Fixation component for multi-electrode implantable medical device

Abstract

An exemplary fixation component for an implantable medical device (IMD) includes a base and tines extending from the base and spaced apart from one another. The tines include a penetrator tine and a protector tine. The penetrator tine includes a curved section defining a deformable preset curvature extending laterally from a proximal section fixed to the base to a distal section across a longitudinal axis of the fixation component, the distal section terminating in a sharp distal end configured to penetrate tissue to form a puncture. The protector tine includes a curved section defining a deformable preset curvature extending outward from the longitudinal axis from a proximal section fixed to the base to a distal section, the distal section terminating in a non-sharp distal end configured to pass through the puncture.

Description

Technical Field

[0001] This disclosure relates to medical device systems, such as relatively compact implantable medical devices and associated fixation components. Background Technology

[0002] In some examples, implantable pacemakers include a pulse generator device to which one or more flexible, elongated leads are coupled. The pulse generator device can be implanted in a subcutaneous pocket remote from the heart, and each of the one or more leads extends from the pulse generator device to a corresponding electrode, is coupled to the electrode, and is positioned at a pacing site in the endocardium or epicardium. Mechanical and / or MRI compatibility issues may be associated with the elongated leads. Relatively compact implantable medical devices (IMDs) have been developed that are fully contained within a relatively compact pocket, and are configured integrally for implantation at a pacing site close to, for example, within the ventricle. Summary of the Invention

[0003] This disclosure describes fixation components, such as those for IMDs, including relatively compact IMDs. An exemplary fixation component has multiple rake teeth, including penetrator rake teeth and protector rake teeth. The penetrator rake teeth and the protector rake teeth can be cooperating with one or more elongated electrodes (e.g., small leads) mounted near the distal end of the IMD. For example, the penetrator rake teeth and the protector rake teeth can define an exoskeleton for cardiac pacing electrodes. Compared to fixation components without the described penetrator rake teeth and / or protector rake teeth, these multiple rake teeth, when deployed, provide improved tissue fixation, improved penetration to a selected depth within the tissue, improved electrode contact with the selected tissue, and / or improved tissue disengagement. In this way, the fixation component can facilitate the implantation and / or removal of the IMD.

[0004] In some examples, the fixation component for an implantable medical device (IMD) may include a base and a plurality of rake teeth. The base defines a longitudinal axis of the fixation component and is fixedly attached to the IMD, which has proximal and distal ends aligned along the longitudinal axis. The plurality of rake teeth extend from the base and are spaced apart from each other. The plurality of rake teeth includes a penetrator rake tooth and a protector rake tooth. The penetrator rake tooth includes: a proximal segment of the penetrator rake tooth, which is fixedly attached to the base and extends from the base in a first direction; a curved segment of the penetrator rake tooth, which defines a deformable predetermined curvature of the penetrator rake tooth and extends laterally from the proximal segment of the penetrator rake tooth and across the longitudinal axis; and a distal segment of the penetrator rake tooth, which extends from the curved segment of the penetrator rake tooth and terminates at a sharp distal end, wherein the sharp distal end is configured to pierce tissue. The protector rake tooth includes: a proximal section of the protector rake tooth, the proximal section of the protector rake tooth being fixedly attached to a base and extending from the base in a first direction; a curved section of the protector rake tooth, the curved section of the protector rake tooth defining a deformable predetermined curvature of the protector rake tooth and extending laterally outward from the longitudinal axis from the proximal section of the protector rake tooth; and a distal section of the protector rake tooth, the distal section of the protector rake tooth extending from the curved section of the protector rake tooth and terminating at a non-sharp distal end.

