JP2006522661A - Fixed subcutaneous cardiac lead - Google Patents

Abstract

Implantable subcutaneous devices and methods use leads and / or electrodes for cardiac monitoring and / or stimulation. Includes one or more fixation elements, for example, inflatable elements, holes, helical fixation elements, grooves, ridges, teeth, barbed teeth, spring loaded teeth, flexible teeth or foldable Constructed to actively and / or passively fix the teeth and / or one or both of the electrode or lead body to the subcutaneous non-thoracic tissue. Another fixing mechanism. A method of implanting a subcutaneous lead according to the present invention provides a lead comprising a lead body, an electrode, and one or more securing elements, and using the securing element, one or both of the lead body and the electrode. Fixing both to subcutaneous non-thoracic tissue at one or more fixation sites. This method may involve using a delivery device such as a sheath to deliver a lead to a subcutaneous non-thoracic implant site.

Description

  The present invention relates generally to leads for subcutaneous implantable cardiac monitoring and / or stimulation devices, and more particularly to anchoring elements for subcutaneous leads and / or electrodes.

  Implantable cardiac rhythm management systems are used as an effective treatment for patients with severe arrhythmias. These systems typically include one or more leads and circuitry to sense signals from one or more internal and / or external surfaces of the heart. Such systems also include circuitry for generating electrical pulses that are applied to the heart tissue at one or more internal and / or external surfaces of the heart. For example, a lead extending into the patient's heart is connected to an electrode, which monitors the heart's electrical signals and delivers pulses to the heart according to various therapies for treating arrhythmias. In order to contact the myocardium.

  A typical implantable defibrillator (ICD) includes one or more endocardial leads to which at least one defibrillation electrode is connected. Such ICDs can deliver high energy shocks to the heart, block ventricular tachyarrhythmias or ventricular fibrillation, and allow the heart to resume normal sinus rhythm. The ICD may also include a pacing function.

Although ICD is very effective in preventing sudden cardiac death (SCD), many people at risk for SCD are not given implantable defibrillators. The main reason for this disappointing reality is the limited number of physicians qualified to perform transvenous lead / electrode implantation and surgical equipment appropriately equipped to accommodate such cardiac surgery A limited number of patients, and a limited number of patients at risk who can safely withstand the required endocardial or epicardial lead / electrode implantation surgery, Is mentioned. For these reasons, subcutaneous ICDs have been developed.
Current ICDs use subcutaneous electrodes that can tend to move into the subcutaneous tissue layer due to, for example, gravity, patient movement, or patient interaction (eg, arm rotation syndrome). Such movement may be detrimental to the performance of the subcutaneous electrode system because the effectiveness of monitoring, detection and defibrillation is typically very sensitive to electrode position / orientation.

  Existing subcutaneous leads typically rely on redundancy to address the problem of subcutaneous electrode movement. For example, a subcutaneous array may include three long coil electrodes and not all three coils may be required when properly positioned. Since movement can occur, three long fingers provide adequate coverage to maintain the effectiveness of defibrillation.

  There is a need for more precise electrode placement that solves the problem of subcutaneous electrode movement. For example, there is a further need for a fixation approach for a subcutaneous lead that provides improved subcutaneous system performance by providing a more consistent defibrillation and / or pacing threshold and potentially lowering such threshold. It is. The present invention fulfills these and other needs and addresses deficiencies in known systems and techniques.

  Implantable subcutaneous devices and methods use leads and / or electrodes for cardiac monitoring and / or stimulation. The apparatus and method use one or more fixation elements, for example, inflatable elements, holes, helical fixation elements, grooves, ridges, teeth, barbed teeth, spring loaded teeth, flexible Immediately and / or passively fix one or both of the teeth or collapsible teeth and the electrode or lead body to the subcutaneous non-thoracic tissue Including other securing mechanisms configured to:

  One embodiment of an implantable subcutaneous lead relates to a lead body with an electrode supported by the lead body, the electrode being configured for subcutaneous non-thoracic placement within a patient. One or more fixation elements are provided on the implantable lead, and the fixation elements are configured to passively fix one or both of the electrode and lead body to subcutaneous non-thoracic tissue.

  Fixing elements may include teeth, barbed teeth, foldable teeth, rigid teeth, spring loaded teeth, and teeth formed from polymers, metals or shape memory alloys. The teeth may be located on the lead, allowing the lead to be axially displaced in the distal direction, and set in subcutaneous non-thoracic tissue in response to the lead being axially displaced in the proximal direction Make it possible.

  An implantable subcutaneous lead system including a lead body and a lead having an electrode is also contemplated, wherein the lead is configured for subcutaneous non-thoracic placement within a patient. A plurality of fixation elements are provided on the lead for passively fixing one or both of the electrode and lead body to the subcutaneous non-thoracic tissue. The delivery sheath is configured to introduce the lead to the desired subcutaneous non-thoracic location within the patient. The lumen of the sheath is dimensioned to at least partially fold the teeth of the fixation element while allowing the lead to be axially disposed within the lumen.

  Another embodiment of a lead according to the present invention relates to an implantable lead system that includes a lead body having a body cross-sectional diameter. The subcutaneous electrode is supported by the lead body, and the subcutaneous electrode is configured for subcutaneous non-thoracic placement within the patient. The anchoring element is provided on the implantable lead, and the anchoring element is configured to secure the lead to subcutaneous non-thoracic tissue.

  The fixation element may be, for example, a helical coil that fixes the lead to the tissue. The fixation element may also include monitoring and / or stimulation electrodes. The lead may have a securing element with a cross-sectional diameter that is larger than the cross-sectional diameter of the lead body. In another embodiment, the lead has a lead longitudinal axis, the anchoring element has a anchoring element longitudinal axis, and the lead longitudinal axis does not coincide with the anchoring element longitudinal axis.

  An implantable lead according to another embodiment of the present invention relates to a lead body with a supported electrode. The electrode is configured for subcutaneous non-thoracic placement within the patient. An inflation fixation element is provided on the implantable lead and is configured to secure one or both of the subcutaneous electrode and the lead body to the subcutaneous non-thoracic tissue. Useful inflatable anchoring elements include a sponge, such as a scleral sponge, and an inflatable portion, such as an inflatable polymer containing additives. A delivery device may be included that includes a sheath configured to introduce a lead to a desired subcutaneous non-thoracic location in a patient. A sheath may be used to compress the inflatable fixation element.

