Multi-electrode implantable medical device

Abstract

In some examples, an implantable medical device includes a device body extending along a longitudinal axis from a proximal portion to a distal portion; a fixing member; and an electrode interface assembly. The fixation member includes penetrator teeth extending away from the distal portion of the device body and configured to penetrate tissue. The electrode interface assembly includes a miniature lead extending away from the distal portion of the device body; an elongate body extending away from the distal portion of the device body, the elongate body defining a recess and a groove, where the groove is configured to receive the miniature lead; and an electrode extending from the elongate body and disposed within the recess.

Description

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 377,625, filed on September 29, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to medical device systems, such as relatively compact implantable medical devices and associated fixation components. Background Art

[0003] In some examples, an implantable cardiac pacemaker includes a pulse generator device to which one or more flexible elongated wires are coupled. The pulse generator device can be implanted in a subcutaneous pouch remote from the heart, and each of the one or more wires extends from the pulse generator device to a corresponding electrode, coupled to the electrode and positioned at a pacing site in the endocardium or epicardium. Mechanical and / or MRI compatibility issues may be associated with the elongated wires. Relatively compact implantable medical devices (IMDs) have been developed that are fully contained within a relatively compact pouch and are constructed as a whole for implantation in close proximity to a pacing site within, for example, a ventricle. Summary of the invention

[0004] The present disclosure describes an IMD including a fixed component having a penetrator rake and an electrode interface assembly. The penetrator rake of the fixed component can be operated in conjunction with one or more elongated electrodes (e.g., small wires) mounted near the distal end of the IMD. For example, the penetrator rake can define an exoskeleton of a cardiac pacing electrode. The penetrator rake can be operated in conjunction with an electrode interface assembly that is configured to control the tissue penetration depth of the penetrator rake. Compared to a fixed component that does not have the described penetrator rake and / or electrode interface assembly, the penetrator rake and electrode interface assembly can provide improved tissue fixation, controlled penetration to a selected depth within the tissue, improved electrode tissue interface, and / or improved tissue detachment when deployed. In this way, the fixed component can facilitate implantation and / or removal of the IMD.

[0005] In some examples, the present disclosure describes an implantable medical device (IMD) comprising: a device body extending along a longitudinal axis from a proximal portion to a distal portion; a fixation component comprising a penetrator rake extending away from the distal portion of the device body and configured to penetrate tissue; and an electrode interface assembly comprising: a small wire extending away from the distal portion of the device body; an elongated body extending away from the distal portion of the device body, the elongated body defining a recess and a groove, wherein the groove is configured to accommodate the small wire; and an electrode extending from the elongated body and disposed in the recess, wherein the electrode is configured to form a circuit with the tissue, and wherein the elongated body is configured to place the electrode in contact with the tissue.

[0006] In some examples, the present disclosure describes an IMD comprising a device body extending along a longitudinal axis from a proximal portion to a distal portion; a fixation component comprising: a penetrator rake extending away from the distal portion of the device body and configured to penetrate tissue; an electrode interface assembly comprising: an elongated body extending from the distal portion of the device body, the elongated body defining a first recess and a second recess; a first electrode extending away from the electrode interface assembly, the first electrode being disposed within the first recess; and a second electrode extending away from the electrode interface assembly, the second electrode being disposed within the second recess, wherein the first electrode is configured to form a first circuit with the tissue, wherein the second electrode is configured to form a second circuit with the tissue, and wherein the elongated body is configured to place the first electrode and the second electrode in contact with the tissue.

[0007] In some examples, the present disclosure describes a medical device system comprising: an IMD comprising: a device body extending from a proximal portion to a distal portion along a longitudinal axis; a small guide wire extending away from the distal portion of the device body, the small guide wire comprising a first electrode disposed on a distal end of the small guide wire; a fixation component comprising a penetrator rake extending from the distal portion of the device body and configured to penetrate tissue; an elongated body extending from the distal portion of the device body, the elongated body defining a groove configured to receive the small guide wire; a second electrode disposed within a recess of the elongated body, wherein the elongated body is configured to place the second electrode in contact with the tissue; and a delivery tool comprising a tubular sidewall defining a lumen into which the IMD can be loaded, wherein the lumen has a distal opening through which the IMD can be deployed.

[0008] In some examples, the present disclosure describes a method of forming an IMD, the method comprising: forming a device body of the IMD, wherein the device body extends from a proximal portion to a distal portion along a longitudinal axis; attaching an electrode interface assembly to the distal portion of the device body, wherein the electrode interface assembly comprises: a small wire extending away from the distal portion of the device body of the IMD; an elongated body extending away from the distal portion of the device body, the elongated body defining a groove configured to receive the small wire; and an electrode extending away from the distal portion of the device body and disposed within a recess in the elongated body, wherein the elongated body is configured to place the electrode in contact with the tissue; and attaching a fixation component to the distal portion of the device body, wherein the fixation component comprises a penetrator rake extending from the distal portion of the device body and configured to penetrate the tissue.

[0009] The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a conceptual diagram illustrating a portion of an exemplary medical device system configured to implant an implantable medical device at a target implantation site.

[0011] FIG. 2A to FIG. 2B is a conceptual diagram illustrating an IMD including a fixing component and an electrode interface assembly.

[0012] Figure 3 It is shown FIG. 2A to FIG. 2B A conceptual diagram of an exploded view of an exemplary IMD.

[0013] Figure 4 It is shown FIG. 2A to FIG. 2B Conceptual diagram of the electrode interface components.

[0014] Figure 5 The implantation site is shown in Fig. FIG. 2A to FIG. 2B Conceptual diagram of an exemplary IMD.

[0015] Figure 6 is a conceptual diagram depicting, in partial cutaway section, an exemplary medical device system including a delivery tool and an IMD.

[0016] Figure 7 is a flow chart illustrating an exemplary method of making an exemplary IMD. DETAILED DESCRIPTION

[0017] The present disclosure describes implantable medical devices (IMDs), components of IMDs, medical device systems including IMDs, and related technologies for using and forming IMDs. An exemplary IMD may include a body, one or more elongated small wires, a fixed component including a base and a plurality of rake teeth, and an electrode interface assembly (EIA). One or more rake teeth of the fixed component may be configured to penetrate tissue, and the EIA may be configured to control the tissue penetration depth of the one or more rake teeth.

[0018] In some examples, the body of the IMD can extend along a longitudinal axis from a proximal portion of the body to a distal portion and can enclose components of the IMD, such as circuitry and a battery. The body of the IMD can support a return electrode configured to allow electrical energy to flow from tissue to the IMD through the return electrode.

[0019] The proximal end of the EIA may be mounted to the body, for example, near the distal end of the body. The EIA may include one or more or all of the electrodes of the IMD, and at least one of the electrodes of the IMD may be mounted in the EIA, for example, in a corresponding recess in the EIA. In some examples, the EIA defines a cannula that is configured to hold a small wire extending from the distal end of the body. The distal end of the small wire may include an electrode, such as one of the one or more electrodes of the IMD. The electrodes of the IMD may be configured to sense electrical signals from tissue and / or deliver electrical therapy to tissue.

[0020] The fixed component of the IMD may include a base and a plurality of rake teeth. The base may define the longitudinal axis of the fixed component, and the proximal end and the distal end of the IMD may be aligned along the longitudinal axis. The longitudinal axes of the fixed component and the IMD may be parallel, and in some cases, the fixed component and the IMD may share the longitudinal axis. The base may be fixedly attached to the IMD near the distal end of the IMD. The plurality of rake teeth include penetrator rake teeth, and may include additional rake teeth, such as support rake teeth, deployment rake teeth, alignment rake teeth, or protector rake teeth. The plurality of rake teeth may be spaced apart from each other around the periphery of the distal end of the IMD and extend from the base. The shape of each corresponding rake tooth in the plurality of rake teeth may be selected to control the deployment, tissue fixation, and / or tissue detachment of the IMD. For example, the shape of the corresponding rake tooth may include the number of preset curves on the corresponding rake tooth, the curvature (e.g., radius) of each preset curve on the corresponding rake tooth, the length of each preset curve, the length of optional straight sections between the preset curves, the width of the corresponding rake tooth or sections thereof (e.g., one or more tapered portions), the thickness of the corresponding rake tooth, the number of cuts along the length of the corresponding rake tooth, the shape of the cuts, or any combination thereof.

