US20030199961A1 - Method and apparatus for fixating a pacing lead of an implantable medical device - Google Patents

Abstract

A method and apparatus for dynamically fixating and removing a lead in a vasculature of a body. At least one segmenting means such as a collar is disposed at a distal end of the lead forming a deployable actuable segment adapted to dynamically assume an engaging and retracted position. In an engaging position, the actuable segment dynamically and varyingly adapts into a shape or shapes to engage a vessel. In a retracted position the shape or shapes collapse thus maintaining the original geometry of the lead in the vasculature. The actuable segment assumes a deployed or retracted position based on the flexural condition of the segment, respectively.

Description

FIELD OF THE INVENTION
• This invention relates generally to implantable medical devices, and, more particularly, to a fixation mechanism for securing a lead of the implantable medical device within a cardiac vessel of a patient.[0001]
DESCRIPTION OF THE RELATED ART
• Since their earliest inception some forty years ago, there has been a significant advancement in body-implantable electronic medical devices. Today, these implantable devices include therapeutic and diagnostic devices, such as pacemakers, cardioverters, defibrillators, neural stimulators, drug administering devices, among others for alleviating the adverse effects of various health ailments. Today's implantable medical devices are also vastly more sophisticated and complex than their predecessors, and are therefore capable of performing considerably more complex tasks for reducing the effects of these health ailments.[0002]
• The implantable medical device is generally implanted within the patient's body and a lead couples the implantable device to a portion of the patient's body, such as the patient's heart, for example. Typically, an electrode is provided at the distal end of the lead, and it is adapted to be disposed at a desired site within a cardiac vessel of the heart, such as a vein. The electrodes typically sense cardiac activity and deliver electrical pacing stimuli (i.e., therapeutic signals) to the patient's heart depending on the sensed cardiac activity.[0003]
• The pacing leads are commonly implanted within the cardiac vessel with the aid of a stylet that is positioned within a lumen in the lead. If the electrode residing on the distal end of the pacing lead becomes dislodged after implantation within the cardiac vessel, the electrode may not be able to properly sense the cardiac activity of the patient and deliver the electrical pulsing stimuli to the desired area of the patient's heart. If the electrode becomes dislodged from the desired location within the patient's cardiac vessel, a significant amount of time and expense may occur to have the dislodged electrode replanted within the desired site of the cardiac vessel. Moreover, upon dislodgment of the electrode, the patient may be subjected to serious health risks as a result of the electrode not being able to properly sense cardiac activity of the patient and/or deliver a proper therapy to the desired site within the patient's heart.[0004]
• The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.[0005]
SUMMARY OF THE INVENTION
• In one aspect of the present invention, an apparatus for fixating a lead disposed within a vessel is provided. The apparatus comprises a fixation segment of the lead at a distal end thereof, and at least one deployable lobe situated on the fixation segment. The deployable lobe is adapted to assume a retracted position and an engaging position, where the engaging position engages the at least one deployable lobe with the vessel. The at least one deployable lobe assumes the engaging position in response to the fixation segment being compressed and assumes the retracted position when the fixation segment is not compressed.[0006]
• In another aspect of the invention, an apparatus for fixating a lead disposed within a vessel is provided. The apparatus comprises at least one deployable lobe situated on a distal portion of the lead. The deployable lobe is adapted to assume a retracted position and an engaging position, where the engaging position engages the at least one deployable lobe with the vessel. The apparatus further comprises a flexible material covering a portion of an outer surface of the lead. The at least one deployable lobe assumes the engaging position by extending outwardly from the lead at the portion of the outer surface by stretching the flexible material.[0007]
• In another aspect of the invention, an apparatus for fixating a lead disposed within a vessel is provided. The apparatus comprises at least one deployable lobe situated on a distal portion of the lead. The deployable lobe is adapted to assume a retracted position and an engaging position, where the engaging position engages the at least one deployable lobe with the vessel. A lumen is coupled to the deployable lobe and is adapted to extend the deployable lobe to the engaging position. The at least one deployable lobe assumes the engaging position by extending outwardly from an outer surface of the lead.[0008]
• In another aspect of the invention, an apparatus for fixating a lead disposed within a vessel is provided. The lead includes an electrical conductor surrounded by a conductor tubing, and an outer tubing that is slideably received over the conductor tubing. The apparatus comprises at least one deployable lobe situated on a distal portion of an outer surface of the conductor tubing of the lead, the deployable lobe adapted to assume a retracted position and an engaging position, the engaging position engaging the at least one deployable lobe with the vessel. A recessed slot is formed lengthwise within an inner surface of the outer tubing. The at least one deployable lobe assumes the retracted position when the recessed slot formed within the outer tubing is in alignment with the deployable lobe and is slideably received within the recessed slot, and assumes an engaging position by extending outwardly from the outer surface of the conductor tubing when the deployable lobe is not in alignment with the recessed slot.[0009]
• In another aspect of the invention a method for fixating a lead disposed within a vessel is provided. The method includes providing a fixation segment surrounding the lead at a distal end thereof, and providing at least one deployable lobe situated on the fixation segment. The deployable lobe is adapted to assume a retracted position and an engaging position, where the engaging position engages the at least one deployable lobe with the vessel. The fixation segment is compressed to have the at least one deployable lobe assume the engaging position.[0010]
• In another aspect of the present invention a method for fixating a lead disposed within a vessel is provided. The method includes providing at least one deployable lobe situated on a distal portion of the lead. The deployable lobe is adapted to assume a retracted position and an engaging position, where the engaging position engages the at least one deployable lobe with the vessel. A flexible material is provided to cover a portion of an outer surface of the lead. The flexible material is extended outwardly from the lead at the portion of the outer surface when the at least one deployable lobe assumes the engaging position.[0011]