[0005] In some examples, an implantable medical device (IMD) may include a housing extending along a longitudinal axis from a proximal end to a distal end; an elongated miniature wire extending from a proximal end of a miniature wire mounted near the distal end of the housing to a distal end of the miniature wire, wherein the distal end of the miniature wire includes a first electrode; a second electrode mounted near the distal end of the housing; and a fixing member. The fixing member includes a base and a plurality of rake teeth. The base defines the longitudinal axis of the fixing member and is fixedly attached to the IMD, which has proximal and distal ends aligned along the longitudinal axis. The plurality of rake teeth extend from the base and are spaced apart from each other. The plurality of rake teeth includes penetrator rake teeth and protector rake teeth. The penetrator rake tooth includes: a proximal section of the penetrator rake tooth, the proximal section of the penetrator rake tooth being fixedly attached to a base and extending from the base in a first direction; a curved section of the penetrator rake tooth, the curved section of the penetrator rake tooth defining a deformable predetermined curvature of the penetrator rake tooth and extending laterally from the proximal section of the penetrator rake tooth and across a longitudinal axis; and a distal section of the penetrator rake tooth, the distal section of the penetrator rake tooth extending from the curved section of the penetrator rake tooth and terminating at a sharp distal end, wherein the sharp distal end is configured to pierce tissue. The protector rake tooth includes: a proximal section of the protector rake tooth, the proximal section of the protector rake tooth being fixedly attached to a base and extending from the base in a first direction; a curved section of the protector rake tooth, the curved section of the protector rake tooth defining a deformable predetermined curvature of the protector rake tooth and extending laterally outward from the longitudinal axis from the proximal section of the protector rake tooth; and a distal section of the protector rake tooth, the distal section of the protector rake tooth extending from the curved section of the protector rake tooth and terminating at a non-sharp distal end.

[0006] In some examples, the medical device system may include an implantable medical device (IMD) and a delivery tool. The IMD may include a housing extending along a longitudinal axis from a proximal end to a distal end; an elongated miniature wire extending from a proximal end of a miniature wire mounted near the distal end of the housing to a distal end of the miniature wire, wherein the distal end of the miniature wire includes a first electrode; a second electrode mounted near the distal end of the housing; and a fixing member including a base and a plurality of rake teeth, the base being near the distal end of the housing, the plurality of rake teeth being fixedly attached to each other at intervals around the periphery of the distal end of the housing. The delivery tool may include a tubular sidewall defining an interior cavity in which the IMD can be loaded, wherein the interior cavity has a distal opening through which the IMD can be deployed. The plurality of rake teeth of the fixing member include penetrator rake teeth and protector rake teeth. The penetrator rake tooth includes: a proximal section of the penetrator rake tooth, the proximal section of the penetrator rake tooth being fixedly attached to a base and extending from the base in a first direction; a curved section of the penetrator rake tooth, the curved section of the penetrator rake tooth defining a deformable predetermined curvature of the penetrator rake tooth and extending laterally from the proximal section of the penetrator rake tooth and across a longitudinal axis; and a distal section of the penetrator rake tooth, the distal section of the penetrator rake tooth extending from the curved section of the penetrator rake tooth and terminating at a sharp distal end, wherein the sharp distal end is configured to pierce tissue. The protector rake tooth includes: a proximal section of the protector rake tooth, the proximal section of the protector rake tooth being fixedly attached to a base and extending from the base in a first direction; a curved section of the protector rake tooth, the curved section of the protector rake tooth defining a deformable predetermined curvature of the protector rake tooth and extending laterally outward from the longitudinal axis from the proximal section of the protector rake tooth; and a distal section of the protector rake tooth, the distal section of the protector rake tooth extending from the curved section of the protector rake tooth and terminating at a non-sharp distal end.

[0007] In some examples, a method of forming a fixation component for an IMD may include: forming a base defining a longitudinal axis of the fixation component; and forming a plurality of rake teeth extending from the base and spaced apart from each other. The plurality of rake teeth includes penetrator rake teeth and protector rake teeth. The penetrator rake tooth includes: a proximal segment of the penetrator rake tooth, the proximal segment of the penetrator rake tooth being fixedly attached to the base and extending from the base in a first direction; a curved segment of the penetrator rake tooth, the curved segment of the penetrator rake tooth defining a deformable predetermined curvature of the penetrator rake tooth and extending laterally from the proximal segment of the penetrator rake tooth and across the longitudinal axis; and a distal segment of the penetrator rake tooth, the distal segment of the penetrator rake tooth extending from the curved segment of the penetrator rake tooth and terminating at a sharp distal end, wherein the sharp distal end is configured to pierce tissue. The protector rake tooth includes: a proximal section of the protector rake tooth, the proximal section of the protector rake tooth being fixedly attached to a base and extending from the base in a first direction; a curved section of the protector rake tooth, the curved section of the protector rake tooth defining a deformable predetermined curvature of the protector rake tooth and extending laterally outward from the longitudinal axis from the proximal section of the protector rake tooth; and a distal section of the protector rake tooth, the distal section of the protector rake tooth extending from the curved section of the protector rake tooth and terminating at a non-sharp distal end.