  The method according to the present invention involves providing a lead having a lead body, a cardiac electrode and a plurality of fixation elements. Manipulating one or more of the lead body, cardiac electrode, and / or a plurality of fixation elements to provide fixation. The plurality of fixation elements may be configured to be fixable to subcutaneous non-thoracic tissue and include teeth configured to be fixedly engaged with the subcutaneous non-thoracic tissue. The position or orientation of the plurality of anchoring elements may facilitate the lead being axially displaced in the distal direction and may resist the lead being axially displaced in the proximal direction. The location or orientation of the plurality of anchoring elements can alternate or add to facilitate the axial displacement of the lead in the distal direction and the lead is rotationally displaced in both clockwise and counterclockwise directions. You may resist.

  A removable sheath having a lumen may be provided to modify at least some positions or orientations of the plurality of anchoring elements when the lead is within the lumen. Removing the lead from the sheath may enable the plurality of anchoring elements for passive engagement, and may remove at least some of the plurality of anchoring elements as it travels or is withdrawn from the sheath lumen. You may return to the initial position or orientation.

  Other embodiments of the plurality of anchoring elements are configured to allow the lead to travel in the longitudinal distal direction and resist the lead from proceeding in the longitudinal proximal direction. The fixation element is configured to permanently fix one or both of the lead body and the heart electrode, and to permanently fix one or both of the lead body and the heart electrode. It may comprise at least one permanent fixing element configured.

  Another embodiment of a method according to the present invention provides a lead having a lead body, a cardiac electrode, and an inflatable anchoring element configured to inflatably secure the lead to subcutaneous non-thoracic tissue. Involved in. The inflatable anchoring element may be inflated at the anchoring site. The inflatable fixation element may expand to an effective diameter that is larger than the diameter of the lead body. The method may further involve providing a sheath having a lumen, advancing the lead through the sheath, and removing the sheath from the lead.

  Removing the sheath may involve tearing the sheath longitudinally and enabling at least one anchoring element of the one or more inflatable anchoring elements. Advancing the lead through the sheath may involve modifying the position or orientation of at least one inflatable anchoring element of one or more inflatable anchoring elements, eg, one Or by compressing at least one inflatable anchoring element of the more inflatable anchoring elements.

  An example of an emergency fixation element is a helical coil configured to urgently fix one or both of the lead body and cardiac electrode to subcutaneous non-thoracic tissue. Another example of an emergency fixation element is a suture configured to urgently fix one or both of the lead body and cardiac electrode to subcutaneous non-thoracic tissue. An example of a permanent fixation element is a portion of a lead configured to facilitate tissue ingrowth between one or both of the lead body and cardiac electrode and subcutaneous non-thoracic tissue.

  One embodiment of an implantable subcutaneous lead relates to a lead body with an electrode supported by the lead body, the electrode being configured for subcutaneous non-thoracic placement within a patient. The lead includes an emergency fixation element, such as a helical coil or suture loop, combined with one or more permanent fixation elements provided on the implantable lead, wherein the fixation element is one of the electrode and the lead body. Or both are configured to be fixed to subcutaneous non-thoracic tissue.

  An implantable subcutaneous lead system according to the present invention relates to a lead having a lead body and electrodes, the lead being configured for subcutaneous non-thoracic placement within a patient. A permanent fixation element is provided on the lead wire to secure one or both of the electrode and lead body to the subcutaneous non-thoracic tissue. The delivery sheath is configured to introduce the lead to the desired subcutaneous non-thoracic location within the patient.

  The above summary of the present invention is not intended to describe each embodiment or every implementation of the present invention. Advantages and achievements will become apparent and appreciated by referring to the following detailed description and claims, taken in conjunction with the accompanying drawings, together with a more complete understanding of the invention.

  While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and are described in detail below. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims.

  In the following description of the illustrated embodiments, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration various embodiments in which the invention may be practiced. It should be understood that other embodiments may be used and structural and functional changes may be made without departing from the scope of the invention.

An apparatus using an implantable lead implemented in accordance with the present invention may incorporate one or more of its features, structures, methods, or combinations thereof described below. For example, a lead for a subcutaneous heart monitor or stimulator may be implemented to include one or more of the features and / or processes described below. Such an apparatus or method need not include all the features or functions described herein, but is implemented to include selected features and functions that combine to provide a unique structure and / or functionality. It is intended that it may be.
Implantable subcutaneous devices and methods according to the present invention use leads and / or electrodes for cardiac monitoring and / or stimulation. Leads and / or electrodes can be one or more anchoring elements, such as inflatable elements, holes, helical anchoring elements, grooves, ridges, teeth, barbed teeth, spring-loaded teeth, flexible Immediately and / or passively fix one or both of the teeth or collapsible teeth and the electrode or lead body to the subcutaneous non-thoracic tissue Including other securing mechanisms configured to:

  A method of implanting a subcutaneous lead according to the present invention provides a lead comprising a lead body, an electrode, and one or more securing elements, and using the securing element, one or both of the lead body and the electrode. Fixing both to subcutaneous non-thoracic tissue at one or more fixation sites. This method may involve using a delivery device such as a sheath to deliver a lead to a subcutaneous non-thoracic implant site.

  Generally speaking, an implantable lead implemented in accordance with the present invention may be used with a subcutaneous heart monitoring and / or stimulation device. One such device is an implantable transthoracic heart monitoring and / or stimulation (ITCS) device that may be implanted under the skin in the patient's thoracic region. An ITCS device, for example, locates all or selected elements of the device at the front, back, sides or other physical location of the patient suitable for monitoring cardiac activity and delivering cardiac stimulation therapy. As may be implanted subcutaneously. The elements of the ITCS device may be located in several different physical locations, such as the chest, abdomen, or the subclavian region, and the electrode elements are each in a different region near, around, in or on the heart. It is understood that

  The primary housing (eg, active or inactive can) of the ITCS device can be located, for example, outside the rib cage at the intercostal or subcostal location, in the abdomen, or in the upper thoracic region (eg, the location below the clavicle, May be configured for positioning on the third rib, etc.). In one implementation, one or more electrodes may be located in the primary housing and / or in other locations around the heart, large blood vessels or coronary blood vessels but not in direct contact therewith.

  In another implementation, the one or more leads incorporating the electrodes can be connected to the heart, large via, for example, one or more leads implanted using a conventional transvenous delivery approach. It may be located in direct contact with the blood vessel or coronary blood vessel. In other implementations, for example, using one or more subcutaneous electrode subsystems or electrode arrays, in an ITCS device configuration using an active can or in a configuration using an inactive can, Sensing and delivering cardiac stimulation energy. The electrodes may be located at an anterior and / or posterior location relative to the heart.