• In another aspect of the present invention, a method for fixating a lead disposed within a vessel is provided. The method includes providing at least one deployable lobe situated on a distal portion of the lead. The deployable lobe is adapted to assume a retracted position and an engaging position, where the engaging position engages the at least one deployable lobe with the vessel. The method further includes providing a lumen coupled to the deployable lobe, and adapted to extend the deployable lobe to the engaging position by extending outwardly from an outer surface of the lead.[0012]
BRIEF DESCRIPTION OF THE DRAWINGS
• The invention may be understood by reference to the following description taken in conjunction with the accompanying drawings, in which the leftmost significant digit(s) in the reference numerals denote(s) the first figure in which the respective reference numerals appear, and in which:[0013]
• FIG. 1 schematically illustrates an implantable medical device, in the form of a pacemaker, according to one embodiment of the present invention;[0014]
• FIGS.[0015]2A,2A′,2B-D show perspective views of a distal portion of a lead having a deployable lobe for fixating the lead to a vessel according to one embodiment of the present invention;
• FIGS.[0016]3A-C show perspective views of the distal portion of the lead having a deployable lobe for fixating the lead to the vessel in accordance with another embodiment of the present invention;
• FIGS.[0017]4A-B show a side view perspective of the distal portion of the lead employing an expandable spring for fixating the lead to the vessel in accordance with another embodiment of the present invention;
• FIGS.[0018]5A-B show a side view perspective of the distal portion of the lead employing a stent for fixating the lead to the vessel in accordance with another embodiment of the present invention;
• FIGS.[0019]6A-B show a side view perspective of the distal portion of the lead employing a balloon for fixating the lead to the vessel in accordance with another embodiment of the present invention;
• FIGS.[0020]7A-C show a side view perspective of the distal portion of the lead employing a pair of flanges for fixating the lead to the vessel in accordance with another embodiment of the present invention; and
• FIGS.[0021]8A-D show perspective views of a distal portion of a lead having a deployable lobe for fixating the lead to a vessel according to another embodiment of the present invention.
• While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but, on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.[0022]
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
• Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.[0023]
• Turning now to the drawings, and specifically referring to FIG. 1, an implantable medical device (IMD) system[0024]100 is shown in accordance with one embodiment of the present invention. The IMD system100 includes an implantablemedical device105 that has been implanted in apatient107. In accordance with the illustrated embodiment of the present invention, theimplantable device105 takes the form of a pacemaker for regulating the patient's heart rhythm. Although theimplantable device105 will be discussed in the form of a pacemaker, it will be appreciated that theimplantable device105 may alternatively take the form of a cardioverter, defibrillator, neural stimulator, drug administering device, and the like without departing from the spirit and scope of the present invention.
• The[0025]implantable device105 is housed within a hermetically sealed, biologically inert outer housing or container, which may itself be conductive so as to serve as an electrode in the pacemaker's pacing/sensing circuit. One or more pacemaker leads, which are collectively identified byreference numeral110, are electrically coupled to theimplantable device105 and extend into the patient'sheart112 through avessel113, such as a vein. The leads110 are coupled to the implantablemedical device105 via aconnector block assembly115. Disposed generally near a distal end of theleads110 are one or more exposedconductive electrodes117 for sensing cardiac activity and/or delivering electrical pacing stimuli (i.e., therapeutic signals) to theheart112. The distal end of thelead110 may be deployed in the ventricle, atrium, coronary sinus, or a cardiac vessel of theheart112.
• Turning now to FIGS.[0026]2A and2A′, a more detailed representation of the distal end of thelead110 is shown in accordance with one embodiment of the present invention. Thelead110 comprises a flexibleelectrical conductor205 for sending diagnostic signals received via the electrode117 (that may be mounted on the terminal end of the lead110) to theimplantable device105, and/or for delivering therapeutic signals to the patient via theelectrode117. In one embodiment, theelectrical conductor205 may include tightly coiled stainless steel or a platinum filament. It will be appreciated, however, that theelectrical conductor205 may be constructed from various other suitable materials without departing from the spirit and scope of the present invention.
• In accordance with one embodiment of the present invention, the[0027]electrical conductor205 is covered by an electrically insulated sheath orconductor tubing215 to protect theelectrical conductor205 from bodily fluids of the patient, and to electrically insulate theconductor205. In one embodiment, theconductor tubing215 may be constructed from polyurethane. It will be appreciated, however, that theconductor tubing215 may be constructed from various other materials, such as silicone, for example, without departing from the spirit and scope of the present invention.
• In accordance with the illustrated embodiment, a[0028]fixation mechanism220 is provided on the mid or distal portion of thelead110 to hold thelead110 substantially stationary within the cardiac vessel of the patient when disposed therein. According to one embodiment, thefixation mechanism220 comprises afixation segment230 that engages and surrounds theconductor tubing215 of thelead110. In accordance with the illustrated embodiment, thefixation segment230 may be constructed of silicone, polyurethane, or the like.
• In accordance with one embodiment of the present invention, the[0029]fixation segment230 comprises one or moredeployable lobes240 that are formed lengthwise on thesegment230 by a pair of elongated, parallel cuts orslits245 made within thefixation segment230. That is, thedeployable lobe240 is formed between the elongated, substantiallyparallel slits245 made within thefixation segment230 that surrounds theconductor tubing215. The spacing between the twoparallel slits245 formed within thefixation segment230 generally defines the width of thedeployable lobe240 formed therebetween. Accordingly, the rigidity of thedeployable lobe240 may be increased by increasing the width of the deployable lobe240 (i.e., increasing the distance between the parallel slits245). Additionally, the rigidity of thelobe240 may be increased by increasing the thickness of thefixation segment230 that surrounds theconductor tubing215. Furthermore, the rigidity of thelobe240 may be altered by using different types of materials for thefixation segment230. In one embodiment, the end portions of the pair ofparallel slits245 formed within thefixation segment230 may be joined by a circular cut250 (within the segment230) so as to reduce the likelihood of theslits245 from spreading or expanding along thefixation segment230.