[0021] IMD includes an electrode interface assembly (EIA), which can be operated in conjunction with a fixed component to control the tissue penetration depth of one or more rake teeth. For example, the EIA can be configured to contact the tissue, and thus resist further tissue penetration to control the tissue penetration depth of the penetrator rake teeth. In some examples, the EIA includes a texture around the outer surface of the EIA, such as to control the tissue penetration depth of the penetrator rake teeth and / or prevent one or more rake teeth from being displaced from the tissue. The EIA may include a proximal section, which is attached to the distal portion of the IMD body and extends distally from the distal portion to the distal end along the longitudinal axis. The EIA may also include a distal section extending from the proximal section of the EIA and defining a non-sharp distal end. The distal section of the EIA may be configured to contact the tissue to control the tissue penetration depth of the penetrator rake teeth. For example, the EIA may be formed (e.g., sized) to have a proximal section and a distal section, and its total length causes contact between the EIA and the tissue at the selected tissue penetration depth of the penetrator rake teeth. Additionally, or alternatively, the EIA can be positioned on the IMD to cause contact between the EIA and tissue at a selected depth of tissue penetration by the penetrator rakes. In any case, the EIA can be configured to achieve a selected distance (e.g., in a range from about 4 mm to about 10 mm) between the sharpened distal sections of the penetrator rakes and the distal end of the EIA.

[0022] The EIA may place a first electrode of the IMD (e.g., a distal-most electrode within the EIA, such as an electrode on the distal end of a small guidewire) at a predetermined depth within the tissue (e.g., at a selected depth of tissue penetration by the penetrator rakes). The EIA may place a second electrode of the IMD (e.g., a proximal-most electrode disposed within a recess within the EIA) in contact with the tissue without penetrating the tissue.

[0023] Multiple rake teeth, when deployed, in conjunction with the EIA, can provide selected tissue fixation. For example, the deformable preset curve of the penetrator rake teeth can have a shape selected to penetrate the tissue in a selected direction and at a selected depth to fix the IMD to the tissue. In addition, the distal section of the EIA can be configured to contact the tissue when the penetrator rake teeth reach a selected depth of tissue penetration, resist further tissue penetration, and thus control the tissue penetration depth of the penetrator rake teeth. Similarly, in another example, the deployed (e.g., undeformed) configuration of the penetrator rake teeth, in conjunction with the EIA, can be selected to fully fix the IMD to the selected tissue.

[0024] The IMD can be loaded into a delivery catheter by deforming a deformable preset curvature of each respective rake tooth in a plurality of teeth, and optionally deforming a deformable portion of an EIA. When deployed at a target implantation site, for example by allowing the rake teeth to transition to a deployed configuration, the rake teeth have a deployment stiffness that enables the rake teeth to penetrate tissue at the target implantation site. By controlling the deployment stiffness, the rake teeth can have improved tissue fixation, including control of the rake tooth penetration depth and the amount of tissue engagement in the lateral direction.

[0025] In some examples, the penetrator rake and the EIA can be operated in conjunction with the small wire. The penetrator rake can be configured to penetrate or cut tissue to form a puncture in the tissue. The EIA can be configured to protect the small wire during deployment, such as by applying force to the small wire in the direction of the penetrator rake during deployment and / or thereafter (e.g., via the inner surface of the cannula defined by the EIA), thereby reducing the undesirable displacement of the small wire or mechanical damage to the structure of the small wire. For example, during deployment from the delivery catheter, the penetrator rake can initially penetrate the selected tissue to form a puncture, and the EIA can apply force to the first small wire, thereby pushing the first small wire toward the penetrator rake and guiding the first small wire into the puncture. When the fixed component is further deployed, the penetrator rake can return to (or at least toward) the undeformed (e.g., deployed) configuration from the deformed (e.g., pre-deployed) configuration. As the miniature lead is inserted into the puncture in the tissue, a portion of the distal portion of the EIA (e.g., the portion defining the cannula) can be inserted into the puncture in the tissue (e.g., to improve surface contact between the EIA and the tissue, to protect the miniature lead, etc.). Upon reaching a selected depth of tissue penetration by the penetrator tines, a portion of the EIA (e.g., the portion of the EIA defining the recess for the proximal-most electrode) can contact the tissue to resist further tissue penetration.

[0026] When the penetrator tines are in the deployed configuration, the small wires can extend in the distal direction between the penetrator tines and the EIA and from the distal end of the EIA so that the small wires extend from the distal end of the body of the IMD to the selected target tissue. In this way, the fixation component and the EIA can provide improved electrode penetration to a selected depth within the selected tissue and improved electrode contact with the selected tissue.

[0027] After deployment at the target implantation site, the deflection stiffness of the penetrator rake teeth enables the clinician to confirm that the penetrator rake teeth are fully fixed to the patient's tissue. For example, a pull test or a drag test can be performed under fluoroscopy to confirm that the penetrator rake teeth have engaged the tissue, thereby confirming the appropriate implantation of the IMD. The pull test or the drag test may include the clinician, for example, pulling or dragging the deployed IMD via a tether connected to the proximal end of the IMD, and observing the movement of the penetrator rake teeth to determine whether the penetrator rake teeth are engaged in the tissue. For example, when the deployed IMD is pulled or dragged in the proximal direction, the penetrator rake teeth embedded in the tissue may deflect or bend. By controlling the deflection stiffness, the penetrator rake teeth may have improved flexibility that enables the clinician to more easily confirm tissue engagement.

[0028] In some examples, the rake teeth can be configured to disengage from tissue. For example, the IMD can be retrieved by a retrieval catheter. During retrieval, a retrieval member of the retrieval catheter can engage a proximal end of the IMD, such as a retrieval structure. The retrieval member can be withdrawn into the retrieval catheter in a proximal direction. When the tissue resists the movement of the rake teeth, withdrawing the retrieval member in the proximal direction can cause the rake teeth to move from an undeformed configuration to a deformed configuration. Compared to rake teeth that do not move from an undeformed configuration to a deformed configuration during retrieval from tissue, the rake teeth can improve tissue disengagement by moving from an undeformed configuration to a deformed configuration during retrieval to facilitate extraction of the IMD.

[0029] In the present disclosure, exemplary systems, devices, and techniques will be described with reference to delivering an IMD configured as a cardiac pacemaker to a target site in a patient's heart. However, it will be understood that the exemplary systems, devices, and techniques of the present disclosure are not limited to delivering such an IMD to a target site in the heart. For example, the exemplary systems, devices, and techniques described herein may be used to deliver other medical devices, such as drug delivery devices, sensing devices, neural stimulation devices, or medical electrical leads. In addition, any such IMD may be delivered to other locations in the patient's body using the exemplary systems, devices, and techniques described herein. In short, the exemplary systems, devices, and techniques described herein may have useful applications in the delivery of a wide variety of implantable medical devices for delivering therapy to a patient or patient sensing.

[0030] Figure 1 is a conceptual diagram illustrating a portion of an exemplary medical device system 100 configured to implant a relatively compact implantable medical device 110 ("IMD 110") at a target implantation site 102. In some examples, such as Figure 1, the target implant site 102 may include an appendage (e.g., Koch's triangle) of the right atrium (RA) of the patient's heart 104. In some examples, the target implant site 102 may include other portions of the heart 104 or other locations within the patient's body. The medical device system 100 may include a delivery tool 106 configured to accommodate and controllably deploy a relatively compact IMD 110. In some examples, a clinician may manipulate the medical device system 100 to reach the target implant site 102. For example, with the IMD loaded therein, the clinician may guide the delivery tool 106 through the inferior vena cava (IVC) or the superior vena cava (SVC) and into the RA. In some examples, other pathways or techniques may be used to guide the delivery tool 106 to other target implant sites within the patient's body.

[0031] Figure 2A and Figure 2B is a conceptual diagram of an IMD 110 including a fixation component 203 and an electrode interface assembly 204 ("EIA 204"). The fixation component 203 and the EIA 204 can be connected (e.g., removably connected, permanently connected) to a body 201 (also referred to as "device body 201") of the IMD 110. The fixation component 203 includes a base 206 and one or more rake teeth 208. The body 201 is defined by a housing 202 that extends from a proximal portion 214 to a distal portion 216 along a longitudinal axis 212. The body 201 may include an interior chamber defined by the housing 202. The housing 202 may include a biocompatible and biostable metal such as titanium. In some examples, the housing 202 may form an airtight seal with the body 201. The housing 202 may include a non-conductive coating and define a return electrode 218 as an uncoated portion of the housing 202. The IMD 110 may include any suitable dimensions. In some examples, an outer diameter of IMD 110 (eg, an outer diameter of body 201 ) can be between about 10 French (Fr) and about 30 Fr, such as about 20 Fr.

[0032] As discussed above, the fixation member 203 may include a base 206 and one or more rakes 208. The base 206 may have a proximal end and a distal end aligned along a longitudinal axis, which may or may not be the longitudinal axis 212 of the body 201. The proximal end of the base 206 may be attached to the distal portion of the body 201.

[0033] One or more tines 208 may extend from the base 206. For example, Figure 2A2, penetrator tines 208A may extend from base 206. Penetrator tines 208A are configured to penetrate tissue to secure IMD 110 to the tissue. Penetrator tines 208A may be configured to maintain one or more electrodes (e.g., first electrode 222 on miniature lead 220) in contact with tissue at a target implant site (e.g., target implant site 102). Penetrator tines 208A may define distal tips 223. Distal tips 223 may be configured to pierce tissue of heart 104 and form a puncture in the tissue.

