closed loop around the left atrial target structures. Theguide wire300 can then be removed to provide more flexibility and improved tissue contact along the left atrial contours. Small adjustments can be made using theloop tensioner524 and/or a variety ofcustom styluses524 that can be inserted into the catheter wire lumen512/514. Once a desired position of theelectrodes530 of theablation catheter20 around the targeted tissue region is achieved, it is contemplated that theablation catheter20 will not need to be repositioned.
• The operator can then conduct a limited electrophysiologic study, checking left atrial pacing thresholds and local electrocardiograms. The operator can then evaluate the radiographic orientation of theelectrodes530 around the left atrium and assign a polarity to the eachrespective electrode530. Optionally, this assignment procedure can be partially automated to reduce the total steps needed to create and optimal extended bipolar vector. The tissue conductance and impedance can be measured at eachelectrode530 at baseline. In an aspect, these measurements can be performed in an automated procedure performed by an automated recorder and potentially integrated into the control algorithm to make voltage adjustments, and/or can be performed manually by the operator. These baseline measurements can be periodically re-measured to assess local ablation effects. The data can be used to adjust the applied ablation energy in an automated fashion when such automated functions are available. It is contemplated that eachelectrode530 of the plurality ofelectrodes530 of theablation catheter20 can be used to monitor, pace and/or deliver energy for ablation. In exemplary aspects, the ablation energy can be delivered to the plurality ofelectrodes530 using a programed computerized protocol synchronized with the cardiac cycle of the subject. In exemplary applications, the operator can selectively initiate a sequence activating eachelectrode530 individually and/or in series.
• It is contemplated that the linear ablation should be completed in less than about 60 seconds (depending on the baseline heart rate and total length of the linear lesion being created). In the exemplary system we will overdrive pace the heart at a rate between100 and120 beats per minute. In order to deliver ablation pulses or train of pulses to each electrode we will discharge the device n*1/2 times the number of electrodes in the array. In our example we use30 electrodes therefor a completed cycle will take 7.5 seconds. Conceivably the entire procedure could be performed in 7.5 milliseconds with commercially available solid-state high voltage relays.
• In an aspect, an electrophysiologic study of conduction block can be performed without any repositioning of theablation catheter20. The operator can perform a programed stimulus protocol to identify gaps in the linear lesion. In the example the operator would perform an electrophysiologic study prior to the ablation. The principal maneuver would be to measure the pacing threshold at each point along theablation catheter20. Theelectrodes530 of theablation catheter20 can be used for measuring the pacing threshold, or other pacing measuring devices can be used. After the ablation is delivered the operator could retest the capture threshold. The anticipated results would be an increase in the local pacing threshold. Furthermore a more standard electrophysiologic study can be performed using pacing electrodes in the pericardial space and/or standard diagnostic electrophysiologic catheters in the right atria, coronary sinus and right ventricle. Conformation that the pulmonary veins are electrically uncoupled from the rest of the left atria is a standard clinical practice. Atrial pacing form inside the lesion boundary can be performed using a remote stimulus electrode, which can optionally be a part of theloop tensioner524. When there is evidence of conduction outside the lesion (as evidenced by capture of the atria), the operator can evaluate the local electrograms to identify potential gaps in the lesion. It is contemplated that the extended bipolar arrangement of theelectrodes530 can be useful in determining timing and direction of local depolarization. Electrodes overlaying these potential incomplete ablation sites can be identified and additional energy can be delivered as needed.
• Once complete electrophysiologic block around the pulmonary veins is verified, it is further contemplated that theablation catheter20 can also be used to evaluate autonomic ganglia that are common along this path. These potential targets can be identified with neuro-stimulus techniques and evaluation of epicardial signals. The operator can choose to deliver RF ablation to these select sites, if desired. After the ablation is complete, it is contemplated that theablation catheter20 can be removed or repositioned to create lesions at additional ablation target sites.
• As described herein, theablation catheter20 is an over-the-wire ablation catheter with an array ofmultiple electrodes530 located on its mid (central)portion508. Theablation catheter20 can be more flexible than other clinically available catheter-based ablation devices to permit tissue contact around the left atrial structures. Theelectrodes530 can be capable of monitoring and/or delivering RF energy, electroporation impulses, and programed cardiac pacing and/or neuro-stimulus. The ability of the disclosedablation catheter20 to individualize the as-extendedbipolar electrode530 can take advantage of the natural geometry inside the pericardial space to deliver energy to a series of electrodes arranged around the target structure.
• In use, once theablation catheter20 is deployed, it is contemplated that a linear lesion can be created without need to reposition thecatheter20. It is further contemplated that theablation catheter20 can provide a stable and contiguous array ofelectrodes530 along the target path that can deliver ablation energy and can also be used to confirm electrophysiologic block using an extended bipolar electrocardiographic technique. It is contemplated that the use ofhigh impedance structures540 positioned along the bipolarly aligned electrodes can further adjust the density of the current applied. It is contemplated that the ability to perform the entire procedure without repositioning of theablation catheter20 can save time and potentially make this approach more effective than standard point-by-point techniques, which often require frequent repositioning and/or advanced noncontact mapping techniques to identify incomplete segments in the ablation lesion. For epicardial techniques performed from the pericardial space, such manipulation is fraught with danger and technical limitations. The disclosedablation catheter20 takes advantage of the natural contours of the left atrial epicardial surface to provide reliable and stable electrode contact.