• In accordance with one embodiment of the present invention, push[0030]tubing260 is disposed around theconductor tubing215 of thelead110, and is attached to thefixation segment230 at one end thereof. At the other end of thefixation segment230, ananchor member265 is affixed to theconductor tubing215 to substantially prevent movement of thefixation segment230 beyond the anchor member265 (i.e., theanchor member265 substantially prevents thefixation segment230 from sliding further down the distal end of the lead110). In one embodiment, thepush tubing260 may be used to apply compression of thefixation segment230 against theanchor member265, by advancing thepush tubing260 toward the distal end of thelead110. The pushing action on thefixation segment230 causes thesegment230 to become compressed, thus causing the extension of thedeployable lobe240 outwardly from the outer surface of thefixation segment230. In an alternative embodiment, thepush tubing260 may be held stationary while the compression of thefixation segment230 is accomplished by withdrawing theconductor tubing215 toward the proximal end of thelead110.
• Prior to the[0031]lead110 being placed within a cardiac vessel of the patient, thedeployable lobe240 assumes a retracted position when there is substantially no compression on thefixation segment230 by thepush tubing260. In the retracted position, thedeployable lobe240 is substantially flat (i.e., not extended outwardly) along the surface of thefixation segment230. When thelead110 is placed within the desired site within the cardiac vessel of the patient, thepush tubing260 is pushed toward the distal end of thelead110. The pushing of thepush tubing260 causes compression of thefixation segment230 against theanchor member265, thereby causing thedeployable lobe240 to extend outwardly or protrude from the surface of thefixation segment230 by assuming an angular flexure or “boomerang” shape (as illustrated in FIG. 2A). In one embodiment, thepush tubing260 may be held in place by using a clip mechanism (not shown) on the proximal end of thelead110, thereby causing constant compression of thefixation segment230 bypush tubing260 until the clip mechanism is removed. The deploying of thelobe240 secures lead110 within the cardiac vessel and, thus, substantially prevents any movement of thelead110 within the cardiac vessel.
• In an alternative embodiment, lead[0032]110 may havelobe240 extended outwardly. In other words, in the resting state,lobes240 would be deployed and during implant the tube is retracted or withdrawn to flattenlobes240 and relieve all the tension to deploy the lead. When the lead is in a desired position the tubing is pushed to dynamically shapelobes240 forming an engaging surface thereof. Further, multiple sets oflobes240 may be located on segments lead110. In this embodiment, the lengths ofsegments245 and the number of slits can vary from subsequent segments oflead110 on which a series ofsegments having lobes240 are located. In yet another embodiment, once the lead is deployed andlobes240 are in an engaged position, a temporary snap-on clip or an anchoring sleeve may be used for chronic implant. Further, the thickness “t” oflobes240 could be varied between segments to enable variability in rigidity and resistance at different segments oflead110 such that eachlobe240 provides varying degrees of flexure.
• In accordance with another embodiment of the present invention, more than one[0033]deployable lobe240 may be provided around the circumference of thefixation segment230 to further secure thelead110 within the cardiac vessel of the patient (as shown in FIG. 2B). For example, twodeployable lobes240 may be provided on opposite sides of thefixation segment230, threedeployable lobes240 may be provided at 120-degree separation points around the circumference of thefixation segment230, or fourdeployable lobes240 may be provided at90-degree separation points around the circumference of thefixation segment230. It will be appreciated that any number ofdeployable lobes240 may be placed around the circumference of thefixation segment230 to aid in securing thelead110 within the cardiac vessel. Furthermore, the spacing (i.e., the degree of separation) between thedeployable lobes240 around the circumference of thefixation segment230 may vary as well. Additionally, the spacing between thedeployable lobes240 around the circumference of thefixation segment230 need not necessarily be uniform, but may be placed at varying positions around the circumference of thefixation segment230. It will be further appreciated that thelead110 may also include two ormore fixation segments230 that are disposed along the distal portion of thelead110 in series. Accordingly, in this embodiment, eachfixation segment230 will have its own set ofdeployable lobes240.
• According to the illustrated embodiment, the[0034]fixation mechanism220 may be further configured with a pair of platinum rings275 (FIG. 2A and2A′), with eachring275 disposed around each end of thefixation segment230 to indicate the degree with which thedeployable lobes240 have been extended outwardly from the surface of thefixation segment230 under an x-ray examination, for example. Accordingly, if the distance between the platinum rings275 is minimal, it will indicate that thelobes240 are deployed (extend outwardly from the surface of the fixation segment230). In another embodiment, it will be appreciated that thedeployable lobes240 of thefixation segment230 may be constructed with a radiopaque material, such as barium, platinum or tantalum loaded rubber or polymer, so as to indicate the degree in which thelobes240 are deployed (in lieu of the platinum rings275) without departing from the spirit and scope of the present invention.
• In accordance with one embodiment of the present invention, a[0035]webbing material280 may be attached between two consecutively spacedlobes240, and deployed when thelobes240 extend outwardly from the surface of the fixation segment230 (as shown in FIG. 2C). In another embodiment of the present invention, theelectrode117 may be disposed on the surface of thefixation segment230 on a side opposite of the deployable lobe240 (FIG. 2D). In yet another embodiment of the present invention, the terminal end of thelead110 may be tapered and/or angled to aid in cardiac vessel selection when theelectrode117 is disposed on the surface of thefixation segment230.
• In accordance with another embodiment, a slip coating or clot resistant slip coating may be applied to the inner surface of the[0036]push tubing260 or to the outer surface of theconductor tubing215 to facilitate the sliding of thepush tubing260 over theconductor tubing215. According to one embodiment, the slip coating may take the form of polyacrylamide PVP, or heparin polyacrylamide hydrophilic coating, or polytetrafluroethylene (PTFE); however, it will be appreciated that the slip coating or slip and anti-coagulant combination coating may include various other equivalent materials without departing from the scope of the present invention.