[0034] In addition to the penetrator rake 208A, the fixed component 203 may include one or more other rakes 208, such as one or more supporting rakes 208B. The rake 208 may include one or more sections. For example, the rake 208 may include an elastically deformable material preset to one or more curved sections and one or more optional substantially straight sections. In some examples, the penetrator rake 208A and / or other rakes may include a preset curvature in a plurality of preset curvatures. In other examples, the rake 208 may define a band shape that is configured to deform along a plane perpendicular to the longitudinal axis 212 and resist torsion outside the plane. For example, each rake 208 may be deformed in a corresponding plane, in which the corresponding rake exists in a stress-free configuration.

[0035] The rake teeth 208 may be configured to have a target deflection stiffness and a target deployment stiffness. The target deflection stiffness may include a measure of the resistance to a force applied to the IMD 110 in the proximal direction when the fixation component 203 engages tissue at the target site 102. In some examples, the target deflection stiffness may be selected to enable the rake teeth 208 to deflect a predetermined amount to enable visualization of the rake teeth 208 under fluoroscopy (e.g., tissue engagement status). In some examples, the target deflection stiffness may be in the range of about 0.2 Newtons (N) to about 0.8N, such as about 0.3N to about 0.6N. The deployment stiffness may include a target deflection stiffness when the fixation component 203 is moved from the distal opening 108 ( Figure 1 The target deployment stiffness is a measure of the force applied by the tines 208 as they move from a deformed configuration to an undeformed configuration after the tines 208 are deployed so that the free distal ends of the tines 208 penetrate the pectinate muscles (PM). In some examples, the target deployment stiffness may be in the range of about 0.6 N to about 1.2 N.

[0036] IMD 110 includes EIA 204 having a proximal section (not shown) defining a proximal end and a distal section 205 defining a non-sharp distal end. Distal section 205 may be an elongated body and may include a first elongated structure 210 and a second elongated structure 224. Figure 2A2, a first elongated structure 210 may extend from a distal portion 216 of the body 201 and may define a cannula (not shown) configured to hold a small guide wire 220. The first elongated structure 210 may be sized to at least partially enter a puncture created by the penetrator rake 208A and a first electrode 222 disposed on a distal end of the small guide wire 220 at a selected depth in the tissue. The first elongated structure 210 may taper from a proximal end toward a distal end (e.g., toward a distal tip 223 of the penetrator rake 208A), e.g., to facilitate insertion of the first elongated structure 210 into the puncture in the tissue. The cannula defined by the first elongated structure 210 may extend from the distal portion 216 of the body 201 to a distal end of the first elongated structure 210 and may be sized to hold the small guide wire 220. In some examples, the cannula may be completely enclosed within the first elongated structure 210. In some examples, the cannula can be partially open, for example, to facilitate deflection of small guidewires 220 toward penetrator rakes 208A when IMD 110 is in the pre-deployment configuration. In some examples, first elongated structure 210 can include a texture (e.g., a roughened, ridged, patterned, or non-smooth or friction-increasing surface texture) disposed on an outer surface of first elongated structure 210 and disposed at least partially along first elongated structure 210.

[0037] The second elongated structure 224 may extend from the distal portion 216 of the body 201 and define a recess (not shown) configured to hold the electrode 226. The second elongated structure 224 may be configured to control the tissue penetration depth of the penetrator rake 208A. For example, the EIA 204 may be formed so that the distal end 228 of the second elongated structure 224 contacts the tissue at a selected depth of tissue penetration of the penetrator rake 208A. The shape of the second elongated structure 224 may be spherical, polygonal, prismatic, or any other geometric shape, wherein the distal end 228 may serve as a non-sharp distal end that contacts the tissue. In addition, the size (e.g., length and / or circumference) of the second elongated structure 224 may be such that the EIA 204 is configured to achieve a selected distance between the distal tip 223 of the penetrator rake head 208A and the distal end 228 of the second elongated structure 224, thereby controlling the tissue penetration depth of the penetrator rake 208A. Similarly, the second elongated structure 224 can be positioned on the IMD 110 to achieve a selected distance between the distal tips 223 and the distal ends 228 of the penetrator rakes 208A. The second elongated structure 224 can be configured to control the tissue penetration depth of the penetrator rakes 208A by contacting the tissue and resisting further penetration of the penetrator rakes 208A. In some examples, the first elongated structure 210 and the second elongated structure 224 can be formed into a single elongated body 205 in a single process. In some examples, the first elongated structure 210 and the second elongated structure 224 can be formed separately and assembled to form a single elongated body 205.

[0038] IMD 110 may contain electronic circuitry, including one or more of sensing circuitry (e.g., for sensing cardiac signals), therapy delivery circuitry (e.g., for generating cardiac pacing pulses), and processing circuitry for controlling the functions of IMD 110, and may include miniature leads 220. Miniature leads 220 may terminate at first electrodes 222. In some examples, first electrodes 222 may be connected to the electronic circuitry without using miniature leads 220.

[0039] The miniature lead 220 may include a feedthrough assembly connected to the electronic circuit. The feedthrough assembly may include a conductor, such as a conductive material, extending through a non-conductive sleeve (such as a polytetrafluoroethylene (PTFE) coating or polyetheretherketone (PEEK) catheter), a portion of which is exposed at the first electrode 222. In order to avoid changing the characteristics of one or more rake teeth 208 (e.g., penetrator rake teeth 208A) made of an electrically susceptible material (e.g., nitinol), the non-conductive sleeve may extend beyond the one or more rake teeth 208. The electronic circuit may be configured to generate electrical pulse therapy via the first electrode 222 and deliver the electrical pulse therapy to tissue proximate to the miniature lead 220, through the tissue to the return electrode 218. The miniature lead 220 may be spaced apart from the distal portion 216 of the body 201, for example, by an airtight feedthrough assembly (at Figure 2A Conductors (not shown) are connected to sensing and therapy delivery circuits within the body 201.

[0040] IMD 110 may also include a second electrode 226. Second electrode 226 may extend from distal portion 216 of body 201 to distal end 228 of second elongated structure 224 via a recess defined by second elongated structure 224. Second electrode 226 may be similar to first electrode 222 in at least some respects. For example, second electrode 226 may be connected to electronic circuitry within body 201 via a corresponding feedthrough assembly. The feedthrough assembly may include a conductor, such as a conductive material, extending through a non-conductive sleeve (such as a PTFE-coated or PEEK catheter), with a portion of the conductor exposed at second electrode 226. First electrode 222 may function in conjunction with second electrode 226 for bipolar pacing and sensing, and / or first electrode 222 and second electrode 226 may each function separately with return electrode 218 for pacing and sensing of different selected tissues. In some examples, body 201 may be covered with an insulating layer, such as medical grade polyurethane, parylene, or silicone. In some examples, the insulating layer can define the return electrode 218 and / or the second electrode 226, for example by removing a portion of the insulating layer to expose a metal surface of the housing 202. The second electrode 226 can be used with the first electrode 222 for pacing and / or sensing.

[0041] As described above, each of the first electrode 222 and the second electrode 226 can be connected to the electronic circuit via a corresponding feedthrough assembly. The feedthrough assembly can terminate at a pad, for example, to connect to a spring connector, which is connected to the electronic circuit. In other examples, each feedthrough assembly can terminate at a separate wire or other conductor that can be connected (e.g., soldered) to the electronic circuit. The corresponding feedthrough assemblies can be electrically isolated from each other.

[0042] The first elongated structure 210 and the second elongated structure 224 may be configured as a feedthrough assembly that places electrodes (e.g., the first electrode 222, the second electrode 226) in a specific arrangement. The feedthrough assemblies may be parallel to each other and parallel to the longitudinal axis 212. The feedthrough assemblies may be placed on the same reference plane (e.g., a reference plane intersecting the longitudinal axis 212, a reference plane parallel to the longitudinal axis 212, etc.). In some examples, one feedthrough assembly may be arranged along the longitudinal axis 212, and another feedthrough assembly may be parallel to the longitudinal axis 212 and offset from the longitudinal axis by a determined distance. In some examples, each feedthrough assembly in the feedthrough assembly may be separated from one or more other feedthrough assemblies and / or the longitudinal axis 212 by a predetermined distance.

[0043] The EIA 204 can be removably or permanently connected to the body 201. The EIA 204 can be pinned, welded, or locked to the body 201 (e.g., via a threaded locking mechanism, via a mechanical locking mechanism, etc.). For example, the proximal portion of the EIA 204 can be disposed within the body 201 and connected to the housing 202 via one or more pins. In another example, the proximal portion of the EIA 204 can be welded to a ring and / or cap of the body 201.

[0044] In some examples, IMD 200 can include a retrieval structure 219 fixedly attached to proximal portion 214 of body 201. Retrieval structure 219 can be configured to temporarily tether IMD 110 to a delivery catheter or retrieval catheter, such as delivery tool 106. In some examples, retrieval structure 219 can be configured to couple to a tether assembly, such as the tether assembly described in U.S. Pat. No. 11,331,475, entitled “TETHER ASSEMBLIES FOR MEDICAL DEVICE DELIVERY SYSTEMS,” which is incorporated herein by reference in its entirety.

