Conduction system pacing lead and method of manufacture

Abstract

An implantable lead includes a distal assembly having a housing having a proximal portion and a distal portion. A tubular inner preform may be at least partially disposed within the housing and includes a proximal end, a distal end opposite the proximal end, a longitudinal groove extending from the distal end toward the proximal end, and a circumferential groove extending partially around the circumference of the inner preform. A coupler made of a conductive material is disposed within the housing and includes a longitudinal channel. The inner preform is mechanically coupled to the coupler. In an embodiment, the housing may be snap-fitted to the coupler. A helical electrode has a proximal portion disposed around the distal portion of the coupler and a distal portion extending distally from the distal portion of the housing.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 586,310, filed September 28, 2023, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to medical electrical leads and associated methods of manufacturing and using them. More specifically, this disclosure relates to implantable medical electrical leads for stimulating the conduction system of the heart. Background Technology

[0004] Cardiac rhythm management systems are used to electrically stimulate a patient's heart to treat various arrhythmias. Stimulation of the heart's natural conduction systems (e.g., the His bundle, left bundle branch, and / or right bundle branch) can selectively pace the right and left ventricles, or simultaneously, potentially avoiding pacing induction asynchrony that can occur when pacing at the right ventricular apex. There is a continuing need for improved conduction system pacing designs. Summary of the Invention

[0005] Example 1 is an implantable lead for use with an implantable medical device (IMD), comprising a tubular lead body, a proximal connector, a distal assembly, a first electrical conductor, and a second electrical conductor. The tubular lead body has a proximal end, a distal end opposite the proximal end, a first lead body lumen extending from the proximal end through the distal end, and a second lead body lumen extending from the proximal end through the distal end. The proximal connector is located at the proximal end of the lead body and is configured to mechanically and electrically couple the lead to the IMD. The distal assembly extends from the distal end of the lead body and includes a housing, a tubular inner preform, a coupler, a helical electrode, and a ring electrode. The housing has a proximal portion and a distal portion. A tubular inner preform is at least partially disposed within a housing and includes a proximal end, a distal end opposite the proximal end, a longitudinal groove extending from the distal end toward the proximal end, and a circumferential groove extending partially around the circumference of the inner preform. A coupler, made of conductive material, is disposed within the housing and includes a proximal portion having a proximal end and a channel extending distally from the proximal end, a distal portion opposite the proximal portion, and an intermediate portion located between the proximal and distal portions, wherein the inner preform is mechanically coupled to the proximal portion of the coupler. A helical electrode has a proximal portion disposed around the distal portion of the coupler and a distal portion extending distally from the distal portion of the housing. An annular electrode is disposed at the junction between the distal end of the lead body and the proximal portion of the housing. A first electrical conductor extends through a first lead body lumen and is mechanically and electrically coupled to the coupler. A second electrical conductor extends through a second lead body lumen and is mechanically and electrically coupled to the annular electrode.

[0006] In Example 2, according to the implantable lead described in Example 1, the distal portion of the housing is a distal preform configured to be mechanically coupled to the intermediate portion of the coupler.

[0007] In Example 3, the implantable lead according to Example 1 or 2, wherein the distal preform includes a recess extending circumferentially around its inner surface, and the intermediate portion of the coupler includes a radial flange that is received in the recess in a snap-fit ​​arrangement.

[0008] In Example 4, the implantable lead according to any one of Examples 1 to 3 is wherein one or both of the proximal and distal portions of the housing are formed by an overmolding process.

[0009] In Example 5, the implantable lead according to any one of Examples 1 to 4, wherein the circumferential groove of the inner preform includes a first end and a second end opposite to the first end, wherein the longitudinal groove is located between the first end and the second end.

[0010] In Example 6, the implantable lead according to any one of Examples 1 to 5, wherein the coupler includes a radial rib extending circumferentially around a proximal portion, the radial rib being configured to be received within a circumferential groove of an inner preform to couple the inner preform to the proximal end of the coupler.

[0011] In Example 7, the implantable lead according to any one of Examples 1 to 6, wherein the annular electrode includes an inner protrusion extending radially inward and received within a longitudinal groove of the inner preform.

[0012] In Example 8, the implantable lead according to any one of Examples 1 to 7, wherein the distal end of the tubular preform includes a chamfered edge.

[0013] In Example 9, the implantable lead according to any one of Examples 1 to 8, wherein the outer shell includes a collar impregnated with a drug or therapeutic agent.

[0014] In Example 10, the implantable lead according to any one of Examples 1 to 9, wherein the proximal end of the inner preform includes a recess.

[0015] In Example 11, an implantable lead according to any one of Examples 1 to 10 is provided, wherein a first electrical conductor is coupled to a coupler in a channel.

[0016] In Example 12, the implantable lead according to any one of Examples 1 to 11 is provided, wherein the proximal portion of the coupler has a first diameter, the middle portion of the coupler has a second diameter, and the distal portion of the coupler has a third diameter.

[0017] In Example 13, the implantable lead according to Example 12 is provided, wherein the first diameter is greater than the second and third diameters.

[0018] In Example 14, the implantable lead according to Example 12 is provided, wherein the second diameter is greater than the first diameter and the third diameter.

[0019] In Example 15, the implantable lead according to any one of Examples 1 to 14, wherein the distal portion of the spiral electrode extends from the distal portion of the housing by a distance ranging from 0.5 mm to 2.5 mm.

[0020] Example 16 is an implantable lead for use with an implantable medical device (IMD), the implantable lead including a tubular lead body, a proximal connector, a distal assembly, and a first conductor. The tubular lead body has a proximal end and a distal end opposite to the proximal end; the proximal connector is located at the proximal end of the lead body and is configured to mechanically and electrically couple the lead to the IMD. The distal assembly extends from the distal end of the lead body and includes a housing, a tubular inner preform, a coupler, and a helical electrode. The housing has a proximal portion and a distal portion. The tubular inner preform is at least partially disposed within the housing and includes a proximal end, a distal end opposite to the proximal end, a longitudinal groove extending from the distal end toward the proximal end, and a circumferential groove extending partially around the circumference of the inner preform. The coupler is made of a conductive material and is disposed within a housing. It includes a proximal portion having a proximal end and a channel extending distally from the proximal end, a distal portion opposite the proximal portion, and an intermediate portion located between the proximal and distal portions. An inner preform is mechanically coupled to the proximal portion of the coupler. A helical electrode has a proximal portion disposed around the distal portion of the coupler and a distal portion extending distally from the distal portion of the housing. A first electrical conductor extends through a lead body and is mechanically and electrically coupled to the coupler within the channel.

[0021] In Example 17, according to the implantable lead described in Example 16, the distal portion of the housing is a distal preform configured to be mechanically coupled to the intermediate portion of the coupler.

[0022] In Example 18, the implantable lead according to Example 17, wherein the distal preform includes a recess extending circumferentially around its inner surface, and the intermediate portion of the coupler includes a radial flange that is received in the recess in a snap-fit ​​arrangement.

[0023] In Example 19, the implantable lead according to Example 16 is wherein one or both of the proximal and distal portions of the housing are formed by an overmolding process.

[0024] In Example 20, the implantable lead according to Example 16, wherein the circumferential groove of the inner preform includes a first end and a second end opposite to the first end, wherein a longitudinal groove is located between the first end and the second end.

[0025] In Example 21, according to the implantable lead of Example 16, the coupler includes a radial rib that extends circumferentially around a proximal portion, the radial rib being configured to be received within a circumferential groove of an inner preform to couple the inner preform to the proximal end of the coupler.

[0026] In Example 22, the implantable lead according to Example 16 further includes an annular electrode, wherein the annular electrode includes an inner protrusion extending radially inward and received within a longitudinal groove of the inner preform.

[0027] In Example 23, the implantable lead according to Example 16 is provided, wherein the distal end of the tubular preform includes a beveled edge.

[0028] In Example 24, the implantable lead according to Example 16 is provided, wherein the outer shell includes a collar impregnated with a drug or therapeutic agent.

[0029] In Example 25, the implantable lead according to Example 16 is provided, wherein the proximal portion of the coupler has a first diameter, the middle portion of the coupler has a second diameter, and the distal portion of the coupler has a third diameter.

[0030] In Example 26, the implantable lead according to Example 25 is provided, wherein the first diameter is greater than the second and third diameters.

[0031] In Example 27, the implantable lead according to Example 25 is provided, wherein the second diameter is greater than the first diameter and the third diameter.

[0032] Example 28 is a distal assembly for an implantable lead, the distal assembly including a housing, a tubular inner preform, a coupler, a helical electrode, and an annular electrode. The housing has a proximal portion and a distal portion. The tubular inner preform is at least partially disposed within the housing and includes a proximal end, a distal end opposite the proximal end, a longitudinal groove extending from the distal end toward the proximal end, and a circumferential groove extending partially around the circumference of the inner preform. The coupler is made of a conductive material and is disposed within the housing, and includes a proximal portion having a proximal end and a channel extending distally from the proximal end, a distal portion opposite the proximal portion, and an intermediate portion located between the proximal and distal portions, wherein the inner preform is mechanically coupled to the proximal portion of the coupler. The helical electrode has a proximal portion disposed around the distal portion of the coupler and a distal portion extending distally from the distal portion of the housing. A ring electrode is disposed at the junction between the distal end of the lead body and the proximal portion of the housing. One or both of the proximal and distal portions of the housing are formed by an overmolding process.

[0033] In Example 29, the distal assembly according to Example 28, wherein the distal portion of the housing includes a recess extending circumferentially around its inner surface, and the intermediate portion of the coupler includes a radial flange received in the recess in a snap-fit ​​arrangement.

