Implantable medical lead

Abstract

An implantable medical lead includes a plurality of barbs supported by a lead body. The lead body includes a biostable material. The barbs include a biodegradable material. The lead body supports a distally extending fixation device at a distal end of the lead body. When the fixation device engages tissue, the plurality of barbs are elastically biased to extend radially outward from the lead body to engage the tissue. The fixation device can support an electrode configured to provide pacing signals to a heart of a patient.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 593,693, filed October 27, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to medical devices such as implantable medical leads. Background Technology

[0004] Various types of implantable medical leads have been implanted to treat or monitor one or more conditions in patients. These implantable medical leads are adapted to allow medical devices to monitor or treat conditions or functions related to the heart, muscles, nerves, brain, stomach, endocrine organs, or other organs and their associated functions. Implantable medical leads include electrodes and / or other elements for physiological sensing and / or therapeutic delivery. Implantable medical leads allow sensing / therapeutic elements to be positioned at one or more target sites to achieve these functions, while the medical device electrically coupled to these elements via the leads is located in different positions.

[0005] Implantable medical leads (e.g., the distal portion of an elongated implantable medical lead) can be implanted at a target site selected to detect a patient's physiological condition and / or deliver one or more therapies. For example, an implantable medical lead can be delivered to a location within the atrium or ventricle of the heart to sense intrinsic cardiac signals and deliver pacing or anti-tachyarrhythmic shock therapy from a medical device coupled to the lead. In other examples, an implantable medical lead can be tunneled to a location adjacent to the spinal cord or other nerves to deliver pain therapy from a medical device coupled to the lead. Implantable medical leads may include fixation components to secure the distal end of the lead to the target site. Summary of the Invention

[0006] An implantable medical lead includes a lead body supporting a fixation device (e.g., an auger or auger) extending distally from the lead body. The lead body also supports a plurality of barbs configured to extend radially outward to engage tissue when the fixation device engages tissue. The lead body and fixation device contain a biostabilizing material. The plurality of barbs contain a biodegradable material. The biodegradable material may be configured to degrade upon exposure to a patient's fluids and / or biological components (e.g., blood and / or blood components such as water, proteins, electrolytes, amino acids, salts, enzymes, hormones, and / or other components). For example, the biodegradable material may be configured to degrade upon exposure to a patient's fluids and / or biological components for a period of less than about 6 months (less than 3 months in some examples). The biostabilizing material may be configured to substantially maintain its physical and chemical integrity when implanted within a patient's tissue.

[0007] In an example, an implantable medical lead includes: a lead body comprising a biostabilizing material defining an outer surface and a distal end, wherein the lead body defines a longitudinal axis surrounding the outer surface and extending through the distal end; a fixation device supported by the lead body and located distally to the distal end, wherein the fixation device is configured for insertion into a patient's tissue; and a plurality of barbs supported by the outer surface and located proximal to the fixation device, wherein the plurality of barbs are positioned about the longitudinal axis, wherein the plurality of barbs are configured to extend radially outward from the outer surface, wherein the plurality of barbs are configured to engage the tissue when inserted into the tissue, and wherein the plurality of barbs comprise a biodegradable material configured to degrade in the patient's fluids.

[0008] In one example, a technique includes: defining an outer surface of a lead body surrounding a longitudinal axis and a distal end of the lead body using a bio-stabilized material; supporting a fixation element configured to engage tissue using the distal end of the lead body; defining a plurality of barbs supported by the outer surface and proximal to the fixation device using a biodegradable material; and using resilient biasing of the plurality of barbs to cause the plurality of barbs to extend radially outward from the outer surface.

[0009] Details of one or more examples are set forth in the accompanying drawings and the following description. Other features, objectives, and advantages will be apparent from the specification, drawings, and claims. Attached Figure Description

[0010] Figure 1 This is a conceptual diagram illustrating an exemplary implantable medical lead inserted at an example target site.

[0011] Figure 2 This is a perspective view showing the distal portion of an exemplary lead.

[0012] Figure 3 yes Figure 2 A schematic end view of the distal portion of the lead wire.

[0013] Figure 4 This is a schematic cross-sectional view of the lead body that supports multiple barbs in the retracted position.

[0014] Figure 5 This is a schematic cross-sectional view of the lead body supporting multiple barbs in the unfolded position.

[0015] Figure 6 This is a schematic cross-sectional view of the lead body supporting multiple barbs at the far side.

[0016] Figure 7This is a schematic top view of multiple barbs supported by the base body.

[0017] Figure 8 yes Figure 7 A schematic cross-sectional view of multiple barbs and the base body, with multiple barbs in the retracted position.

[0018] Figure 9 yes Figure 7 and Figure 8 A schematic cross-sectional view of multiple barbs and the base body, with the multiple barbs in the unfolded position.

[0019] Figure 10 This is a schematic cross-sectional view of a barb defined by a single-angle cut.

[0020] Figure 11 This is a schematic cross-sectional view of a barb defined by a double-angle cut.

[0021] Figure 12 This is a perspective view showing the distal portion of an exemplary lead.

[0022] Figure 13 yes Figure 12 A schematic end view of the distal portion of the lead wire.

[0023] Figure 14 A perspective view of the distal portion of an exemplary lead is shown.

[0024] Figure 15 yes Figure 14 A schematic end view of the distal portion of the lead wire.

[0025] Figure 16 An exemplary technique for supporting multiple barbs with a lead body is shown. Detailed Implementation

[0026] This disclosure describes an implantable medical lead configured to deliver pacing to a patient's heart. The implantable medical lead includes a lead body comprising a bio-stabilizing material. The lead body supports a plurality of barbs comprising a biodegradable material. A fixation device extends distally from the distal end of the lead body. The plurality of barbs are configured to extend radially outward from the lead body to engage tissue when the fixation device engages tissue. The fixation device may support an electrode configured to provide a pacing signal to the patient's heart. For example, the plurality of barbs may be configured to engage tissue when the fixation device positions the electrode at or near a target site, such as tissue of the left bundle branch (LBB), His bundle (HB), right bundle branch (RBB), or other ventricles and / or cardiac tissue of the patient's heart.

[0027] For conduction pacing, positioning and / or maintaining the electrode in a location sufficiently close to the heart's conduction pacing system can facilitate more efficient delivery of the pacing to the system. Therefore, movement of the implantable lead supporting the electrode relative to the target site (e.g., in a proximal or distal direction) during and / or after implantation can alter the electrode position and affect the effectiveness of conduction pacing. For example, after implantation of the lead, blood flow through the heart can exert fluid forces on the lead, generating a proximal force and potentially causing movement of the lead and the supported electrode relative to the target site. Similarly, cardiac pulsation and / or other patient activities can exert forces on the lead and the supported electrode, causing potential movement of the lead and the supported electrode relative to the target site.

[0028] Although this article describes implantable medical leads primarily in the context of an example where they are configured to deliver pacing to a patient’s heart, the components and techniques described herein are applicable to leads configured to deliver other therapies and / or configured to be implanted at different locations within a patient’s body.

[0029] This disclosure includes a medical system comprising an implantable medical lead. The implantable medical lead includes a plurality of barbs configured to mitigate and / or reduce movement of the implantable medical lead relative to a target site. The implantable medical lead includes a fixation device supporting a fixation electrode. Mitigating and / or reducing movement of the implantable medical lead can reduce and / or mitigate movement of the fixation electrode relative to the target site, for example, limiting changes in the position of the fixation electrode that may affect the effectiveness of conduction system pacing. The plurality of barbs are configured to extend radially outward from the lead body of the implantable medical lead to engage tissue within the target site when the fixation device engages tissue within the target site. In an example, the fixation device is a auger.

[0030] Multiple barbs are defined by a biodegradable material (e.g., a biodegradable polymer) configured to degrade upon contact with tissue. The biodegradable material may be configured to degrade upon exposure to a patient's fluids and / or biological components (e.g., blood and / or blood components such as water, proteins, electrolytes, amino acids, salts, enzymes, hormones, and / or other components). For example, the biodegradable material may be configured to degrade upon exposure to a patient's fluids and / or biological components for a period of less than about 6 months (less than 3 months in some examples). The lead body and / or fixation device contain a biostabilizing material. This biostabilizing material may be configured to substantially maintain its physical and chemical integrity when implanted within a patient's tissue.

[0031] Therefore, implantable medical leads can be configured such that multiple barbs help retain the distal portion of the lead during and / or after implantation. These barbs may degrade as scar tissue forms around the distal portion of the lead in the patient's body. Furthermore, the degradation of the multiple barbs can facilitate the removal of the implantable medical lead some time after implantation in the patient, if necessary.

[0032] Multiple barbs are resiliently biased to extend radially outward from the distal portion of the lead to establish a deployment position. In an example, the resilient bias limits the outward radial extension of the barbs to, for example, limit the possibility of thrombosis that may occur as the barbs penetrate deeper. For example, the distal portion of the lead may define a body radius extending from the longitudinal axis of the implanted medical lead to the outer surface supporting the multiple barbs. One or more barbs may define a barb radius extending from the outer surface to the free end of the barb. In an example, the barb radius may be less than about thirty percent of the body radius. In some examples, the implanted medical lead includes two or more barbs to help limit movement of the distal portion of the lead while limiting the outward radial extension of individual barbs.

[0033] In some examples, the medical system includes a delivery catheter defining an inner lumen. An implantable medical lead may be configured to translate and / or rotate within the lumen. The inner surface defining the lumen may be configured to apply force to a plurality of barbs to substantially prevent elastic biasing from causing the barbs to extend radially outward. The medical system may be configured such that retraction of the delivery catheter relative to the proximal side of the implantable medical lead substantially releases the plurality of barbs, causing the plurality of barbs to extend radially outward. In an example, the plurality of barbs are configured to flexibly bend distally from an deployed position (e.g., if repositioning of a fixation electrode is required) when the delivery catheter subsequently moves distally to re-encapsulate the plurality of barbs. If, after re-encapsulation, the delivery catheter returns to a position proximal to the plurality of barbs, the plurality of barbs are elastically biased to return to the deployed position.

[0034] Figure 1 This is a conceptual diagram illustrating a portion of an example medical device system 100, which includes an implantable medical lead 112 positioned at a target site 114 within a patient 116. The implantable medical lead 112 includes an elongated lead body 118 defining a proximal portion 119 (“lead proximal portion 119”) and a distal portion 120 (“lead distal portion 120”) of the implantable medical lead 112. In some examples, such as... Figure 1As shown, target site 114 may include a portion of heart 122, such as the atrioventricular septal wall of the right atrium (RA) of heart 122, or the ventricular septal wall of the right ventricle (RV) of heart 122, or other locations within the body of patient 116. A clinician may manipulate the distal portion 120 of the lead through the vascular system of patient 116 to position the distal portion 120 at or near target site 114. For example, a clinician may guide the distal portion 120 of the lead through the superior vena cava (SVC) and into the RA to reach target site 114 on the atrioventricular septal wall, such as a target site within the Koch triangle region. In some examples, other approaches or techniques may be used to guide the distal portion 120 of the lead to other target implantation sites within the body of patient 116. Medical device system 100 may include a delivery catheter and / or external components (not shown), and implantable medical lead 112 may be guided and / or manipulated within the lumen of the delivery catheter to access target site 114.

[0035] The implantable medical lead 112 can be configured to provide stimulation (e.g., pacing) to the native conduction system 123 of the heart 122. For example, in one or more embodiments described herein, the target site 114 may be the Koch triangle region or the basal (e.g., high basal or high septal) region or the apical (e.g., low septal or near-apex) region of the atrioventricular septum of the patient's heart. Implantation in the atrioventricular septum or ventricular septum can facilitate pacing of the left bundle branch, right bundle branch, or ventricular myocardium. Implantation in the basal region of the ventricular septum can facilitate pacing of the bundle branches. Implantation in the apical region can facilitate pacing of Purkinje fibers.