[0045] Figure 3 It is shown FIG. 2A to FIG. 2B 1. A conceptual diagram of an exploded view of an exemplary IMD 110. Figure 3 As shown in FIG. 1 , IMD 110 includes a fixing component 203, an EIA 204, and a main body 201. Figure 3 Figure 1 and previous references FIG. 2A to FIG. 2B As described above, the fixing member 203 may include a base 206 and a plurality of rake teeth 208 (eg, penetrating rake teeth 208A and supporting rake teeth 208B).

[0046] EIA 204 may include a cap 305, an elongated body 205 extending distally from cap 305, and a proximal portion 302 extending proximally from cap 305. Cap 305 may be configured to be fixed within body 201 (e.g., within groove 312) when IMD 110 is assembled. Cap 305 may isolate electronic circuits disposed within an interior chamber 315 of body 201 from blood or other bodily fluids of a patient. Cap 305 may have a larger outer diameter than elongated body 205 or proximal portion 302. First elongated structure 210 and second elongated structure 224 may extend from a distal end of cap 305. Cap 305 may include a plurality of openings (not shown) sized to allow feedthrough assemblies (e.g., feedthrough assemblies 303, 306) to enter body 201. Proximal portion 302 may be configured to be at least partially inserted into interior chamber 315. The proximal portion 316 of the feed-through assembly can extend proximally from the proximal portion 302 and into the internal chamber 315 to connect to the electronic circuit (not shown). A plurality of openings can be connected to the cannula 301 and the recess 304 of the first elongated structure 210 and the second elongated structure 224, respectively. In some examples, the proximal portion 302 can include an opening 317. The opening 317 can be configured to receive a pin or the like, for example, to attach the EIA 204 to the body 201.

[0047] The small wire 220 may include an insulating sleeve 309 and a feed-through assembly 303. Figure 3 , the feed-through assembly 303 can be disposed within an insulating sleeve 309. When assembled, the small wire 220 can extend from the distal portion 216 and can be disposed within the cannula 301. The cannula 301 can be defined by the first elongated structure 210 of the elongated body 205 of the EIA 204. The cannula 301 can be curved, for example, along the curvature of the penetrating rake 208A. In some examples, such as Figure 3 , the cannula 301 may be partially open and expose the small wire 220. In other examples, the cannula 301 may be completely closed. The first electrode 222 may be exposed at the distal end of the small wire 220. In some examples, the first electrode 222 may extend along the entire length of the small wire 220 (e.g., along the length of the feedthrough assembly 303). In other examples, such as Figure 3 As shown in FIG. 3 , the first electrode 222 may be disposed on the distal end of the small lead 220 and connected to the electronic circuitry within the inner chamber 315 via a feedthrough assembly 303 .

[0048] Second electrode 226 can be disposed on a distal end of feedthrough assembly 306. Feedthrough assembly 306 can be disposed within recess 304 within second elongated structure 224 and connected to electronic circuitry within interior chamber 315. In some examples, such as Figure 3, the feedthrough assembly 306 includes a therapeutic agent delivery module 307 (also referred to as a "therapeutic substance dispensing device 307") disposed at the distal end of the feedthrough assembly 306. The therapeutic agent delivery module 307 can deliver a therapeutic agent (e.g., a steroid) to the target implant site 102 to reduce inflammation that may be caused by contact with the second electrode 226. In some examples, the therapeutic agent delivery module 307 can be a monolithic controlled release device (MCRD). In other examples, the therapeutic agent delivery module 307 may include a telescopic cylindrical structure disposed in a recess defined in or by the feedthrough assembly 306 and the second electrode 226. The telescopic therapeutic agent delivery module 307 can be configured to be pushed out of the feedthrough assembly 306 and / or retracted into the feedthrough assembly.

[0049] The housing 202 may define the body 201 and one or more features (eg, the groove 312, the opening 314, etc.) disposed on the body 201. Figure 3 3, the reference electrode 218 may be, for example, a conductive strip that is removably secured to the outer surface of the housing 202 via a pin 310. A portion of the outer surface of the housing 202 may have a smaller outer diameter so that when the reference electrode 218 is secured to the housing 202, the reference electrode 218 is flush with the outer surface of the housing 202. The opening 314 may be configured to receive the pin 308 and may be aligned with the opening 317 on the EIA 204 to allow the pin 308 to enter the opening 314 and the opening 317 and secure the EIA 204 to the housing 202. The EIA 204 may be removed from the housing 202 by removing the pin 308 from the opening 314 and the opening 317.

[0050] Figure 4 It is shown FIG. 2A to FIG. 2B Conceptual diagram of EIA 204. Figure 4 304, the cannula 301 and the recess 304 can be disposed on the same reference plane (e.g., along the longitudinal axis 212). In other examples, the cannula 301 and the recess 304 can be disposed on different reference planes and / or not disposed along the longitudinal axis 212. The proximal portion 302 of the EIA 204 can define a channel 404 extending proximally from the cap 305 to the proximal end of the proximal portion 302. The channel 404 can be configured to retain the proximal portion 316 of a feedthrough assembly (e.g., feedthrough assembly 303, feedthrough assembly 306) disposed within the EIA 204.

[0051] The cannula 301 can taper to a distal end 402 of the cannula 301. In some examples, such as Figure 4, distal end 402 may be chamfered, for example, to prevent distal end 402 from further piercing and / or penetrating tissue. The outer surface of distal end 402 may have a smaller radius of curvature than the proximal end of first elongated structure 210. In other examples, the outer surface of distal end 402 may have the same radius of curvature as the proximal end of first elongated structure 210.

[0052] Figure 5 1 is a conceptual diagram of an IMD 110 implanted at a target implant site 102. The rake teeth 208 may define a deformable preset curvature that is configured to position the small wire 220, the electrode 222, and the electrode 226 at a selected tissue at the target implant site 102. The target implant site 102 includes a portion of the right atrium RA wall, such as the atrioventricular septum having an atrial surface 502 and a ventricular surface 506. In some examples, the target implant site may include Koch's triangle or other locations within the heart 104, such as at least one of the atrial septum or the ventricular septum. In other examples, the target implant site 102 may include other tissue in the patient's body. When deployed at the target implant site 102, the rake teeth 208 may have a deployment stiffness that enables the corresponding rake teeth 208 (e.g., penetrator rake teeth 208A, support rake teeth 208B, etc.) to penetrate the selected tissue at the target implant site 102. For example, the IMD 110 may be secured at the target implantation site 102 by the rakes 208 of the fixation member 203 penetrating the myocardium (such as the pectinate muscle layer). The rakes 208 may be configured to pass through the distal opening 108 ( Figure 1 ) is released when the spring loading is deployed outward, allowing the free distal ends of the rake teeth 208 (e.g., the free distal ends 223 of the penetrator rake teeth 208A) to penetrate the myocardium. It should be noted that alternative suitable implantation sites for the fixation member 203 can be along any suitable surface of the heart or other tissue in the patient's body. By controlling the deployment stiffness, the rake teeth 208 can have improved tissue fixation, including control of the penetration depth and the amount of tissue engagement in the lateral direction.

[0053] The EIA 204 may operate in conjunction with the rake 208. For example, the EIA 204 (e.g., the second elongated structure 224 of the EIA 204) may be configured to control the tissue penetration depth X of the penetrator rake 208A. The depth X may include the distance between the sharp distal tip of the penetrator rake 208A and the distal end 228 of the second elongated structure 224, and / or the length of the distal segment of the penetrator rake 208A, the small wire 220, and / or the first elongated structure 210 that penetrates the tissue. In some examples, the tissue penetration depth X of the penetrator rake 208A may be in the range of about 1 millimeter (mm) to about 20 mm, such as in the range of about 4 mm to about 10 mm. The EIA 204 may control the tissue penetration depth by contacting the tissue and resisting further penetration of the penetrator rake 208A. In such an example, the tissue penetration depth X of the penetrator rake 208A may be in the range of about 4 mm to about 10 mm.

[0054] IMD 110 may be implanted at target implant site 102 such that first electrode 222 and second electrode 226 are in contact with selected tissue. When positioned in such a manner, first electrode 222 and second electrode 226 of mini-lead 220 may function in conjunction for bipolar pacing and sensing, and / or first electrode 222 and second electrode 226 may each function individually with return electrode 218 for pacing and sensing of different selected tissues. For example, first electrode 222 of mini-lead 220 may pace and / or sense ventricular tissue, and second electrode 226 may pace and / or sense atrial tissue.

[0055] Figure 6 1 is a conceptual diagram of a partially broken-away section of an exemplary medical device system 100 including a delivery tool 106 and an IMD 110. For illustrative purposes, the distal end of the delivery tool 106 is enlarged relative to the handle 602. Figures 2A to 5 The medical device system 100 is described using the fixation component 203 , but in other examples, the medical device system 100 may include other fixation components.