[0034] In Example 30, according to the distal assembly of Example 28, the circumferential groove of the inner preform includes a first end and a second end opposite to the first end, wherein a longitudinal groove is located between the first end and the second end.

[0035] In Example 31, according to the distal assembly of Example 28, the coupler includes a radial rib extending circumferentially around the proximal portion, the radial rib being configured to be received within a circumferential groove of the inner preform to couple the inner preform to the proximal end of the coupler.

[0036] In Example 32, the distal assembly according to Example 28, wherein the annular electrode includes an inner protrusion that extends radially inward and is received within a longitudinal groove of the inner preform.

[0037] Example 33 is an implantable lead configured to be coupled to an implantable medical device (IMD), the implantable lead including a tubular lead body, a distal assembly, and a first conductor. The tubular lead body has a proximal end and a distal end opposite to the proximal end. The distal assembly extends from the distal end of the lead body and includes a housing, a tubular inner preform, a coupler, and a helical electrode. The housing has a proximal portion and a distal portion. The tubular inner preform is at least partially disposed within the housing and includes a proximal end and a distal end opposite to the proximal end. The coupler is made of a conductive material and is disposed within the housing, and includes a proximal portion having a proximal end and a channel extending distally from the proximal end, a distal portion opposite to the proximal portion, and an intermediate portion located between the proximal and distal portions, wherein the inner preform is disposed around the proximal portion of the coupler and is mechanically coupled to the proximal portion of the coupler. The spiral electrode has a proximal portion disposed around the distal portion of the coupler and a distal portion extending distally from the distal portion of the housing. A first electrical conductor extends through the lead body and is mechanically and electrically coupled to the coupler within the channel.

[0038] In Example 34, the implantable lead according to Example 33 is wherein one or both of the proximal and distal portions of the housing are formed by an overmolding process.

[0039] In Example 35, the implantable lead according to Example 34, wherein the distal component further includes an annular electrode disposed at the junction between the distal end of the lead body and the proximal portion of the housing.

[0040] While several embodiments have been disclosed, other embodiments of the invention will become apparent to those skilled in the art from the following detailed description, which illustrates and describes illustrative embodiments of the invention. Therefore, the drawings and detailed description should be considered illustrative in nature and not restrictive. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of a conduction system pacing (CSP) system according to some embodiments of the present disclosure.

[0042] Figure 2A This is an embodiment of the subject matter of this disclosure. Figure 1 A plan view of the lead wire.

[0043] Figure 2B This is an embodiment of the subject matter of this disclosure. Figure 2A A three-dimensional view of the lead wire component.

[0044] Figure 2C This is an embodiment of the subject matter of this disclosure. Figure 2B A cross-sectional view of the component.

[0045] Figure 2D According to embodiments of this disclosure Figure 2A A cross-sectional view of a portion of the lead wire.

[0046] Figure 2E This is an embodiment of the subject matter of this disclosure. Figure 2A A perspective view of the replacement component for the lead wire in the diagram.

[0047] Figure 2F This is an embodiment of the subject matter of this disclosure. Figure 2E A cross-sectional view of the component.

[0048] Figure 3 This is an embodiment of the subject matter of this disclosure. Figure 2A A partial cross-sectional view of a portion of the lead wire.

[0049] Figure 4 According to embodiments of this disclosure Figure 3 A three-dimensional view of the inner preform of the lead wire.

[0050] Figure 5 According to embodiments of this disclosure Figure 3 A three-dimensional view of a coupler with leads.

[0051] Figure 6 This is a partial cross-sectional view of a portion of an alternative lead according to an embodiment of the present disclosure.

[0052] Figure 7 According to embodiments of this disclosure Figure 6 A three-dimensional view of the inner preform of the lead wire.

[0053] Figure 8 According to embodiments of this disclosure Figure 6 A three-dimensional view of a coupler with leads.

[0054] Figure 9 This is a partial cross-sectional view of a portion of an alternative lead according to an embodiment of the present disclosure.

[0055] Figure 10 This is a partial cross-sectional view of a portion of an alternative lead according to an embodiment of the present disclosure.

[0056] Figure 11 This is a partial cross-sectional view of a portion of an alternative lead according to an embodiment of the present disclosure.

[0057] While the invention is readily adaptable to various modifications and alternatives, specific embodiments have been shown by way of example in the accompanying drawings and are described in detail below. However, it is not intended that the invention be limited to the specific embodiments described. Rather, the invention is intended to cover all modifications, equivalents, and alternatives that fall within the scope of the invention as defined by the appended claims. Detailed Implementation

[0058] This disclosure relates (among other things) to the use of a dedicated conduction system of the heart. Specifically, this disclosure relates to medical electrical leads having one or more electrodes configured to be fixed in contact with or near the nerve fibers of the natural conduction system, particularly the left and / or right bundle branches of the heart.

[0059] Figure 1 This is a schematic diagram of a conduction system pacing (CSP) system according to some embodiments of the present disclosure. Figure 1 A CSP system 10 is shown, including an implantable pulse generator 12 and a lead 14. The lead 14 is implanted in the heart 16. The implantable pulse generator 12 may include a circuitry for sensing bioelectrical signals and / or delivering electrical stimulation via the lead 14. The implantable pulse generator 12 may include a lead interface 18 (e.g., a head). The lead 14 may include a proximal end 20, a distal end 22, and a fixation element 24 disposed at the distal end 22.

[0060] Lead 14 may further include a proximal connector having one or more electrical contacts (not shown) at a proximal end 20, one or more electrical elements (e.g., ring electrodes) at a distal end 22, and one or more electrical conductors (e.g., one or more coils or one or more cable conductors) (not shown) extending within one or more lumens, the lumens extending from the electrical contacts to the electrical elements within lead 14. Lead interface 18 can connect pulse generator 12 to the electrical contacts at the proximal end 20 of lead 14 to electrically connect pulse generator 12 to the electrical elements.

[0061] like Figure 1 As shown, lead 14 is implanted in the right ventricle 46, at the interventricular septum 42, near the left bundle branch 38 and / or right bundle branch 40 of the dedicated conduction system. Lead 14 operates to transmit an electrical signal between a target nerve (e.g., left bundle branch 38 and / or right bundle branch 40) and an implantable pulse generator 12. In some embodiments, lead 14 may enter the vascular system through a vascular access site (not shown) formed in the wall of the left subclavian vein (not shown), extending through the left brachiocephalic vein (not shown) and the superior vena cava 36 to reach the right ventricle 46. In various other embodiments, other suitable vascular access sites may also be used.

[0062] The fixation element 24 can secure the lead 14 to cardiac tissue, such as areas of tissue through which stimulation of the left bundle branch 38 and / or right bundle branch 40 can be directly stimulated. In some embodiments, the fixation element 24 can be electrically coupled to the implantable pulse generator 12 by, for example, an electrical conductor such as a coil extending to the proximal end 20 of the lead 14 to abut against the lead interface 18. Thus, the fixation element 24 can mechanically and electrically couple the lead 14 to the tissue and facilitate the transmission of electrical energy from the conduction system in sensing mode and to the conduction system in stimulation mode. In some embodiments, the fixation element 24 is a fixed fixation element, such as a helix fixed to the lead 14. Such a fixation element 24 can be deployed by rotating the lead 14 itself to implant the fixation element 24 into the tissue. Active fixation elements for the fixation element 24 can allow for precise placement of the lead 14. Active fixation elements for the fixation element 24 can also provide mapping capabilities because the user does not need to worry about accidental entanglement of the helix in the tissue.

[0063] Although Figure 1 Only a single lead is shown connected to the implantable pulse generator 12 and implanted for cardiac stimulation, but various other embodiments may have alternative leads and / or one or more additional leads for sensing bioelectrical activity and / or stimulating other areas of the heart 16.

[0064] In some embodiments, as will be discussed in more detail herein, the CSP system 10 is capable of both pacing and defibrillation therapy. In such embodiments, the lead 14 may also include one or more high-voltage defibrillation electrodes ( Figure 1 (Not shown in the image) is used to deliver a defibrillation shock that can terminate ventricular fibrillation.

[0065] Figure 2A This is a perspective view of a lead 110 according to an embodiment of the subject matter of this disclosure. The lead 110 has a proximal region 114, a distal region 116 terminating at a distal tip 117, and a longitudinal axis 118. Generally, the proximal region 114 is sized to form the following portion of the lead 110 extending from the pulse generator 12 to the location where the lead 110 enters the right atrium 26 via the superior vena cava 36, ​​while the distal region 116 is sized to extend within the heart 16 to the location where the lead 110 is attached to the interior of the heart 16 (see [link to relevant documentation]). Figure 1 ).

[0066] As shown, lead 110 comprises a flexible, elongated lead body 120, a proximal connector 122, and a distal assembly 124. The flexible, elongated lead body 120 typically defines a longitudinal axis 118 of lead 110. As further shown, lead body 120 has a proximal end 126 and a distal end 128 opposite to proximal end 126. Additionally, connector 122 is located at proximal end 126 of lead body 120, and distal assembly 124 is located at and extends from distal end 128 of lead body 120. In embodiments, connector 122 may include terminal pins and one or more contacts to electrically connect one or more active electrodes to implantable pulse generator 12. In some embodiments, connector 122 is a conventional bipolar connector. In other embodiments, such as a quadrupole lead, connector 122 will be configured accordingly.

[0067] In the illustrated embodiment, lead 110 includes an electric shock coil 130 positioned along distal region 116. As shown, the electric shock coil 130 is positioned between a first electric shock coil coupler 136 and a second electric shock coil coupler 138.