  Referring now to FIGS. 1A and 1B of the drawings, a configuration of an ITCS device that is implanted at different locations in a patient's chest region by using an incision instrument is shown. In the particular configuration shown in FIGS. 1A and 1B, the ITCS device includes a housing 102 in which various cardiac monitoring, detection, processing and energy delivery circuits may be housed. The housing 102 is typically configured to include one or more electrodes (eg, a can electrode and / or an indifferent electrode). Although the housing 102 is typically configured as an active can, it will be appreciated that a non-active can configuration may be implemented, in which case two electrodes spaced from the housing 102 are used. An ITCS system according to this approach is clearly distinguished from conventional approaches because it is preferably configured to include a combination of two or more electrode subsystems implanted subcutaneously.

  In the configuration shown in FIGS. 1A and 1B, the subcutaneous electrode 104 may be positioned below the skin in the thoracic region and may be located distally from the housing 102. Subcutaneous and, where appropriate, housing electrodes may be positioned around the heart in various locations and orientations, eg, at various anterior and / or posterior locations relative to the heart. Subcutaneous electrode 104 is electrically coupled to circuitry within housing 102 via lead assembly 106. One or more conductors (eg, coils or cables) are provided in the lead assembly 106 to electrically couple the subcutaneous electrode 104 to the circuitry of the housing 102. One or more sensing, sensing / pace or defibrillation electrodes are provided on the electrode support, housing 102 and / or distal electrode assembly (shown as subcutaneous electrode 104 in the configuration shown in FIGS. 1A and 1B). It may be located in an elongated structure.

  In one configuration, the lead assembly 106 is generally flexible. In another configuration, the lead assembly 106 is made somewhat flexible, but is a resilient spring or mechanical memory that maintains the desired configuration after being shaped or manipulated by a physician. Have For example, the lead assembly 106 may include a gooseneck or blade system, which may be distorted under manual force to take a desired shape. In this way, the lead assembly 106 may be shaped to accommodate the unique anatomical configuration of a given patient and generally maintains a custom shape after implantation. Shaping the lead assembly 106 according to this configuration may occur before and during implantation of the ITCS device.

  According to a further configuration, the lead assembly 106 includes a rigid electrode support assembly, such as a rigid elongated structure that positionally stabilizes the subcutaneous electrode 104 relative to the housing 102. In this configuration, the rigidity of the elongated structure maintains the desired spacing between the subcutaneous electrode 104 and the housing 102 and maintains the desired orientation of the subcutaneous electrode 104 / housing 102 relative to the patient's heart. The elongate structure may be made of a structurally flexible (structural plastic) composite material or a metal material and includes or is covered by a biocompatible material. Proper electrical insulation between the housing 102 and the subcutaneous electrode 104 is provided when the elongated structure is formed from a conductive material such as metal.

  In one configuration, the rigid electrode support assembly and housing 102 define a single (unitary) structure (ie, a single housing / unit). The electronic components and electrode conductors / connectors are disposed within or on the housing / electrode support assembly of a single ITCS device. At least two electrodes are supported in a single structure near opposite ends of the housing / electrode support assembly. The single structure may have, for example, an arcuate shape or an inclined shape.

  According to another configuration, the rigid electrode support assembly defines a physically separable unit relative to the housing 102. The rigid electrode support assembly includes mechanical and electrical couplings that facilitate mating engagement with corresponding mechanical and electrical couplings of the housing 102. For example, the header block arrangement may be configured to include both electrical and mechanical couplings that provide mechanical and electrical connections between the rigid electrode support assembly and the housing 102. The header block arrangement may be provided on the housing 102, on the rigid electrode support assembly, or both. Alternatively, mechanical / electrical couplers may be used to provide mechanical and electrical connections between the rigid electrode support assembly and the housing 102. In such a configuration, a variety of different electrode support assemblies of various shapes, sizes and electrode configurations may be made available for physically and electrically connecting to standard ITCS devices.

  It is noted that the electrode and lead assembly 106 may be configured to assume a variety of shapes. For example, the lead assembly 106 may have a wedge shape, a chevron shape, a flat oval shape, or a ribbon shape, and the subcutaneous electrode 104 may include a number of spaced electrodes, such as an electrical array or band. Further, two or more subcutaneous electrodes 104 may be attached to a plurality of electrode support assemblies 106 to achieve a desired spaced relationship within the subcutaneous electrodes 104. Accordingly, the subcutaneous leads of the present invention may be appropriately shaped for a particular electrode or family of electrodes and electrode support assemblies.

  Next, referring to FIG. 2, an ITCS device 200 including a can 250 with a lead 241 inserted into the subcutaneous incision 220 is illustrated. The lead wire 241 includes an electrode 230 and a lead body 240. The electrode 230 is illustrated here at the distal end of the lead body 240. The subcutaneous incision tract 220 is in the patient's subcutaneous tissue, as shown in FIGS. 1A and 1B. Lead 241 may itself be inserted into hypodermic incision 220 or may be inserted using sheath 320 as shown in FIG. 3A.

  In FIG. 3A, the proximal end of the lead body 240 extends from the sheath 320 and the electrode 230 is placed within the lumen of the sheath 320. Electrode 230 is illustrated including anchoring elements 232 and 234 provided at the distal and proximal ends of electrode 230, respectively. It should be understood that any number of such fixation elements may be used to fix the electrode 230 in the subcutaneous tissue.

  The anchoring elements 232 and 234 may include, for example, an expandable anchoring mechanism, such as a sponge-like material that is not required or preferably compressed into the lumen of the sheath 320 during delivery. According to one delivery approach, the lead 241 may be inserted into a subcutaneous incision tract, such as the subcutaneous incision tract 220 as shown in FIG. After positioning the sheath 320 at the desired location within the subcutaneous tissue, the sheath 320 may be withdrawn or otherwise separated from the lead 241. Withdrawing sheath 320 from electrode 230 and lead body 240 allows anchoring elements 232 and 234 to expand and apply electrode 230 into the subcutaneous tissue.

  A suitable material for making the fixation elements 232 and 234 is a scleral sponge. However, anchoring elements 232 and 234 may be made from any implantable material that can be expanded. Expansion of the fixation elements 232 and 234 may occur by being released from the sheath 320 from ingestion of bodily fluids, from injected material, or for other expansion reasons. For example, fluid may be injected into a balloon fixation element that is inflatable with a one-way valve or stopper.