• As will be appreciated by one skilled in the art, the methods and systems described above in relation to theablation catheter system600 may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the methods and systems may take the form of a computer program product on a computer-readable storage medium having computer-readable program instructions (e.g., computer software) embodied in the storage medium. More particularly, the present methods and systems may take the form of web-implemented computer software. Any suitable computer-readable storage medium may be utilized including hard disks, CD-ROMs, optical storage devices, or magnetic storage devices.
• Some embodiments of the methods and systems discussed above and below can be described with reference to block diagrams and flowchart illustrations of methods, systems, apparatuses and computer program products. It will be understood that each block of the block diagrams and flowchart illustrations, and combinations of blocks in the block diagrams and flowchart illustrations, respectively, can be implemented by computer program instructions. These computer program instructions may be loaded onto a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions which execute on the computer or other programmable data processing apparatus create a means for implementing the functions specified in the flowchart block or blocks.
• These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including computer-readable instructions for implementing the function specified in the flowchart block or blocks. The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions that execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks.
• Accordingly, blocks of the block diagrams and flowchart illustrations support combinations of means for performing the specified functions, combinations of steps for performing the specified functions and program instruction means for performing the specified functions. It will also be understood that each block of the block diagrams and flowchart illustrations, and combinations of blocks in the block diagrams and flowchart illustrations, can be implemented by special purpose hardware-based computer systems Thal perform the specified functions or steps, or combinations of special purpose hardware and computer instructions.
• The methods and systems that have been introduced above, and discussed in further detail below, have been and will be described as comprised of units. One skilled in the art will appreciate that this is a functional description and that the respective functions can be performed by software, hardware, or a combination of software and hardware. A unit can be software, hardware, or a combination of software and hardware. The units can comprise the ablation control software806 as illustrated inFIG. 44 and described below. In one exemplary aspect, the units can comprise a computer800 as illustrated inFIG. 44 and described below.
• FIG. 44 is a block diagram illustrating an exemplary operating environment for performing the disclosed methods. This exemplary operating environment is only an example of an operating environment and is not intended to suggest any limitation as to the scope of use or functionality of operating environment architecture. Neither should the operating environment be interpreted as having any dependency or requirement relating to any one or combination of components illustrated in the exemplary operating environment.
• The present methods and systems can be operational with numerous other general purpose or special purpose computing system environments or configurations. Examples of well known computing systems, environments, and/or configurations that can be suitable for use with the systems and methods comprise, but are not limited to, personal computers, server computers, laptop devices, and multiprocessor systems. Additional examples comprise set top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments that comprise any of the above systems or devices, and the like.
• The processing of the disclosed methods and systems can be performed by software components. The disclosed systems and methods can be described in the general context of computer-executable instructions, such as program modules, being executed by one or more computers or other devices. Generally, program modules comprise computer code, routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The disclosed methods can also be practiced in grid-based and distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules can be located in both local and remote computer storage media including memory storage devices.
• Further, one skilled in the art will appreciate that the systems and methods disclosed herein can be implemented via a general-purpose computing device in the form of a computer800. The components of the computer800 can comprise, but are not limited to, one or more processors or processing units803, a system memory808, and a system bus813 that couples various system components including the processor803 to the system memory808. In the case of multiple processing units803, the system can utilize parallel computing.
• The system bus813 represents one or more of several possible types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, and a processor or local bus using any of a variety of bus architectures. By way of example, such architectures can comprise an Industry Standard Architecture (ISA) bus, a Micro Channel Architecture (MCA) bus, an Enhanced ISA (EISA) bus, a Video Electronics Standards Association (VESA) local bus, an Accelerated Graphics Port (AGP) bus, and a Peripheral Component Interconnects (PCI), a PCI-Express bus, a Personal Computer Memory Card Industry Association (PCMC1A), Universal Serial Bus (USB) and the like. The bus813, and all buses specified in this description can also be implemented over a wired or wireless network connection and each of the subsystems, including the processor803, a mass storage device804, anoperating system805, ablation control software806, data807, anetwork adapter809, system memory808, an Input/Output Interface812, adisplay adapter810, a display device811, and a human machine interface802, can be contained within one or more remote computing devices814 at physically separate locations, connected through buses of this form, in effect implementing a fully distributed system.