[0068] Figure 2B It is a 3D view of the electric shock coil coupling components 136 and 138, and Figure 2C Cross-sections of the electric shock coil couplings 136 and 138 are shown. Figure 2BAs shown, the electric shock coil couplers 136 and 138 include a first portion 131, a second portion 133, and a third portion 135. The diameter of the outer surface of the first portion 131 and the third portion 135 is smaller than the diameter of the outer surface of the second portion 133. The first portion 131 and the third portion 135 include recesses 134 formed by portions with further reduced diameters. Each recess 134 is located adjacent to the second portion 133. The outer surface of the second portion is configured to be substantially the same as the outer surface of the electric shock coil and the flexible elongated body 120. The first portion 131 and the third portion 135 are configured to overlap the electric shock coil 130 or the polymer tube forming the flexible elongated body 120. An opening 139 allows material to flow into the electric shock coil couplers 136 and 138 to securely couple the electric shock coil couplers 136 and 138, and thus the electric shock coil 130, to the lead 110. The opening 139 is partially formed within the recess 134. The first shock coil coupler 136 or the second shock coil coupler 138 includes a channel 137 configured to receive an electrical conductor, such as Figure 2C As shown. The conductor mechanically and electrically connects the shock coil 130 to the implantable pulse generator 12.

[0069] Figure 2E This is a perspective view of an alternative arrangement for the electric shock coil couplings 136′ and 138′. Figure 2F A cross-section of an alternative arrangement for the electric shock coil couplings 136′ and 138′ is shown. (See diagram.) Figure 2E As shown, the electric shock coil couplers 136′ and 138′ include a first portion 131′, a second portion 133′, and a third portion 135′. The diameter of the outer surface of the first portion 131′ and the third portion 135′ is smaller than the diameter of the outer surface of the second portion 133′. The first portion 131′ includes a recess 134′ formed by a portion with a further reduced diameter. The recess 134′ is adjacent to the second portion 133′. The outer surface of the second portion 133′ is configured to be substantially the same as the outer surface of the electric shock coil and the flexible elongated body 120. The first portion 131′ and the third portion 135′ are configured to overlap or abut against the electric shock coil 130 or the polymer tube forming the flexible elongated body 120. An opening 139′ in the first portion 131′ allows material to flow into the electric shock coil couplers 136′ and 138′ to securely couple the electric shock coil couplers 136′ and 138′, and thus the electric shock coil 130, to the lead 110. The opening 139' is partially formed within the recess 134'. The third portion 135' includes a smooth outer surface and has no openings or recesses.

[0070] The first shock coil coupler 136' and / or the second shock coil coupler 138' include a channel 137' configured to receive an electrical conductor, such as Figure 2FAs shown. The electrical conductor mechanically and electrically connects the shock coil 130 to the implantable pulse generator 12. A channel 137' is located on the inner surface 141 of the shock coil couplers 136', 138'. The channel 137' is located below and extends between the second portion 133' and the third portion 135'. The channel 137' includes a first end having a first ramped surface 142 and a second end having a second ramped surface 143. The first ramped surface 142 and the second ramped surface 143 are angled toward the longitudinal axis 145 extending through the shock coil couplers 136', 138'. (See again) Figure 2A A ring electrode 132 is also included along the distal region 122. In some embodiments, the ring electrode 132 may be completely surrounded by an insulating material, such that the ring electrode 132 is inactive. The ring electrode 132 is mechanically and electrically connected to the implantable pulse generator 12 via an electrical conductor converging with it.

[0071] The distal region 116 also includes a helical electrode 144 extending distally from the distal tip 117 of the lead 110. In one embodiment, the helical electrode 144 is configured to operate as a fixation element that can be rotated into the tissue to secure the lead 110 to a desired portion within the heart 16. Alternatively, in another embodiment, the helical electrode 144 is configured to sense electrical activity in the heart 16 or to apply stimulation pulses to the cardiac tissue. This allows a physician to use the helical electrode 144 to map the cardiac tissue and thereby identify optimal attachment sites. In other embodiments, the fixation helix is ​​not electrically active and operates solely as a fixation means.

[0072] The distal region 116 also includes a drug collar 140 located on the distal assembly 124. The drug collar 140 includes an exposed surface and is impregnated with a drug or therapeutic agent. The drug collar 140 is configured to deliver a drug or therapeutic agent to desired tissue within the heart 16. In some embodiments, the drug collar 140 is an overmolded collar. In some embodiments, the drug collar 140 is a pre-molded collar.

[0073] Figure 2D It is along Figure 2AA cross-sectional view of lead 110 taken from a 2D-2D line in the figure illustrates the construction of lead body 120 according to some embodiments of the present disclosure. As shown, in the illustrated embodiment, lead body 120 is a quad-lumen design having a first lumen 150, a second lumen 152, a third lumen 154, and a fourth lumen 156 extending therethrough. As shown, the first lumen 150 receives a first conductor 160, which in the illustrated embodiment is a coil-shaped conductor (which may be a single-strand or multi-strand coil) and, as explained elsewhere, may be electrically coupled to a helical electrode 144. Additionally, the second lumen 152, the third lumen 154, and the fourth lumen 156 may each receive an additional conductor 162, 164, 166, which may be a solid or stranded cable design. In embodiments, conductors 162, 164, and 166 may be electrically coupled to, for example, one of a ring electrode 132, an electric shock coil 130, or a spiral electrode 144. In embodiments, one or more of conductors 162, 164, and 166 may be electrically inactive and are provided solely as structural components, for example, to provide the lead 110 with the tensile strength that might be desired in cases where the lead 110 needs to be removed from the patient or repositioned after implantation. In the illustrated embodiment, the lead body 120 is a two-part construction comprising a core member 170 and an outer layer 172, which may be made of the same material or may be composed of different materials. However, it should be emphasized that… Figure 2D The specific four-lumen lead body design shown is merely exemplary, and other lead body configurations may be used within the scope of this disclosure.

[0074] Figure 3 This is a cross-sectional view of a portion of the distal region 116 of the lead 110 according to an embodiment of the present disclosure. As shown, in the illustrated embodiment, the distal assembly 124 extends from the distal end 128 of the lead body 120 and includes a coupler 200, an inner preform 202, and a housing 204. The housing 204 includes a proximal portion 203 and a distal portion 205, the distal portion 205 forming the distal tip 117 of the lead 110. As further shown, the helical electrode 144 has a proximal portion 206 fixed to the coupler 200 and a distal portion 207 extending distally from the distal tip 117 of the lead 110.

[0075] As shown, the housing 204 surrounds and encloses at least the proximal portion 206 of the coupler 200, the tubular inner preform 202, and the helical electrode 144. In embodiments, the housing 204 is securely attached to the coupler 200 and the tubular inner preform 202. In various embodiments, the housing 204 is formed of a polymer material by an overmolding process (e.g., injection molding). In some embodiments, the proximal portion 203 and the distal portion 205 are formed of the same polymer material. In some embodiments, the proximal portion 203 and the distal portion 205 are formed of different polymer materials. In embodiments, the distal portion 205 of the housing 204 may include a drug-eluting polymer, thereby eliminating the need for a separately supplied drug collar 140.

[0076] As further shown, in the illustrated embodiment, the diameter of the drug collar 140 decreases in the direction from proximal to distal, thereby defining a tapered structure in the distal end of the distal assembly 124. In other embodiments, the distal assembly 124 is substantially of uniform diameter along substantially its entire length.

[0077] Coupler 200 is made of a conductive material and is disposed within housing 204. As shown, coupler 200 includes a channel 211 extending distally from the proximal end of coupler 200, thereby forming a blind via. As further shown, a first conductor 160 extends from connector 122 ( Figure 2A The first conductor 160 extends through the coupler 200 and is mechanically and electrically coupled within the channel 211. The first conductor 160 is connected via the coupler 200 to the implantable pulse generator 12 ( Figure 1 Electrical pulses and signals are carried between the first conductor 160 and the spiral electrode 144. In some embodiments, the first conductor 160 is a multi-strand coiled wire and extends proximally through the lead 110 in the first lead body lumen 150.

[0078] Coupler 200 is configured to engage with tubular inner preform 202. In some embodiments, coupler 200 and tubular inner preform 202 are configured to be mechanically coupled via snap-fit ​​connection or other connection.

[0079] In the illustrated embodiment, conductor 162 is disposed within the second lead body cavity 152 and is mechanically and electrically coupled to an annular electrode 132. As shown, the annular electrode 132 includes a protrusion 153 that extends radially inward and includes an opening for receiving conductor 162, which can be secured to the annular electrode 132 by any suitable means (e.g., welding, crimping, riveting, and similar methods). In this embodiment, the second conductor 212 is a stranded cable. Conductor 162 is embedded in the pulse generator 12 ( Figure 1Electrical pulses and signals are carried between the ring electrode 132 and the annular electrode 132.

[0080] Figure 4 This is a perspective view of a tubular inner preform 202 according to an embodiment of the present disclosure. The tubular inner preform 202 has a proximal end 301 and a distal end 303 opposite to the proximal end 301. A longitudinal groove 305 extends partially along the tubular inner preform 202 from the distal end 303 toward the proximal end 301. The longitudinal groove 305 provides expansion for the inner preform 202 when it is engaged with the coupler 200, and also receives the protrusion 153 of the annular electrode 132. A circumferential groove 307 extends partially around the circumference of the inner preform 202. The distal end 303 of the inner preform 202 includes a chamfered edge 309 that facilitates receiving the proximal end 401 of the coupler 200 when the tubular inner preform 202 and the coupler 200 are joined together.