  Another embodiment of the inflatable fixation element is illustrated in FIGS. 3B and 3C. In FIG. 3B, the inflation collar 330 and the inflation lead portion 340 are illustrated in a pre-inflation configuration. The inflatable collar 330 and lead portion 340 may be components made from, for example, a mixture of biocompatible polymer and water soluble additive. Illustratively, water soluble additives such as silicone rubber and glycerol represent one combination of materials useful for making the inflation collar 330 and the inflation lead portion 340.

  This combination of materials expands after implantation due to water ingress by osmosis. Using the polymer / additive composition, the absorbed water supplied by the body's aqueous environment penetrates the polymer and dissolves the separated additive particles to provide component expansion. Subsequent reaction forces generated within the polymer phase eventually balance the osmotic forces so that no destructive expansion occurs. The inflated tip or collar 330 may itself provide a press fit within the sac (pocket) to ensure fixation. In addition, by using other compositions, the water sac may bind within the component enough to form a hole in communication with the component surface, which promotes tissue ingrowth To do.

  FIG. 3C illustrates an expanded collar 350 and an expanded lead portion 360. After implantation, the collar 330 and lead portion 340 (shown in FIG. 3B) expand to become an expanded collar 350 and an expanded lead portion 360. In order to secure the lead 241 in tissue, the expanded collar 350 and portion 360 may be used in combination and / or alone.

  Referring now to FIG. 4, an embodiment of a lead 241 that includes an electrode 230 provided with another fixed arrangement is illustrated. Lead 241 is here shown to include electrode 230 having teeth 410, 420, 430, 440, 450 and 460 projecting outwardly from body / lead body 240 of electrode 230. Also illustrated are a number of diagonal grooves 470, 471, 472, 473, and 474.

  The teeth 410-460 are shown biased away from the lead body 240 by manufacturing the teeth 410-460 using a mechanically resilient material having a spring-like quality, such as metal or plastic, for example. It is. Teeth 410-460 may be angled away and proximally oriented, as illustrated in FIG. 4, to allow lead 241 to be easily inserted into the incision tract in the distal direction. Resists being pulled proximally. Teeth 410-460 urgently secure lead 241 in the subcutaneous tissue.

  After the lead 241 is placed and urgently fixed in the subcutaneous tissue, the grooves 470-474 provide an area for promoting tissue ingrowth, which makes the lead 241 permanent in the subcutaneous tissue. Secure to. The grooves 470-474 are indicated by a series of parallel lines oriented diagonally with respect to the longitudinal axis of the lead body 240. It is contemplated that any number of grooves may be implemented at any angle or at a different angle. For example, as illustrated in FIG. 5, the cross-hatch pattern of grooves 510 may be incorporated to promote tissue ingrowth after the lead 241 is placed in the subcutaneous tissue. The grooves 470-474 may be any suitable size, shape, depth or spacing.

  As illustrated in FIG. 6, one or more ridges 610 may be used in combination with or instead of grooves for permanent tissue fixation. Ridge 610 may be configured to provide permanent fixation of lead body 240 resulting from tissue ingrowth. Both the groove 510 (FIG. 5) and the ridge 610 may also provide a degree of emergency fixation, depending on the size of the groove 510 or ridge 610. Urgently, the groove 510 or ridge 610 provides initial fixation with tissue. As time progresses, the initially unfinished encapsulation shrinks, resulting in a tighter bond with the lead 241. As further illustrated in FIG. 6, a plurality of teeth 620, 630, 640, 650, 660 and 670 may be used to urgently secure lead body 240 and / or lead electrode, as described above. It may be used in combination with a fixation technique. Features such as a plurality of teeth 620, 630, 640, 650, 660 and 670 may be located on the lead body 240 and / or the electrode 230. Teeth 620-670 and / or ridges 610 and / or grooves are used in various combinations with other emergency fixation techniques known in the art such as, for example, suture attachment points (not shown) of lead 241. Also good.

  Referring now to FIG. 7, another fixed arrangement according to the present invention is illustrated. According to this embodiment, the anchoring arrangement includes one or more textured surfaces or regions 710 on the lead body 240 and / or the electrode 230 of the lead 241. The textured surface 710 may be used as a single permanent fixation method or in combination with other permanent fixation arrangements such as the set of grooves 720 shown in FIG.

  The textured surface 710 promotes tissue ingrowth and permanently secures the lead body 240 into the subcutaneous tissue. The textured surface 710 may be a surface treatment from a manufacturing process such as, for example, a porous region of the lead body 240, a coating with surface irregularities, a depression formed in the lead body 240 and / or the lead electrode 230, sanding or scratching, or the like. Other suitable texturing may be used.

  In general, at least one emergency fixation mechanism is used in combination with a permanent fixation mechanism to allow sufficient time to fix the permanent fixation mechanism in the subcutaneous tissue. A suitable emergency fixation mechanism is, for example, a suture disposed at the distal end of lead 241.

  According to other fixation arrangements similar to those described above and with reference to FIG. 7, the lead body 240 and / or electrode 230 permanently fixes the lead body 240 and / or electrode 230 within the subcutaneous tissue. It may be configured to incorporate a tissue adhesion site that facilitates. For example, the bonding site may include a gap in the sleeve of the lead body 240 at one or more locations on the sleeve. The bonding site may include an exposed portion of one or more electrodes 230 or an insulation of the lead 241 or other exposed portions of the cover.

  According to another configuration, the adhesion site may include a suture having a porous surface that promotes or facilitates adherence of the subcutaneous tissue. For example, a metal annular structure may be disposed at the adhesion site. For example, a metal ring having a porous surface property may be used to facilitate cell adhesion to the adhesion site. The annular structure may incorporate the electrode 230 or may be separated from the electrode 230.

  According to a further configuration, the adhesion site may include a material that promotes or promotes adherence of the subcutaneous tissue. For example, the bulk outer sleeve of the lead body 240 may be made of a first polymeric material that substantially prevents tissue ingrowth. Selective portions of the lead body 240 are formed using a second polymeric material that promotes tissue ingrowth or promotes adhesion between the adhesion site and the subcutaneous tissue in contact with the adhesion site. May include an adhesive site. The second polymeric material may have, for example, different pores, pore sizes or pore size distributions than those of the first polymeric material. As a further example, the second polymeric material may differ with respect to hydrophobicity relative to the first polymeric material.