[0036] The implantable medical lead 112 includes a fixation device 124 configured to penetrate cardiac tissue at or near a target site 114. For example, the fixation device 124 of the implantable medical lead 112 may be configured to penetrate to or near the left bundle branch (LBB), right bundle branch (RBB), other specific conduction tissue, or other ventricular tissue of the heart 122. In some examples, the fixation device 124 supports a fixation device electrode (e.g., fixation device electrode 130). Figure 2The fixation device electrode is configured to provide pacing, for example, to the heart 122. The fixation device 124 may be electrically connected to a conductor (not shown) extending from the fixation device 124 through an implantable medical lead 112. In an example, the conductor is electrically connected to a therapy delivery circuit 127 of the implantable medical device (IMD) 126. The therapy delivery circuit 127 may be configured to provide electrical signals (e.g., to the fixation device electrode) via the conductor through the fixation device 124. The fixation device electrode may conduct the electrical signals to target tissue of the heart 122, thereby depolarizing, for example, the myocardium of the ventricle, and consequently, causing regular interval contractions. In an example where the fixation device 124 penetrates to a location at or near the HB, RBB, LBB, or other specific conduction tissue of the heart 122, cardiac pacing delivered via the fixation device 124 (e.g., through the fixation device electrode) may provide conduction system pacing (CSP) of the heart 122, which may provide further physiological activation and contraction of the heart 122. The fixation device 124 (e.g., a fixation electrode or another electrode) may also be electrically connected via a conductor to the sensing circuitry 129 of the IMD 126. The sensing circuitry 129 may be configured to sense the electrical activity of the heart 122 via the fixation device 124. In this example, the IMD 126 includes processing circuitry 131, communication circuitry 133, and / or memory 135.

[0037] In the example, the fixing device 124 defines the auger (e.g., auger component 132). Figure 2 The auger extends distally at the distal end of the distal portion 120 of the lead. The auger can support the fixation device electrode. The fixation device 124 can be configured such that when the auger is rotated about a longitudinal axis defined by the lead body 118, the auger engages tissue at the target site 114. For example, the lead body 118 can be configured such that torque on the lead body 118 (e.g., on the proximal portion 119 of the lead) causes rotation of the distal portion 120 of the lead. Rotation of the distal portion 120 of the lead causes rotation of the auger about the longitudinal axis. In this example, the fixation device 124 (e.g., the auger) is configured to place the fixation device electrode proximal to the conduction system 123 such that the IMD 126 can provide pacing to the heart 122 via the implantable medical lead 112.

[0038] For conduction pacing, positioning and / or maintaining the electrode in a position sufficiently close to the heart's conduction pacing system can facilitate more efficient delivery of the pacing to the system. Therefore, during and / or after implantation, movement of the implantable lead supporting the electrode relative to the target site (e.g., in a proximal or distal direction) can alter the electrode position and affect the effectiveness of conduction pacing. For example, after implantation of the lead, blood flow through the heart can exert fluid forces on the lead, generating a proximal force and potentially causing movement of the lead and the supported electrode relative to the target site. Similarly, the patient's cardiac pulsation and / or other activities can exert forces on the lead and the supported electrode, causing potential movement of the lead and the supported electrode relative to the target site.

[0039] Implantable medical lead 112 includes multiple barbs (e.g., barbs 136, 152, 158). Figure 2 The plurality of barbs are configured to mitigate and / or reduce movement of the implantable medical lead 112 (e.g., distal portion 120 of the lead) relative to the target site 114. Mitigating and / or reducing movement of the implantable medical lead 112 reduces and / or reduces movement of the fixation device electrode relative to the target site 114. The plurality of barbs are supported by the distal portion 120 of the lead and are configured to extend radially outward from the lead body 118. The barbs are configured to engage tissue within the target site 114 when the fixation device 124 engages tissue within the target site 114. For example, the distal portion 120 of the lead may be configured such that when the fixation device 124 (e.g., an auger of the fixation device 124) positions the fixation device electrode near the conduction system 123, a portion of the distal portion 120 of the lead may be implanted within the tissue of the target site 114 (e.g., within the tissue of the ventricular septum or atrioventricular septum). The distal portion 120 of the lead may be configured such that barbs are implanted within the tissue when a portion of the distal portion 120 of the lead is implanted within the tissue. The barbs may be configured to extend radially outward from the distal portion 120 to engage the tissue and to mitigate and / or reduce movement of the distal portion 120 of the lead relative to the target site 114, and thus reduce and / or mitigate movement of the fixation device electrode relative to the target site 114. The barbs are defined by a biodegradable material configured to degrade after engagement with the tissue. For example, the barbs may be defined by a biodegradable polymer.

[0040] The barbs are resiliently biased to extend radially outward from the distal portion 120 of the lead. In an example, the resilient bias limits the outward radial extension of the barbs from the distal portion 120 of the lead. The resilient bias can limit the outward radial extension to, for example, limit the possibility of thrombosis that may occur as the barbs penetrate deeper. For example, the distal portion 20 of the lead may define a body radius extending from the longitudinal axis of the implanted medical lead 112 to the outer surface supporting the barbs. One or more barbs may define a barb radius extending from the outer surface to the radially outward free end of the barb. In some examples, the barb radius may be less than about twenty percent of the body radius.

[0041] In some examples, medical system 100 includes a defined lumen (e.g., catheter lumen 149). Figure 4 Delivery catheters (e.g., delivery catheter 151) Figure 4 The implantable medical lead 112 (e.g., the distal portion 120 of the lead) may be configured to translate and / or rotate within the lumen. The delivery catheter (e.g., the inner surface defining the lumen) may be configured to apply force to the barb when the distal portion 120 of the lead is within the lumen to substantially prevent elastic bias from causing the barb to extend radially outward. The medical system 100 may be configured such that proximal retraction of the delivery catheter relative to the lead body 118 substantially releases the barb, causing the barb to extend radially outward. In the example, the barb is configured to flexibly bend (e.g., distally) if the delivery catheter is subsequently moved distally to retrieve the barb (e.g., if repositioning of the fixation electrode is required).

[0042] Figure 2 This is a perspective view showing a portion of an example implantable medical lead 112. Figure 3 This is an end view of an implantable medical lead 112. The implantable medical lead 112 includes a lead body 118 defining a longitudinal axis L, a distal lead portion 120, and a fixation device 124. The distal lead portion 120 includes a distal end 128 of the implantable lead 112 (“distal lead end 128”). The longitudinal axis L extends through the lead body 118 (e.g., through the proximal lead portion 119 and the distal lead portion 120) and the distal lead end 128. The fixation device 124 extends distal to the distal lead end 128 (e.g., in a distal direction D). In this example, the longitudinal axis L is substantially parallel to the distal direction D and the proximal direction P, which is opposite to the distal direction D. Figure 3 In the example, the distal direction D extends out of the paper, and the proximal direction P extends into the paper. In this example, the implantable medical lead 112 defines a radial direction R that is substantially perpendicular to the longitudinal axis L.

[0043] Note that, although Figure 2 (and for example) Figures 3 to 13The radial direction R is depicted as a single vector perpendicular to the longitudinal axis L for illustration purposes; however, the radial direction R can be defined by any vector perpendicular to and extending from the longitudinal axis L. For example, in Figure 2 In the diagram, a first vector R1, extending from and perpendicular to the longitudinal axis L, extends in the radial direction R. A second vector R2, also extending from and perpendicular to the longitudinal axis L, also extends in the radial direction R.

[0044] The fixation device 124 includes a body 125 (“fixation device body”) configured to pierce and potentially penetrate into or through target tissue. In an example, the fixation device body 125 defines a auger member 132 that defines a helical shape (e.g., a helical shape about a longitudinal axis L). In an example, the fixation device body 125 (e.g., auger member 132) extends distally from the lead distal end 128 to the fixation distal end 134. As the fixation device body 125 extends distally from the lead distal end 128 to the fixation distal end 134, the cross-sectional dimensions of the fixation device body 125 (e.g., dimensions parallel to the radial direction R, such as diameter) can decrease. In an example, the fixation device body 125 is configured to decrease in cross-sectional dimensions from those defined by the lead distal end 128 (e.g., by the lead outer surface 140). In an example, the fixation device 124 includes a conductor (e.g., a conductive material). In an example, the fixation device body 125 is a conductor. The conductor may have a non-conductive coating, such as, but not limited to, polytetrafluoroethylene (PTFE). The conductor of the fixation device 124 is electrically connected to the conductor of the implantable medical device 112 (e.g., the second conductor 115). Figure 4 In some examples, the conductor of the fixation device 124 includes the conductor of the implantable medical lead 112 (e.g., an extension of the conductor of the implantable medical lead).

[0045] The fixation device 124 (e.g., fixation device body 125) may support the fixation device electrode 130 (e.g., between the distal end 128 of the lead and the distal end 134 of the fixation device). In some examples, the fixation device electrode 130 is part of the fixation device body 125. For example, when the fixation device body 125 is substantially covered by a non-conductive coating, the fixation device electrode 130 may be a portion of the fixation device body 125 that is not coated with a non-conductive coating. In some examples, the fixation device electrode 130 may include a portion of the fixation device body 125 between the distal end 128 of the lead and the distal end 134 of the fixation device. In some examples, the fixation device electrode 130 may be a component supported by the fixation device body 125 but substantially separable from the fixation device body. The fixation device 124 may be configured such that when the fixation device body 125 (e.g., auger member 132) is embedded in tissue (e.g., target site 114), Figure 1 When the fixation device electrode 130 is placed in or around the tissue, the fixation device electrode 130 is exposed to the tissue. The conductors of the fixation device 124 may be configured to connect the fixation device electrode 130 to the therapy delivery circuit 127 and / or the sensing circuit 129. Figure 1 Electrical connection.

[0046] The distal portion 120 of the lead includes a plurality of barbs 136 (“barbs 136”) configured to mitigate and / or reduce movement of the fixation device 124 (e.g., fixation device electrode 130) relative to tissue when the fixation device 124 engages with tissue. The barbs 136 may include, for example, barbs 137, 138, 139, 141, and / or other barbs. The barbs 136 are configured to mitigate and / or reduce movement of the distal portion 120 of the lead (e.g., in the distal direction D) when the fixation device 124 engages with tissue. The barbs 136 are configured to engage tissue within the target site 114 when the fixation device 124 engages with tissue within the target site 114. For example, the distal portion 120 of the lead may be configured such that when the fixation device 124 (e.g., auger member 132) engages tissue and positions the fixation device electrode 130 in the conduction system 123 of the heart 122 (… Figure 1 When the lead body 118 is near the target site 114, a portion of the support barb 136 of the distal portion 120 is also implanted within the tissue. The barb 136 can engage the tissue to mitigate and / or reduce movement of the fixation device electrode 130 relative to the target site 114. For example, the barb 136 can be configured to engage the tissue such that when a proximal force is applied to the lead body 118 (e.g., due to blood flow through the heart 122, the beating of the heart 122, and / or other activities of the patient 116), the barb 136 applies a distal force on the lead body 118 to mitigate and / or reduce movement of the fixation device electrode 130 relative to the target site 114.

[0047] The barb 136 is defined by a biodegradable material configured to degrade upon contact with tissue. This biodegradable material may be configured to degrade upon exposure to fluids and / or biological components of patient 116 (e.g., blood and / or blood components such as water, proteins, electrolytes, amino acids, salts, enzymes, hormones, and / or other components). For example, the biodegradable material may be configured to degrade upon exposure to fluids and / or biological components of patient 116 for less than about 6 months (less than 3 months in some examples). In examples, the biodegradable material is configured to dissolve within the fluids and / or biological components of patient 116. In some examples, the biodegradable material is a material configured to be metabolized by patient 116 (e.g., to undergo biotransformation). In some examples, the biodegradable material is a biodegradable polymer. The biodegradable polymer may include, for example, glycolic acid, lactic acid, and / or trimethylene carbonate. In examples, the biodegradable polymer includes collagen and / or poly(α-ester). In examples, the biodegradable material...