[0081] Figure 5 This is a perspective view of a coupler 200 according to an embodiment of the present disclosure. As shown, the coupler 200 includes a proximal end 401 and a distal end 403 opposite to the proximal end 401. The coupler 200 includes a proximal portion 405, a distal portion 409 opposite to the proximal portion 405, and an intermediate portion 407 located between the proximal portion 405 and the distal portion 409. The coupler 200 includes radial ribs 415 extending circumferentially around the proximal portion 405, configured to be received within a circumferential groove 307 of a tubular inner preform 202 to couple the tubular inner preform 202 to the proximal portion 405 of the coupler 200. The intermediate portion 407 includes a radial flange 413 extending outwardly from a surface of the intermediate portion 407. The radial flange 413 provides enhanced coupling with a housing 204, for example by providing a mechanical interlock between the coupler 200 and the housing 204.

[0082] As shown in the figure, the proximal portion 405 of the coupler 200 has a first diameter, the middle portion 407 of the coupler 200 has a second diameter, and the distal portion 409 of the coupler 200 has a third diameter. Figure 5 In the illustrated embodiment, the first diameter is larger than both the second and third diameters. (Return to Reference) Figure 3 The proximal portion 206 of the spiral electrode 144 is disposed around and fixed to the distal portion 409 of the coupler 200, and also includes a shoulder 411 adjacent to the spiral electrode 124. Thus, the spiral electrode 144 surrounds and extends distally from the distal portion 409 of the coupler 200.

[0083] Figure 6This is a cross-sectional view of another arrangement of the distal region 522 of the alternative lead 514 according to an embodiment of the present disclosure. In addition to as combined Figure 6 As described, lead 514 can be constructed in substantially the same manner as lead 110. As shown, except for the gradually tapering portion 541 near the distal tip 523, the outer diameter of lead 514 is substantially the same along the distal region 522. Figure 3 The diameter of the tapering portion (defined by the tapering drug collar 540 in the lead 110) decreases toward the distal tip 523. In this arrangement, the drug collar 540 is tapering.

[0084] The distal region 522 of lead 514 is similar to the distal region of lead 110 and includes a distal assembly 525 comprising a coupler 500, a housing 504, and a helical electrode 524. The housing 504 includes a proximal portion 503 and a distal portion 505 forming the distal tip 523. In an embodiment, the proximal portion 503 is formed from a polymer material by an overmolding process (e.g., injection molding). In the illustrated embodiment, the distal portion 505 of the housing 504 is a pre-formed component configured to be mechanically coupled to the coupler 500 at its intermediate portion. As shown, the distal portion 505 includes a radial recess 506 and a protrusion 507 configured to secure the distal portion 505 to the coupler 500, as described in more detail below. In an embodiment, the distal portion 505 may be formed from a relatively rigid polymer material, such as polyetheretherketone (PEEK), tecothane, or similar materials. In some embodiments, the proximal portion 503 and the distal portion 505 are formed of the same polymer material. In some embodiments, the proximal portion 503 and the distal portion 505 are formed of different polymer materials.

[0085] The housing 504 surrounds and includes at least a portion of the coupler 500, the tubular inner preform 502, and the helical electrode 524 in the same manner as the distal assembly 124 of the lead 110. In some embodiments, the housing 504 may contact each of the coupler 500, the tubular inner preform 502, and the helical electrode 524. In some embodiments, the housing 504 may contact some, but not all, of the coupler 500, the tubular inner preform 502, and the helical electrode 524.

[0086] Coupler 500 is made of conductive material and is disposed within housing 504. In an embodiment, helical electrode 524 is connected to coupler 500 in the same manner as described above for coupling lead 110. Coupler 500 includes a channel 511 extending distally from its proximal end, thereby forming a blind via. First conductor 510 is connected within first lead body cavity 515 from connector 122 (see...) Figure 2AThe first conductor extends and is mechanically and electrically coupled to the coupler 500 in the channel 511. The first conductor carries electrical pulses and signals between the implantable pulse generator 12 and the helical electrode 524 via the coupler 500. In some embodiments, the first conductor 510 is a multi-strand coiled wire and extends proximally through the lead 514 in the first lead body lumen 515. In embodiments, the conductor 510 may be constructed in the same manner as the conductor 110 described above.

[0087] Coupler 500 is configured to engage with tubular inner preform 502. In some embodiments, coupler 500 and tubular inner preform 502 are configured to be mechanically coupled via snap-fit ​​connection or other connection. Additionally, the distal portion 505 of housing 504 is configured to be mechanically coupled to coupler 500 via snap-fit ​​connection.

[0088] The annular electrode 532 is located on the distal portion 522 of the lead 514. The annular electrode 532 is connected to the implantable pulse generator 12 via a second conductor (not shown) extending proximally from the annular electrode 532. Figure 1 ).

[0089] Figure 7 This is a perspective view of a tubular inner preform 502 according to an embodiment of the present disclosure. The tubular inner preform 502 has a proximal end 601 and a distal end 603 opposite to the proximal end 601. A longitudinal groove 605 extends partially along the tubular inner preform 502 from the distal end 603 toward the proximal end 601. The longitudinal groove 605 provides expansion for the inner preform 502 when it is engaged with the coupler 500. A circumferential groove 607 extends partially around the circumference of the inner preform 502. The distal end 603 of the inner preform 502 includes a chamfered edge 609 that facilitates receiving the proximal end 701 of the coupler 500 when the tubular inner preform 502 and the coupler 500 are joined together. The proximal end 601 also includes a U-shaped recess 610.

[0090] Figure 8This is a perspective view of a coupler 500 according to an embodiment of the present disclosure. As shown, the coupler 500 has a proximal end 701 and a distal end 703 opposite to the proximal end 701. In the illustrated embodiment, the distal end 703 is circular or hemispherical, although in other embodiments, the distal end 703 may take different shapes, such as flat / planar, conical, or frusto-conical. As further shown, the coupler 500 includes a proximal portion 705 terminating at the proximal end 701, a distal portion 709 opposite to the proximal portion 705 and terminating at the distal end 703, and an intermediate portion 707 located between the proximal portion 705 and the distal portion 709. As shown, the coupler 500 includes a radial rib 715 that extends circumferentially around a proximal portion 705 and is configured to be received within a circumferential groove 607 of a tubular inner preform 502 to couple the tubular inner preform 502 to the proximal portion 705 of the coupler 500.

[0091] The intermediate portion 707 of the coupler 500 includes a radial flange 713 extending outwardly from the surface of the intermediate portion 707. The radial flange 713 is configured to be received in a recess 506 in the distal portion 505 of the housing 504 to snap-fit ​​the distal portion 505 (see [link]). Figure 6 Mechanically coupled to coupler 500. Additionally, a protrusion 507 extending inwardly from the inner surface of the distal portion 505 of housing 504 operates to engage the proximal surface of radial flange 713, forming part of a snap-fit ​​arrangement (see...). Figure 6 ).

[0092] The proximal portion 705 of the coupler 500 has a first diameter, the middle portion 707 of the coupler 500 has a second diameter, and the distal portion 709 of the coupler 500 has a third diameter. Figure 9 In the embodiment shown, the second diameter is larger than both the first and third diameters. Also refer to... Figure 6 The distal portion 709 includes a shoulder 711 adjacent to a helical electrode 524. The helical electrode 524 surrounds the distal portion 709 and extends distally from the distal portion 709. The proximal portion 705 also includes an aperture 717 leading to the channel 511.

[0093] Figure 9 This is a cross-sectional view of another arrangement of the distal portion 822 of the lead 814 according to an embodiment of the present disclosure. In the embodiment, in addition to as combined Figure 9As described, lead 814 can be constructed in substantially the same manner as leads 110 and 514 described above. As shown, lead 814 includes a tubular lead body 820 having a proximal end (not shown) and a distal end 821 opposite to the proximal end. A distal assembly 825 extends from the distal end 821 of lead body 814. A first lead body lumen 815 extends from the proximal end through the distal end 821 of lead body 814, and a second lead body lumen 813 extends from the proximal end through the distal end 821 of lead body 814. The first lead body lumen 815 receives a first conductor 810, and the second lead body lumen 813 receives a second conductor 812. A proximal connector at the proximal end of lead body 820 is configured to mechanically and electrically couple lead 814 to IMD 12 (see [link to IMD]). Figure 1 The first conductor 810 and the second conductor 812 are mechanically and electrically connected to the IMD 12 via a proximal connector (not shown). Figure 1 ).

[0094] The distal assembly 825 includes a housing 804, a coupler 800, a helical electrode 824, and a ring electrode 832. The housing includes a proximal housing component 803 and a distal housing component 805. In some embodiments, the proximal housing component 803 takes the form of a drug ring impregnated with a drug or therapeutic agent to be delivered to target tissue in the heart. In the illustrated embodiment, the distal housing component 805 includes a tapering portion 841 whose diameter decreases toward the distal tip 823 of the lead 814.

[0095] Coupler 800 is formed of a conductive material and includes a proximal portion 840 and a distal portion 842. A first channel 811 extends distally within the proximal portion 840 from its proximal end, thereby forming a blind via. The first channel 811 is configured to receive a first conductor 810 and facilitate mechanical and electrical coupling of the first conductor 810 to coupler 800. A second channel 817 extends distally within the proximal portion 840 from the proximal end of coupler 800 and forms a second blind via. The second channel 817 is configured to receive a second conductor 812, which is mechanically and electrically coupled to coupler 800 within the second channel 817.

[0096] The helical electrode 824 includes a proximal portion disposed around the distal portion 842 of the coupler 800, as described elsewhere herein with respect to other embodiments. The helical electrode 824 extends a distance D from the distal tip 823 of the lead, which can be selected to optimize for specific clinical needs in conduction system pacing. In embodiments, the distance D can range from 0.5 mm to 2.5 mm. The helical electrode 824 can receive or transmit electrical pulses to the IMD 12 via the coupler 800 and the first conductor 810 and / or the second conductor 812.