  In one particular configuration, the first polymeric material may comprise a first type of PTFE (polytetrafluoroethylene) and the second polymeric material at the adhesion site may comprise a second type of PTFE. In one particular arrangement, the first type of PTFE includes a first type of ePTFE (expanded polytetrafluoroethylene), and the second type of PTFE includes a second type of ePTFE. The second type of ePTFE is preferably different from the first type of ePTFE for one or more of pores, pore size or pore size distribution. Further details of fixation approaches involving surface texture, selective material use, and other arrangements that facilitate lead / electrode fixation via tissue ingrowth are filed on Dec. 4, 2001 of the same applicant. US patent application Ser. No. 10 / 004,708 (GUID.031US01), entitled “Apparatus and Method for Stabilizing an Improvable Lead”. Which is incorporated herein by reference.

  Referring now to FIGS. 8A and 8B, details of an emergency fixation element according to another embodiment of the present invention are shown. Lead 800 is illustrated including a plurality of teeth 810, 820, 830, 840, 845 (FIG. 8B), 850, 860, 870, 880 and 890 (FIG. 8A). The teeth 810-890 are regularly arranged in a 90 degree circumferential arrangement and are shown regularly spaced along the length of the lead 800. However, other angles, regularity or irregularity, or number of teeth may be used according to this embodiment. Teeth 810-890 are shown to be curved when extending from the body of lead 800 in this illustrative example. The curvature may help facilitate emergency fixation by providing the lead 800 to move easily in the first direction (eg, axial displacement in the distal direction), while the first Responsive to movement in the two directions (eg, axial displacement in the proximal direction) helps to set the teeth in the tissue. It is contemplated that the teeth may be straight or may have a curvature that tends to move away from or toward the body of lead 800.

  Teeth constructed in accordance with the present invention may also be curved into more than one plane, as illustrated in FIGS. 9A and 9B. Lead 900 (lead and / or electrode) is shown including teeth 910, 920, 930, 935 (FIG. 9B), 940, 950 and 960 (FIG. 9A). As shown, the teeth 910-960 curve upward away from the lead 900 with respect to the longitudinal axis of the lead 900. The teeth 910-960 also curve around the circumference of the body of the lead 900 relative to the second reference plane.

  The complex curvature illustrated in FIGS. 9A and 9B may be advantageous for optimal placement and fixation of the lead 900 within the subcutaneous tissue. This complex curvature facilitates insertion and withdrawal of the lead 900 as the lead 900 rotates in the first direction. When lead 900 does not rotate, teeth 910-960 are set in the tissue. Further, if the lead 900 rotates in the opposite direction, the teeth 910-960 may be forced into the subcutaneous tissue.

  Another tooth configuration that uses complex curvature is illustrated in FIGS. 9C and 9D in order to optimally place and secure lead 900 within the subcutaneous tissue. This complex curvature provides fixation from proximal displacement and from lead 900 rotation. Teeth 921, 923, 931, 933, 951 and 953 are set in the tissue due to outward and upward spring bias of lead 900. This type of lead anchoring arrangement may be achieved by direct distal insertion, compressing the teeth 921, 923, 931, 933, 951 and 953 during displacement and upon release of the distal movement, the teeth 921, 923, 931, 933, 951, and 953 spring outward from the lead 900 for fixation.

  Additional tooth configurations that use complex curvatures are illustrated in FIGS. 9E and 9F in order to optimally place and secure lead 900 within the subcutaneous tissue. This complex curvature provides fixation from both proximal and distal displacement and from rotation of lead 900. Teeth 922, 932, 942, 952, 962 and 972 are set in the tissue due to the outward and upward spring bias of lead 900. This type of lead anchoring arrangement may be achieved by the use of a sheath as described above, compressing the teeth 922, 932, 942, 952, 962 and 972 during displacement and upon removal of the sheath. , Teeth 922, 932, 942, 952, 962, and 972 spring outward from lead 900 for fixation.

  FIG. 9G is an enlarged cross-sectional view of another embodiment of a lead implemented to include a fixation arrangement in accordance with the present invention. The teeth 973 and 974 are set in the tissue to spring bias outward and upward from the lead 900. This type of lead anchoring arrangement may be achieved by the use of a sheath as previously described, compressing teeth 973 and 974 during displacement, and upon removal of the sheath, teeth 973 and 974 are anchored. Bounce outward from lead 900 for

  Figures 10A, 10B, 10C and 10D illustrate various shapes of teeth according to the present invention. In FIG. 10A, the teeth 1010 are shown protruding from the lead 900. The tooth 1010 has a single tip 1080. The teeth 1010 are shaped to spring away from the lead 900 body.

  For ease of explanation, considering the leads in the planes of FIGS. 10A, 10B, 10C and 10D, lead 900 moves from left to right in the plane of the drawings. If the lead 900 is inserted from left to right in this drawing, the teeth 1010 tend to fold into the lead 900, allowing the lead 900 to travel forward. When the lead 900 is pulled from right to left in FIG. 10A, the teeth 1010 tend to be set in the tissue by a single tip 1080.

  Similar to the tooth of FIG. 10A, the tooth 1020 of FIG. 10B is also bent and set under the same movement. However, the teeth 1020 are not as substantial as the teeth 1010 of FIG. 10A and may more easily fold and compress under left-to-right movement and provide less resistance to right-to-left movement. Good.

  Referring now to FIG. 10C, the tooth 1030 is illustrated with a first point 1050 and a second point 1040. The shape of the tooth 1030 forms a barb 1060 along the second point 1040. The barb 1060 not only provides resistance to right-to-left movement, similar to a hook return, but also provides resistance to left-to-right movement after being set. This arrangement provides ease of insertion in the left-to-right direction, resistance to right-to-left movement, and then also provides resistance to left-to-right movement after being set.

  Referring to FIG. 10D, upright teeth 1012 are illustrated projecting vertically from the lead 900 body. Upright teeth 1012 may be compressed during lead 900 delivery and / or may be spring biased into the lumen of a sheath (eg, sheath 320 of FIG. 3A) when the sheath is removed. An upright tooth 1012 is set in the tissue. In another embodiment, the stiffness of the upright teeth 1012 may be designed such that a set level of resistance is provided by the upright teeth 1012 as it moves into the tissue. By adjusting the stiffness, the level of fixation of lead 900 and the associated ease of insertion / reposition may be predetermined by design. The stiffness may be varied by material selection, shape, and other means known in the art.