• The computer800 typically comprises a variety of computer readable media. Exemplary readable media can be any available media that is accessible by the computer800 and comprises, for example and not meant to be limiting, both volatile and non-volatile media, removable and non-removable media. The system memory808 comprises computer readable media in the form of volatile memory, such as random access memory (RAM), and/or non-volatile memory, such as read only memory (ROM). The system memory808 typically contains data such as data807 and/or program modules such asoperating system805 and ablation control software806 that are immediately accessible to and/or are presently operated on by the processing unit803.
• In another aspect, the computer800 can also comprise other removable/non removable, volatile/non-volatile computer storage media. By way of example,FIG. 1 illustrates a mass storage device804 which can provide non-volatile storage of computer code, computer readable instructions, data structures, program modules, and other data for the computer800. For example and not meant to be limiting, a mass storage device804 can be a hard disk, a removable magnetic disk, a removable optical disk, magnetic cassettes or other magnetic storage devices, flash memory cards, CD-ROM, digital versatile disks (DVD) or other optical storage, random access memories (RAM), read only memories (ROM), electrically erasable programmable read-only memory (EEPROM), and the like.
• Optionally, any number of program modules can be stored on the mass storage device804, including by way of example, anoperating system805 and ablation control software806. Each of theoperating system805 and ablation control software806 (or some combination thereof) can comprise elements of the programming and the ablation control software806. Data807 can also be stored on the mass storage device804. Data807 can be stored in any of one or more databases known in the art. Examples of such databases comprise, DB20, Microsoft® Access, Microsoft® SQL Server, Oracle®, mySQL, PostgreSQL, and the like. The databases can be centralized or distributed across multiple systems.
• In another aspect, the user can enter commands and information into the computer800 via an input device (not shown). Examples of such input devices comprise, but are not limited to, a keyboard, pointing device (e.g., a “mouse”), a microphone, a joystick, a scanner, tactile input devices such as gloves, and other body coverings, and the like. These and other input devices can be connected to the processing unit803 via a human machine interface802 that is coupled to the system bus813, but can be connected by other interface and bus structures, such as a parallel port, game port, an IEEE1394 Port (also known as a Firewire port), a serial port, or a universal serial bus (USB).
• In yet another aspect, a display device811 can also be connected to the system bus813 via an interface, such as adisplay adapter810. It is contemplated that the computer800 can have more than onedisplay adapter810 and the computer800 can have more than one display device811. For example, a display device can be a monitor, an LCD (Liquid Crystal Display), or a projector. In addition to the display device811, other output peripheral devices can comprise components such as speakers (not shown) and a printer (not shown) which can be connected to the computer800 via Input/Output Interface812. Any step and/or result of the methods can be output in any form to an output device. Such output can be any form of visual representation, including, but not limited to, textual, graphical, animation, audio, tactile, and the like. Likewise, therouting console610, recording console650, andsignal generator700 can communicate with the computer800 and its components through the Input/Output Interface812.
• The computer800 can operate in a networked environment using logical connections to therouting console610, recording console650, andsignal generator700 and/or to one or more remote computing devices814. By way of example, a remote computing device can be a personal computer, portable computer, a server, a router, a network computer, a wireless connected tablet or mobile device, a peer device or other common network node, and so on. Logical connections between the computer800 and a remote computing device814 can be made via a local area network (LAN) and a general wide area network (WAN). Such network connections can be through anetwork adapter809. Anetwork adapter809 can be implemented in both wired and wireless environments. Such networking environments are conventional and commonplace in offices, enterprise-wide computer networks, intranets, cellular networks and the Internet815.
• For purposes of illustration, application programs and other executable program components such as theoperating system805 are illustrated herein as discrete blocks, although it is recognized that such programs and components reside at various times in different storage components of the computing device800, and are executed by the data processor(s) of the computer. An implementation of ablation control software806 can be stored on or transmitted across some form of computer readable media. Any of the disclosed methods can be performed by computer readable instructions embodied on computer readable media. Computer readable media can be any available media that can be accessed by a computer. By way of example and not meant to be limiting, computer readable media can comprise “computer storage media” and “communications media.” “Computer storage media” comprise volatile and non-volatile, removable and non-removable media implemented in any methods or technology for storage of information such as computer readable instructions, data structures, program modules, or other data. Exemplary computer storage media comprises, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by a computer.