[0097] In the illustrated embodiment, the coupler 800 includes a circumferential recess 844 located near the distal end of the proximal portion 840 of the coupler 800. Additionally, a protrusion 850 extends radially inward at the proximal end of the distal housing member 805. Figure 9 As can be seen, the protrusion 850 is received in the circumferential recess 844 to form a snap-fit ​​connection between the coupler 800 and the distal housing component 805.

[0098] Figure 10 This is a cross-sectional view of another arrangement of the distal portion 922 of the lead 914 according to an embodiment of the present disclosure. In the embodiment, in addition to as combined Figure 9 As described, lead 914 can be constructed in substantially the same manner as leads 110, 514, and 814 described above. In the illustrated embodiment, lead 914 includes a tubular lead body 920 having a proximal end (not shown) and a distal end 921 opposite to the proximal end. A distal assembly 925 extends from the distal end 921 of the lead body 920. A first lead body cavity 915 extends from the proximal end through the distal end 921 of the lead body 920, and a second lead body cavity 913 extends from the proximal end through the distal end 921 of the lead body. A first conductor 910 is received within the first lead body cavity 915, and a second conductor 912 is received within the second lead body cavity 913.

[0099] As shown in the figure, the distal assembly 925 includes a housing 905, a coupler 900, and a spiral electrode 924. Although in Figure 10Not shown, but in embodiments, the distal assembly 925 may further include one or more annular electrodes as described with respect to other embodiments. The coupler 900 is formed of a conductive material and includes a proximal portion 940 and a distal portion 942. A first channel 911 extends distally within the proximal portion 940 from its proximal end, thereby forming a blind via. The first channel 911 is configured to receive a first conductor 910 and facilitate mechanical and electrical coupling of the first conductor 910 to the coupler 900. A second channel 917 extends distally within the proximal portion 940 from the proximal end of the coupler 900 and forms a second blind via. The second channel 917 is configured to receive a second conductor 912, which is mechanically and electrically coupled to the coupler 900 within the second channel 917. In the illustrated embodiment, a conductive support tube 943 is disposed above the proximal portion of the coupler 900 and extends proximally within the lead body 920. When present, the support tube operates as a structural interface for coupling the distal component 925 to the lead body 920 and providing structural support to the coupler 900.

[0100] As shown, the helical electrode 924 includes a proximal portion disposed around the distal portion 942 of the coupler 900, as described elsewhere herein with respect to other embodiments. The helical electrode 924 extends a distance D from the distal tip 923 of the lead. In various embodiments, the distance D can be selected to optimize for specific clinical needs. For example, in CSP applications, the distance D can be selected to provide optimal conduction system pacing. In embodiments, the distance D can range from 0.5 mm to 2.5 mm. The helical electrode 924 can receive or transmit electrical pulses to the IMD 12 via the coupler 900 and the first conductor 910 and / or the second conductor 912.

[0101] In the illustrated embodiment, the coupler 900 includes a circumferential recess 944 located near the distal end of the proximal portion 940 of the coupler 900. Additionally, a protrusion 950 extends radially inward at the proximal end of the housing 905. Figure 10 As can be seen, the protrusion 950 is received in the circumferential recess 944 to form a snap-fit ​​connection between the coupler 900 and the housing 905, and to engage with the coupling. Figure 9 The described embodiments are similar. For example... Figure 10 As further shown, in this embodiment, the protrusion 950 has an inclined proximal surface to facilitate assembly of the outer housing 905 and the coupler 900, i.e., by allowing the outer housing 905 to slide on the coupler 900 in a distal to proximal direction. Additionally, the distal surface of the protrusion 950 is generally parallel to the wall forming the circumferential recess 944 so that it abuts the wall once a snap-fit ​​connection has been formed, thereby resisting separation of the coupler 900 and the outer housing 905.

[0102] Figure 11 This is a cross-sectional view of another arrangement of the distal portion 1022 of the lead 1014 according to an embodiment of the present disclosure. In the embodiment, in addition to as combined Figure 10 As described, lead 1014 can be constructed in substantially the same manner as leads 110, 514, 814, and 914 described above. In the illustrated embodiment, lead 1014 includes a tubular lead body 1020 having a proximal end (not shown) and a distal end 1021 opposite to the proximal end. A distal assembly 1025 extends from the distal end 1021 of the lead body 1020. A first lead body lumen 1015 extends from the proximal end through the distal end 1021 of the lead body 1020, and a second lead body lumen 1013 extends from the proximal end through the distal end 1021 of the lead body. A first conductor 1010 is received within the first lead body lumen 1015, and a second conductor 1012 is received within the second lead body lumen 1013.

[0103] As shown, the distal assembly 1025 includes a housing 1004, a coupler 1000, a helical electrode 1024, and an annular electrode 1032. As further shown, the coupler 1000 is disposed and secured within the housing 1004, and the helical electrode 1024 has a portion disposed within the housing 1004 and extending distally from the housing 1004, as in other embodiments of this disclosure. Additionally, in the illustrated embodiment, the housing 1004 includes a proximal housing member 1003 and a distal housing member 1005. The illustrated embodiment also includes a drug collar 1040 disposed on the distal housing member 1005. As shown, the diameter of the drug collar 1040 decreases from proximal to distal, thereby defining a tapering portion of the distal assembly 1025. In other embodiments, the housing 1004 is substantially of uniform diameter along its substantially entire length. As further shown, the distal tip 1023 is generally rounded or rounded to provide a relatively streamlined profile. When coupled with the tapering profile of the region just near the distal tip 1023, the overall shape of the distal portion of the lead 1014 (excluding the spiral electrode 1024) presents a bullet-shaped profile, which tends to provide better tissue penetration than a blunter or flatter distal tip.

[0104] Coupler 1000 is formed of a conductive material and includes a proximal portion 1060 and a distal portion 1061. The outer diameter of the proximal portion 1060 is larger than the outer diameter of the distal portion 1061. Coupler 1000 is disposed within a housing 1004. Coupler 1000 includes a proximal end 1063 and includes a first channel 1011 extending distally from the proximal end 1063 to form a first blind via. The first channel 1011 is configured to receive a first conductor 1010 and facilitate mechanical and electrical coupling of the first conductor 1010 to coupler 1000. A second channel 1017 extends distally from the proximal end 1063 within the proximal portion 1060 to form a second blind via. As shown, the second channel 1017 is configured to receive a second conductor 1012 and facilitate mechanical and electrical coupling of the second conductor 1012 to coupler 1000.

[0105] The proximal housing component 1003 is mechanically coupled to the proximal portion 1060 of the coupler 1000 via a first snap-fit ​​connection. The first snap-fit ​​connection is formed between a protrusion 1052 extending from the inner surface of the proximal housing component 1003 and a mating recess 1065 on the outer surface of the coupler 1000. In some embodiments, such as Figure 11 As shown, the protrusion 1052 may include a ramp-shaped or inclined distal surface to facilitate the coupling process.

[0106] Additionally, the distal housing component 1005 defines the distal tip 1023 of the lead 1014 and is mechanically coupled to the proximal portion 1060 of the coupler via a second snap-fit ​​connection. As shown, the protrusion 1051 extends radially inward from the inner surface of the distal housing component 1005 and engages with a corresponding recess 1066 on the outer surface of the coupler 1000. In some embodiments, such as Figure 11 As shown, the protrusion 1051 may include a ramped or inclined proximal surface to facilitate the coupling process. As further shown, the coupler 1000 also includes a circumferential flange 1050 extending from the outer surface of the coupler 1000 and received within a corresponding recess 1067 in the inner surface of the distal housing member 1005. Thus, the interaction between the protrusion 1051 and the recess 1066, and the interaction between the circumferential flange 1050 and the recess 1067, form a second snap-fit ​​connection.

[0107] As further shown, the arrangement of the distal housing component 1005, the distal portion 1061 of the coupler 1000, and the spiral electrode 1024 defines a narrow chamber or space 106 that can perform various functions, as will be explained in more detail below.

[0108] As in various other embodiments, the helical electrode 1024 includes a proximal portion disposed around the distal portion 1042 of the coupler 1000, and a distal portion extending a distance from the distal tip 1023 of the lead, the distance of which can be selected to optimize for specific clinical needs of conduction system pacing, as described in conjunction with other embodiments. The helical electrode 1024 can be connected via the coupler 1000 and the first conductor 1010 and / or the second conductor 1012 from the IMD 12 ( Figure 1 ) Receive electrical pulses or transmit electrical pulses to IMD 12.

[0109] An annular electrode 1032 is partially disposed above the proximal housing member 1003 and mechanically coupled to the proximal housing member 1003 via a third snap-fit ​​connection. The third snap-fit ​​connection is formed by the interaction of a protrusion 1053 extending from the outer surface of the proximal housing member 1003 with a corresponding recess 1069 on the inner surface of the annular electrode 1032. As shown, the proximal surface of the protrusion 1053 is sloped or inclined in a manner similar to the convexity 1051 of the distal housing member 1005, which facilitates the assembly of the annular electrode 1032 and the proximal housing member 1003.

[0110] like Figure 11 As shown, a portion 1070 of the distal housing component 1005 overlaps with a portion of the proximal housing component 1003 during assembly. The overlapping portion 1070 is positioned such that a first snap-fit ​​connection is located proximal to the overlapping portion 1070, and a second snap-fit ​​connection is located distal to the overlapping portion. During the assembly of the distal assembly 1025, the proximal housing component 1003 may be advanced distally over the proximal portion 1060 of the coupler 1000 until the protrusion 1052 snaps into a corresponding recess on the coupler 1000. Then, the distal housing component 1005 may be advanced proximally over the distal portion 1061 until the protrusion 1051 snaps into a corresponding recess on the coupler 1000. Finally, the annular electrode 1032 may be advanced distally over the proximal housing component 1003 until the protrusion 1053 snaps into a corresponding recess on the annular electrode 1032.