[0056] During use, the IMD 110 can be loaded into the delivery tool 106 for deployment to a target implantation site (e.g., the target implantation site 102). The delivery tool 106 can include a handle 602, an elongated outer member 610, and an elongated inner member 612 extending within a lumen 616 of the outer member 610. The outer member 610 can include a distal end 614 configured to engage the IMD 110 by abutting the proximal portion 214 of the body 201 (e.g., as shown in a cutaway cross-section). The entire IMD 110 can be loaded within a tubular sidewall 618 that defines, for example, a distal portion of the outer member lumen 610 already loaded therein by pulling the IMD 110 through the lumen distal opening 108 with the body proximal portion 214 leading. In some examples, when the IMD 110 is loaded into the lumen 616, the inner surface 620 of the tubular sidewall 618 may engage the tines 208 of the fixed member 203 to deform the tines 208 (as per arrow L) and then maintain each of the tines 208 of the loaded IMD 110 in a deformed configuration, such as a spring-loaded configuration.

[0057] Handle 602 can be configured to control movement of delivery tool 106 and / or deployment of IMD 110. A clinician can advance delivery tool 106 through the patient's vasculature, for example, from a femoral or jugular vein access point and through the IVC or SVC ( Figure 1 ) to position the medical device system 100. The delivery tool 106 may include an articulation feature to facilitate navigation of the distal portion of the delivery tool 106. For example, the inner member 612 of the delivery tool 106 may include a pull wire assembly (not shown) integrated into the inner member and coupled to another control member 604 of the handle 602 that, when moved according to arrow A, causes the inner member 612 and the outer member 610 to bend along their distal portions.

[0058] In some examples, the proximal end of the outer member 610 can be coupled to the control member 606 of the handle 602 so that the entire outer member 610 can be moved relative to the inner member 612 via the control member 606. For example, when positioning the medical device system 100 near the target implantation site 102 ( Figure 1), the clinician can retract the outer member 610 relative to the IMD 110 and the inner member 612 as indicated by arrow W, thereby releasing the spring-loaded fixation component 203 to deploy the IMD 110 outward through the distal opening 108, so that the rake teeth 208 engage the selected tissue to secure the IMD 110 at the implantation site. Additionally, or alternatively, the delivery tool 106 can be configured such that the clinician can push the inner member 612 relative to the outer member 610 to push the IMD 110 outward through the distal opening 108 for deployment. The length of the outer member 610 between the handle 602 and the distal opening 108 can be between about 100 cm and about 120 cm.

[0059] The penetrator rake 208A may be configured to penetrate or cut selected tissue to form a puncture. The EIA 204 may be configured to protect the small wire 220 during deployment. In some examples where the first electrode 222 is molded into the EIA 204, the EIA 204 may protect the first electrode 222 and the second electrode 226 during deployment. In some examples, during deployment from the delivery tool 106, the penetrator rake 208A may initially penetrate the selected tissue of the atrial surface 502 to form a puncture. Moreover, the EIA 204 (e.g., the cannula 301 of the first elongated structure 210) may push the small wire 220 toward the penetrator rake 208A, thereby guiding the first elongated structure 210 and the small wire 220 into the puncture. For example, the first elongated structure 210 may be configured to push the small wire 220 toward the penetrator rake 208A by applying a force to the small wire 220 in the direction of the penetrator rake 208A during and / or after deployment. By pushing the small wire 220 toward the penetrator rake 208A, the EIA 204 can reduce undesired displacement of the small wire 220 (e.g., relative to the penetrator rake 208A) and / or reduce mechanical damage to the small wire 220 (e.g., as the small wire 220 passes out of the delivery tool 106). In other examples where the first electrode 222 is molded into the first elongated structure 210, the first elongated structure 210 can be shaped to place the first electrode 222 near the distal end 223 of the penetrator rake 208A, for example, to guide the first electrode 222 and the first elongated structure 210 into the puncture.

[0060] As the fixation member 203 is further deployed, the penetrator rake 208A may return from the deployed configuration, e.g. Figure 3208A reaches a selected tissue penetration depth, the EIA 204 can begin to contact the tissue and resist further tissue penetration. When in the deployed configuration, the small wire 220 can extend in the distal direction between the penetrator rake 208A and the first elongated structure 210. In this way, the small wire 220 can extend from the distal portion 216 of the body 201 of the IMD 110 to reach a selected target tissue, such as tissue near the ventricular surface 506. In a similar manner, the second electrode 226 can be pushed against the tissue at the atrial surface 502 by the EIA 204 and optionally the penetrator rake 208A and the support rake 208B. In this way, the IMD 110 can be configured to penetrate the atrioventricular septum to achieve pacing and / or sensing at the ventricular surface 506 via the first electrode 222 and pacing and / or sensing at the atrial surface 502 via the second electrode 226.

[0061] In some examples, the deflection stiffness of the rake teeth 208 can enable a clinician to confirm that the rake teeth 208 are adequately secured to the patient's tissue after deployment at the target implant site 102. For example, a pull test or a drag test can be performed under fluoroscopy to confirm that the rake teeth 208 have engaged the tissue, thereby confirming proper implantation of the IMD 110. The pull test or the drag test can include the clinician pulling or dragging the deployed IMD 110 and observing the movement of the rake teeth 208 to determine whether the rake teeth 208 are engaged in the tissue, such as the rake teeth 208 embedded in the tissue deflect or bend when the deployed IMD 110 is pulled or dragged. By controlling the deflection stiffness, the rake teeth 208 can have improved flexibility that enables the clinician to more easily confirm tissue engagement.

[0062] IMD 110 may be manufactured using any suitable techniques. Figure 7 is a flow chart illustrating an exemplary method of manufacturing IMD 110. Although reference is made to Figures 2A to 5 The IMD 110 shown in FIG. Figure 7 The technique is not shown in FIG. 1 , but the technique can be used to manufacture other IMDs, such as IMDs having other fixed components.

[0063] The manufacturer may form the body 201 extending from the proximal portion 214 to the distal portion 216 along the longitudinal axis 212 (702). In some examples, forming the body 201 may include forming a biocompatible and biostable metal, such as titanium, into a hermetically sealed housing 202. The hermetically sealed housing 202 may then define the body 201 and the interior chamber 315. In some examples, forming the housing 202 may include forming one or more features defined by the housing 202, including, but not limited to, the groove 312, the opening 314, or the retrieval structure 219. Forming the body 201 may include pre-processing or post-processing steps, such as applying a non-conductive coating and defining the return electrode 218 as an uncoated portion of the body 201. In some examples, the return electrode 218 may be manufactured separately and attached to the body 201, for example, to a portion of the proximal portion 214 of the body 201 having a smaller outer diameter. In some examples, body 201 can be sized such that an outer diameter of IMD 110 (eg, an outer diameter of body 201 ) can be between about 10 French (Fr) and about 30 Fr, such as about 20 Fr.

[0064] The manufacturer may attach the EIA 204 to the distal portion 216 of the body 201 (704). The EIA 204 may be attached using one or more known techniques, such as adhesives, fasteners, screws, welding, pins, etc. The EIA 204 may include a proximal portion 302, a cap 305, and an elongated body 205 extending distally from the cap 305. The EIA 204 may be attached to the distal portion 216 of the body 201 such that the elongated body 205 including the first elongated structure 210 and the second elongated structure 224 extends distally from the distal portion 216 of the body 201 along the longitudinal axis 212. The manufacturer may attach the EIA 204 to the body 201 by inserting the proximal portion 302 into the body 201 and securing the proximal portion 302 to the housing 202 defining the body 201 using one or more known techniques.

[0065] In some cases, the EIA 204 may be integrally formed and then attached to the body 201. For example, the EIA 204 may be integrally formed from a polymer by one or more of molding, overmolding, additive manufacturing such as 3D printing, and / or subtractive manufacturing such as machining or etching. In some examples, the EIA 204 is formed to include a first elongated structure 210 extending from the cap 305. The first elongated structure 210 may be formed to define a cannula 301 that extends the length of the first elongated structure to the distal end 402. The first elongated structure 210 may be formed to partially, completely, or not enclose the cannula 301. The EIA 204 may be formed as a single component. In other examples, the components of the EIA 204 (e.g., the elongated body 205, the first elongated structure 210, the second elongated structure 224) may be formed separately and assembled to form the EIA 204.

[0066] In some examples, the EIA 204 is formed to define a recess 304 in the second elongated structure 224 through which the second electrode 226 and the feedthrough assembly 306 can extend. The distal end 228 of the second elongated structure 224 can be configured to contact tissue to control the tissue penetration depth of the penetrator rake 208A. In other examples, the material forming the EIA 204 can be overmolded around the first electrode 222, the second electrode 226, and the corresponding feedthrough assemblies 303 and 306 as part of the process of forming the EIA 204. In such an example, the first elongated structure 210 can be shaped to place the first electrode 222 at the tissue penetration depth of the penetrator rake 208A, for example, without using the small wire 220.