• The methods and systems can employ Artificial Intelligence techniques such as machine learning and iterative learning. Examples of such techniques include, but are not limited to, expert systems, case based reasoning, Bayesian networks, behavior based AI, neural networks, fuzzy systems, evolutionary computation (e.g. genetic algorithms), swarm intelligence (e.g. ant algorithms), and hybrid intelligent systems (e.g. Expert inference rules generated through a neural network or production rules from statistical learning).
• The proposed procedures are performed under conscious sedation and local anesthesia in a standard cardiac catheterization laboratory. The patient is prepped in the typical manner for an electrophysiologic study with an additional sterile field exposing the anterior chest and upper abdomen. Stimulus and mapping catheters are positioned in the RA, RV, and CS position. Percutaneous access to the pericardial space is achieved using a modified Seldinger technique or clinically available pericardial access tool. A small volume of iodinated contrast is injected into the pericardial space for visualization of key cardiac landmarks. The percutaneous track is expanded to accommodate catheter insertion. The clinical goal of the procedure will be to position a multi-electrode ablation catheter within the pericardial space for the purpose of ablation. The catheter will follow a course that circumferentially divides the more anterior left atrial structures from the pulmonary veins. Once in a stable position, the catheter's multi-electrode array will be used to deliver a single linear ablation lesion that can electrophysiologically isolate arrhythmogenic substrate of pulmonary veins from the greater left atrium.
• As further described herein, it is contemplated that epicardial positioning theablation catheter20 can have mechanical advantages over endocardial multi-electrode arrays. Theablation catheter20 can tailor the circumference of the loop formed by theelongate shaft500 of thecatheter20 with little effort to provide full coverage. The flexibility of theablation catheter20 can provide a mechanism for secure tissue contact around complex anatomic geometry. It is further contemplated that the natural spatial limitation of the pericardial space provides a natural mechanism to assure electrode approximation. Furthermore, the risks of performing ablation from the epicardial surface place theablation electrode530 closer to some important bystander structures that necessitate the delivery of ablative energy with programed directional vectors. (SeeFIG. 23). With RF energy ablation, extended bipolar ablation can result in 40-50% deeper lesion in the direction of the programed vector. With IE ablation, the potential for creating a preferential directional injury vector can be greater because there is limited or no thermal energy. Typically, unipolar applications utilize an externalized grounding pad that results in a diffuse or spherical virtual electrode, while currently known bipolar ablation techniques typically utilize electrode pairs that are in very close proximity, require equipment is cumbersome, and require entry into both the pericardium and the left atrial blood pool.
• In exemplary aspects, it is contemplated that theablation catheter20 can be modified to deliver gene therapy. In these aspects, it is contemplated that theelongate shaft500 of theablation catheter20 can be modified to have irrigation side ports. It is further contemplated that a DNA or RNA vector can be delivered via the catheter using a tailored electroporation impulse.
• In other exemplary aspects, it is contemplated that theablation catheter20 can be employed in a method for prostate ablation. In these aspects, it is contemplated that, in patients with benign prostatic hypertrophy and urinary obstruction, theablation catheter20 can be positioned to deliver irreversible electroporation impulses in an extended bipolar or unipolar configuration.High impedance structures540 can be further utilized by theablation catheter20 in an extended bipolar configuration to increase the density current at targeted areas. In use, the ablation catheter can be advanced over aguide wire300 that has been delivered into the bladder non-traumatically. It is contemplated that this technique can provide substantial advantages over current procedures, which are typically traumatic to the transitional endothelium of the urethra. With irreversible electroporation, it is contemplated that the impulse can be tailored to minimize inflammation and damage to the greater tissue architecture.
• In other exemplary aspects, it is contemplated that theablation catheter20 can be used to preserve erectile function. In these aspects, theablation catheter20 can be used to ablate selected nerve axons.
• In further exemplary aspects, it is contemplated that theablation catheter20 can be configured for therapy for solid tumors. Typically, current electroporation devises are created to place a pair of needle electrodes into the tumor using open and minimally-invasive surgical techniques. However, it is contemplated that theablation catheter20, with its over-the-wire electrode array, can be used in treating tumors which can be accessed through the vascular space (e.g., palliative therapy for renal cell carcinoma that is extending into the vena cava).
• In still further exemplary aspects, it is contemplated that theablation catheter20 can be used to treat pulmonary hypertension where there is substantial endothelial remodeling and hypertrophy of the pulmonary vascular structures. In these aspects, theablation catheter20 can be used to “prune” the smooth muscle mass in these hypertrophied vessels and potentially lead to a favorable remodeling. It is contemplated that the electrodes of theablation catheter20 can be advanced around the hilum of the kidneys (using laparoscopic techniques) for purposes performing renal denervation and managing malignant refractory hypertension.
• Although several embodiments of the invention have been disclosed in the foregoing specification, it is understood by those skilled in the art that many modifications and other embodiments of the invention will come to mind to which the invention pertains, having the benefit of the teaching presented in the foregoing description and associated drawings. It is thus understood that the invention is not limited to the specific embodiments disclosed hereinabove, and that many modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although specific terms are employed herein, as well as in the claims which follow, they are used only in a generic and descriptive sense, and not for the purposes of limiting the described invention, nor the claims which follow.