[0008] 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

[0009] Figure 1 This is a conceptual diagram illustrating a portion of an exemplary medical device system configured to implant a relatively compact implantable medical device at a target implantation site.

[0010] Figures 2A to 2G It is a conceptual diagram illustrating a relatively compact IMD that includes fixed components.

[0011] Figure 3 It is a diagram illustrating implantation at an exemplary target implantation site. Figures 2A to 2G A conceptual diagram of an exemplary IMD is shown in the image.

[0012] Figure 4A and Figure 4B This is a conceptual diagram illustrating an exemplary fixed component.

[0013] Figures 5A to 5D This is a conceptual diagram illustrating an exemplary fixing component, which includes protector rake teeth having multiple curved sections.

[0014] Figure 6This is a conceptual diagram illustrating an exemplary fixing component, which includes protector rake teeth having multiple curved sections.

[0015] Figure 7A and Figure 7B This is a conceptual diagram illustrating an exemplary fixing component including guide rake teeth.

[0016] Figure 8A and Figure 8B This is a conceptual diagram illustrating an exemplary fixing component including unfolded rake teeth.

[0017] Figure 9 This is a conceptual diagram illustrating a partial cross-section of an exemplary medical device system, including a delivery tool and an IMD.

[0018] Figure 10 This is a flowchart illustrating an exemplary method for manufacturing an exemplary fixed component.

[0019] Figure 11A and Figure 11B This is a conceptual diagram illustrating the distal end of an exemplary corresponding penetrator rake tooth. Detailed Implementation

[0020] This disclosure describes an implantable medical device (IMD) including a fixation component with multiple rake teeth, components of such an IMD, a medical device system including such an IMD, and related technologies. An exemplary IMD may include a housing and one or more elongated miniature wires. The housing extends along a longitudinal axis from a proximal end to a distal end of the housing and may enclose components of the IMD, such as circuitry and a battery. A first elongated miniature wire extends from a proximal end to a distal end of the miniature wire. The proximal end of the first miniature wire is attached to the housing, such as near the distal end of the housing. The distal end of the first miniature wire may include an electrode, such as a first electrode of the IMD. The IMD may include additional electrodes, which may or may not be included as part of the elongated miniature wire extending from the housing of the IMD. The electrodes of the IMD may be configured to sense electrical signals from tissue and / or deliver electrical therapy to tissue.

[0021] An exemplary fixing component for an IMD may include a base and a plurality of rake teeth. The base may define a longitudinal axis of the fixing component, and the proximal and distal ends of the IMD may be aligned along this longitudinal axis. The longitudinal axes of the fixing component and the IMD may be parallel, and in some cases, the fixing component and the IMD may share a longitudinal axis. The base may be securely attached to the IMD near the distal end of the IMD. 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 respective rake tooth of the plurality of rake teeth may be selected to control unfolding, tissue fixing, and / or tissue detachment. For example, the shape of a respective rake tooth may include the number of preset curves on the respective rake tooth, the curvature (e.g., radius) of each preset curve on the respective rake tooth, the length of each preset curve, the length of optional straight segments between preset curves, the width of the respective rake tooth or a segment thereof (e.g., one or more tapered portions), the thickness of the respective rake tooth, the number of cuts along the length of the respective rake tooth, the shape of the cuts, or any combination thereof.

[0022] The plurality of rake teeth may include penetrating rake teeth and protective rake teeth. When deployed, the plurality of rake teeth can provide the desired tissue fixation. For example, the deformable preset curves of the penetrating rake teeth and / or protective rake teeth may have a shape selected to penetrate tissue in a selected direction and at a selected depth to fix the IMD to the tissue. The deployed (e.g., undeformed) configuration of the penetrating rake teeth and / or protective rake teeth may be selected to fully fix the IMD to the selected tissue.

[0023] An IMD can be loaded into a delivery catheter by deforming a plurality of rake teeth with a pre-defined curvature. When deployed at the target implantation site, for example by allowing the rake teeth to transform into a deployable configuration, the rake teeth have a deployment stiffness that allows each rake tooth to penetrate the tissue at the target implantation site. By controlling the deployment stiffness, the rake teeth can have improved tissue fixation, including control over the rake tooth penetration depth and the amount of tissue engagement in the lateral direction.