[0067] The manufacturer may form a texture on EIA 204 (e.g., on the outer surface of first elongated structure 210). The manufacturer may use one or more known techniques to produce the texture, including but not limited to no polish or reduced polish on the textured portion of EIA 204, laser etching the textured portion of EIA 204, or etching the textured portion of EIA 204 using one or more other etching techniques.

[0068] The manufacturer may then attach fixation component 203 to body 201 of IMD 110 (706). Fixation component 203 may be attached to body 201 using one or more known techniques, such as adhesives, fasteners, screws, welding, etc. In some examples, fixation component 203 may be formed and then attached to body 201. For example, fixation component 203 may be formed to include base 206 and rakes 208.

[0069] Forming the base 206 may include forming a base having a proximal end and a distal end aligned along the longitudinal axis. The proximal end of the base 206 may be attached to the distal portion 216 of the body 201 or the cap 305 of the EIA 204. Forming the base 206 may include cutting a conduit, such as a metal conduit, a nickel-titanium alloy conduit, or a stainless steel conduit, to define the base 206. Forming the base 206 may include pre-processing steps or post-processing steps, such as grinding, coating, heat treating, or polishing the substrate defining the base 206.

[0070] Forming the rake teeth 208 may include extending the rake teeth 208 from the base 206 and spacing the rake teeth 208 from each other. The rake teeth 208 may include penetrator rake teeth 208A. The penetrator rake teeth 208A may include a proximal section that is attached to the distal portion 216 of the body 201 and extends from the distal end along a first direction. The penetrator rake teeth 208A may also include a curved section that defines a deformable preset curvature of the penetrator rake teeth 208A and extends laterally from the proximal section of the penetrator rake teeth 208A along a second direction and crosses the longitudinal axis 212. The penetrator rake teeth 208A may also include a distal section extending from the curved section of the penetrator rake teeth 208A and terminating at a sharp distal end 223. The sharp distal end 223 may be configured to penetrate tissue (e.g., at the target implantation site 102) to secure the IMD 110 to the tissue.

[0071] In some examples, the base 206 and the rake teeth 208 may be integrally formed. For example, the base 206 and the rake teeth 208 may be integrally formed from a conduit such as a metal conduit, a nickel-titanium alloy conduit, or a stainless steel conduit. In some examples, forming the base 206 and the rake teeth 208 from a single conduit may include removing material from the single conduit to define the base 206 and the rake teeth 208. In some examples, removing material from a single conduit may include one or more of the following: machining, chemical etching, laser etching, stamping, or water cutting. In some examples, forming the rake teeth 208 may include forming one or more cones on one or more of the rake teeth 208. For example, forming the one or more cones may include any other of the above techniques for removing material from a single conduit. In some examples, the one or more cones may be formed when removing material from a single conduit.

[0072] In some examples, forming the teeth 208 may include bending each of the teeth 208 to define one or more curved sections. In some examples, each curve of the teeth 208 and / or each tooth may be bent individually or simultaneously, for example by using a fixture configured to bend one or more curves on one or more of the teeth 208. After the teeth 208 are bent (and held in the bent configuration), forming the teeth 208 may also include heat treating the bent teeth 208 to cause the teeth 208 to remain in the bent configuration. For example, heat treating the bent teeth 208 may cause the microstructure of the material of the teeth 208 to adopt a configuration such that the rest state of the teeth 208 (e.g., without the application of external forces) is the bent configuration.

[0073] In some examples, forming the tines 208 may further include sharpening distal ends of the tines 208. For example, forming the penetrator tines 208A may include laser etching distal ends 223 of the penetrator tines 208A to define an infinitely or nearly infinitely sharp pointed edge (within tolerances of common manufacturing processes).

[0074] In some examples, forming the tines 208 may also include forming one or more cuts, engravings, embossings, or other variations in thickness of the tines 208. For example, the cuts, engravings, embossings, or other variations in thickness of the tines 208 may be formed by laser etching or chemical etching.

[0075] The following examples illustrate exemplary subject matter described herein.

[0076] Embodiment 1: An implantable medical device (IMD), comprising: a device body extending along a longitudinal axis from a proximal portion to a distal portion; a fixation component comprising a penetrator rake extending away from the distal portion of the device body and configured to penetrate tissue; and an electrode interface assembly comprising: a small wire extending away from the distal portion of the device body; an elongated body extending away from the distal portion of the device body, the elongated body defining a recess and a groove, wherein the groove is configured to accommodate the small wire; and an electrode extending from the elongated body and disposed in the recess, wherein the electrode is configured to form a circuit with the tissue, and wherein the elongated body is configured to place the electrode in contact with the tissue.

[0077] Example 2: An IMD according to Example 1, wherein the electrode includes a second electrode and the circuit includes a second circuit, and wherein the small wire also includes: a slender member extending away from the distal portion of the device body and extending to the sharp distal end of the penetrator rake; and a first electrode disposed on the slender member, the first electrode being configured to form a first circuit with the tissue.

[0078] Embodiment 3: An IMD according to Embodiment 2, wherein when the IMD is implanted in an atrium of a patient's heart, the first electrode is configured to deliver stimulation therapy to a ventricle of the heart or to sense cardiac signals from the ventricle, and the second electrode is configured to deliver stimulation therapy to the atrium or to sense cardiac signals from the atrium.

[0079] Embodiment 4: The IMD of any one of Embodiments 2 and 3, wherein each of the first electrode and the second electrode is connected to an electronic circuit disposed within the device body of the IMD via a corresponding feedthrough component of a plurality of feedthrough components.

[0080] Embodiment 5: The IMD of Embodiment 4, wherein the plurality of feedthrough components are disposed on a same reference plane parallel to the longitudinal axis.

[0081] Embodiment 6: The IMD of any one of Embodiments 4 and 5, wherein each feedthrough component of the plurality of feedthrough components is electrically isolated from any other feedthrough component of the plurality of feedthrough components.

[0082] Embodiment 7: The IMD of any one of Embodiments 4 to 6, wherein a feedthrough component of the plurality of feedthrough components is concentric with the device body.

[0083] Embodiment 8: The IMD of any one of Embodiments 4 to 6, wherein each feedthrough assembly of the plurality of feedthrough assemblies is equidistant from a radial center of the device body.

[0084] Embodiment 9: The IMD according to any one of embodiments 1 to 8, further comprising a return electrode disposed on the device body.

[0085] Embodiment 10: The IMD of any one of Embodiments 1 to 9, wherein the electrode further comprises a therapeutic substance dispensing device disposed within an aperture defined by the electrode.

[0086] Embodiment 11: The IMD of any one of embodiments 1 to 10, wherein the therapeutic substance dispensing device comprises a monolithic controlled release device.

[0087] Embodiment 12: The IMD of Embodiment 11, wherein the therapeutic substance dispensing device is configured to extend away from the corresponding feedthrough assembly of the electrode and toward a distal end of the electrode.

[0088] Embodiment 13: An IMD according to any one of Embodiments 1 to 12, wherein the slender body of the electrode interface assembly includes a texture disposed at least partially around an outer surface of the slender body, and wherein the texture is configured to increase adhesion between the outer surface of the slender body and the tissue.

[0089] Embodiment 14: The IMD of any of Embodiments 1-13, wherein the shape of the elongated body is configured to control the depth of penetration of the penetrating rakes into the tissue.

[0090] Embodiment 15: The IMD of any one of Embodiments 1 to 14, wherein the device body of the IMD comprises a housing defining an internal chamber, and wherein the proximal portion of the electrode interface assembly is secured within the internal chamber.

[0091] Embodiment 16: The IMD of Embodiment 15, wherein the electrode interface assembly is removably secured within the inner chamber.

[0092] Embodiment 17: The IMD of Embodiment 15, wherein the electrode interface assembly is permanently secured to the housing.

[0093] Embodiment 18: An IMD according to any one of embodiments 1 to 17, wherein the fixation component also includes a base having a proximal end and a distal end aligned along the longitudinal axis, wherein the proximal end of the base is attached to the distal portion of the device body, and wherein the penetrator rake is configured to extend away from the distal end of the base.

[0094] Embodiment 19: An IMD according to any one of embodiments 1 to 18, wherein the fixation component further comprises one or more support tines extending from the distal portion of the device body, wherein when the one or more support tines are in an expanded configuration, the one or more support tines are configured to be fixed to the tissue.

[0095] Embodiment 20: The IMD of any of Embodiments 1-19, wherein the penetrator rakes are configured to attach the IMD to the tissue.

[0096] Embodiment 21: The IMD of any of Embodiments 1-20, wherein the tissue comprises myocardial tissue, and wherein the penetrator rakes are configured to penetrate at least one of the atrial septum, the ventricular septum, or the atrioventricular septum.