Claims (19)

What is claimed is:

1. A method, comprising:

positioning a catheter external to a heart of a subject, such that a central portion of the catheter at least partially encircles the left pulmonary veins and the right pulmonary veins of the heart, the central portion of the catheter including a set of electrodes; and

delivering electrical energy to at least a portion of the left atrium of the heart using two or more electrodes of the set of electrodes, the portion of the left atrium including: a first wall portion of the left atrium; the endocardial space of the left atrium; and a second wall portion of the left atrium.

2. The method ofclaim 1, the delivering the electrical energy including ablating tissue in the first wall portion and the second wall portion of the left atrium to create a lesion.

3. The method ofclaim 1, the delivering the electrical energy including ablating tissue in the portion of the left atrium to create a circumferential lesion in the wall of the left atrium without repositioning the catheter.

4. The method ofclaim 1, the delivering the electrical energy including ablating tissue in the portion of the left atrium to create a lesion in the wall of the left atrium via irreversible electroporation.

5. The method ofclaim 1, the delivering the electrical energy including ablating tissue in the portion of the left atrium to create a lesion around an ostium or ostia of one or more of the left pulmonary veins and the right pulmonary veins formed in the left atrium.

6. The method ofclaim 1, the delivering the electrical energy including delivering direct current impulses.

7. The method ofclaim 1, the delivering the electrical energy including delivering biphasic impulses.

8. The method ofclaim 1, the delivering the electrical energy including delivering the electrical energy in synchronization with the cardiac cycle of the subject.

9. The method ofclaim 1, further comprising monitoring the cardiac cycle of the subject, the delivering the electrical energy including delivering the electrical energy in synchronization with the cardiac cycle of the subject.

10. The method ofclaim 1, further comprising monitoring the cardiac cycle of the subject using one or more electrodes of the set of electrodes, the delivering the electrical energy including delivering the electrical energy in synchronization with the cardiac cycle of the subject.

11. The method ofclaim 1, the electrical energy including one or more current impulses, the delivering the electrical energy including delivering one or more current impulses for every heartbeat of the subject.

12. The method ofclaim 1, wherein the portion of the left atrium is a first portion, further comprising delivering electrical energy to a second portion of the left atrium using two or more electrodes of the set of electrodes.

13. The method ofclaim 1, wherein the portion of the left atrium is a first portion, the positioning the catheter including positioning the catheter in a first position, further comprising:

repositioning the catheter in a second position different from the first position, such that the central portion of the catheter at least partially encircles the left pulmonary veins and the right pulmonary veins external to the heart; and

delivering electrical energy to a second portion of the left atrium using two or more electrodes of the set of electrodes.

14. The method ofclaim 1, wherein the delivering includes:

identifying one or more intended current vectors for delivering the electrical energy, the one or more intended current vectors passing through the endocardial space of the left atrium;

selecting, based on the one or more intended current vectors, the two or more electrodes; and

delivering the electrical energy using the two or more electrodes and along the one or more current vectors.

15. The method ofclaim 1, further comprising surgically creating an opening in the body of the patient to permit passage of the catheter prior to positioning the catheter.

16. The method ofclaim 1, the positioning the catheter including manually positioning the catheter.

17. The method ofclaim 1, the positioning the catheter including positioning the central portion of the catheter in a pericardial space of the heart using a Seldinger technique.

18. The method ofclaim 1, further comprising surgically exposing the anterior chest of the patient prior to positioning the catheter.

19. The method ofclaim 1, further comprising surgically exposing the upper abdomen of the patient prior to positioning the catheter.

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