[0048] The lead body 118 and / or fixation device 124 comprise a biostabilizing material. This biostabilizing material may be configured to substantially maintain its physical and chemical integrity when implanted within the tissue of the patient 116. The biostabilizing material may be a material configured to substantially resist degradation effects that could otherwise occur when the material is exposed to the fluids and / or biological components of the patient 116. For example, the biostabilizing material may be configured to substantially resist degradation effects when exposed to blood and / or blood components such as water, proteins, electrolytes, amino acids, salts, enzymes, hormones, and / or other components. For example, the biostabilizing material may be configured to substantially resist degradation effects when exposed to the fluids of the patient 116 for a period exceeding 3 months, 6 months, or longer. In an example, the biostabilizing material comprises polyurethane. In an example, the polyurethane comprises polycarbonate, polyether, and / or polyester.

[0049] Therefore, the implantable medical lead 112 can be configured to engage the tissue of the patient 116 using the fixation device 124 and barbs 136. The implantable medical lead 112 can be configured to engage the tissue to position the fixation device electrode 130 in a location sufficiently close to the conduction system 123 to deliver paced conduction to the heart 122. The fixation device 124 and barbs 136 resist movement of the implantable medical lead 112 (e.g., the distal portion 120 of the lead) to limit and / or reduce movement of the fixation device electrode 130 relative to the target site 114. The lead body 118 and / or the fixation device 124 contain a bio-stabilized material, while the barbs 136 contain a biodegradable material. Therefore, the implantable medical lead 112 is configured such that the barbs 136 can help retain the distal portion 120 of the lead during and / or after implantation. The barb 136 may degrade as scar tissue forms around the distal portion 120 of the lead in the patient's body (the scar tissue, for example, may anchor the distal portion 120 of the lead more firmly). Furthermore, the degradation of the barb 136 may facilitate the removal of the implanted medical lead 112 some time after implantation in the patient 116, if necessary. For example, the degradation of the barb 136 may limit and / or substantially prevent the growth of scar tissue around the barb 136 after implantation.

[0050] The lead body 118 defines an outer surface 140 (“lead outer surface 140”) of the distal portion 120 of the lead. The lead outer surface 140 is configured to support a barb 136. The distal portion 120 of the lead is configured such that the lead outer surface 140 supports the barb 136 at a position proximal to the retaining device 124 and the distal end 128 of the lead (e.g., displaced in the proximal direction P). In an example, the barb 136 is arranged around (e.g., substantially around) a longitudinal axis L. For example, the barb 136 may define a periphery PB around the longitudinal axis L. In an example, the periphery PB is a periphery on the lead outer surface 140. The periphery PB may be, for example, a closed curve around the longitudinal axis L, an open curve such as a helical curve, or some other curve. In some examples, the periphery PB defines a curved shape (e.g., circular or elliptical), a curved shape (e.g., including curved and linear portions), or a polygonal shape around the longitudinal axis L.

[0051] In some examples, the outer surface 140 of the lead may be defined by a single component of the implantable medical lead 112, such as an outer layer or other surface including a portion of the lead body 118. In some examples, the outer surface 140 of the lead may be defined by two or more components including the lead body 118, such as a first surface defined by a first component of the lead body 118 and a second surface defined by a second component of the lead body 118. In examples, the lead body 118 includes multiple components, such as a first conductor 111, an insulating material 113, a second conductor 115, etc. Figures 4 to 6) and / or other components. Insulating material 113 may be configured to electrically isolate the first conductor 111 from the second conductor 115. In an example, the lead body 118 may include a torque coil (e.g., extending about a longitudinal axis L) configured to transmit torque about the longitudinal axis L from the proximal portion 119 of the lead to the distal portion 120 of the lead. Figure 1 The torque coil may include at least some portions of the second conductor 115. In some examples, the lead body 118 is configured such that the implantable medical lead 112 is a lumenless lead. For example, the lead body 118 may be configured such that the implantable medical lead lacks an internal lumen extending from the proximal portion 119 of the lead to the distal portion 120 of the lead.

[0052] In the example, the outer surface 140 is configured to surround the longitudinal axis L. The outer surface 140 may be configured such that a cross-sectional region of the lead body 118 defines a closed curve (e.g., a periphery PS) around the longitudinal axis L. In the example, the cross-sectional region is perpendicular to the longitudinal axis L. In some examples, the periphery PS defines a curved shape (e.g., circular or elliptical), a curved shape (e.g., including curved and linear portions), or a polygonal shape around the longitudinal axis L. In some examples, the lead body 118 defines the periphery PS in a geometric plane (e.g., a plane perpendicular to the longitudinal axis L), and the barb 136 defines the periphery PB in the geometric plane, and the periphery PS substantially coincides with the periphery PB. In some examples, the lead body 118 defines the periphery PS in a geometric plane, and the barb 136 defines the periphery PB in the geometric plane, and the periphery PS surrounds and / or intersects the periphery PB. In some examples, the lead body 118 defines the periphery PS in a geometric plane, and the barb 136 defines the periphery PB in the geometric plane, and the periphery PB surrounds and / or intersects the periphery PS.

[0053] In some examples, the lead body 118 is configured such that the peripheral PS is substantially circular (e.g., circular or nearly circular to the extent permitted by manufacturing tolerances). The lead body 118 may be configured such that the peripheral PS defines a substantially circular cross-sectional area surrounding the lead body 118 (e.g., the distal portion 120 of the lead) along a longitudinal axis L (e.g., centered on the longitudinal axis L). In some examples, the substantially circular cross-sectional area defines a diameter smaller than seven French (Fr) (such as about five Fr).

[0054] The barb 136 can be positioned in a substantially symmetrical pattern around the longitudinal axis L. In an example, the barb 136 can be arranged such that an individual barb (e.g., barb 137) and an adjacent barb (e.g., barb 138) define a first central angle of the perimeter P, and an individual barb (e.g., barb 137) and another adjacent barb (e.g., barb 141) define a second central angle of the perimeter P, which is substantially equal to the first central angle (e.g., equal to or nearly equal to to the extent permitted by manufacturing tolerances). In an example, the first and second central angles define the vertices intersecting the longitudinal axis L. In an example, the angles opposite the first and second central angles differ from each other by within 30 degrees, within 15 degrees in some examples, and / or within 5 degrees in some examples.

[0055] For example, barb 137 may define a free end 144 and an axis S1 extending from the longitudinal axis L to the free end 144. Barb 138 may define a free end 146 and an axis S2 extending from the longitudinal axis L to the free end 146. Barb 141 may define a free end 148 and an axis S3 extending from the longitudinal axis L to the free end 148. Barbs 137, 138, and 141 may be positioned in a substantially symmetrical manner about the longitudinal axis L (e.g., positioned via the lead outer surface 140), such that axes S1 and S2 define a central angle A1, and axes S1 and S3 define a central angle A2 that is substantially equal to central angle A1. In the example, barb 139 may define a free end 150 and an axis S4 extending from the longitudinal axis L to the free end 150. Axes S3 and S4 may define a central angle A3 that is substantially equal to central angle A1 and / or central angle A2. Axis S2 and axis S4 may define a central angle A4 that is substantially equal to central angles A1, A2, and / or A3. Barb 136 may include other barbs that define similar central angles that are substantially equal to central angles A1, A2, A3, and / or A4.

[0056] In some examples, the lead body 118 supports the electrode 142 (“body electrode 142”). In some examples, the implantable medical lead 112 is configured such that when the fixation device body 125 and the barb 136 are embedded in tissue (e.g., target site 114), Figure 1When the implantable medical lead 112 is embedded in or around the tissue, the main electrode 142 is exposed to the tissue. In some examples, the implantable medical lead 112 is configured such that the main electrode 142 is outside the tissue when the fixation device body 125 and the barbs 136 are embedded in the tissue. For example, the implantable medical lead 112 may be configured such that the main electrode 142 is positioned in the chamber of the heart 122 when the fixation device body 125 and the barbs 136 are embedded in the tissue. When the fixation device body 125 and the barbs 136 engage the tissue, the position of the main electrode 142 relative to the tissue including the target site 114 may depend on the anatomy of the patient 116. In examples, the electrode 142 at least partially surrounds the longitudinal axis. The electrode 142 may have various shapes, such as serrations, spirals, screws, rings, etc. In some examples, the electrode 142 is a ring electrode configured to surround the longitudinal axis L. The implantable medical lead 112 may include a conductor (e.g., a first conductor 111). Figure 4 The conductor is configured to electrically connect the main electrode 142 to the therapy delivery circuit 127 and / or the sensing circuit 129.

[0057] The barb 136 may be configured to limit its radial extension relative to the outer surface 140 of the lead wire. For example, when the fixation device 124 engages the tissue of the patient 116, the barb 136 may limit its radial extension to reduce and / or limit penetration into the tissue of the patient 116. Limiting the radial extension of the barb 136 may mitigate and / or eliminate scar tissue growth and / or other effects, such as thrombosis that might develop without limited radial extension. In examples, the barb 136 is configured such that the radial extension from the outer surface 140 of the lead wire to the free ends 144, 146, 148, 150 is less than about thirty percent of the radial extension from the longitudinal axis L to the outer surface 140, and in some examples less than about twenty percent.

[0058] For example, the distal portion 120 of the lead may be defined as a body radius RL extending radially from the longitudinal axis L to the outer surface 140. The barb 137 may be defined as a barb radius RB extending radially from the outer surface 140 to the free end 144 (e.g., when the free end 144 is displaced from the outer surface 140). In some examples, the barb radius RB is less than about thirty percent of the body radius RL. In some examples, the barb radius RB is less than about twenty percent of the body radius RL. In some examples, the periphery PB is a substantially circular periphery defining a first diameter, defined by at least three of the free ends 144, 146, 148, and / or 150. The periphery PS is a circular periphery defining a second diameter, defined by the outer surface 140. The first diameter may be about thirty percent larger than the second diameter, and in some examples, about twenty percent larger. For example, when the outer surface 140 is configured such that the second diameter is about 5 Fr (e.g., about 1.667 mm), the barb 136 may, in some examples, define the first diameter as less than about 5.3 Fr (e.g., less than about 2.167 mm), and / or in some examples, less than about 5.2 Fr (e.g., less than about 2.000 mm). The barb radius RB may be substantially parallel to the body radius RL.

[0059] The distal portion 120 of the lead may be configured to increase the distal force applied to the distal portion 120 when a proximal force is applied to the lead body 118 (e.g., due to blood flow through the heart 122, the beating of the heart 122, and / or other activities of the patient 116). In an example, the distal portion 120 may be configured to increase the distal force using one or more barbs in addition to barbs 136. The distal portion 120 may be configured to increase the distal force while limiting the outward radial extension of the individual barbs to, for example, mitigate and / or eliminate scar tissue growth and / or other effects, such as thrombosis that might develop without limited radial extension. For example, each individual barb may be configured to define a barb radius similar to a barb radius RB, such that the barb radius is less than approximately thirty percent of the body radius RL.

[0060] For example, the distal portion 120 of the lead may include a second plurality of barbs 152 (“barbs 152”) configured to mitigate and / or reduce movement of the fixation device 124 (e.g., fixation device electrode 130) relative to the tissue when the fixation device 124 engages with tissue. Barbs 152 may include, for example, barbs 153, 154, 155, 156, and / or other barbs. The distal portion 120 of the lead may include a third plurality of barbs 158 (“barbs 158”) configured to mitigate and / or reduce movement of the fixation device 124 (e.g., fixation device electrode 130) relative to the tissue when the fixation device 124 engages with tissue. Barbs 158 may include, for example, barbs 159, 160, 161, 162, and / or other barbs. Figure 2 In the middle, barbs 156 and 162 are hidden by the distal portion 120 of the lead wire. Figure 3 In this configuration, barbs 152 and 158 are hidden by the distal portion 120 of the lead wire. In the example, barb 136 is configured to be positioned distal to barb 152. Barb 152 can be configured to be positioned distal to barb 158.