[0097] Embodiment 22: An implantable medical device (IMD), comprising: a device body extending from a proximal portion to a distal portion along a longitudinal axis; a fixation component comprising: a penetrator rake extending away from the distal portion of the device body and configured to penetrate tissue; an electrode interface assembly, the electrode interface assembly comprising: an elongated body extending from the distal portion of the device body, the elongated body defining a first recess and a second recess; a first electrode extending away from the electrode interface assembly, the first electrode being disposed within the first recess; and a second electrode extending away from the electrode interface assembly, the second electrode being disposed within the second recess, wherein the first electrode is configured to form a first circuit with the tissue, wherein the second electrode is configured to form a second circuit with the tissue, and wherein the elongated body is configured to place the first electrode and the second electrode in contact with the tissue.

[0098] Embodiment 23: The IMD of Embodiment 22, wherein the first electrode is farther from the distal portion of the device body than the second electrode.

[0099] Example 24: An IMD according to any one of Examples 22 and 23, wherein when the IMD is implanted in an atrium of a patient's heart, the first electrode is configured to deliver stimulation therapy to a ventricle of the heart or sense cardiac signals from the ventricle, and the second electrode is configured to deliver stimulation therapy to an atrium or sense cardiac signals from the atrium.

[0100] Embodiment 25: The IMD of any one of Embodiments 22 to 24, wherein each of the first electrode and the second electrode is connected to electronic circuitry disposed within the device body via a corresponding feedthrough component of a plurality of feedthrough components.

[0101] Embodiment 26: The IMD of Embodiment 25, wherein the plurality of feedthrough assemblies are disposed on a same reference plane parallel to the longitudinal axis.

[0102] Embodiment 27: The IMD of any of Embodiments 25 and 26, wherein each feedthrough component of the plurality of feedthrough components is electrically isolated from any other feedthrough component of the plurality of feedthrough components.

[0103] Embodiment 28: The IMD of any one of Embodiments 25 to 27, wherein a feedthrough component of the plurality of feedthrough components is concentric with the device body.

[0104] Embodiment 29: The IMD of any one of Embodiments 25 to 27, wherein each feedthrough assembly of the plurality of feedthrough assemblies is equidistant from a radial center of the device body.

[0105] Embodiment 30: The IMD of any one of Embodiments 22 to 29, further comprising a return electrode disposed on the device body.

[0106] Embodiment 31: The IMD of any one of Embodiments 22 to 30, wherein one or more of the first electrode or the second electrode comprises a therapeutic substance dispensing device disposed within a corresponding orifice defined by the first electrode or by the second electrode.

[0107] Embodiment 32: The IMD of Embodiment 31, wherein the therapeutic substance dispensing device comprises a monolithic controlled release device.

[0108] Embodiment 33: An IMD according to any one of Embodiments 22 to 32, wherein the slender body of the electrode interface assembly includes a texture disposed at least partially around an outer surface of the slender body, wherein the texture is configured to increase adhesion between the outer surface of the slender body and the tissue.

[0109] Embodiment 34: The IMD of any of Embodiments 22-33, wherein the shape of the elongated body is configured to control the depth of penetration of the penetrating rakes into the tissue.

[0110] Embodiment 35: The IMD of any of Embodiments 22 to 34, wherein the device body comprises a housing defining an internal chamber, and wherein the proximal portion of the electrode interface assembly is secured within the internal chamber.

[0111] Embodiment 36: The IMD of Embodiment 35, wherein the electrode interface assembly is removably secured within the inner chamber.

[0112] Embodiment 37: The IMD of Embodiment 35, wherein the electrode interface assembly is permanently secured to the housing.

[0113] Embodiment 38: An IMD according to any one of Embodiments 22 to 37, wherein the fixation component further comprises a base having a proximal end and a distal end aligned along the longitudinal axis, wherein the proximal end of the base is attached to the distal portion of the device body, and wherein the penetrator rake is configured to extend away from the distal end of the base.

[0114] Embodiment 39: An IMD according to any one of Embodiments 22 to 38, wherein the fixation component further comprises one or more support tines extending from the distal portion of the device body, wherein when in the expanded configuration, the one or more support tines are configured to be fixed to the tissue.

[0115] Embodiment 40: The IMD of any of Embodiments 22-39, wherein the penetrator rakes are configured to attach the IMD to the tissue.

[0116] Embodiment 41: The IMD of any of Embodiments 22-40, wherein the tissue comprises myocardial tissue, and wherein the penetrator rake is configured to penetrate at least one of the atrial septum, the ventricular septum, or the atrioventricular septum.

[0117] Embodiment 42: A medical device system, the medical device system comprising: an implantable medical device (IMD), the IMD comprising: a device body extending from a proximal portion to a distal portion along a longitudinal axis; a small wire extending away from the distal portion of the device body, the small wire comprising a first electrode disposed on the distal end of the small wire; a fixing component comprising a penetrator rake extending from the distal portion of the device body and configured to penetrate tissue; an elongated body extending from the distal portion of the device body, the elongated body defining a groove configured to receive the small wire; a second electrode disposed within a recess of the elongated body, wherein the elongated body is configured to place the second electrode in contact with the tissue; and a delivery tool comprising a tubular side wall defining a lumen into which the IMD can be loaded, wherein the lumen has a distal opening through which the IMD can be deployed.

[0118] Embodiment 43: The medical device system according to Embodiment 40, wherein the first electrode is configured to form a first circuit with the tissue, and wherein the second electrode is configured to form a second circuit with the tissue.

[0119] Example 44: A medical device system according to any one of Examples 42 and 43, wherein when the IMD is implanted in an atrium of a patient's heart, the first electrode is configured to deliver stimulation therapy to a ventricle of the heart or sense cardiac signals from the ventricle, and the second electrode is configured to deliver stimulation therapy to the atrium or sense cardiac signals from the atrium.

[0120] Embodiment 45: A medical device system according to any one of Embodiments 42 to 44, wherein the first electrode is farther away from the distal portion of the device body than the second electrode.

[0121] Embodiment 46: A medical device system according to any one of Embodiments 42 to 45, wherein each of the first electrode and the second electrode is connected to an electronic circuit disposed within the device body via a corresponding feedthrough component among a plurality of feedthrough components.

[0122] Embodiment 47: The medical device system of Embodiment 46, wherein the plurality of feedthrough assemblies are disposed on a same reference plane along the longitudinal axis.

[0123] Embodiment 48: The medical device system of any of Embodiments 46 and 47, wherein each feedthrough assembly in the plurality of feedthrough assemblies is electrically isolated from any other feedthrough assembly in the plurality of feedthrough assemblies.

[0124] Embodiment 49: A medical device system according to any one of Embodiments 46 to 48, wherein a feedthrough assembly among the plurality of feedthrough assemblies is concentric with the device body.

[0125] Embodiment 50: A medical device system according to any one of Embodiments 46 to 48, wherein each feedthrough assembly of the plurality of feedthrough assemblies is equidistant from a radial center of the device body.

[0126] Embodiment 51: According to any one of Embodiments 42 to 50, the IMD further includes a return electrode disposed on the device body.

[0127] Embodiment 52: The medical device system of any one of Embodiments 42 to 51, wherein the second electrode further comprises a therapeutic substance dispensing device disposed within an orifice defined by the second electrode.

[0128] Embodiment 53: The medical device system of Embodiment 52, wherein the therapeutic substance dispensing device comprises a monolithic controlled release device.

[0129] Embodiment 54: The medical device system of Embodiment 52, wherein the therapeutic substance dispensing device is configured to extend from a corresponding feedthrough assembly of the second electrode toward a distal end of the second electrode.

[0130] Embodiment 55: A medical device system according to any one of Embodiments 42 to 54, wherein the slender body includes a texture disposed at least partially around an outer surface of the slender body, wherein the texture is configured to increase adhesion between the outer surface of the slender body and the tissue.

[0131] Embodiment 56: The medical device system of any one of Embodiments 42 to 55, wherein the shape of the elongated body is configured to control the depth of penetration of the penetrating rake into the tissue.

[0132] Embodiment 57: The medical device system of Embodiment 56, wherein the first electrode disposed on the distal end of the miniature guidewire is positioned to penetrate through the puncture created in the tissue by the penetrating rake.

[0133] Embodiment 58: According to any one of embodiments 42 to 57, the medical device system, wherein the device body includes a shell that defines an internal chamber of the device body, and wherein the proximal portion of the electrode interface assembly is fixed within the internal chamber.

[0134] Embodiment 59: The medical device system of Embodiment 58, wherein the electrode interface assembly is removably secured within the inner chamber.

[0135] Embodiment 60: The medical device system of Embodiment 58, wherein the electrode interface assembly is permanently fixed to the housing.

[0136] Example 61: A medical device system according to any one of Examples 42 to 60, wherein the fixing component also includes a base having a proximal end and a distal end aligned along the longitudinal axis, wherein the proximal end of the base is attached to the distal portion of the device body, and wherein the penetrator rake is configured to extend away from the distal end of the base.

[0137] Embodiment 62: According to any one of embodiments 42 to 61, the fixation component further includes one or more support tines extending from the distal end of the base, wherein when in the expanded configuration, the one or more support tines are configured to be fixed to the tissue.