  Referring now to FIG. 11, an ITCS system 200 including a can 250 with a lead 241 inserted into the incision path 220 is illustrated. Lead 241 includes electrode 230, illustrated here at the distal end of lead body 240. The subcutaneous incision path 220 is in the patient's subcutaneous tissue, as illustrated in FIGS. 1A and 1B. An offset helix 260 is used as an effective anchoring element to secure the lead 241 in tissue in accordance with the present invention. Typically, the spiral 260 is configured to define all or at least a portion of the electrode 230.

  FIG. 12 illustrates a lead 241 inserted into the pulling sheath 320 as described in the previous embodiment. After placement of the lead 241 in the subcutaneous tissue, the sheath 320 is withdrawn from the subcutaneous tunnel, typically to peel away. The lead 241 may be secured in the tissue by rotating the lead 241 as described in more detail below.

  13 and 14 show a plan view and an end view, respectively, of an embodiment of the present invention. In FIG. 13, the helical coil 260 may be used as a fixation element that secures the lead body 240 in the tissue when the electrode 230 is positioned at a desired location. The helical coil 260 is adhered to the distal end of the lead body 240 at an adhesion point 262. The rotation of the lead body 240 causes the helical coil 260 to rotate, thereby causing the sharp end 400 to rotate.

  The helical coil 260 is illustrated with a uniform coil pitch, cylindrical cross section, constant thickness, although any spiral or screw-like structure may be used in accordance with the present invention. Intended. The helix may be non-uniform and / or may have a tapered cross-section, the pitch may be non-uniform, and the coil shape and thickness deviate from the scope of the present invention. It may vary.

  As lead 241 rotates, sharp end 400 contacts the incised tissue tract wall and penetrates into the subcutaneous tissue. As lead 241 rotates further, sharp end 400 advances through the tissue, repeatedly penetrates the wall, and advances forward as shown by turns of helical coil 260. This effectively screws the helical coil 260 into the tissue wall, thus securing the lead 241.

  In the embodiment illustrated in FIGS. 13 and 14, the helical coil 260 appears to be larger in diameter than the lead body 240. The advantage of using a helical coil 260 that is larger than the lead body 240 ensures that the sharp end 400 penetrates the tunnel wall when the lead is in the dissected tissue tunnel and provides fixation during rotation. If the helical coil 260 is less than or equal to the diameter of the lead body 240, the lead body is sharp unless the lead body 240 is pushed distally along the incision tunnel until penetration occurs. The end 400 may be prevented from starting to penetrate. Pushing the lead in this manner may cause the electrode 230 to move distally from the optimal fixation location.

  Referring now to FIGS. 15 and 16, there are illustrated plan and end views, respectively, of another embodiment of the present invention. In FIG. 15, an offset helical coil 661 may be used as a fixation element that secures the lead body 240 in the tissue when the electrode 230 is positioned at the desired location. The offset helical coil 661 is adhered to the distal end of the lead body 240 at an adhesion point 662. The rotation of the lead body 240 causes the rotation of the offset helical coil 661 and causes the sharp end 600 to rotate.

  As lead body 240 rotates, sharp end 600 contacts the incised tissue tract wall and penetrates into the subcutaneous tissue. As lead body 240 rotates further, sharp end 600 advances through tissue, repeatedly penetrates the wall, and advances forward as indicated by the winding of offset helical coil 661. This effectively screws the offset helical coil 661 into the tissue wall and thus secures the lead 241.

  In the embodiment illustrated in FIGS. 15 and 16, as best seen in FIG. 16, the offset helical coil 661 appears to have a central axis that is offset relative to the longitudinal axis of the lead body 240. The advantage of using an offset helical coil 661 offset from the lead body 240 ensures that the sharp end 600 penetrates the tunnel wall when there is a lead in the dissected tissue tunnel and provides fixation during rotation. .

  Coils 260 and 661 may be manufactured using a spring material, such as metal, for example, so that coils 260 and 661 deform into sheath 320 when advanced to their fixed location. Upon removal of the sheath 320, the coils 260 and 661 are in a larger or offset configuration, affecting fixation in the tissue. Coils 260 and 661 may also be manufactured using a shape memory alloy, such as Nitinol, so that coils 260 and 661 have a first non-penetrating shape when advanced through the incision tract. To do. When subjected to body temperature or artificially heated, the coils 260 and 661 return to the shape as described above and affect fixation.

  It should be understood that any number, type, or combination of fixed elements is contemplated, and that the numbers, types, and combinations presented above are merely examples. Various modifications and variations can be made to the preferred embodiments discussed above without departing from the scope of the invention. Accordingly, the scope of the invention should not be limited by the particular embodiments described above, but should be defined only by the claims set forth below and their equivalents.

1 is a diagram of a transthoracic heart monitoring and / or stimulation device implanted in a patient. FIG. 1 is a diagram of a transthoracic heart monitoring and / or stimulation device implanted in a patient. FIG. FIG. 2 is a view of a lead according to the present invention inserted into an incised subcutaneous passage through a can; FIG. 6 is a plan view of a lead that is placed in a sheath prior to deployment of a fixation element in accordance with the present invention. FIG. 3 is a plan view of a lead having an expansion region prior to expansion in accordance with the present invention. FIG. 3 is a plan view of a lead having an expanded region after expansion in accordance with the present invention. FIG. 4 is an enlarged view of one embodiment of a lead having electrodes, the lead being implemented to include a fixed arrangement in accordance with the present invention. FIG. 4 is an enlarged view of another embodiment of a lead having electrodes, wherein the lead is implemented to include a fixed arrangement in accordance with the present invention. FIG. 5 is an enlarged view of a further embodiment of a lead having electrodes, the lead being implemented to include a fixed arrangement in accordance with the present invention. FIG. 6 is an enlarged view of yet another embodiment of a lead having electrodes, wherein the lead is implemented to include a fixed arrangement in accordance with the present invention. FIG. 5 is an enlarged view of a further embodiment of a lead having electrodes, the lead being implemented to include a fixed arrangement in accordance with the present invention. FIG. 8B is an end view of the embodiment illustrated in FIG. 8A. FIG. 4 is an enlarged view of another embodiment of a lead having electrodes, wherein the lead is implemented to include a fixed arrangement in accordance with the present invention. FIG. 9B is an end view of the embodiment illustrated in FIG. 9A. FIG. 4 is an enlarged view of another embodiment of a lead having electrodes, wherein the lead is implemented to include a fixed arrangement in accordance with the present invention. FIG. 9C is an end view of the embodiment illustrated in FIG. 9C. FIG. 4 is an enlarged view of another embodiment of a lead having electrodes, wherein the lead is implemented to include a fixed arrangement in accordance with the present invention. FIG. 9E is an end view of the embodiment illustrated in FIG. 9E. FIG. 6 is an enlarged cross-sectional view of another embodiment of a lead implemented to include a fixed arrangement in accordance with the present invention. FIG. 3 is a cross-sectional view of various teeth according to the present invention. FIG. 3 is a cross-sectional view of various teeth according to the present invention. FIG. 3 is a cross-sectional view of various teeth according to the present invention. FIG. 3 is a cross-sectional view of various teeth according to the present invention. FIG. 5 is a view of a lead according to the present invention, inserted into the incised subcutaneous passage through the can and illustrated with an offset spiral electrode / fixing element secured to the tissue. FIG. 6 is a plan view of a lead that is placed in a sheath prior to deployment of a fixation element in accordance with the present invention. FIG. 4 is an enlarged view of one embodiment of a lead having electrodes, the lead being implemented to include a fixed arrangement in accordance with the present invention. FIG. 14 is an enlarged end view of the embodiment of FIG. 13. FIG. 5 is an enlarged view of a further embodiment of a lead having electrodes, the lead being implemented to include a fixed arrangement in accordance with the present invention. FIG. 16 is an enlarged end view of the embodiment of FIG.