[0061] The barbs 152, 158 and individual barbs therein may be configured similarly to barb 136. For example, individual barbs within barbs 152, 158 may be configured to define a barb radius similar to barb radius RB. The barbs 152, 158 may be configured to engage such that when a proximal force is applied to the lead body 118, the barbs 152, 158 (e.g., in addition to the force applied by barb 136) apply an additional distal force to the lead body 118, for example, to mitigate and / or reduce movement of the fixture electrode 130 relative to the target portion 114. The barbs 152, 158 may be configured such that the additional distal force is added to the distal force of barb 136.

[0062] In the example, barbs 136, 152, and 158 are resiliently biased to extend radially outward (e.g., in the radial direction R) from the distal portion 120 of the lead. In the example, barbs 136, 152, and 158 are configured such that the resilient bias limits the radial outward extension from the distal portion 120 of the lead (e.g., limiting the barb radius RB to less than approximately thirty percent of the body radius RL, and in some examples less than approximately twenty percent). In some examples, the medical system 100 includes a delivery catheter configured to deliver an implantable medical lead 112 to a target site 114. Figure 1 The delivery catheter can be configured to apply one or more forces to the barbs 136, 152, 158 to substantially prevent resilient bias from causing the barbs 136, 152, 158 to extend radially outward as the delivery catheter surrounds the distal portion 120 of the lead wire.

[0063] For example, Figure 4 This is a schematic diagram depicting the distal portion 120 of the lead wire within the lumen 149 (“catheter lumen 149”) of the delivery catheter 151. The catheter lumen 149 is defined by the body 147 (“catheter body 147”) of the delivery catheter 151. The catheter body 147 defines an inner surface 157 (“catheter inner surface 157”) surrounding the catheter lumen 149. Figure 4 The inner surface 157 of the catheter is depicted applying forces (e.g., force FB1 on barb 136), forces (e.g., force FB2 on barb 153), and forces (e.g., force FB3 on barb 159) to the barb 156. The delivery catheter 151 may be configured such that the forces FB1 on barb 136, FB2 on barb 152, and / or FB3 on barb 158 substantially prevent elastic bias from causing the barbs 136, 152, 158 to extend radially outward.

[0064] The inner surface 157 of the catheter can be subjected to similar forces on the barbs 138, 139, 141, 154, 155, 156, 160, 161, and 162. Although for clarity, in Figure 5 In this design, the inner surface 157 of the catheter is depicted as having a small displacement relative to the barbs 137, 153, 159, 139, 155, 161, but the delivery catheter 151 and / or the barbs 136, 152, 158 can be configured such that when the barbs 136, 152, 158 are positioned within the catheter lumen 149, the inner surface 157 contacts one or more of the barbs 136, 152, 158. The delivery catheter 151 can be configured to define an inner diameter LD of the catheter lumen 149 such that when the barbs 136, 152, 158 are within the catheter lumen 149, the inner surface 157 applies force to the barbs 136, 152, 158 to substantially prevent the barbs 136, 152, 158 from extending radially outward.

[0065] In some examples, the barb 137 defines a length from the free end 144 to the fixed end 145, which is from about 1 mm to about 3 mm. In the examples, when the barb 137 is in the retracted position, the length is substantially parallel to the longitudinal axis L. The barb 137 may define a width of from about 0.5 mm to about 1.5 mm. The width may be perpendicular to the length. In the examples, when the barb 137 is in the retracted position, the width is substantially perpendicular to the radial direction R and substantially perpendicular to the longitudinal axis L. The barb 137 may define a depth of from about 0.5 mm to about 1.5 mm. The depth may be perpendicular to both the length and the width. In the examples, when the barb 137 is in the retracted position, the depth is substantially parallel to the radial direction R and substantially perpendicular to the longitudinal axis L.

[0066] Figure 5This is a schematic diagram depicting the distal portion 120 of the lead wire positioned relative to the delivery catheter 151 such that the barbs 136, 152, 158 are distal to the opening 163 (“catheter lumen opening 163”) defined by the catheter body 147. The catheter lumen opening 163 leads to the catheter lumen 149. In this example, the catheter body 147 defines the catheter lumen opening 163 at the distal end 165 (“catheter distal end 165”) of the delivery catheter 151. Figure 5 In the catheter, barbs 136, 152, and 158 are positioned distal to the inner surface 157 of the catheter, such that the elastic biasing of barbs 136, 152, and 158 causes them to extend radially outward (e.g., in the radial direction R) from the outer surface 140 of the guide wire. The delivery catheter 151 is in... Figure 4 and Figure 5 The section is depicted as a cross section, in which the cutting plane is cut in a plane defined by the longitudinal axis L and the radial direction R.

[0067] The distal portion 120 of the lead can be configured to translate relative to the catheter body 147 (e.g., the catheter inner surface 157) in a distal direction D and / or a proximal direction P when the distal portion 120 of the lead is positioned within the catheter lumen 149. The distal portion 120 of the lead can be configured to rotate relative to the catheter body 147 (e.g., the catheter inner surface 157) about a longitudinal axis L when the distal portion 120 of the lead is positioned within the catheter lumen 149. The catheter lumen opening 163 can be configured to allow the distal portion 120 of the lead to pass through it. In the example, the implantable medical lead 112 (e.g., the proximal portion 119 of the lead) Figure 1 The distal portion 120 of the lead is configured to move relative to the catheter body 147 in the distal direction D, in the proximal direction P, and / or rotate relative to the catheter body 147 about the longitudinal axis L. In the example, the delivery catheter 151 is configured to move relative to the lead body 118 in the proximal direction P to move the distal portion 120 of the lead relative to the catheter body 147 in the distal direction D. The delivery catheter 151 may be configured to move relative to the lead body 118 in the distal direction D to move the distal portion 120 of the lead relative to the catheter body 147 in the proximal direction P.

[0068] The medical system 100 can be configured such that proximal retraction of the delivery catheter 151 relative to the lead body 118 substantially releases barbs 137 and / or other barbs among barbs 136, 152, 158, such that barbs 136, 152, 158 extend radially outward to engage the tissue of the patient 116. Although the discussion below and elsewhere primarily concerns barb 137, this discussion is applicable to any of the other barbs among barbs 138, 139, 141, 153, 154, 155, 156, 159, 160, 161, 162 and / or the other barbs of the implantable medical lead 112.

[0069] In the example, the barb 137 is configured to transition from a retracted position when the distal portion 120 of the lead is positioned within the catheter lumen 149 to an extended position when the distal portion 120 of the lead is positioned distal to the catheter lumen 149 (e.g., distal to the catheter lumen opening 163). In the example, the barb 137 is configured to define a first displacement from the outer surface 140 of the lead in the retracted position and a second displacement from the outer surface 140 of the lead in the extended position, wherein the second displacement is greater than the first displacement. In the example, the first and second displacements are substantially perpendicular to the longitudinal axis L. In the example, the first displacement is substantially parallel to the second displacement. In some examples, the first and second displacements are substantially parallel to a vector V1 extending from and orthogonal to the outer surface 140 of the lead.

[0070] For example, Figure 4 The barb 137 is depicted in the retracted position, wherein the free end 144 defines a first displacement D1 from the outer surface 140 of the lead wire. Figure 5 A barb 137 in the deployed position is depicted, wherein the free end 144 defines a second displacement D2 from the outer surface 140 of the lead wire. The second displacement D2 is greater than the first displacement D1. The barb 137 can be configured to cause the free end 144 to be significantly displaced in the radial direction R (e.g., relative to the outer surface 140 of the lead wire and / or the longitudinal axis L) when the barb 137 changes from the retracted position to the deployed position.

[0071] In the example, the barb 137 includes a fixed end 145 configured to be substantially stationary relative to the lead outer surface 140. The barb 137 may be configured such that the fixed end 145 remains substantially stationary relative to the lead outer surface 140 when the free end 144 is displaced relative to the lead outer surface 140 (e.g., when the barb 137 changes from a retracted position to a fixed position). In the example, the barb 137 is configured such that at least some portions of the barb 137 (e.g., the portion including the free end 144) substantially rotate about the fixed end 145 when the free end 144 is displaced relative to the lead outer surface 140. For example, the barb 137 may include a body 164 (“barb body 164”) defining the free end 144 and the fixed end 145. The barb 137 can be configured such that at least some portions of the barb body 164 (e.g., by bending or flexing) rotate substantially about the fixed end 145 to displace the free end 144 from a first displacement D1 (e.g., in the retracted position) to a second displacement D2 (e.g., in the deployed position). The barb 137 can be configured such that when the barb body 164 rotates substantially about the fixed end 145 to displace the free end 144 from the first displacement D1 to the second displacement D2, the fixed end 145 substantially acts as a fixed pivot point for the barb body 164. In the example, when the barb 137 is in the retracted position, the free end 144 is proximal to the fixed end 145. When the barb 137 is in the deployed position, the free end 144 may be proximal to the fixed end 145.

[0072] The barb body 164 can be configured to flex and / or bend when the barb 137 changes from an extended position to a retracted position. For example, the barb body 164 can be configured to flex and / or bend when the free end 144 changes from defining a first displacement D2 (e.g., in the extended position) to defining a second displacement D1 (e.g., in the retracted position). In the example, the barb body 164 is a substantially elastically deformable element that exhibits a shape change when an external force (e.g., force FB1) is applied to the barb body 164, and substantially reverses that shape change when the external force is removed.

[0073] The distal portion 120 of the lead wire can be configured such that when the barbs 136, 152, 158 engage tissue, the distal portion 120 provides a first resistance as the lead wire body 118 moves in a first direction, and provides a second resistance different from the first resistance as the lead wire body 118 moves in a second direction. In an example, the barb 137 is configured to provide a first resistance greater than the second resistance. For example, the barb 137 can be configured to provide a first resistance by applying a force FP to the lead wire body 118 in the proximal direction P when (e.g., by a clinician) a given amount of force is applied to the lead wire body 118 in the distal direction D. The barb 137 can be configured to provide a second resistance by applying a force FD to the lead wire body 118 in the distal direction D when (e.g., by a clinician) a given amount of force is applied to the lead wire body 118 in the proximal direction P. The barb 137 can be configured such that the force FP is greater than the force FD, such that the barb 137 resists movement of the lead body 118 in the proximal direction P to a greater extent than it resists movement of the lead body 118 in the distal direction. In some examples, the barb 137 can be configured to substantially flatten (e.g., reduce distance D2) when the tissue and the lead body 118 move relative to the tissue in the proximal direction P.

[0074] In the example, barb 137 is elastically biased to extend outward (e.g., in the radial direction R) from the outer surface 140 of the lead. When barb 137 (e.g., by force FB1) Figure 4 When the barb 137 is displaced from the deployed position (e.g., away from the deployed position), the resilient bias of the barb 137 can produce a tendency for the barb 137 to return or attempt to return to the deployed position. For example, the resilient bias can cause the barb 137 to be substantially established in the deployed position without any external force (e.g., force FB1) acting on the barb 137. The barb 137 can be configured such that when an external force is removed (e.g., when the delivery catheter 151 is moved proximally relative to the lead body 118 such that the barb 137 is distal to the catheter lumen opening 163), the resilient bias causes the barb 137 to change from the retracted position to the deployed position.