[0111] Leads 814, 914, and 1014 each have a first electrical conductor and a second electrical conductor, both mechanically coupled to their respective couplers. In an embodiment, the first conductors 810, 910, and 1010 are coil-shaped conductors, each defining a coil conductor lumen sized, among other things, to receive a stylet or guide wire to facilitate precise placement of the lead. In an embodiment, the second conductors 812, 912, and 1012 may comprise solid or stranded wire cable, which, among other things, enhances the overall tensile strength of the respective lead, which is advantageous if the lead must withstand tensile loads during lead removal. In an embodiment, the coil-shaped first and second conductors in each lead can be electrically active, i.e., electrically coupled to a pulse generator (…). Figure 1 The circuitry within the lead provides redundant electrical paths between the pulse generator and the corresponding helical electrode. In an alternative embodiment, only the coiled first conductor in each lead is electrically active, and the second conductor is provided solely for structural purposes. Alternatively, in an embodiment, the second conductor is electrically active, and a coiled conductor is present to provide the aforementioned coiled conductor lumen to receive a wick or similar device to facilitate lead delivery and placement.

[0112] Various components of the leads disclosed herein can be made of any known or later-developed lead construction material. For example, the lead body (e.g., lead body 1020) can be made of any flexible electrical insulating material suitable for human implantation. Exemplary materials used as the body may include polyurethane, silicone rubber, and copolymers of both, and may include surface treatments or other treatments (e.g., plasma treatment, lubricating coatings, and similar treatments) based on the functional requirements of the lead. Various conductors can also be made of any known or later-developed lead conductor material.

[0113] Similarly, components of the distal assemblies of the various leads described herein can be any known or later-developed material. In various embodiments, the housing material can be selected from a range of non-conductive materials, such as polyethersulfone (PES), polyurethane-based thermoplastics, ceramics, polypropylene, and polyetheretherketone (sold under the brand name PEEK™). Additionally, the coupler (e.g., coupler 1000) and the helical electrode (e.g., helical electrode 1024) can be made of any known or later-developed conductive material, typically metals such as Elgiloy, MP35N, tungsten, tantalum, iridium, platinum, titanium, palladium, stainless steel, and alloys of any of these materials. In various embodiments, the helical electrode may include surface treatments or coatings (such as an iridium oxide coating) to enhance the electrical properties of the helical electrode.

[0114] The implantable leads disclosed herein are applicable to numerous design / feature variations tailored to enhance the performance, usability, and deliverability of the respective leads. For efficiency, exemplary variations will be specifically referenced. Figure 11 The description is based on leads 1014, but those skilled in the art will readily recognize their applicability to other embodiments of this disclosure.

[0115] In an embodiment, the design of the distal tip 1023 can be consistent with... Figure 11 The differences shown are designed to provide unique capabilities suitable for conduction system pacing applications. For example, in one embodiment, the inner surface of the distal tip 1023 may also be rounded (i.e., in addition to the outer surface).

[0116] In an embodiment, the distal tip 1023 may be more than Figure 11 The more pronounced taper shown effectively creates a relatively sharp point for enhanced tissue penetration. Alternatively, the distal tip 1023 can be configured to have a relatively flat end (i.e., in a plane orthogonal to the longitudinal axis) to resist excessive tissue penetration. In such an embodiment, the internal chamber 1068 can be filled with material to prevent tissue ingress. In one such embodiment, the filling material can be a drug-eluting material that can provide alternative or additional drug elution capability to the lead 1014 to provide a higher level of drug penetration than... Figure 11 The blunter tip profile is shown.

[0117] In an alternative embodiment, the distal tip 1023 may be formed of a soft material, or alternatively may include a soft polymer distal extension configured to fold or otherwise deform when the helical electrode is screwed into the target tissue in order to resist excessive coring or tunneling of the target tissue.

[0118] In one embodiment, the length of the distal housing component 1005 can be selected such that all or part of the distal portion 1061 and a portion of the spiral electrode 1024 disposed therearound extend beyond the distal tip 1023, i.e., exposed to and able to contact the tissue. In this way, the penetration depth of the active distal electrode component can be increased without increasing the length of the spiral electrode 1024 itself. In other embodiments, the distal housing component 1005 may be made of a conductive material and thereby form part of the distal electrode of the lead 1014.

[0119] In further embodiments, other design variations of the distal housing component 1005 may be employed to influence tissue penetration during the deployment of the helical electrode 1024. For example, in one embodiment, the distal tip 1023 may form a flange (not shown) with an outer diameter larger than the outer diameter of the remainder of the distal housing component 1005. Optionally, the flange may be integrally formed with the distal housing component 1005, or alternatively, it may be formed of a polymeric material (optionally configured for drug elution) coupled to or formed on the distal housing component 1005. When present, the flange functions as a distal stop to limit tissue penetration.

[0120] In embodiments, the lead body 1020 may have a larger diameter than the distal assembly 1025, with the transition portion therebetween forming a natural stop for defining the penetration depth, for example, by inhibiting the migration of the distal assembly 1025 across the ventricular septum after implantation. Alternatively or additionally, fork teeth or other passive fixation elements may be provided at the transition portion from the lead body to the distal assembly, for example, at the distal end of the shock coil (if present). In some embodiments, the entire distal housing component 1005 may be formed of a drug-eluting polymer material.

[0121] The design and function of the helical electrode (e.g., helical electrode 1024) in various embodiments can be selectively adapted to optimized conduction system pacing applications. In the various illustrated embodiments, the helical electrode 1024 has a generally uniform diameter along its length. In other embodiments, the diameter of the helical electrode may vary along its length. In one embodiment, the outer diameter of the helical electrode 1024 increases from proximal to distal. In such an embodiment, the distal region of the helical electrode 1024 can effectively function as a spring to resist excessive forward propulsion into the tissue. Alternatively, the outer diameter of the helical electrode 1024 may decrease from proximal to distal to facilitate improved initial penetration into the tissue during implantation. In other embodiments, the diameter of the helical electrode may initially increase from proximal to distal and then decrease toward the distal end of the helical electrode 1024. In any of the various embodiments, the distal portion of the helical electrode 1024 (i.e., the portion designed to penetrate the target tissue) may have a constant or variable pitch along its length.

[0122] In embodiments, the helical electrode 1024 may include a coating along a portion of its length. For example, in embodiments, the exposed portion of the helical electrode 1024 may be coated with a polymer, such as parylene or a similar material, to facilitate tissue penetration. Alternatively or additionally, a drug-eluting polymer coating may be applied over a portion of the helical electrode 1024. In some embodiments, the coating may be configured to activate the left bundle branch 38 or the right bundle branch 40, or both. In some embodiments, the coating may be configured to increase impedance and thus improve the battery life of the power source in the implantable pulse generator 12.

[0123] In an embodiment, a biodegradable covering, such as a mannitol cap, may be provided to encapsulate all or part of the distal portion of the helical electrode 1024 (i.e., the portion extending from the distal tip 1023) to further assist lead deployment (i.e., this is achieved by minimizing the possibility of the helical electrode snagging on tissue or delivery devices and by providing a protective shield to avoid damage to the helical electrode during advancement into the ventricle).

[0124] In one embodiment, the outer surface of the coil conductor 1010 is encapsulated in an electrically insulating material, such as a polymer sleeve or coating. In one embodiment, this sleeve or coating is made of silicone, although other materials, such as ETFE, PTFE, polyurethane, and similar materials, may also be used. When present, the sleeve or coating operates to mechanically support the coil conductor 1010 under axial tension (i.e., to prevent the coil conductor from being stretched axially under tension) and under torsional loads (e.g., when the lead 1014 is rotated to secure the helical electrical conductor 1024 to tissue). In another embodiment, the inner surface of the conductor 1010 is uncoated, which can be useful during implantation. For example, when a bare metal mandrel is inserted into the interior of the coil conductor 1010, the contact between the mandrel and the inner surface of the conductor 1010 operates to provide electrical continuity between the mandrel and the helical electrode 1024. Therefore, the stent can be electrically connected to auxiliary devices (such as a pacing system analyzer), and the spiral electrode 1024 can then be used to map target cardiac tissue.

[0125] In an embodiment, the blind hole defined by channel 1011 can also serve as a mandrel stop, similarly enabling electrical coupling between the mandrel and the helical electrode 1024, thereby further enabling the mandrel to be used for tissue mapping as described above. In an embodiment, coupler 1000 may include one or more features (e.g., recesses, slots, etc.) configured to receive and engage the end of the mandrel within channel 1011 to facilitate delivery and retrieval of lead 1014. Such exemplary features are described in commonly assigned U.S. Patent No. 8,532,792, the entire contents of which are incorporated herein by reference.

[0126] In an alternative embodiment, the distal component 1025 may be configured as an open-ended design, having a longitudinal lumen partially defined by channel 1011 but extending through the distal portion 1061 of coupler 1000. Such an embodiment allows lead 1014 to be delivered via guidewire in a manner similar to conventional coronary leads.

[0127] In some embodiments, conductor 1010 may include one or more transmissive marker strips (not shown) selectively spaced along its length to provide implantation clinicians with enhanced visualization of the distal portion 1022 during implantation. When present, the marker strips may be placed on the outer or inner surface of the coiled conductor 1010. Additionally or alternatively, the transmissive marker strips may be selectively positioned along the associated delivery mandrel.