• Turning now to FIG. 3A, a[0037]fixation mechanism300 for thelead110 is shown in accordance with another embodiment of the present invention. In this particular embodiment, the distal end of thelead110 is configured with at least onedeployable lobe305 that may extend outwardly so as to protrude from the surface of theconductor tubing215. In one embodiment, the portion of theconductor tubing215 that covers thedeployable lobe305 comprises aflexible material310. In accordance with one embodiment, theflexible material310 is provided in the form of a balloon-like material (such as polyisoprene, polyurethane, or silicone, for example) that may stretch when thedeployable lobe305 is extended outwardly from the surface of theconductor tubing215. In one embodiment, thedeployable lobe305 may be fixedly attached to theelectrical conductor205 at apoint306, and provided with a joint308 to permit thedeployable lobe305 to be substantially parallel with theconductor tubing215 when assuming a retracted position or to extend outwardly or protrude from the surface of theconductor tubing215 by assuming an angular or “boomerang” shape (as depicted in FIG. 3A). Alternatively, thedeployable lobe305 at thepoint306 may be fixedly attached to a “stopper” mechanism (not shown) disposed within theconductor tubing215, as opposed to be attached to the electrical conductor205 (as shown in FIG. 3A), without departing from the spirit and scope of the present invention. It will further be appreciated, in another embodiment, that theflexible material310 may be omitted from covering thedeployable lobe305 providing that theelectrical conductor205 is covered with an insulating material to protect theconductor205 from bodily fluids of the patient.
• In accordance with the illustrated embodiment, the[0038]conductor tubing215 comprises a bitumen tubing, with afirst lumen317 accommodating theelectrical conductor205 and asecond lumen318 for accommodating a push-pull wire320 for actuating thedeployable lobe305. Prior to thelead110 being placed within a cardiac vessel of the patient, thedeployable lobe305 is retracted by pulling the push-pull wire320 within thelumen318. In the retracted position, thedeployable lobe305 assumes a substantially linear (or straightened) position, where theflexible material310 is not extended outwardly from theconductor tubing215 of thelead110. When thelead110 is placed at the desired site within the cardiac vessel, the push-pull wire320 is pushed within thelumen318 toward thedeployable lobe305. The pushing of the push-pull wire320 within thelumen318 causes thedeployable lobe305 to extend outwardly or protrude from the surface of theconductor tubing215 by assuming an angular or “boomerang” shape. As thedeployable lobe305 extends outwardly or protrudes from the surface of theconductor tubing215, thedeployable lobe305 stretches theflexible material310 resting thereon. The push-pull wire320 is pushed within thelumen318 until the apex of thedeployable lobe305 engages the cardiac vessel, thereby securing thelead110 within the cardiac vessel and, thus, substantially preventing any movement of thelead110 therein.
• It will be appreciated that more than one[0039]deployable lobe305 may be provided for thelead110 to further secure thelead110 within the cardiac vessel (as shown in FIG. 3B). For example, twodeployable lobes305 may be provided on opposite sides of thelead110, threedeployable lobes305 may be provided at 120-degree separation points around the circumference of thelead110, or fourdeployable lobes305 may be provided at90-degree separation points around the circumference of thelead110. It will further be appreciated that any number ofdeployable lobes305 may be placed around the circumference of thelead110 to aid in securing thelead110 within the cardiac vessel. Furthermore, the spacing (i.e., the degree of separation) between thedeployable lobes305 around the circumference of thelead110 may vary as well. Additionally, the rigidity of thedeployable lobe305 may be altered by increasing or decreasing the width of thedeployable lobe305.
• In accordance with one embodiment of the present invention, the[0040]electrode117 may be placed on the terminal end of thelead110. In another embodiment, theelectrode117 may be placed on a side of thelead110 opposite from the side the deployable lobe305 (in the case where onedeployable lobe305 is utilized) for the fixation mechanism300 (as shown in FIG. 3C).
• Turning now to FIG. 4A, a[0041]fixation mechanism400 for thelead110 is shown in accordance with another embodiment of the present invention. In this particular embodiment, the distal end of thelead110 is configured with anexpandable spring405 that encircles theelectrical conductor205 and is attached thereto by acrimp bus410. In accordance with the illustrated embodiment, theexpandable spring405 is housed within asleeve head415 when theexpandable spring405 assumes a retracted position. A portion of theconductor tubing215 includes theflexible material310, such as a stretchable balloon-like material, for example, which is capable of expanding beyond the diameter of theconductor tubing215 when theexpandable spring405 is pushed out from thesleeve head415.
• Prior to the[0042]lead110 being placed within a cardiac vessel of the patient, theexpandable spring405 is retracted within thesleeve head415 by rotating theelectrical conductor205 in one direction (e.g., counter-clockwise). In the retracted position, theexpandable spring405 is compressed by thesleeve head415, and theflexible material310 attached to theconductor tubing215 is not extended outwardly from theconductor tubing215 of the lead110 (i.e., theflexible material310 has substantially the same diameter as the conductor tubing215). When thelead110 is placed at the desired site within the cardiac vessel, theelectrical conductor205 is rotated in the other direction (e.g., clockwise), which causes theexpandable spring405 to be ejected from thesleeve head415, and causes thespring405 to expand theflexible material310 outwardly or protrude from the surface of the conductor tubing215 (as shown in FIG. 4B). As theexpandable spring405 extends outwardly from the surface of theconductor tubing215, thespring405 stretches theflexible material310 resting thereon. Theelectrical conductor205 is rotated until theflexible material310 engages the cardiac vessel, thereby securing thelead110 within thecardiac vessel113 and, thus, substantially preventing any movement of thelead110 therein. In another embodiment of the present invention, it will be appreciated that theflexible material310 may be placed underneath theexpandable spring405 and the exposedspring405 may be further used as an electrode.
• Turning now to FIG. 5A, a[0043]fixation mechanism500 is shown in accordance with another embodiment of the present invention. In this particular embodiment, the distal end of thelead110 is configured with astent505 that may be expanded so as to protrude from the surface of the conductor tubing215 (as shown in FIG. 5B). In one embodiment, the portion of theconductor tubing215 that covers thestent505 comprises aflexible material310. In accordance with the illustrated embodiment, theflexible material310 is provided in the form of a balloon-like material that may stretch when thestent505 is expanded outwardly from the surface of theconductor tubing215. In one embodiment of the present invention, thestent505 may take the form of a spring or coil. In another embodiment, thestent505 may be placed around theconductor tubing215 as opposed to being located within theconductor tubing215.