Claims (77)

Embedded lead wire arrangement,
A lead body;
A cardiac electrode supported by the lead body and configured for subcutaneous non-thoracic placement within a patient;
A plurality of fixation elements provided on one or both of the cardiac electrode and the lead body and configured to fix the lead array to subcutaneous non-thoracic tissue;
Embedded lead wire array comprising:   The lead wire arrangement according to claim 1, wherein the plurality of fixing elements include teeth.   The lead wire arrangement according to claim 2, wherein the teeth include barbs.   The lead arrangement according to claim 2, wherein the protrusion of the tooth longitudinal axis is non-parallel to the longitudinal axis of the lead body.   The plurality of anchoring elements comprise teeth formed from a material having a spring memory, the teeth being located in the lead wire array, allowing the lead wire array to be axially displaced in a distal direction. The lead arrangement of claim 1, wherein the lead arrangement is set in subcutaneous non-thoracic tissue in response to axial displacement in a proximal direction.   The lead arrangement according to claim 1, wherein the plurality of fixing elements include foldable teeth.   7. A lead according to claim 6, comprising a sheath having a lumen dimensioned to at least partially fold the foldable teeth and allowing the lead wire arrangement to be axially displaced within the lumen. Line array.   The lead arrangement according to claim 7, wherein the sheath comprises a longitudinal prestress line arrangement to facilitate separation of the sheath while the sheath is withdrawn from the patient.   The plurality of fixing elements include teeth radially outwardly biased from the lead wire array, the teeth are oriented in the lead wire array, and the lead wire array rotates in a first direction. The lead wire arrangement of claim 1, wherein the lead wire array resists rotation in a second direction.   The lead arrangement according to claim 1, wherein at least one fixing element of the plurality of fixing elements has a fixing element cross-sectional diameter, and the fixing element cross-sectional diameter is larger than a cross-sectional diameter of the lead body.   The lead arrangement according to claim 10, wherein the at least one fixing element of the plurality of fixing elements comprises a helical coil.   The helical coil is configured to be compressible when in a non-deployed configuration, and the cross-sectional diameter of the helical coil is substantially equal to or greater than the cross-sectional diameter of the lead body in the non-deployed configuration. The lead wire arrangement according to claim 11, which is smaller than the lead wire arrangement.   The lead body has a lead longitudinal axis, at least one securing element of the plurality of securing elements has a securing element longitudinal axis, and the lead longitudinal axis is relative to the securing element longitudinal axis. The lead arrangement according to claim 1, which does not match.   The lead wire arrangement according to claim 1, wherein at least one of the plurality of fixing elements is part of the electrode. The lead body comprises a longitudinal axis;
The lead arrangement according to claim 1, wherein at least one of the plurality of fixing elements comprises a longitudinal axis aligned substantially perpendicular to the longitudinal axis of the lead body.   The lead arrangement according to claim 1, wherein at least one fixation element of the plurality of fixation elements is configured to actively fix the lead body or electrode to subcutaneous non-thoracic tissue.   The lead arrangement according to claim 1, wherein at least one fixation element of the plurality of fixation elements is configured to expandably fix one or both of the cardiac electrode and the lead body to subcutaneous non-thoracic tissue.   18. The lead arrangement according to claim 17, comprising at least one fixation element of the plurality of fixation elements configured to urgently fix one or both of the lead body and the cardiac electrode to subcutaneous non-thoracic tissue.   The lead arrangement includes a sheath having a longitudinal prestress line arrangement to facilitate sheath separation while the sheath is withdrawn from a patient, the sheath including at least one inflatable fixation element. 18. The lead arrangement according to claim 17, comprising a lumen dimensioned to partially fold, allowing the lead arrangement to be axially displaced within the lumen.   The lead arrangement according to claim 17, wherein the at least one inflatable fixation element is provided on the cardiac electrode.   The lead arrangement according to claim 17, wherein the at least one inflatable securing element comprises a sponge.   The lead arrangement according to claim 17, wherein the at least one inflatable anchoring element comprises a scleral sponge.   The lead array according to claim 1, wherein the plurality of fixing elements comprise a plurality of sponges arranged in a spaced relationship.   The lead arrangement according to claim 1, wherein the plurality of fixing elements comprise inflatable portions of the lead body.   25. The lead arrangement according to claim 24, wherein the expandable portion of the lead body includes an additive in a polymer.   26. The lead arrangement according to claim 25, wherein the additive comprises glycerol.   25. The lead arrangement according to claim 24, wherein the expandable portion of the lead body includes an expandable polymer.   28. The lead array of claim 27, wherein the expandable polymer comprises a hydrogel.   The lead arrangement according to claim 1, wherein at least one of the plurality of fixing elements includes an inflatable collar coupled to the lead body.   30. The lead arrangement of claim 29, wherein the expandable collar includes an additive in the polymer.   31. The lead arrangement according to claim 30, wherein the additive comprises glycerol.   At least one fixation element of the plurality of fixation elements comprises an inflatable portion provided in the implantable lead wire arrangement, the inflatable portion being a tissue ingrowth for permanent fixation. The lead wire arrangement of claim 1, wherein the lead wire array is configured to provide a hole that facilitates.   34. The lead arrangement according to claim 32, comprising at least one fixation element of the plurality of fixation elements configured to urgently fix one or both of the lead body and the cardiac electrode to subcutaneous non-thoracic tissue.   The inflatable portion includes first and second additives, the first additive is configured to provide expansion, and the second additive is configured to provide the pores. The lead wire arrangement according to claim 32.   The expandable portion includes a polymer having first and second loading concentrations, wherein the first loading concentration is configured to provide swelling, and the second loading concentration provides the pores. 33. The lead array of claim 32 configured.   The lead arrangement according to claim 1, wherein at least one fixation element of the plurality of fixation elements comprises a textured surface configured to promote tissue ingrowth.   37. A lead array according to claim 36, wherein the textured surface comprises a ridge.   37. A lead array according to claim 36, wherein the textured surface comprises grooves. Providing a lead comprising a lead body, a cardiac electrode and a plurality of fixation elements;