[0128] In various embodiments, the drug delivery mechanism may differ from the various drug loops described in the illustrated embodiments. For example, in one embodiment, the drug loop (e.g., drug loop 1040) may have radially projecting ribs or rings on its outer surface to enhance tissue contact and fixation. In another embodiment, the drug delivery component may be disposed within the exposed distal portion of the helical electrode 1024, for example, as part of or an extension of the distal portion 1061 of the coupler 1000. When present, this component may supplement or replace the drug loop 1040.

[0129] The specific embodiments shown and described herein employ a single ring electrode (e.g., ring electrode 1032), thereby enabling bipolar pacing and sensing between the ring electrode and the helical electrode. Various embodiments are readily adaptable to other multipolar configurations. In embodiments, the various leads can be quadrupole designs, for example, having three or more ring electrodes in addition to the helical electrode, which may be particularly advantageous in simultaneously performing right and left bundle branch pacing using a single lead.

[0130] Various modifications and additions may be made to the exemplary embodiments discussed without departing from the scope of the invention. For example, while the embodiments described above relate to specific features, the scope of the invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Therefore, the scope of the invention is intended to cover all such alternatives, modifications, and variations, as well as all equivalents thereof, that fall within the scope of the claims.

Claims

1. An implantable lead for use with an implantable medical device (IMD), the implantable lead comprising: A tubular lead body has a proximal end, a distal end opposite to the proximal end, a first lead body lumen extending from the proximal end through the distal end, and a second lead body lumen extending from the proximal end through the distal end. A proximal connector, located at the proximal end of the lead body, is configured to mechanically and electrically couple the lead to the IMD; A distal assembly extending from the distal end of the lead body, the distal assembly comprising: An outer casing having a proximal portion and a distal portion; A tubular inner preform, which is at least partially disposed within the housing, and includes: a proximal end, a distal end opposite to the proximal end, a longitudinal groove extending from the distal end toward the proximal end, and a circumferential groove extending partially around the circumference of the inner preform. A coupler made of conductive material is disposed within the housing and includes: a proximal portion having a proximal end and a channel extending distally from the proximal end, a distal portion opposite to the proximal portion, and an intermediate portion located between the proximal portion and the distal portion, wherein the inner preform is mechanically coupled to the proximal portion of the coupler; A spiral electrode, the spiral electrode having a proximal portion disposed around the distal portion of the coupler and a distal portion extending distally from the distal portion of the housing; and A ring electrode is disposed at the junction between the distal end of the lead body and the proximal portion of the housing. A first electrical conductor, extending through the lumen of the first lead body, and mechanically and electrically coupled to the coupler; and The second electrical conductor extends through the lumen of the second lead body and is mechanically and electrically coupled to the annular electrode.

2. The implantable lead according to claim 1, wherein, The distal portion of the outer casing is a distal preform configured to be mechanically coupled to the middle portion of the coupler.

3. The implantable lead according to claim 1 or 2, wherein, The distal preform includes a recess extending circumferentially around its inner surface, and the intermediate portion of the coupler includes a radial flange that is received in the recess in a snap-fit ​​arrangement.

4. The implantable lead according to any one of claims 1 to 3, wherein, One or both of the proximal and distal portions of the outer shell are formed by an overmolding process.

5. The implantable lead according to any one of claims 1 to 4, wherein, The circumferential groove of the inner preform includes a first end and a second end opposite to the first end, wherein the longitudinal groove is located between the first end and the second end.

6. The implantable lead according to any one of claims 1 to 5, wherein, The coupler includes radial ribs that extend circumferentially around the proximal portion, the radial ribs being configured to be received within a circumferential groove of the inner preform to couple the inner preform to the proximal end of the coupler.

7. The implantable lead according to any one of claims 1 to 6, wherein, The annular electrode includes an inner protrusion that extends radially inward and is received within a longitudinal groove of the inner preform.

8. The implantable lead according to any one of claims 1 to 7, wherein, The distal end of the tubular inner preform includes a beveled edge.

9. The implantable lead according to any one of claims 1 to 8, wherein, The outer casing includes a collar impregnated with a drug or therapeutic agent.

10. The implantable lead according to any one of claims 1 to 9, wherein, The proximal end of the inner preform includes a recess.

11. The implantable lead according to any one of claims 1 to 10, wherein, The first electrical conductor is coupled to the coupler in the channel.

12. The implantable lead according to any one of claims 1 to 11, wherein, The proximal portion of the coupler has a first diameter, the middle portion of the coupler has a second diameter, and the distal portion of the coupler has a third diameter.

13. The implantable lead according to claim 12, wherein, The first diameter is larger than the second diameter and the third diameter.

14. The implantable lead according to claim 12, wherein, The second diameter is larger than the first diameter and the third diameter.

15. The implantable lead according to any one of claims 1 to 14, wherein, The distal portion of the spiral electrode extends from the distal portion of the housing by a distance ranging from 0.5 mm to 2.5 mm.

16. An implantable lead for use with an implantable medical device (IMD), said implantable lead comprising: The tubular lead body has a proximal end and a distal end opposite to the proximal end; A proximal connector, located at the proximal end of the lead body, is configured to mechanically and electrically couple the lead to the IMD; A distal assembly extending from the distal end of the lead body, the distal assembly comprising: An outer casing having a proximal portion and a distal portion; A tubular inner preform, which is at least partially disposed within the housing, and includes: a proximal end, a distal end opposite to the proximal end, a longitudinal groove extending from the distal end toward the proximal end, and a circumferential groove extending partially around the circumference of the inner preform. A coupler made of conductive material is disposed within the housing and includes: a proximal portion having a proximal end and a channel extending distally from the proximal end, a distal portion opposite the proximal portion, and an intermediate portion located between the proximal portion and the distal portion, wherein an inner preform is mechanically coupled to the proximal portion of the coupler; and A spiral electrode, the spiral electrode having a proximal portion disposed around the distal portion of the coupler and a distal portion extending distally from the distal portion of the housing; and A first electrical conductor extends through the lead body and is mechanically and electrically coupled to the coupler within the channel.

17. The implantable lead according to claim 16, wherein, The distal portion of the outer casing is a distal preform configured to be mechanically coupled to the middle portion of the coupler.

18. The implantable lead according to claim 17, wherein, The distal preform includes a recess extending circumferentially around its inner surface, and the intermediate portion of the coupler includes a radial flange that is received in the recess in a snap-fit ​​arrangement.

19. The implantable lead according to claim 16, wherein, One or both of the proximal and distal portions of the outer shell are formed by an overmolding process.

20. The implantable lead according to claim 16, wherein, The circumferential groove of the inner preform includes a first end and a second end opposite to the first end, wherein the longitudinal groove is located between the first end and the second end.

21. The implantable lead according to claim 16, wherein, The coupler includes radial ribs that extend circumferentially around the proximal portion, the radial ribs being configured to be received within a circumferential groove of the inner preform to couple the inner preform to the proximal end of the coupler.

22. The implantable lead according to claim 16, further comprising: An annular electrode, wherein the annular electrode includes an inner protrusion that extends radially inward and is received within a longitudinal groove of the inner preform.

23. The implantable lead according to claim 16, wherein, The distal end of the tubular inner preform includes a beveled edge.

24. The implantable lead according to claim 16, wherein, The outer casing includes a collar impregnated with a drug or therapeutic agent.

25. The implantable lead according to claim 16, wherein, The proximal portion of the coupler has a first diameter, the middle portion of the coupler has a second diameter, and the distal portion of the coupler has a third diameter.

26. The implantable lead according to claim 25, wherein, The first diameter is larger than the second diameter and the third diameter.

27. The implantable lead according to claim 25, wherein, The second diameter is larger than the first diameter and the third diameter.

28. A distal assembly for an implantable lead, the distal assembly comprising: An outer casing having a proximal portion and a distal portion; A tubular inner preform, which is at least partially disposed within the housing, and includes: a proximal end, a distal end opposite to the proximal end, a longitudinal groove extending from the distal end toward the proximal end, and a circumferential groove extending partially around the circumference of the inner preform. A coupler made of conductive material is disposed within the housing and includes: a proximal portion having a proximal end and a channel extending distally from the proximal end, a distal portion opposite to the proximal portion, and an intermediate portion located between the proximal portion and the distal portion, wherein the inner preform is mechanically coupled to the proximal portion of the coupler; A spiral electrode, the spiral electrode having a proximal portion disposed around the distal portion of the coupler and a distal portion extending distally from the distal portion of the housing; and A ring electrode is disposed at the junction between the distal end of the lead body and the proximal portion of the housing. The proximal and distal portions of the outer shell are formed by an overmolding process.

29. The distal assembly of claim 28, wherein, The distal portion of the housing includes a recess extending circumferentially around its inner surface, and the intermediate portion of the coupler includes a radial flange that is received in the recess in a snap-fit ​​arrangement.

30. The distal assembly of claim 28, wherein, The circumferential groove of the inner preform includes a first end and a second end opposite to the first end, wherein the longitudinal groove is located between the first end and the second end.

31. The distal assembly of claim 28, wherein, The coupler includes radial ribs that extend circumferentially around the proximal portion, the radial ribs being configured to be received within a circumferential groove of the inner preform to couple the inner preform to the proximal end of the coupler.

32. The distal component of claim 28, wherein, The annular electrode includes an inner protrusion that extends radially inward and is received within a longitudinal groove of the inner preform.