[0075] The barb 137 can be elastically biased such that when an external force, such as force FB1, is applied to the barb body 164 (e.g., free end 144) to hold the barb 137 in the retracted position, the elastic bias causes the barb body 164 (e.g., free end 144) to exert a reaction force FR opposite to the external force (e.g., opposing force FB1). For example, when the catheter inner surface 157 exerts force FB1 on the barb body 164, the elastic bias of the barb body 164 can cause the barb body 164 to apply force FR on the catheter inner surface 157.

[0076] Although the free end 144 is depicted as displaced in the radial direction R from the lead outer surface 140 when the free end 144 and the lead outer surface 140 define a displacement D1, this is not necessary. In some examples, the displacement D1 may define a displacement extending from the lead outer surface 140 in a direction opposite to the radial direction R. For example, the barb 137 may be configured such that, in the retracted position, the free end 144 is displaced from the lead outer surface 140 in a direction opposite to the radial direction R (e.g., in the retracted position, the free end 144 may be closer to the longitudinal axis L than the lead outer surface 140). In some examples, the displacement D1 may be substantially zero. For example, the barb 137 may be configured such that, in the retracted position, the free end 144 is substantially flush with the lead outer surface 140 (e.g., flush or nearly flush to the extent permitted by manufacturing tolerances).

[0077] In some examples, the barb 137 is configured to insert into a recess 166 defined by the lead body 118 (e.g., the lead outer surface 140) when the lead outer surface 140 supports the barb 137. For example, the barb 137 (e.g., the retaining end 145) may be coupled to a base body 168 configured to insert into the recess 166. Figure 4 and Figure 5 In the diagram, portions of the recess 166 and the base body 168 are depicted with dashed lines. The base body 168 may support a barb 137. The barb 137 may be configured such that the base body 168 and the barb body 164 define a substantially continuous integral body. In some examples, the base body 168 supports at least one of two or more barbs 136, 152, and / or 158. The base body 168 may extend from the fixed end 145 in a proximal direction P or a distal direction D to support at least one barb from two or more barbs 136, 152, and / or 158. For example, as... Figure 5 As depicted, the base body 168 may be configured to support barbs 137 (e.g., fixation end 145) and extend from fixation end 145 in a proximal direction P to support barbs in barbs 152 (e.g., barb 153) and / or barbs in barbs 158 (e.g., barb 159). The base body 168 may be defined by a biodegradable material (e.g., a biodegradable polymer) configured to degrade after contact with the tissue of the patient 116. In the example, barbs 137, 153, 159 comprise biodegradable material, and the base body 168 comprises biodegradable material.

[0078] In the example, the base body 168 is configured to support each of the barbs in two or more of the barbs among barbs 136, barb 152, and / or barb 158 at the fixed end of each barb. For example, barb 153 (e.g., the body of barb 153) may define a free end 170 and a fixed end 172, the free end being configured to extend radially outward from the outer surface 140 of the lead wire, and the fixed end being configured to be substantially stationary relative to the outer surface 140 of the lead wire. Barb 159 (e.g., the body of barb 159) may define a free end 174 and a fixed end 176, the free end being configured to extend radially outward from the outer surface 140 of the lead wire, and the fixed end being configured to be substantially stationary relative to the outer surface 140 of the lead wire. The base body 168 may be configured to support at least two of the following: a barb 137 at a fixed end 145, a barb 153 at a fixed end 172, and / or a barb 159 at a fixed end 176. In the example, the base body 168 is configured to support the barb 137 (e.g., at a fixed end 145), the barb 153 (e.g., at a fixed end 172), and the barb 159 (e.g., at a fixed end 176).

[0079] In some examples, the outer surface 140 supports the second base body 169 ( Figure 2 The second base body supports at least one of two or more barbs 136, 152, and / or 158. The distal lead portion 120 may include any number of base bodies supporting at least one of two or more barbs 136, 152, and / or 158. The distal lead portion 120 may support the second base body 169 and / or other base bodies in a recess configured similar to the recess 166.

[0080] In the example, the lead body 118 is configured to define one or more rounded boundaries of the recess 166. If necessary, the rounded boundaries can, for example, facilitate the removal of the implanted medical lead 112 once the barbs 136, 152, 158 have degraded within the patient 116. For example, the recess 166 may extend from a first end 182 (“first recess end 182”) defined by the lead body 118 (e.g., outer surface 140) to a second end 184 (“second recess end 184”) defined by the lead body 118 (e.g., outer surface 140). In the example, the first recess end 182 is proximal to the second recess end 184. At least one of the first recess end 182 and / or the second recess end 184 may be configured to define a curvature (e.g., a smooth curve). For example, the first recess end 182 may define a curvature C1 in a geometric plane including a longitudinal axis L and a radial direction R. For example, the second end portion 184 of the recess may define a curvature C2 in a geometric plane including the longitudinal axis L and the radial direction R.

[0081] In the example, support surface 186 may define at least some portions of the boundary of recess 166. Support surface 186 is part of lead outer surface 140. Base body 168 may be configured to contact support surface 186 when base body 168 is inserted into recess 166. In the example, support surface extends substantially from first end 182 of recess to second end 184 of recess. Curvature C1 and / or curvature C2 may extend from support surface 186 in a radial direction R such that, for example, lead body 118 defines a curved boundary at at least some portions of first end 182 and / or second end 184 of recess. In the example, curvature C1 and / or curvature C2 defines a concave surface that is recessed upward relative to support surface 186. In the example, curvature C1 and / or curvature C2 defines a negative curvature relative to a vector orthogonal to support surface 186.

[0082] In some examples, the lead body 118 is configured to define one or more rounded boundaries (e.g., similar to curvatures C1 and / or C2) of the support surface 186, which extend substantially at least partially from the first end 182 of the recess to the second end 184 of the recess. The one or more rounded boundaries may define curvature in a geometric plane substantially perpendicular to the longitudinal axis L. In some examples, the lead body 118 defines the recess 166 such that the rounded boundaries substantially surround the entire support surface 186.

[0083] In the example, barb 137 is configured to... Figure 5 The unfolded position (e.g., free end 144 proximal to fixed end 145) is flexibly bent (e.g., distally) to a distal position where free end 144 is distal to fixed end 145. The barb 137 can be configured to present a distal position when the delivery catheter 151 moves from a first position proximal to a second position distal to the barb 137. If necessary, the distal bending of the barb 137 can allow the delivery catheter 151 to substantially re-wrap the barb 137 (e.g., and other barbs among barbs 136, 152, 158) to aid, for example, moving the distal portion 120 of the lead to a new position in the patient 116 (e.g., moving the distal portion 120 of the lead to locate the target site 114 during pacing mapping).

[0084] For example, Figure 6 This is a schematic diagram depicting the barb 137 in its distal position. The free end 144 is located distal to the fixed end 145 in its distal position. Barbs 139, 153, and 155 are depicted similarly. The delivery catheter 151 is... Figure 4 and Figure 5The section is depicted as a cross-section, wherein the cutting plane is taken in a plane defined by the longitudinal axis L and the radial direction R. The barb 137 and / or portions of the base body 168 (e.g., portions within the recess 166) are depicted with dashed lines.

[0085] The barb 137 can be configured to move from the deployed position when a distal force is applied to the barb body 164. Figure 5 As shown in the diagram, the delivery catheter 151 is moved to a distal position. For example, the barb body 164 may be configured to move from an deployed position to a distal position when a distal force is applied to the delivery catheter 151. In the example, the delivery catheter 151 (e.g., the distal end 165 of the catheter) is configured to move from a first position proximal to the barb 137 (e.g., as shown in the diagram) to a distal position. Figure 5 (As shown) Move to the second position on the far side of the barb 137 (e.g., as shown) Figure 6 As shown, a distal force is applied to the barb body 164. In the example, the delivery catheter 151 is configured such that when the distal end 165 of the catheter moves from a position proximal to the barb 137 to a position distal to the barb 137, the lumen diameter LD causes the distal end 165 of the catheter to apply a distal force to the barb body 164.

[0086] The barb 137 (e.g., barb body 164) may be configured such that the fixed end 145 remains substantially stationary relative to the lead body 118 when the free end 144 moves from the deployed position to the distal position. The catheter inner surface 157 may be configured to apply a force (e.g., a force toward the longitudinal axis L) to the barb body 164 to substantially retain the barb 137 in the distal position. For example, the catheter inner surface 157 may be configured to apply a force to retain the barb 137 in the distal position when the distal end 165 of the catheter is distal to the barb 137.

[0087] The barb 137 (e.g., barb body 164) can be configured to move from a distal position to an deployed position when the catheter inner surface 157 (and / or another object or body) ceases to apply force to hold the barb 137 in the distal position. In the example, the barb 137 is resiliently biased to move from the distal position to the deployed position. The resilient bias of the barb 137 can produce a tendency for the barb 137 to return or attempt to return to the deployed position when in the distal position. The barb 137 can be configured such that when the delivery catheter 151 moves proximally relative to the lead body 118, the resilient bias causes the barb 137 to change from the distal position to the deployed position, such that the barb 137 is distal to the catheter lumen opening 163.

[0088] For example, the barb 137 can be elastically biased such that when an external force is applied to the barb body 164 to hold the barb 137 in a distal position, the elastic bias causes the barb body 164 to exert a reaction force opposite to the external force. For example, when the catheter inner surface 157 applies a force FB4 to the barb body 164 to hold the barb body 164 in a distal position, the elastic bias of the barb body 164 can cause the barb body 164 to exert a reaction force FR2 on the catheter inner surface 157.

[0089] The barb 137 may include an integral body defining the barb body 164 and the base body 168. In the example, the integral body also includes at least the body of the barb 153 and / or the body of the barb 159. The barbs 137, 153, and 159 may be defined by cuts that substantially separate the barbs 137, 153, and 159 from the base body 168.

[0090] For example, Figure 7 It is a schematic top view of a structural body 188 that defines the barb base 168 and defines one or more barbs (such as barb 137, barb 153 and barb 159). Figure 8 It is the cross-section of the main structure 188, in which the barbs 137, 153, and 159 are in the retracted position. Figure 9 This is a cross-section of the structural body 188, in which barbs 137, 153, and 159 are in the unfolded position. The structural body 188 is a single, integral body such that a first portion of the material including the barb base 168 is continuous with a second portion of the material defining the barbs 137, 153, and 159. For example, the structural body 188 can be configured such that the boundary between the barb body 164 (e.g., the first portion) and the base body 168 (e.g., the second portion) can be continuous, such that there is no defined material interface between the structural body 188 and the barb body 164 and the base body 168. Figure 8 and Figure 9 In this context, the cross-section is taken in a plane that includes the main axis LS and the structural radial direction RS perpendicular to the main axis LS.

[0091] The structural body 188 defines a main axis LS that extends through a first end 190 (“main body first end 190”) and a second end 192 (“main body second end 192”) of the structural body 188. The structural body 188 is configured to be inserted into a recess 166. Figure 5 , Figure 6In the example, the first end 190 of the main body can be configured to contact the first end 178 of the recess 166 when the structural body 188 is inserted into the recess 166. The second end 192 of the main body can be configured to contact the second end 180 of the recess 166 when the structural body 188 is inserted into the recess 166. In the example, the structural body 188 is configured such that when the structural body 188 is inserted into the recess 166, the main body axis LS is substantially parallel to the longitudinal axis L and / or the structural radial direction RS is substantially parallel to the radial direction R.

[0092] The barb 137 is defined by a cut CT1 in the structural body 188, which substantially separates the barb 137 from the base body 168. The barb 153 is defined by a cut CT2 in the structural body 188, which substantially separates the barb 153 from the base body 168. The barb 159 is defined by a cut CT3 in the structural body 188, which substantially separates the barb 159 from the base body 168. In the example, cut CT1 is configured to displace the free end 144 of the barb 137 from the fixed end 145 in the proximal direction P when the barb 137 is in the retracted or extended position. Cut CT2 can be configured to displace the free end 170 of the barb 153 from the fixed end 172 in the proximal direction P when the barb 153 is in the retracted or extended position. The cut CT3 can be configured to displace the free end 174 of the barb 159 from the fixed end 176 in the proximal direction P when the barb 159 is in the retracted or extended position.