• Prior to the[0044]lead110 being placed within a cardiac vessel of the patient, thestent505 assumes an unexpanded state by rotating theelectrical conductor205 in one direction (e.g., in a counter-clockwise direction). In the unexpanded state, the diameter of thestent505 substantially matches the diameter of theconductor tubing215 of thelead110, where theflexible material310 is not stretched or expanded outwardly therefrom. When thelead110 is placed within the cardiac vessel at the desired site, theelectrical conductor205 is rotated in the opposite direction (e.g., a clockwise direction), which causes thestent505 to expand in diameter. When the diameter of thestent505 is expanded so as to exceed the diameter of theconductor tubing205, theflexible material310 resting thereon expands outwardly from the surface of theconductor tubing215. As thestent505 expands or protrudes from the surface of theconductor tubing215, thestent505 stretches theflexible material310 resting thereon. Theelectrical conductor205 is rotated until thestent505 and theflexible material310 resting thereon engages the cardiac vessel, thereby securing thelead110 within the cardiac vessel and substantially preventing any movement of thelead110 therein.
• Turning now to FIG. 6A, a[0045]fixation mechanism600 is shown in accordance with another embodiment of the present invention. In this particular embodiment, the distal end of thelead110 is configured with adeployable lobe605 that may be expanded so as to protrude from the outer surface of theconductor tubing215. In one embodiment, thedeployable lobe605 takes the form of a balloon that resides on a side surface of theconductor tubing215 of thelead110. In an alternative embodiment, thedeployable lobe605 may be configured so as to surround the circumference of thelead110. In the illustrated embodiment, theconductor tubing215 comprises a bilumen tubing with afirst lumen612 accommodating theelectrical conductor205 and asecond lumen613 with aport620 used for injecting a gas or liquid solution within thesecond lumen613 to expand thedeployable lobe605.
• In accordance with one embodiment of the present invention, prior to the[0046]lead110 being placed within a cardiac vessel of the patient, thedeployable lobe605 remains deflated on the side-surface of theconductor tubing215 of the lead110 (as shown in FIG. 6A). When thelead110 is placed at a desired site within the cardiac vessel, a liquid solution or gas is injected into thelumen613 via theport620. In accordance with one embodiment, the liquid solution may include saline and the gas may include carbon dioxide. It will be appreciated, however, that various other liquid solutions or gases may be used in lieu of the examples provided without departing from the spirit and scope of the present invention.
• The injecting of the solution or gas within the[0047]lumen613 causes thedeployable lobe605 to expand by filling thelobe605 with the solution or gas and, thus, protrude or expand outwardly from the outer surface of the conductor tubing215 (as shown in FIG. 6B). The solution or gas is injected through theport620 until thedeployable lobe605 engages the cardiac vessel, thereby securing thelead110 within the cardiac vessel and, thus, substantially preventing any movement of thelead110 therein. Subsequent to filling thedeployable lobe605 with the desired amount of solution or gas, theport620 may be removed, and thelumen613 may be sealed at the opening formed by theport620 with an adhesive or a self-sealing rubber grommet, for example, so as to prevent any leakage of the solution or gas from the lumen613 (and, thus, preventing thedeployable lobe605 from deflating). In accordance with another embodiment, theconductor tubing215 may be provided as a single lumen, and thedeployable lobe605 may be provided with an opening (not shown) therein to inject a gas or solution to inflate thedeployable lobe605. In this particular embodiment, the opening within thedeployable lobe605 may then be sealed to prevent any leakage of the gas or solution injected therein, and, thus, substantially prevent deflation of thedeployable lobe605.
• In accordance with one embodiment, the[0048]electrode117 may be placed on the terminal end of thelead110. In another embodiment, theelectrode117 may be placed on a side of thelead110 opposite from the side thedeployable lobe605 on thelead110.
• Turning now to FIG. 7A, a[0049]fixation mechanism700 for thelead110 is shown in accordance with another embodiment of the present invention. In this particular embodiment, the distal end of thelead110 is configured with a pair ofdeployable lobes705 that may extend outwardly so as to protrude from the surface of theconductor tubing215. Although twodeployable lobes705 are shown in FIG. 7A, it will be appreciated that only one or more than twodeployable lobes705 may be disposed around the circumference of theconductor tubing215 without departing from the spirit and scope of the present invention.
• In one embodiment, the[0050]deployable lobe705 may take the form of a flange, and may be fixedly attached to afixation segment708 that is engaged with and encircles theconductor tubing215. In one embodiment, thedeployable lobe705 may be constructed out of a plastic (e.g., silicon or some other polymer) or may be constructed out of a metal. Thedeployable lobe705 may be fixedly attached to thefixation segment708 at apivot point706 to allow thedeployable lobe705 to be substantially parallel to the surface of theconductor tubing215 when assuming a retracted position or to extend outwardly or protrude from the surface of theconductor tubing215 when thedeployable lobe705 is extended outwardly from the surface of the conductor tubing215 (i.e., when thedeployable lobe705 rotates about the pivot point706). Pushtubing710 surrounds theconductor tubing215, and anend portion715 of thepush tubing710 engages aninner edge717 of thedeployable lobe705.
• In the illustrated embodiment, the[0051]inner edge717 of thedeployable lobe705 is sloped or tapered so as to cause thedeployable lobe705 to eject outwardly when theend portion715 of thepush tubing710 slides between the outer surface of theconductor tubing215 and theinner edge717 of thedeployable lobe705. That is, when thepush tubing710 is pushed towards the distal end of thelead110, theend portion715 of thepush tubing710 slides between the outer surface of theconductor tubing215 and theinner edge717 of thedeployable lobe705, thereby causing thelobe705 to rotate about thepivot point706 and extend outwardly from the outer surface of theconductor tubing215.
• When the[0052]push tubing710 is pulled away from the distal end of thelead110, thedeployable lobe705 will retract until thedeployable lobe705 is substantially parallel to the outer surface of theconductor tubing215. A slip coating may be applied to the inner surface of thepush tubing710 or to the outer surface of theconductor tubing215 to facilitate the sliding of thepush tubing710 over theconductor tubing215. According to one embodiment, the slip coating may take the form of polyacrylamide or polytetrafluroethylene (PrFE); however, it will be appreciated that the slip coating may include various other materials. In the illustrated embodiment, a moldedtransitional piece720 is provided between thedeployable lobe705 and the outer surface of theconductor tubing215 to provide a gradual transition between the outer surface of theconductor tubing215 and thedeployable lobe705.