[0138] Embodiment 63: The medical device system of any one of Embodiments 42-62, wherein the penetrator rake is configured to attach the IMD to the tissue.

[0139] Example 64: The medical device system of any one of Examples 42 to 63, wherein the tissue comprises myocardial tissue, and wherein the penetrator rake is configured to penetrate at least one of the atrial septum, the ventricular septum, or the atrioventricular septum.

[0140] Embodiment 65: The medical device system of any of Embodiments 42-64, wherein the penetrator tines are retainable in a deformed configuration by the delivery tool when the IMD is loaded into the lumen of the delivery tool.

[0141] Example 66: The medical device system of Example 65, wherein the penetrator rakes are configured to expand to an undeformed configuration and penetrate the tissue when the IMD is deployed from the delivery tool.

[0142] Embodiment 67: The medical device system of any one of Embodiments 42-66, wherein the delivery tool is configured to deploy the IMD by pushing the IMD distally out of the lumen of the delivery tool.

[0143] Example 68: The medical device system of any one of Examples 42-67, wherein the delivery tool is configured to deploy the IMD by retracting the delivery tool proximally relative to the IMD.

[0144] Example 69: A method of forming an implantable medical device (IMD), the method comprising forming a device body of the IMD, wherein the device body extends from a proximal portion to a distal portion along a longitudinal axis; attaching an electrode interface assembly to the distal portion of the device body, wherein the electrode interface assembly comprises: a small wire extending away from the distal portion of the device body of the IMD; an elongated body extending away from the distal portion of the device body, the elongated body defining a groove configured to receive the small wire; and an electrode extending away from the distal portion of the device body and disposed within a recess in the elongated body, wherein the elongated body is configured to place the electrode in contact with the tissue; and attaching a fixation component to the distal portion of the device body, wherein the fixation component comprises a penetrator rake extending from the distal portion of the device body and configured to penetrate the tissue.

[0145] Example 70: A method according to Example 69, wherein the electrode includes a second electrode, and wherein the small wire includes: a slender member extending from the distal portion of the device body to the sharp distal end of the penetrator rake; and a first electrode disposed on the distal end of the slender member.

[0146] Example 71: A method according to Example 70, wherein the IMD is configured to be implanted in an atrium of a patient's heart, wherein the first electrode is configured to deliver stimulation therapy to a ventricle of the heart or sense cardiac signals from the ventricle, and wherein the second electrode is configured to deliver stimulation therapy to the atrium or sense cardiac signals from the atrium.

[0147] Embodiment 72: The method according to any one of Embodiments 70 and 71, further comprising connecting each of the first electrode and the second electrode to an electronic circuit disposed within the device body via a corresponding feedthrough component among a plurality of feedthrough components.

[0148] Embodiment 73: A method according to Embodiment 72, wherein the plurality of feed-through components are arranged on a same reference plane parallel to the longitudinal axis.

[0149] Embodiment 74: The method of any one of Embodiments 72 and 73, wherein each feedthrough component of the plurality of feedthrough components is electrically isolated from any other feedthrough component of the plurality of feedthrough components.

[0150] Embodiment 75: A method according to any one of Embodiments 72 to 74, wherein a feedthrough component among the plurality of feedthrough components is concentric with the device body.

[0151] Embodiment 76: A method according to any one of Embodiments 72 to 74, wherein each feedthrough assembly of the plurality of feedthrough assemblies is equidistant from the radial center of the device body.

[0152] Embodiment 77: According to any one of embodiments 69 to 76, the method also includes attaching a return electrode to the device body.

[0153] Embodiment 78: The method of any one of Embodiments 69 to 77, wherein the electrode further comprises a therapeutic substance dispensing device disposed within the orifice defined by the first electrode.

[0154] Embodiment 79: The method of Embodiment 78, wherein the therapeutic substance dispensing device comprises a monolithic controlled release device.

[0155] Embodiment 80: The method of Embodiment 78, wherein the therapeutic substance dispensing device is configured to extend from a corresponding feedthrough assembly of the first electrode toward a distal end of the first electrode.

[0156] Embodiment 81: According to any one of embodiments 69 to 80, the method also includes applying a texture at least partially around the outer surface of the slender body of the electrode interface assembly, wherein the texture is configured to increase adhesion between the outer surface of the slender body and the tissue.

[0157] Embodiment 82: The method of Embodiment 81, wherein applying the texture comprises forming one or more indentations in the outer surface of the elongated body using an etching technique.

[0158] Embodiment 83: The method of any one of Embodiments 69 to 82, further comprising molding a polymer into the elongated body having a predetermined shape.

[0159] Embodiment 84: The method of Embodiment 83, wherein the shape of the elongated body is configured to control the depth of penetration of the penetrating rake into the tissue.

[0160] Embodiment 85: A method according to any one of Embodiments 69 to 84, wherein forming the device body includes shaping the shell of the IMD to define an internal chamber, and wherein attaching the electrode interface assembly to the distal portion of the device body includes securing the proximal portion of the electrode interface assembly within the internal chamber.

[0161] Embodiment 86: A method according to any one of embodiments 69 to 85, wherein the fixation component further includes one or more support tines extending from the distal portion of the device body, wherein when in the expanded configuration, the one or more support tines are configured to be fixed to the tissue.

[0162] Embodiment 87: The method of Embodiment 86, wherein the penetrator rake is configured to attach the IMD to the tissue.

[0163] Example 88: The method of any one of Examples 69 to 87, wherein the tissue comprises myocardial tissue, and wherein the penetrator rake is configured to penetrate at least one of the atrial septum, the ventricular septum, or the atrioventricular septum.

[0164] Various examples of the disclosure have been described. Any combination of the described systems, operations, or functions is contemplated. These and other examples are within the scope of the following claims.

Claims

1. An implantable medical device (IMD), comprising: a device body extending along a longitudinal axis from a proximal portion to a distal portion; a fixation component including penetrator tines extending away from the distal portion of the device body and configured to penetrate tissue; and An electrode interface assembly, the electrode interface assembly comprising: a small guide wire extending away from the distal portion of the device body; an elongated body extending away from the distal portion of the device body, the elongated body defining a recess and a groove, wherein the groove is configured to receive the small guidewire; and An electrode extends from the elongated body and is disposed within the recess, wherein the electrode is configured to form an electrical circuit with the tissue, and wherein the elongated body is configured to place the electrode in contact with the tissue.

2. The IMD of claim 1 , wherein the electrode comprises a second electrode, and the circuit comprises a second circuit, and wherein the small lead further comprises: an elongated member extending away from the distal portion of the device body and to the sharpened distal ends of the penetrator tines; and A first electrode is disposed on the elongated member, the first electrode being configured to form a first electrical circuit with the tissue.

3. An IMD according to claim 2, wherein when the IMD is implanted in an atrium of a patient's heart, the first electrode is configured to deliver stimulation therapy to a ventricle of the heart or sense cardiac signals from the ventricle, and the second electrode is configured to deliver stimulation therapy to the atrium or sense cardiac signals from the atrium. 4 . The IMD of claim 2 , wherein each of the first electrode and the second electrode is connected to an electronic circuit disposed within the device body of the IMD via a corresponding feedthrough component of a plurality of feedthrough components. The IMD of claim 4 , wherein the plurality of feedthrough assemblies are disposed on a same reference plane parallel to the longitudinal axis.

6. The IMD of any one of claims 4 and 5, wherein each feedthrough component of the plurality of feedthrough components is electrically isolated from any other feedthrough component of the plurality of feedthrough components.

7. The IMD of any one of claims 4 to 6, wherein a feedthrough component of the plurality of feedthrough components is concentric with the device body.

8. The IMD of any one of claims 4 to 6, wherein each feedthrough assembly of the plurality of feedthrough assemblies is equidistant from a radial center of the device body.

9. The IMD of any one of claims 1 to 8, further comprising a return electrode disposed on the device body.

10. The IMD of any one of claims 1 to 9, wherein the electrode further comprises a therapeutic substance dispensing device disposed within an aperture defined by the electrode.

11. The IMD of any one of claims 1 to 10, wherein the therapeutic substance dispensing device comprises a monolithic controlled release device.

12. The IMD of claim 11, wherein the therapeutic substance dispensing device is configured to extend away from a corresponding feedthrough assembly of the electrode and toward a distal end of the electrode.

13. An IMD according to any one of claims 1 to 12, wherein the slender body of the electrode interface assembly includes a texture disposed at least partially around an outer surface of the slender body, and wherein the texture is configured to increase adhesion between the outer surface of the slender body and the tissue.

14. The IMD of any one of claims 1 to 13, wherein the shape of the elongated body is configured to control the depth of penetration of the penetrating rakes into the tissue.

15. The IMD of any one of claims 1 to 18, wherein the fixation component further comprises one or more support tines extending from the distal portion of the device body, wherein the one or more support tines are configured to be fixed to the tissue when the one or more support tines are in an expanded configuration.

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