[0093] The structural body 188 (e.g., barb 137) can be configured to define a spacing G1 (e.g., between the base body 168 and barb 137), a spacing G2 (e.g., between the base body 168 and barb 153), and / or a spacing G3 (e.g., between the base body 168 and barb 159) when barbs 137 are in the deployed position. In the example, the cut CT1 is configured to allow the free end 144 to be displaced from the fixed end 145 in the structural radial direction RS when barb 137 is in the deployed position (e.g., to define spacing G1). The cut CT2 can be configured to allow the free end 170 to be displaced from the fixed end 172 in the structural radial direction RS when barb 153 is in the deployed position (e.g., to define spacing G2). The cut CT3 can be configured to allow the free end 174 to be displaced from the fixed end 176 in the radial direction RS of the structure (e.g., to define a spacing G3) when the barb 159 is in the deployed position. In the example, the structural body 188 can be fabricated by cutting the structural body 188 to create the cut CT1 to define the barb 137, creating the cut CT2 to define the barb 153, and / or creating the cut CT3 to create the barb 159. After creating the cut CT1, the barb 137 can be elastically biased such that the barb 137 tends to be in the deployed position (e.g., in the absence of an externally applied force on the barb 137). After creating the cut CT2, the barb 153 can be elastically biased such that the barb 153 tends to be in the deployed position (e.g., in the absence of an externally applied force on the barb 153). After creating the cut CT3, the barb 159 can be elastically biased such that the barb 159 tends to be in the deployed position (e.g., in the absence of an externally applied force on the barb 159).

[0094] In some examples, cuts CT1, CT2, and / or CT3 may be single-angle cuts defined at substantially constant angles to the body axis LS (e.g., constant or nearly constant to the extent permitted by manufacturing tolerances). In some examples, cuts CT1, CT2, and / or CT3 may define two or more angles to the body axis LS. For example, Figure 10 An exemplary barb 194 is depicted, defined by a notch CT4, which is at a substantially constant angle AG1 defined by the body axis LS. Figure 11 An exemplary barb 196 is depicted, defined by a notch CT5 that defines two angles AG2 and AG3 relative to the body axis LS (e.g., notch CT5 can be a double-angle notch). In the example, notch CT5 defines the free end 198 of barb 196 using angle AG2. In the example, angle AG2 is greater than angle AG3. Notch CT5 can define any number of angles relative to the body axis LS. Barbs 194 and 196 are examples of barbs 137.

[0095] In the example, the distal portion of the implanted lead 112 includes a plurality of barbs arranged in a substantially coiled and / or spiral pattern around the outer surface of the lead. In some examples, the barbs may be arranged to define a coiled and / or spiral shape around a longitudinal axis L. For example, Figure 12 This is a perspective view showing a portion of an exemplary implantable medical lead 112, including the distal portion 202 of the lead. Figure 13 This is an end view of the distal portion 202. Figure 13 In the middle, the distal direction D leaves the page, and the proximal direction P enters the page. The distal portion 202 of the leader is an example of the distal portion 120 of the leader.

[0096] The distal portion 202 of the lead supports a plurality of barbs 204 (“barbs 204”). The barbs 204 may include, for example, barbs 206, 208, 210, 212, 214, 216, 218, 220, 222, and / or other similarly depicted barbs. In the example, the barbs 204 are configured to extend radially outward from a barb base 226 having a base body 228. The base body 228 defines a body axis LS2 extending from a first end 230 of the body defined by the base body 228 to a second end 232 of the body defined by the base body 228. One or more barbs of the barbs 204 (e.g., substantially all barbs) may extend radially outward (e.g., in the radial direction R) from the base body 228 between the first end 230 and the second end 232 of the body. In the example, the outer surface 140 of the lead supports the barb base 228. The barb 204 is an example of barbs 136, 152, and 158. The base body 228 is an example of base body 168. The first end 230 of the body is an example of first end 190 of the body. The second end 232 of the body is an example of second end 192 of the body.

[0097] In the example, barb 206 includes a barb body 234 defining a free end 236 and a fixed end 238. Barb 206 is an example of barb 137. For example, the distal portion 202 of the lead may be defined as a body radius RL extending radially from the longitudinal axis L to the outer surface 140. Barb 206 may be defined as a barb radius RB extending radially from the outer surface 140 to the free end 236 (e.g., when the free end 236 is displaced from the outer surface 140). In the example, barb 206 is configured to change from a retracted position (e.g., when the distal portion 202 of the lead is positioned within the catheter lumen 149) to an extended position when the distal portion 202 of the lead is positioned distal to the catheter lumen 149 (e.g., distal to the catheter lumen opening 163).

[0098] For example, barb 206 (e.g., barb body 234) can be configured such that the free end 236 defines a first displacement D1 in the retracted position. Figure 4 The barb 206 (e.g., barb body 234) can be configured such that the free end 236 defines a second displacement D2 in the unfolded position. Figure 5 The barb 206 can be configured to significantly displace the free end 236 in the radial direction R (e.g., relative to the lead outer surface 140 and / or the longitudinal axis L) when the barb 206 changes from the retracted position to the extended position.

[0099] The barb body 234 can be configured such that the body axis LS2 defines a helical shape around the longitudinal axis L. For example, the barb body 234 can be configured such that when the barb body 234 extends about the longitudinal axis L, the first end portion 230 of the body is proximal to the second end portion 232 of the body. In an example, the barb 204 and / or the base body 228 are configured to be inserted into a recess 240 defined by the lead body 118 (e.g., the lead outer surface 140) when the lead outer surface 140 supports the barb 204. In an example, the recess 240 extends from the first end portion 242 of the recess to the second end portion 244 of the recess. The recess 240 is an example of the recess 166. The first end portion 242 of the recess is an example of the first end portion 182 of the recess. The second end portion 244 of the recess is an example of the second end portion 184 of the recess. In an example, the support surface 186 ( Figure 5 , Figure 6 It extends from the first end 244 of the recess to the second end 244 of the recess. Figure 13 The recess 240 and the second end 244 of the recess are depicted in dashed lines.

[0100] The distal portion 202 of the lead wire can be configured such that when the barb 204 (e.g., barb 206) engages the tissue, the distal portion 202 provides a first rotational resistance as the lead body 118 moves in a first rotational direction, and provides a second rotational resistance different from the first rotational resistance as the lead body 118 moves in a second rotational direction. The barb 206 can be configured to provide a first resistance greater than the second resistance. For example, the barb 206 can be configured to provide the first rotational resistance when a torque is applied to the lead body 118 in a rotational direction RT1 about the longitudinal axis L. For example, the barb 206 can be configured to provide the second rotational resistance when a torque is applied to the lead body 118 in a rotational direction RT2 about the longitudinal axis L (opposite to the rotational direction RT1). Therefore, the distal portion 202 of the lead wire can be configured such that the barb 206 resists rotation of the lead body 118 in the first rotational direction to a greater extent than it resists rotation of the lead body 118 in the second rotational direction. In the example, the fixing device 124 (e.g., the auger member 132) is configured to increase its engagement with the tissue when a torque is applied in the rotation direction RT2.

[0101] The barb 206 can be configured to provide a first rotational resistance by applying a torque T1 in the rotational direction RT1 when (e.g., by a clinician) a given amount of torque is applied to the lead body 118 in the rotational direction RT2. The barb 206 can also be configured to provide a second rotational resistance by applying a torque T2 to the lead body 118 in the rotational direction RT2 when (e.g., by a clinician) a given amount of torque is applied to the lead body 118 in the rotational direction RT1. In some examples, the barb 206 is configured such that the torque T1 is greater than the torque T2, such that the barb 206 resists rotation of the lead body 118 in the rotational direction RT2 to a greater extent than it resists rotation of the lead body 118 in the rotational direction RT1. The barb 206 can be configured to substantially flatten (e.g., reduce distance D2) when the barb 206 engages with tissue and the lead body 118 rotates in the rotational direction RT1. Figure 5 In some examples, the barb 206 is configured such that the torque T2 is greater than the torque T1, such that the barb 206 resists the lead body 118 from rotating in the rotation direction RT1 to a greater extent than it resists the lead body 118 from rotating in the rotation direction RT2. The barb 206 may be configured to substantially flatten out when the barb 206 engages with tissue and the lead body 118 rotates in the rotation direction RT2 (e.g., reducing the distance D2). Figure 5 )).

[0102] In the example, the retaining device 124 (e.g., auger member 132) is configured to increase its engagement with the tissue when torque is applied in the rotational direction RT2. For example, when viewed in the distal direction D along the longitudinal axis L, the auger member 132 may be a right-hand auger. The barb 206 may be configured to provide greater resistance to the rotation of the lead body 118 and the auger member 132 in the counterclockwise direction when the magnitude of torque is applied to the lead body 118 in the distal direction D along the longitudinal axis L, compared to the clockwise direction. In the example, the retaining device 124 (e.g., auger member 132) is configured to increase its engagement with the tissue when torque is applied in the rotational direction RT1. For example, when viewed in the distal direction D along the longitudinal axis L, the auger member 132 may be a left-hand auger. The barb 206 can be configured to provide greater resistance to the rotation of the lead body 118 and the auger assembly 132 when the magnitude of the torque applied to the lead body 118 in the clockwise direction is viewed along the longitudinal axis L in the distal direction D, compared to the counterclockwise direction.

[0103] The barb 206 can be configured to flexibly bend in the distal direction D when a distal force is applied to the barb body 234. For example, the barb body 234 can be configured to move from the deployed position when a distal force is applied to the delivery catheter 151. Figure 12 and Figure 13 (As depicted) moves to the distal position. In the example, when the barb 206 changes from the deployed position to the distal position, the free end 236 is displaced from the fixed end 238 in the distal direction D. For example, the barb body 234 may be configured such that when the barb 206 is in the deployed position, the free end 236 is proximal to the fixed end 238, substantially flush with the fixed end, or distal to the fixed end 238. When the barb 206 changes from the deployed position to the distal position, the barb body 234 may be configured to displace the free end 236 from the fixed end 238 in the distal direction D and / or increase the displacement of the free end 236 from the fixed end 238 in the distal direction D.

[0104] In the example, the delivery catheter 151 (e.g., distal end 165) is configured to apply a distal force on the barb body 234 as the delivery catheter 151 (e.g., lumen opening 163) moves from a first position proximal to the barb 206 to a second position distal to the barb 206. In the example, the delivery catheter 151 is configured such that the lumen diameter LD causes the distal end 165 to apply a distal force on the barb body 206 as the distal end 165 moves from a position proximal to the barb 137 to a position distal to the barb 137. The barb 206 (e.g., barb body 234) may be configured such that the fixed end 238 is substantially stationary relative to the lead body 118 when the free end 236 moves from the deployed position to the distal position. The inner surface 157 of the catheter may be configured to apply a force (e.g., a force toward the longitudinal axis L) to the barb body 234 to substantially hold the barb 234 in the distal position. For example, the inner surface 157 of the catheter can be configured to apply force to hold the barb 234 in the distal position when the distal end 165 of the catheter is distal to the barb 234.

[0105] In the example, the fixing device 124 defines the screw element. For example, Figure 14 This is a perspective view showing a portion of an exemplary implantable medical lead 112 including a distal portion 260 of the lead, which includes a fixation device 261. Figure 15 This is an end view of the distal portion at 260 degrees. Figure 15 In the middle, the distal direction D leaves the page, and the proximal direction P enters the page. The fixing device 261 includes a fixing device body 262 that defines a helical member 264 that defines a helical shape (e.g., a helical shape around a longitudinal axis L). The distal portion 202 of the lead is an example of the distal portions 120, 202 of the lead.