• In one embodiment, the[0053]end portion715 of thepush tubing710 is tapered so as to facilitate the passage of theend portion715 of thepush tubing710 underneath thedeployable lobe705. Furthermore, the distal tip of thedeployable lobe705, which engages the cardiac vessel when thelobe705 is extended outwardly, may be rounded to prevent damage to the cardiac vessel when engaged therewith.
• In one embodiment of the present invention, the[0054]deployable lobe705 may be covered byflexible material310 that is attached to the moldedtransition piece720 and thepush tubing710 to reduce the likelihood of tissue engrowth or bodily fluids of the patient from ingressing underneath thepush tubing215. In accordance with one embodiment, theflexible material310 is provided in the form of a balloon-like material (such as polyisoprene, polyurethane, or silicone, for example) that may stretch when thedeployable lobe705 is extended outwardly from the surface of theconductor tubing215. In accordance with an alternative embodiment, it will be appreciated that theflexible material310 may be omitted, if so desired.
• Prior to the[0055]lead110 being placed within a cardiac vessel of the patient, thedeployable lobes705 are retracted by pulling thepush tubing710 away from the distal end of thelead110. In the retracted position, thedeployable lobe705 assumes a substantially parallel position relative to the outer surface of theconductor tubing215, where thedeployable lobe705 is not extended outwardly from theconductor tubing215 of thelead110. When thelead110 is placed at the desired site within the cardiac vessel, thepush tubing710 is pushed toward the distal end of thelead110. This pushing action will cause theend portion715 of thepush tubing710 to slide under thedeployable lobe705, which will cause thedeployable lobe705 to extend outwardly or protrude from the surface of theconductor tubing215 rotating outwardly about thepivot point706. As thedeployable lobe705 extends outwardly or protrudes from the surface of theconductor tubing215, thedeployable lobe705 stretches theflexible material310 resting thereon. The pushing action of thepush tubing710 resumes until the distal tip of thedeployable lobe705 engages the cardiac vessel, thereby securing thelead110 within the cardiac vessel. It will be appreciated that thepush tubing710 may be held in place with a clip mechanism (not shown), as discussed previously.
• Turning now to FIG. 7B, the[0056]fixation mechanism700 is shown in accordance with another embodiment of the present invention. In this particular embodiment, aunipolar lead740 is surrounded by anouter coil745, and anouter tubing750 surrounds theouter coil745. By rotating theouter coil745 in one direction (i.e., clockwise, for example), it will cause theend portion752 of theouter tubing750 to go under thedeployable lobe705 and cause thelobe705 to extend outwardly from theouter tubing750 when thelobe705 rotates about thepivot point706 as illustrated in FIG. 7C. When it is desired to retract thelobe705 such that it becomes substantially parallel with the surface of theouter tubing750, theouter coil745 may be rotated in the opposite direction (i.e., counter-clockwise, for example) to cause theouter tubing750 to disengage from underneath thedeployable lobe705, and thus cause thelobe705 to retract and become substantially parallel in relation to the surface of theouter tubing750.
• Turning now to FIG. 8A, a fixation mechanism[0057]800 for thelead110 is shown in accordance with another embodiment of the present invention. In this particular embodiment, the distal end of thelead110 is configured with at least onedeployable lobe805 that may extend outwardly so as to protrude from the surface of aconductor tubing815 that surrounds anelectrical conductor810. In one embodiment, thedeployable lobe805 takes the form of a polyurethane strip material that may be fixedly attached to the outer surface of theconductor tubing815 at each end of thelobe805. It will be appreciated that thedeployable lobe805, as opposed to being provided in the form of a polyurethane strip, may be constructed out of various other materials, such as silicone, for example, without departing from the spirit and scope of the present invention.
• In accordance with the illustrated embodiment, the[0058]electrical conductor810 is slideably received within an opening of anouter tubing820 that surrounds theelectrical conductor810. Referring to FIG. 8B, thedeployable lobe805 is shown in the retracted position, where thelobe805 is received within a recessedslot825 formed within the opening of theouter tubing820. FIG. 8D illustrates a cross-sectional view of theouter tubing820 with theopening822 in which theelectrical conductor810 is slideably received and the recessedslot825 formed within theopening822 for receiving thedeployable lobe805.
• Typically, the[0059]electrical conductor810 will have a natural tendency to remain retracted within theopening822 of theouter tubing820. A stylet (not shown) is utilized to push out theelectrical conductor810 from theopening822 of theouter tubing820, as is conventional in the art. FIG. 8C shows theelectrical conductor810 extended from theopening822 of theouter tubing820. When theelectrical conductor810 is extended from theopening822 of theouter tubing820 using the stylet, thedeployable lobe805 on the outer surface of theconductor tubing815 is exposed. Once thedeployable lobe805 is exposed, theelectrical conductor810 may then be rotated either clockwise or counter-clockwise using the stylet (not shown) within a recessedopening830 of theelectrical conductor810. By rotating theelectrical conductor810, thedeployable lobe805 is no longer in alignment with the recessedslot825, and, therefore, may not be received within the slot. Subsequent to rotation by the stylet, theelectrical conductor810 will attempt to retract within theopening822 of theouter tubing820, and because thedeployable lobe805 is not in alignment with the recessedslot825, will cause thedeployable lobe805 to extend outwardly (or “buckle”) from the outer surface of the conductor tubing815 (as illustrated in FIG. 8A).
• Prior to the[0060]lead110 being placed within a cardiac vessel of the patient, thedeployable lobe805 assumes a retracted position within the recessedslot825 of theouter tubing820 as illustrated in FIG. 8B. In the retracted position, thedeployable lobe805 assumes a substantially parallel position relative to the outer surface of theconductor tubing815, where thedeployable lobe805 is not extended outwardly from the surface of theconductor tubing815 of thelead110. When thelead110 is placed at the desired site within the cardiac vessel, a stylet (not shown) is used to push out theelectrical conductor810 from theopening822 of theouter tubing820 until thedeployable lobe805 is exposed (as illustrated in FIG. 8C). The stylet is then used to rotate theelectrical conductor810 either clockwise or counter-clockwise until thedeployable lobe805 is no longer in alignment with the recessedslot825 formed within theopening822 of theouter tubing820. When the stylet is removed, theelectrical conductor810 will naturally attempt to retract within theopening822 of theouter tubing820. Because thedeployable lobe805 is not in alignment with the recessedslot825 of theopening822 of theouter tubing820, thedeployable lobe805 will extend outwardly from the outer surface of the conductor tubing815 (as illustrated in FIG. 8A), thereby causing the apex of thelobe805 to engage the side of the cardiac vessel and fixedly secure thelead110 therein.
• The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.[0061]