Manipulating at least one of the lead body, the cardiac electrode, and one or more of the plurality of fixation elements, wherein the plurality of fixation elements are fixable to subcutaneous non-thoracic tissue Configured to be
Method.   40. The method of claim 39, wherein the plurality of fixation elements comprise teeth configured to be fixedly engaged with subcutaneous non-thoracic tissue.   40. The method of claim 39, wherein the position or orientation of the plurality of anchoring elements facilitates the axial displacement of the lead wire in the distal direction and resists axial displacement of the lead wire in the proximal direction. .   The position or orientation of the plurality of securing elements facilitates the axial displacement of the lead in the distal direction and resists rotational displacement of the lead in both clockwise and counterclockwise directions. 40. The method of claim 39.   40. One or more of the plurality of anchoring elements resists the lead from rotating in a first direction and allows the lead to rotate in a second direction. Method. Providing a removable sheath having a lumen;
Modifying at least some positions or orientations of the plurality of securing elements when the lead is within the lumen;
40. The method of claim 39, comprising:   45. The method of claim 44, wherein removing the lead from the sheath includes enabling a plurality of anchoring elements for passive engagement.   Returning the at least some of the plurality of fixation elements to an initial position or orientation when the at least some of the plurality of fixation elements are advanced beyond or pulled out of the lumen of the sheath. Item 45. The method according to Item 44.   The lead wire engages a plurality of fixing elements by rotating the lead wire in a first direction, and disengages the plurality of fixing elements by rotating the lead wire in a second direction. 40. The method of claim 39, configured to resist.   40. The plurality of anchoring elements are configured to allow the lead to travel longitudinally in a distal direction and resist the lead from proceeding longitudinally in a proximal direction. Method.   The plurality of fixation elements includes at least one emergency fixation element configured to urgently fix one or both of the lead body and the heart electrode, and one or both of the lead body and the heart electrode. 40. The method of claim 39, comprising: at least one permanent securing element configured to be secured.   50. The method of claim 49, wherein the at least one emergency fixation element comprises a helical coil configured to emergencyally fix one or both of the lead body and the cardiac electrode to subcutaneous non-thoracic tissue.   50. The method of claim 49, wherein the at least one emergency fixation element comprises a suture configured to emergencyly fix one or both of the lead body and the cardiac electrode to subcutaneous non-thoracic tissue.   The at least one permanent fixation element comprises a portion of the lead configured to promote tissue ingrowth between one or both of the lead body and the cardiac electrode and subcutaneous non-thoracic tissue. 50. The method of claim 49.   50. The method of claim 49, wherein the at least one emergency fixation element comprises a helical fixation element configured to affix to subcutaneous non-thoracic tissue as the lead rotates. Providing a lead comprising a lead body, a cardiac electrode and an inflatable fixation element;
Inflating the inflatable anchoring element, wherein the inflated anchoring element is configured to anchor the lead array to subcutaneous non-thoracic tissue;
Method.   55. The method of claim 54, wherein the expandable fixation element expands to an effective diameter that is larger than the diameter of the lead body.   The inflatable anchoring element comprises one or more inflatable anchoring elements configured to expand to securely engage subcutaneous non-thoracic tissue at one or more anchoring sites. 55. The method of claim 54. Providing a sheath having a lumen;
Advancing the lead through the sheath;
Removing the sheath from the lead;
55. The method of claim 54, comprising:   58. The method of claim 57, wherein removing the sheath comprises tearing the sheath longitudinally.   58. The method of claim 57, wherein removing the sheath comprises enabling at least one fixation element of the one or more inflatable fixation elements.   58. The method of claim 57, wherein advancing the lead through the sheath includes modifying a position or orientation of at least one inflatable fixation element of the one or more inflatable fixation elements. .   58. The method of claim 57, wherein advancing the lead through the sheath comprises compressing at least one inflatable fixation element of the one or more inflatable fixation elements. Embedded lead wire,
A lead body;
A cardiac electrode supported by the lead body and configured for subcutaneous non-thoracic placement within a patient;
An inflatable fixation element provided on the implantable lead, the inflatable fixation configured to inflately fix one or both of the cardiac electrode and the lead body to subcutaneous non-thoracic tissue Elements and
Embedded lead wire comprising:   64. The lead according to claim 62, wherein the inflatable fixation element is provided on the cardiac electrode.   64. The lead according to claim 62, wherein the inflatable securing element comprises a sponge.   64. A lead according to claim 62, wherein the inflatable anchoring element comprises a scleral sponge.   64. The lead of claim 62, wherein the inflatable securing element comprises a plurality of sponges arranged in a spaced relationship.   64. A lead according to claim 62, wherein the inflatable securing element comprises an inflatable portion of the lead body.   68. The lead according to claim 67, wherein the inflatable portion of the lead body includes an additive in a polymer.   69. A lead according to claim 68, wherein the additive comprises glycerol.   68. The lead according to claim 67, wherein the expandable portion of the lead body comprises an expandable polymer.   71. The lead according to claim 70, wherein the expandable polymer comprises a hydrogel.   64. A lead according to claim 62, wherein the inflatable securing element comprises an inflatable collar coupled to the lead body.   The lead according to claim 72, wherein the expandable collar includes an additive in the polymer.   74. A lead according to claim 73, wherein the additive comprises glycerol.   64. The lead of claim 62, further comprising a delivery device configured to introduce the lead to a desired subcutaneous non-thoracic location in a patient.   76. A lead system according to claim 75, wherein the lumen of the delivery device is dimensioned to compress the inflatable securing element while allowing the lead to be axially displaced within the lumen.   76. The lead system of claim 75, wherein the delivery device comprises a sheath having a longitudinal prestress line array to facilitate separation of the sheath while the sheath is withdrawn from the patient.

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