[0106] The fixation device body 262 (e.g., helical member 264) may extend distally from the distal end 128 of the lead to the distal end 266 of the fixation device. In the example, the fixation device 261 includes a conductor (e.g., a conductive material). In the example, the fixation device body 262 is a conductor. The conductor may have a non-conductive coating, such as, but not limited to, polytetrafluoroethylene (PTFE). The conductor of the fixation device 261 is electrically connected to the conductor of the implantable medical device 112 (e.g., a second conductor 115). Figure 4 In some examples, the conductor of fixation device 261 includes the conductor of implantable medical lead 112 (e.g., an extension of the conductor of implantable medical lead). Fixation device 261 (e.g., fixation device body 262) may (e.g., between the distal end 128 of the lead and the distal end 266 of the fixation device) support fixation device electrode 130. In some examples, fixation device electrode 130 is part of fixation device body 262. For example, when fixation device body 262 is substantially covered by a non-conductive coating, fixation device electrode 130 may be a portion of fixation device body 262 not coated with a non-conductive coating. In some examples, fixation device electrode 130 may include a portion of fixation device body 262 between the distal end 128 of the lead and the distal end 266 of the fixation device. In some examples, fixation device electrode 130 may be a component supported by fixation device body 266 but substantially separable from the fixation device body. The fixation device 261 can be configured such that when the fixation device body 262 (e.g., helical member 264) is embedded in tissue (e.g., target site 114), Figure 1 When the fixation device electrode 130 is placed in or around the tissue, the fixation device electrode 130 is exposed to the tissue. The conductors of the fixation device 261 may be configured to connect the fixation device electrode 130 to the therapy delivery circuit 127 and / or the sensing circuit 129. Figure 1 Electrical connection

[0107] When viewed along the longitudinal axis L in the distal direction D, the helical member 264 can be a right-handed helical member (e.g., when the barb 206 ( Figure 12 (It is configured to provide greater resistance to the rotation of the lead body 118 when a torque is applied in the rotation direction RT1). In the example, when viewed in the distal direction D along the longitudinal axis L, the helical member 264 can be a left-handed helical member (e.g., when the barb 206 ( Figure 12 () is configured to provide greater resistance to the rotation of the lead body 118 when a torque is applied in the rotation direction RT2).

[0108] As used herein, when a first portion of a system (e.g., medical system 12) is substantially parallel to a second portion of the system or an axis defined by the system, this can mean that the first portion is parallel to or nearly parallel to the second portion or axis within the limits of manufacturing tolerances. In some examples, when the first portion is substantially parallel to the second portion or axis, this can mean that a first vector defined by the first component of the system and a second vector defined by the second component or axis define an angle of less than 10 degrees, in some examples less than 5 degrees, and in some examples less than 1 degree. When a first portion of the system is substantially perpendicular to the second portion of the system or an axis defined by the system, this can mean that the first portion is perpendicular to or nearly perpendicular to the second portion or axis within the limits of manufacturing tolerances. In some examples, when the first portion is substantially perpendicular to the second portion or axis, this can mean that a first vector defined by the first component of the system and a second vector defined by the second component define an angle of at least 80 degrees, in some examples at least 85 degrees, and in some examples at least 89 degrees.

[0109] As used herein, when a first part of a system (e.g., medical system 12) supports a second part of the system, this means that when the second part applies a first force to the first part, the first part responds to the first force by applying a second force to the second part. The first and / or second forces can be contact-driven forces and / or distance-acting forces. For example, the first and / or second forces can be mechanical, magnetic, gravitational, or some other type of driving force. The first part of the system can be a portion of the system or a component of the system. The second part of the system can be another part of the system or another part of the same or different components. In some examples, when the first part of the system supports the second part of the system, this can mean that the second part is mechanically supported and / or mechanically connected to the first part.

[0110] IMD 126 may include therapy delivery circuitry 127, sensing circuitry 129, processing circuitry 131, communication circuitry 133, memory 135, sensors, and / or other components. In some examples, memory 135 includes computer-readable instructions that, when executed by processing circuitry 131, therapy delivery circuitry 127, sensing circuitry 129, communication circuitry 133, and / or other circuitry, cause IMD 126 and the processing circuitry 131, therapy delivery circuitry 127, sensing circuitry 129, communication circuitry 133, and / or other circuitry to perform various functions of IMD 126 and the processing circuitry 131, therapy delivery circuitry 127, sensing circuitry 129, communication circuitry 133, and / or other circuitry categorized herein. Memory 135 may include any volatile, non-volatile, magnetic, optical, or electrical medium, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), electrically erasable programmable ROM (EEPROM), ferroelectric RAM (FRAM), flash memory, or any other digital medium.

[0111] The processing circuitry 131, therapy delivery circuitry 127, sensing circuitry 129, communication circuitry 133, and / or other circuitry may include fixed-function circuitry and / or programmable processing circuitry. The processing circuitry 131, therapy delivery circuitry 127, sensing circuitry 129, communication circuitry 133, and / or other circuitry may include any and more of a microprocessor, controller, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), or equivalent discrete or analog logic circuitry. In some examples, the processing circuitry 131, therapy delivery circuitry 127, sensing circuitry 129, communication circuitry 133, and / or other circuitry may include multiple components, such as one or more microprocessors, one or more controllers, one or more DSPs, one or more ASICs, or one or more FPGAs, and any combination of other discrete or integrated logic circuitry. The functionality of the processing circuitry 131, therapy delivery circuitry 127, sensing circuitry 129, communication circuitry 133, and / or other circuitry as described herein may be embodied in software, firmware, hardware, or any combination thereof.

[0112] In some examples, processing circuitry 131, therapy delivery circuitry 127, sensing circuitry 129, and / or other circuitry may receive the corresponding values ​​of each of a plurality of cardiac sensing parameters, cardiac therapy parameters (e.g., cardiac pacing parameters), and / or electrode vectors via communication circuitry 133 (e.g., from an external device). Processing circuitry 131, therapy delivery circuitry 127, sensing circuitry 129, and / or other circuitry may store such parameters and / or electrode vectors in memory 135. Processing circuitry 131, therapy delivery circuitry 127, sensing circuitry 129, and / or other circuitry may be electrically coupled to electrodes 130, 142. Processing circuitry 131, therapy delivery circuitry 127, sensing circuitry 129, and / or other circuitry may generate electrotherapy and deliver it to the heart 122 via electrodes 130, 142. Electrotherapy may include, for example, pacing pulses or any other suitable electrical stimulation. Processing circuitry 131, therapy delivery circuitry 127, sensing circuitry 129, and / or other circuitry can deliver electrical stimulation therapy via electrodes 130, 142 based on one or more therapy parameter values ​​that can be stored in memory 135. In some examples, processing circuitry 131, therapy delivery circuitry 127, sensing circuitry 129, and / or other circuitry may include capacitors, current sources, and / or regulators.

[0113] Processing circuitry 131, therapy delivery circuitry 127, sensing circuitry 129, and / or other circuitry may be configured to monitor signals from electrodes 130, 142 to monitor the electrical activity of the heart 122. Sensing circuitry 129 may include circuitry for acquiring electrical signals, such as filters, amplifiers, and analog-to-digital circuitry. The electrical signals acquired by sensing circuitry 129 may include inherent and / or pacing cardiac electrical activity, such as atrial depolarization and / or ventricular depolarization. Sensing circuitry 129 may filter, amplify, and digitize the acquired electrical signals to generate raw digital data. Processing circuitry 131 may receive the digitized data generated by sensing circuitry 129. In some examples, processing circuitry 131 may perform various digital signal processing operations on the raw data, such as digital filtering. Communication circuitry 133 may include any suitable hardware (e.g., an antenna), firmware, software, or any combination thereof for communicating with another device, for example, outside the patient.

[0114] The IMD 126 may include a housing 121 configured to encapsulate processing circuitry 131, therapy delivery circuitry 127, sensing circuitry 129, communication circuitry 133, memory 135, and / or other circuitry within the medical system 100. The housing 121 may be configured to isolate the processing circuitry 131, therapy delivery circuitry 127, sensing circuitry 129, communication circuitry 133, memory 135, and / or other circuitry from ambient fluids that contact the outer surface of the housing 121.

[0115] Figure 16The diagram illustrates a technique used to support multiple barbs. Although the primary reference... Figures 1 to 15 The technology is described in medical system 100, but in other examples, the technology can be applied to other medical systems.

[0116] The technology includes an outer surface 140 (1402) of a lead body 118 defining the distal portions 120, 202, 260 of an implantable medical lead 112 using a bio-stabilized material. The lead body 118 may support fixation devices 124, 261. In an example, the lead body 118 supports fixation devices 124, 261 such that fixation devices 124, 261 extend distally to the distal end 128 of the lead. Fixation devices 124, 261 may support fixation device electrodes 130 electrically coupled to processing circuitry 131, therapy delivery circuitry 127, and / or other circuitry of the implantable medical device 112.

[0117] The technology includes using an outer surface 140 to support barbs 136, 152, 158, 204 (1404) comprising a biodegradable material. The outer surface 140 may support the barbs 136, 152, 158, 204 at locations proximal to the fixtures 124, 261. In an example, the outer surface 140 supports the barbs 136, 152, 158, 204 at locations proximal to the fixtures 124, 261 and distal to the body electrode 142 of the lead distal portions 120, 202, 260. In an example, the technology includes using an elastic bias to extend the barbs 136, 152, 158, 204 from the outer surface 140 in a radially outward direction. In an example, the barbs 136, 152, 158, 204 extend radially from a longitudinal axis L extending through the lead body 118 and the lead distal end 128.

[0118] The lead body 118 may be defined by a body radius RL extending radially from the longitudinal axis L to the outer surface 140. The barb 137 may be defined by a barb radius RB extending radially from the outer surface 140 to the free end 144 of the barb 137. The barb radius RB may be less than approximately thirty percent of the body radius RL. In the example, an elastic bias causes the barb 137 to change from a retracted position defined by a distance D1 to an extended position defined by a distance D2 greater than D1. In some examples, the catheter inner surface 157 holds the barb 137 in the retracted position. An elastic bias may cause the barb 137 to change to the extended position when the barb 137 moves relative to the catheter body 147 to a position distal to the catheter lumen opening 163. In the example, the barb 137 changes from the extended position to the distal position when the barb 137 moves relative to the catheter body 147 from a position distal to the catheter lumen opening 163 to a position proximal to the catheter lumen opening.

[0119] The outer surface 140 supports the barbs 136, 152, 158, 205 within recesses 166, 240 defined by the outer surface 140. In the example, base bodies 168, 228 support the barbs 136, 152, 158, 204, and the outer surface 140 supports the base bodies 168, 228. In some examples, the base bodies 168, 228 are inserted into the recesses 166, 240. The base bodies 168, 228 may define body axes LS, LS2 extending from the first end portion 190, 230 of the body to the second end portion 192, 232 of the body. In some examples, when the base bodies 168, 228 are inserted into the recesses 166, 240, the body axes LS, LS2 are parallel to the longitudinal axis L. In some examples, when the base bodies 168, 228 are inserted into the recesses 166, 240, the body axes LS, LS2 define a spiral and / or helical shape around the longitudinal axis L.

[0120] Various embodiments of this disclosure have been described. Any combination of the described systems, operations, or functions is contemplated. These and other embodiments are within the scope of the appended claims.

[0121] The following embodiments illustrate the technical solutions described herein.