Claims (37)

What is claimed:

1. An apparatus for fixating a lead disposed within a vessel, comprising:

a segment at a distal end of the lead;

at least one deployable lobe situated at the segment, the deployable lobe adapted to assume a retracted position and an engaging position, the engaging position engaging the at least one deployable lobe with the vessel; and

wherein the at least one deployable lobe assumes the engaging position in response to the segment being compressed and assumes the retracted position when the fixation segment is not compressed.

2. The apparatus ofclaim 1, wherein the at least one deployable lobe is formed between a pair of elongated, substantially parallel slits in the segment.

3. The apparatus ofclaim 1, wherein the compression of the segment causes the deployable lobe to extend outwardly from an outer surface of the segment.

4. The apparatus ofclaim 1, wherein by not compressing the segment causes the deployable lobe to retract and become substantially parallel to an outer surface of the fixation segment.

5. The apparatus ofclaim 3, wherein compression of the segment causes the deployable lobe to extend outwardly from the outer surface of the fixation segment and form an angular shape having an apex.

6. The apparatus ofclaim 5, wherein the apex of the angular shape formed by the deployable lobe engages the vessel, thereby substantially fixating the lead within the vessel.

7. The apparatus ofclaim 1, further comprising:

push tubing surrounding the lead and secured to the segment at one end thereof; and

an anchor member for securing an opposite end of the segment to the lead; and

wherein pushing of the push tubing toward the segment causes compression of the segment against the anchor member.

8. An apparatus for fixating a lead disposed within a vessel, comprising:

at least one deployable lobe situated on a distal portion of the lead, the deployable lobe adapted to assume a retracted position and an engaging position, the engaging position engaging the at least one deployable lobe with the vessel;

a flexible material covering a portion of an outer surface of the lead; and

wherein the at least one deployable lobe assumes the engaging position by deforming of the flexible material a segment from the lead at the portion of the outer surface and assumes the retracted position by rectifying said deforming of the segment.

9. The apparatus ofclaim 8, wherein the at least one deployable lobe comprises an expandable spring within the lead, and wherein the spring stretches the flexible material outwardly from the lead when the spring assumes the engaging position.

10. The apparatus ofclaim 9, wherein the expandable spring is expanded to stretch the flexible material by rotating a conductor that is disposed within the lead.

11. The apparatus ofclaim 9, wherein the expandable spring and flexible material engage the vessel when assuming the engaging position, thereby substantially fixating the lead within the vessel.

12. The apparatus ofclaim 8, wherein the flexible material comprises at least one of polyisoprene, polyurethane, and silicone.

13. The apparatus ofclaim 8, wherein the at least one deployable lobe comprises a stent within the lead, and wherein the stent stretches the flexible material outwardly from the lead when the stent assumes the engaging position.

14. The apparatus ofclaim 13, wherein the stent and flexible material engage the vessel when assuming the engaging position, thereby substantially fixating the lead within the vessel.

15. The apparatus ofclaim 13, wherein the stent is expanded to stretch the flexible material by rotating a conductor that is disposed within the lead.

16. The apparatus ofclaim 8, wherein the at least one deployable lobe comprises a flange within the lead, and wherein the flange bends to form an angular shape that stretches the flexible material outwardly from the lead when the flange assumes the engaging position.