33. An implantable lead configured to be coupled to an implantable medical device (IMD), the implantable lead comprising: The tubular lead body has a proximal end and a distal end opposite to the proximal end; A distal assembly extending from the distal end of the lead body, the distal assembly comprising: An outer casing having a proximal portion and a distal portion; A tubular inner preform, which is at least partially disposed within the housing and includes a proximal end and a distal end opposite to the proximal end; A coupler made of conductive material is disposed within the housing and includes: a proximal portion having a proximal end and a channel extending distally from the proximal end, a distal portion opposite the proximal portion, and an intermediate portion located between the proximal portion and the distal portion, wherein an inner preform is disposed around the proximal portion of the coupler and is mechanically coupled to the proximal portion of the coupler; and A spiral electrode, the spiral electrode having a proximal portion disposed around the distal portion of the coupler and a distal portion extending distally from the distal portion of the housing; and A first electrical conductor extends through the lead body and is mechanically and electrically coupled to the coupler within the channel.

34. The implantable lead according to claim 33, wherein, One of the proximal and distal portions of the outer shell is formed by an overmolding process.

35. The implantable lead according to claim 34, wherein, The distal assembly also includes an annular electrode disposed at the junction between the distal end of the lead body and the proximal portion of the housing.

36. An implantable lead for use with an implantable medical device (IMD), the implantable lead comprising: The tubular lead body has a proximal end and a distal end opposite to the proximal end; A proximal connector, located at the proximal end of the lead body, is configured to mechanically and electrically couple the lead to the IMD; A distal assembly extending from the distal end of the lead body, the distal assembly comprising: An outer casing having a proximal casing component and a distal casing component; A coupler made of conductive material is disposed within the housing and includes: a proximal portion having a proximal end and a first channel extending distally from the proximal end; and a distal portion opposite the proximal portion, wherein the proximal housing component is mechanically coupled to the proximal portion of the coupler via a first snap-fit ​​connection, and the distal housing component is mechanically coupled to the proximal portion of the coupler via a second snap-fit ​​connection; A spiral electrode, the spiral electrode having a proximal portion disposed around the distal portion of the coupler and a distal portion extending distally from the distal portion of the housing; and A ring electrode is partially disposed above the proximal housing component and is mechanically coupled to the proximal housing component via a third snap-fit ​​connection; A first electrical conductor, extending through the lead body and mechanically and electrically coupled to the coupler; and A second electrical conductor extends through the lead body and is mechanically and electrically coupled to the annular electrode.

37. The implantable lead according to claim 36, wherein, The coupler includes a second channel extending from the proximal end to the distal end, and a third electrical conductor is mechanically and electrically coupled to the coupler in the second channel.

38. The implantable lead according to claim 36 or 37, wherein, The distal housing component overlaps with the proximal housing component.

39. The implantable lead according to any one of claims 36 to 38, wherein, The first snap-fit ​​connection is located on the proximal side of the overlap, and the second snap-fit ​​connection is located on the distal side of the overlap.

40. The implantable lead according to any one of claims 36 to 39, wherein, The distal housing component includes a collar impregnated with a drug or therapeutic agent.

41. The implantable lead according to any one of claims 36 to 40, wherein, The coupler includes a first recess, a second recess, and a flange.

42. The implantable lead according to claim 41, wherein, The first snap-fit ​​connection includes a proximal housing protrusion that engages with the first recess, and the second snap-fit ​​connection includes a distal housing protrusion that engages with the second recess.

43. The implantable lead according to claim 41, wherein, The distal housing includes a recess configured to receive the flange.

44. The implantable lead according to any one of claims 36 to 43, wherein, The first electrical conductor is coupled to the coupler in the first channel.

45. The implantable lead according to any one of claims 36 to 44, wherein, The proximal portion of the coupler has a first diameter, and the distal portion of the coupler has a second diameter.

46. ​​The implantable lead according to claim 45, wherein, The first diameter is larger than the second diameter.

47. The implantable lead according to any one of claims 36 to 46, wherein, The distal portion of the spiral electrode extends from the distal portion of the housing by a distance ranging from 0.5 mm to 2.5 mm.

48. The implantable lead according to any one of claims 36 to 47, wherein, The outer surfaces of the annular electrode, the proximal housing component, and the distal housing component are flush.

49. The implantable lead according to any one of claims 36 to 48, wherein, The distal housing component has an outer diameter that tapers gradually from its proximal end to its distal end.

50. The implantable lead according to any one of claims 36 to 49, wherein, The third snap-fit ​​connection includes a protruding portion of the ...

51. An implantable lead for use with an implantable medical device (IMD), the implantable lead comprising: A tubular lead body has a proximal end, a distal end opposite to the proximal end, a first lead body lumen extending from the proximal end through the distal end, and a second lead body lumen extending from the proximal end through the distal end. A proximal connector, located at the proximal end of the lead body, is configured to mechanically and electrically couple the lead to the IMD; A distal assembly extending from the distal end of the lead body, the distal assembly comprising: An outer casing having a proximal casing component and a distal casing component; A coupler made of conductive material, disposed within the housing, includes: a proximal portion having a proximal end and a first channel extending distally from the proximal end, and a distal portion opposite the proximal portion, wherein the proximal housing component is mechanically coupled to the proximal portion of the coupler via a first snap-fit ​​connection, and the distal housing component is mechanically coupled to the proximal portion of the coupler via a second snap-fit ​​connection; and A spiral electrode, the spiral electrode having a proximal portion disposed around the distal portion of the coupler and a distal portion extending distally from the distal portion of the housing; and A first electrical conductor extends through the lumen of the first lead body and is mechanically and electrically coupled to the coupler within the first channel.

52. The implantable lead according to claim 51, wherein, The coupler includes a second channel extending from the proximal end to the distal end, and a third electrical conductor extends through the second lead body lumen and is mechanically and electrically coupled to the coupler in the second channel.

53. The implantable lead according to claim 51, wherein, The distal housing component overlaps with the proximal housing component.

54. The implantable lead according to claim 53, wherein, The first snap-fit ​​connection is located on the proximal side of the overlap, and the second snap-fit ​​connection is located on the distal side of the overlap.

55. The implantable lead according to claim 51, wherein, The distal housing component includes a collar impregnated with a drug or therapeutic agent.

56. The implantable lead according to claim 51, wherein, The coupler includes a first recess, a second recess, and a flange.

57. The implantable lead according to claim 56, wherein, The first snap-fit ​​connection includes a proximal housing protrusion that engages with the first recess, and the second snap-fit ​​connection includes a distal housing protrusion that engages with the second recess.

58. The implantable lead according to claim 56, wherein, The distal housing includes a recess configured to receive the flange.

59. The implantable lead according to claim 51, wherein, The proximal portion of the coupler has a first diameter, and the distal portion of the coupler has a second diameter.

60. The implantable lead according to claim 59, wherein, The first diameter is larger than the second diameter.

61. The implantable lead according to claim 51, wherein, The distal portion of the spiral electrode extends from the distal portion of the housing by a distance ranging from 0.5 mm to 2.5 mm.

62. The implantable lead according to claim 51, wherein, The distal housing component has an outer diameter that tapers gradually from its proximal end to its distal end.

63. The implantable lead according to claim 51, further comprising: The annular electrode, wherein the third snap-fit ​​connection includes a proximal housing protrusion that engages with a recess on the interior of the annular electrode.

64. A distal assembly for a lead body, the distal assembly comprising: An outer casing having a proximal casing component and a distal casing component; A coupler made of conductive material is disposed within the housing and includes: a proximal portion having a proximal end and a first channel extending distally from the proximal end and configured to receive a first electrical conductor; and a distal portion opposite the proximal portion, wherein the proximal housing component is mechanically coupled to the proximal portion of the coupler via a first snap-fit ​​connection, and the distal housing component is mechanically coupled to the proximal portion of the coupler via a second snap-fit ​​connection. A spiral electrode, the spiral electrode having a proximal portion disposed around the distal portion of the coupler and a distal portion extending distally from the distal portion of the housing; and A ring electrode is partially disposed above the proximal housing component and is mechanically coupled to the proximal housing component via a third snap-fit ​​connection.

65. The distal assembly of claim 64, wherein, The coupler includes a second channel extending from the proximal end to the distal end and configured to receive a second conductor.

66. The distal assembly of claim 64, wherein, The distal housing component overlaps with the proximal housing component.

67. The distal component of claim 66, wherein, The first snap-fit ​​connection is located on the proximal side of the overlap, and the second snap-fit ​​connection is located on the distal side of the overlap.

68. The distal assembly of claim 64, wherein, The distal housing component includes a collar impregnated with a drug or therapeutic agent.

69. An implantable lead for use with an implantable medical device (IMD), said implantable lead comprising: A tubular lead body has a proximal end, a distal end opposite to the proximal end, a first lead body lumen extending from the proximal end through the distal end, and a second lead body lumen extending from the proximal end through the distal end. A proximal connector, located at the proximal end of the lead body, is configured to mechanically and electrically couple the lead to the IMD; A distal assembly extending from the distal end of the lead body, the distal assembly comprising: An outer casing having a proximal casing component and a distal casing component; A coupler made of conductive material, disposed within a housing, includes: a proximal portion and a distal portion opposite the proximal portion, the proximal portion having a proximal end, a first channel extending distally from the proximal end, and a second channel extending distally from the proximal end, wherein the proximal housing component is mechanically coupled to the proximal portion of the coupler via a first snap-fit ​​connection, and the distal housing component is mechanically coupled to the proximal portion of the coupler via a second snap-fit ​​connection; and A spiral electrode having a proximal portion disposed around the distal portion of the coupler and a distal portion extending distally from the distal portion of the housing; A coil-shaped first electrical conductor extending through the lumen of the first lead body and mechanically and electrically coupled to the coupler within the first channel; and A stranded cable-shaped second conductor extends through the lumen of the second lead body and is mechanically and electrically coupled to the coupler within the second channel.

70. The implantable lead according to claim 69, wherein, The distal assembly also includes an annular electrode, which is partially disposed above the proximal housing component and mechanically coupled to the proximal housing component via a third snap-fit ​​connection.

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