[0122] Example 1: An implantable medical lead configured for implantation within a patient's tissue, the implantable medical lead comprising: a lead body comprising a biostabilizing material defining an outer surface and a distal end, wherein the lead body defines a longitudinal axis surrounding the outer surface and extending through the distal end; a fixation device supported by the lead body and extending distally to the distal end, wherein the fixation device is configured for insertion into the patient's tissue; and a plurality of barbs supported by the outer surface and located proximal to the fixation device, wherein the plurality of barbs are positioned about the longitudinal axis. The multiple barbs are configured to extend radially outward from the outer surface. The plurality of barbs are configured to engage the tissue when inserted into it, and the plurality of barbs contain a biodegradable material configured to degrade in the patient's fluid.

[0123] Example 2: The implantable medical lead according to Example 1 further includes an electrode supported by the lead body, wherein the electrode is located proximal to the plurality of barbs.

[0124] Example 3: An implantable medical lead according to Example 1 or Example 2, wherein one of the plurality of barbs includes a barb body defining a fixed end supported by the lead body and defining a free end opposite to the fixed end, wherein the barb body is elastically biased to extend radially outward from the outer surface.

[0125] Example 4: An implantable medical lead according to Example 1 or Example 2, wherein one of the plurality of barbs includes a barb body defining a fixed end supported by the lead body and defining a free end opposite to the fixed end, and wherein the barb body is elastically biased to change from a retracted position to an extended position, in the retracted position the free end defines a first displacement relative to the outer surface, and in the extended position the free end defines a second displacement from the free end to the outer surface, wherein the second displacement is greater than the first displacement.

[0126] Example 5: The implantable medical lead according to Example 4, wherein the barb body is configured to bend from the unfolded position to the distal position, and wherein the barb body is configured to increase the distal displacement between the free end and the fixed end when the barb body changes from the unfolded position to the distal position.

[0127] Example 6: The implantable medical lead according to Example 5, wherein the barb body is elastically biased to change from the distal position to the unfolded position.

[0128] Example 7: An implantable medical lead according to any one of Examples 4 to 6, the implantable medical lead further includes a catheter, the catheter including a catheter body defining an inner lumen and defining an inner lumen opening, the inner lumen opening opening into the inner lumen at a distal end of the catheter body, wherein the fixation device, the plurality of barbs and the lead body are configured to translate within the inner lumen and through the inner lumen opening, and wherein the catheter body is configured to capture the barb body to overcome the elastic bias when the plurality of barbs are located within the inner lumen and proximal to the inner lumen opening.

[0129] Example 8: An implantable medical lead according to any one of Examples 3 to 7, wherein the barb body is configured to position the free end proximal to the fixed end in the retracted position and the extended position.

[0130] Example 9: An implantable medical lead according to any one of Examples 3 to 8, wherein: The lead body defines a body radius that extends substantially perpendicularly from the longitudinal axis to the outer surface, and the barb body defines a barb radius that extends substantially parallel to the body radius and from the outer surface to the free end when the barb body is in the unfolded position, and the barb radius is less than thirty percent of the body radius.

[0131] Example 10: An implantable medical lead according to any one of Examples 3 to 9, wherein the fixed end is connected to the barb base, and wherein the barb base is inserted into a recess defined by the lead body.

[0132] Example 11: An implantable medical lead according to any one of Examples 10, wherein the barb base, the fixed end, and the free end define an integral body.

[0133] Example 12: The implantable medical lead according to Example 11, wherein the integral body defines an incision extending radially inward toward the longitudinal axis, and wherein the incision separates the free end and the barb base.

[0134] Example 13: An implantable medical lead according to any one of Examples 10 to 12, wherein the integral body defines a plane passing through the longitudinal axis and the recess, wherein the recess is configured to define at least one curvature in the plane.

[0135] Example 14: An implantable medical lead according to any one of Examples 1 to 13, wherein the fixation device defines a spiral drill that surrounds the longitudinal axis and is configured to engage the patient's tissue when the fixation device is inserted into the patient's tissue.

[0136] Example 15: An implantable medical lead according to any one of Examples 1 to 14, wherein the bio-stable material has a first solubility in an aqueous environment, and the biodegradable material has a second solubility in the aqueous environment greater than the first solubility.

[0137] Example 16: An implantable medical lead according to any one of Examples 1 to 15, the implantable medical lead further comprising a second plurality of barbs supported by the outer surface and proximal to the plurality of barbs, wherein the second plurality of barbs are positioned about the longitudinal axis, wherein the second plurality of barbs are resiliently biased to extend radially outward from the outer surface, wherein the second plurality of barbs are configured to engage the tissue when the second plurality of barbs are inserted into the tissue, and wherein the second plurality of barbs contain a biodegradable material configured to degrade in the patient's fluid.

[0138] Example 17: An implantable medical lead according to any one of Examples 1 to 16, wherein the plurality of barbs are positioned along a closed periphery surrounding the longitudinal axis.

[0139] Example 18: An implantable medical lead according to any one of Examples 1 to 17, wherein the plurality of barbs are positioned along a spiral drill surrounding the longitudinal axis.

[0140] Example 19: An implantable medical lead according to any one of Examples 1 to 18, wherein the biodegradable material is a biodegradable polymer.

[0141] Example 20: An implantable medical lead according to Example 19, wherein the biodegradable polymer is a copolymer of glycolic acid and trimethylene carbonate.

[0142] Example 21: An implantable medical lead according to any one of Examples 1 to 20, wherein the biodegradable material is configured to be metabolized by the patient.

[0143] Example 22: An implantable medical lead according to any one of Examples 1 to 21, wherein: The plurality of barbs are configured to apply a distal force to the lead body when the plurality of barbs engage the tissue and apply a force of a magnitude to the lead body in the proximal direction, the plurality of barbs are configured to apply a proximal force to the lead body when the plurality of barbs engage the tissue and apply a force of the magnitude to the lead body in the distal direction, and the plurality of barbs are configured such that the distal force is greater than the proximal force.

[0144] Example 23: A method comprising: The outer surface of the lead body surrounding the longitudinal axis of the lead body and the distal end of the lead body are defined using a bio-stabilized material; the distal end of the lead body is used to support a fixation device configured to engage tissue; a plurality of barbs supported by the outer surface and proximal to the fixation device are defined using a biodegradable material; and the resilient bias of the plurality of barbs causes the plurality of barbs to extend radially outward from the outer surface.

[0145] Example 24: According to the method of Example 23, the method further includes using the lead body to support the electrode at a position near the plurality of barbs.

[0146] Example 25: According to the method described in Example 23 or Example 24, the method further includes: using the lead body to support the fixed end of the barb among the plurality of barbs; and using the elastic bias to change the barb from a retracted position to an extended position, wherein in the retracted position, the free end opposite to the fixed end defines a first displacement from the outer surface, and in the extended position, the free end defines a second displacement from the outer surface, wherein the second displacement is greater than the first displacement.

[0147] Example 26: According to the method of Example 25, the method further includes using the distal end of the delivery catheter to increase the distal displacement between the free end and the fixed end.

[0148] Example 27: According to the method of Example 26, the method further includes using the elastic bias to reduce the distal displacement between the free end and the fixed end.

[0149] Example 28: The method according to any one of Examples 25 to 27, further comprising using the elastic bias to position the free end distal to the fixed end.

[0150] Example 29: The method according to any one of Examples 25 to 28, further comprising: defining a body radius extending substantially perpendicularly from the longitudinal axis to the outer surface using the lead body, and defining a barb radius substantially parallel to the body radius and extending from the outer surface to the free end using the elastic bias, wherein the barb radius is less than 30 percent of the body radius.

[0151] Example 30: The method according to any one of Examples 25 to 29, the method further includes using the recess of the outer surface to support the barb base of the fixed end.

[0152] Example 31: The method according to any one of Examples 23 to 30, further comprising: The fixation device is used to engage the patient's tissue; and when the fixation device engages the patient's tissue, the multiple barbs are used to engage the patient's tissue.

[0153] Example 32: The method according to any one of Examples 23 to 31, further comprising using the catheter body to capture the plurality of barbs to overcome the resilient bias when the plurality of barbs are located within the lumen defined by the catheter body.

[0154] Example 33: The method according to any one of Examples 23 to 32, the method further includes using an elastic bias of a second plurality of barbs to cause the second plurality of barbs to extend radially outward from the outer surface.

Claims

1. An implantable medical lead configured for implantation within a patient's tissue, the implantable medical lead comprising: A lead body comprising a bio-stabilizing material defining an outer surface and a distal end, wherein the lead body defines a longitudinal axis that is surrounded by the outer surface and extends through the distal end; A fixation device, supported by the lead body and located distal to the distal end, wherein the fixation device is configured to be inserted into the patient's tissue; and Multiple barbs, which are supported by the outer surface and located near the fixing device. The plurality of barbs are positioned around the longitudinal axis. The plurality of barbs are configured to extend radially outward from the outer surface. The plurality of barbs are configured to engage the tissue when the plurality of barbs are inserted into the tissue, and The plurality of barbs contain a biodegradable material configured to degrade in the patient’s fluid.

2. The implantable medical lead according to claim 1, wherein the implantable medical lead further comprises an electrode supported by the lead body, wherein the electrode is located proximal to the plurality of barbs.

3. The implantable medical lead according to claim 1 or claim 2, wherein one of the plurality of barbs includes a barb body defining a fixed end supported by the lead body and defining a free end opposite to the fixed end, wherein the barb body is resiliently biased to extend radially outward from the outer surface.

4. The implantable medical lead according to claim 1 or claim 2, wherein one of the plurality of barbs includes a barb body defining a fixed end supported by the lead body and defining a free end opposite to the fixed end, and wherein the barb body is elastically biased to transition from a retracted position to an extended position, wherein in the retracted position the free end defines a first displacement from the outer surface, and in the extended position the free end defines a second displacement from the free end to the outer surface, wherein the second displacement is greater than the first displacement.

5. The implantable medical lead of claim 4, wherein the barb body is configured to bend from the deployed position to the distal position, and wherein the barb body is configured to increase the distal displacement between the free end and the fixed end when the barb body changes from the deployed position to the distal position.

6. The implantable medical lead of claim 5, wherein the barb body is resiliently biased to change from the distal position to the deployed position.

7. The implantable medical lead according to any one of claims 4 to 6, further comprising a catheter, the catheter including a catheter body defining an inner lumen and defining an inner lumen opening at a distal end of the catheter body into the inner lumen. The fixing device, the plurality of barbs, and the lead wire body are configured to translate within the cavity and pass through the cavity opening, and The catheter body is configured to capture the barb body to overcome the elastic bias when the plurality of barbs are located within the lumen and proximal to the lumen opening.

8. The implantable medical lead according to any one of claims 3 to 7, wherein the barb body is configured to position the free end proximal to the fixed end in the retracted position and the extended position.

9. The implantable medical lead according to any one of claims 3 to 8, wherein: The lead body defines a body radius that extends substantially perpendicularly from the longitudinal axis to the outer surface. The barb body defines a barb radius that is substantially parallel to the body radius and extends from the outer surface to the free end when the barb body is in the deployed position. The radius of the barb is less than 30 percent of the radius of the main body.

10. The implantable medical lead according to any one of claims 3 to 9, wherein the fixed end is coupled to the barb base, and wherein the barb base is inserted into a recess defined by the lead body.

11. The implantable medical lead according to any one of claims 10, wherein the barbed base, the fixed end, and the free end define an integral body.

12. The implantable medical lead of claim 11, wherein the integral body defines a plane passing through the longitudinal axis and the recess, wherein the recess is configured to define at least one curvature in the plane.

13. The implantable medical lead according to any one of claims 1 to 12, wherein the fixation device defines a auger that surrounds the longitudinal axis and is configured to engage the patient's tissue when the fixation device is inserted into the patient's tissue.

14. The implantable medical lead according to any one of claims 1 to 13, wherein the plurality of barbs are positioned along a closed periphery surrounding the longitudinal axis.

15. The implantable medical lead according to any one of claims 1 to 13, wherein the plurality of barbs are positioned along a helix surrounding the longitudinal axis.

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