17. The apparatus ofclaim 16, wherein the flange bends to form the angular shape by pushing a wire attached to one end thereof.

18. The apparatus ofclaim 16, wherein the flange and flexible material engage the vessel when assuming the engaging position, thereby substantially fixating the lead within the vessel.

19. The apparatus ofclaim 8, wherein the at least one deployable lobe comprises a flange that is attached to the lead at one end thereof by a hinge member, and wherein the flange rotates outwardly about the hinge member and stretches the flexible material outwardly from the lead when the flange assumes the engaging position.

20. The apparatus ofclaim 19, wherein the flange rotates outwardly about the hinge member by pushing an outer tubing that surrounds the lead underneath the flange.

21. The apparatus ofclaim 20, wherein an inner edge of the flange is sloped to facilitate the outward rotation of the flange when the outer tubing is engaged therewith.

22. An apparatus for fixating a lead disposed within a vessel, comprising:

at least one deployable lobe situated on a distal portion of the lead, the deployable lobe adapted to assume a retracted position and an engaging position, the engaging position engaging the at least one deployable lobe with the vessel;

a lumen coupled to the deployable lobe, and adapted to extend the deployable lobe to the engaging position; and

wherein the at least one deployable lobe assumes the engaging position by extending outwardly from an outer surface of the lead.

23. The apparatus ofclaim 22, wherein the deployable lobe takes the form of a balloon-like material.

24. The apparatus ofclaim 22, wherein the deployable lobe is extended outwardly from the outer surface of the lead by inflation of the lobe via the lumen.

25. The apparatus ofclaim 24, wherein the deployable lobe is extended outwardly from the outer surface of the lead by inflation of the lobe by injecting a gas or liquid into the lumen.

26. The apparatus ofclaim 22, wherein the deployable lobe engages the vessel when assuming the engaging position, thereby substantially fixating the lead within the vessel.

27. An apparatus for fixating a lead disposed within a vessel, the lead including an electrical conductor surrounded by a conductor tubing and an outer tubing that is slideably received over the conductor tubing, the apparatus comprising:

at least one deployable lobe situated on a distal portion of an outer surface of the conductor tubing of the lead, the deployable lobe adapted to assume a retracted position and an engaging position, the engaging position engaging the at least one deployable lobe with the vessel;

a recessed slot formed lengthwise within an inner surface of the outer tubing; and

wherein the at least one deployable lobe assumes the retracted position when the recessed slot formed within the outer tubing is in alignment with the deployable lobe and is slideably received within the recessed slot, and assumes an engaging position by extending outwardly from the outer surface of the conductor tubing when the deployable lobe is not in alignment with the recessed slot.

28. The apparatus ofclaim 27, wherein the deployable lobe comprises a flexible strip, and wherein each end of the flexible strip is fixedly attached to the outer surface of the conductor tubing.

29. The apparatus ofclaim 27, wherein the electrical conductor is rotated within the outer tubing to align or unalign the deployable lobe with the recessed slot formed lengthwise within the inner surface of the outer tubing.

30. The apparatus ofclaim 27, wherein the engaging position of the deployable lobe is achieved by pushing the electrical conductor out from the outer tubing until the deployable lobe is exposed from the recessed slot, and rotating the electrical conductor until the deployable lobe is not in alignment with the recessed slot formed within the outer tubing.

31. The apparatus ofclaim 27, wherein the retracted position of the deployable lobe is achieved by rotating the electrical conductor until the deployable lobe is in alignment with the recessed slot formed within the outer tubing and the deployable lobe is slideably received within the recessed slot.

32. A method for fixating a lead disposed within a vessel, comprising:

providing a fixation segment surrounding the lead at a distal end thereof;

providing at least one deployable lobe situated on the fixation segment, the deployable lobe adapted to assume a retracted position and an engaging position, the engaging position engaging the at least one deployable lobe with the vessel; and

compressing the fixation segment to have the at least one deployable lobe assume the engaging position.

33. A method for fixating a lead disposed within a vessel, comprising:

providing at least one deployable lobe situated on a distal portion of the lead, the deployable lobe adapted to assume a retracted position and an engaging position, the engaging position engaging the at least one deployable lobe with the vessel;

providing a flexible material covering a portion of an outer surface of the lead; and

extending the flexible material outwardly from the lead at the portion of the outer surface when the at least one deployable lobe assumes the engaging position.

34. A method for fixating a lead disposed within a vessel, comprising:

providing at least one deployable lobe situated on a distal portion of the lead, the deployable lobe adapted to assume a retracted position and an engaging position, the engaging position engaging the at least one deployable lobe with the vessel; and

providing a lumen coupled to the deployable lobe, and adapted to extend the deployable lobe to the engaging position by extending outwardly from an outer surface of the lead.

35. A method for fixating a lead disposed within a vessel, the lead including an electrical conductor surrounded by a conductor tubing and an outer tubing that is slideably received over the conductor tubing, the method comprising:

providing at least one deployable lobe situated on a distal portion of an outer surface of the conductor tubing of the lead, the deployable lobe adapted to assume a retracted position and an engaging position, the engaging position engaging the at least one deployable lobe with the vessel;

forming a recessed slot lengthwise within an inner surface of the outer tubing; and

retracting the deployable lobe when the recessed slot formed within the outer tubing is in alignment with the deployable lobe and is slideably received within the recessed slot, thereby assuming the retracted position; and

extending the deployable lobe outwardly from the outer surface of the conductor tubing when the deployable lobe is not in alignment with the recessed slot and is withdrawn therefrom, thereby assuming the engaging position.

36. The method ofclaim 35 wherein a slip anti-coagulant (heparin) coating is used on the conductor tubing.

37. The method ofclaim 35 wherein the lobes are annealed to enable deployment in an engaging position.

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