[0024] In some examples, the penetrator rake teeth and the protector rake teeth may operate in conjunction with a first miniature guide wire. The penetrator rake teeth are configured to penetrate or cut tissue to form a puncture within that tissue. The protector rake teeth are configured to protect the first miniature guide wire during deployment, such as by reducing unwanted displacement of the first miniature guide wire or mechanical damage to its structure. For example, during deployment from a delivery catheter, the penetrator rake teeth may initially penetrate selected tissue to form a puncture. Moreover, during deployment, the protector rake teeth may push the miniature guide wire toward the penetrator rake teeth, thereby guiding the miniature guide wire and the protector rake teeth into the puncture. Upon further deployment of the fixation component, the penetrator rake teeth and the protector rake teeth may return from a deformed (e.g., pre-deployed) configuration to (or at least toward) an undeformed (e.g., deployed) configuration. When the penetrator rake teeth and the protector rake teeth are in the deployed configuration, the first miniature guide wire may extend distally between the penetrator rake teeth and the protector rake teeth, such that the first miniature guide wire extends from the distal end of the IMD's housing to the selected target tissue. In this way, the fixation component can provide improved electrode penetration to a selected depth within a selected tissue and improved electrode contact with the selected tissue.

[0025] After deployment at the target implantation site, the deflection stiffness of the rake teeth allows clinicians to confirm that the rake teeth are adequately secured to the patient's tissue. For example, a pull or drag test can be performed under fluorescence microscopy to confirm that the rake teeth have engaged with the tissue, thereby confirming proper implantation of the IMD. The pull or drag test may involve the clinician pulling or dragging the deployed IMD, for example, via a tether attached to the proximal end of the IMD, and observing the movement of the rake teeth to determine whether they are engaged in the tissue. For example, when the deployed IMD is pulled or dragged in a proximal direction, the rake teeth embedded in the tissue may deflect or bend. By controlling the deflection stiffness, the rake teeth can have a flexibility that allows clinicians to more easily confirm improved tissue engagement.

[0026] In some examples, multiple rake teeth can be configured to detach from the tissue. For example, an IMD can be retrieved via a retrieval catheter. During retrieval, a retrieval member of the retrieval catheter can engage the proximal end of the IMD, such as a retrieval structure. The retrieval member can be retracted into the retrieval catheter in a proximal direction. When the retrieval catheter contacts the multiple rake teeth, the retrieval catheter can cause the multiple rake teeth to move from the undeformed structure to the deformed structure. By moving from the undeformed structure to the deformed structure during retrieval, the multiple rake teeth can improve tissue detachment to facilitate the removal of the IMD.

[0027] In some examples, the fixing components may include additional fixing rake teeth. For example, the plurality of rake teeth may also include at least one of one or more support rake teeth, one or more guide rake teeth, or one or more unfolding rake teeth. In some examples, one or more support rake teeth may be configured to engage selected tissue. In some examples, one or more guide rake teeth may be used during unfolding to determine and / or control the orientation of the IMD. For example, the one or more guide rake teeth may include rake teeth having a length greater than the other rake teeth. One or more guide rake teeth may be configured to provide a visual indication of the IMD's orientation to a clinician, for example via fluorescein microscopy, prior to unfolding the penetrator rake teeth and / or support rake teeth. In some examples, one or more unfolding rake teeth may be configured to increase the unfolding force of the IMD to, for example, improve tissue penetration by the penetrator rake teeth and / or support rake teeth.

[0028] In this disclosure, exemplary systems, devices, and techniques are described with reference to the delivery of an IMD configured as a pacemaker to a target site in a patient's heart. However, it will be understood that the exemplary systems, devices, and techniques of this disclosure are not limited to delivering such IMDs to target sites in the heart. For example, the exemplary systems, devices, and techniques described herein can be used to deliver other medical devices, such as drug delivery devices, sensing devices, neurostimulation devices, or medical leads. Additionally, any such IMD can be delivered to other locations within a patient's body using the exemplary systems, devices, and techniques described herein. In short, the exemplary systems, devices, and techniques described herein have useful applications in the delivery of a wide variety of implantable medical devices for the delivery of treatment or patient sensing to a patient.

[0029] Figure 1 This is a conceptual diagram illustrating a portion of an exemplary medical device system 100 configured to implant a relatively compact implantable medical device 200 (“IMD 200”) at a target implantation site 102. In some examples, such as Figure 1 As illustrated, the target implantation site 102 may include an appendage to the right atrium (RA) of the patient's heart 104. In some examples, the target implantation site 102 may include other parts of the heart 100 or other locations within the patient's body. The medical device system 100 may include a delivery tool 106 configured to house and controllably deploy a relatively compact IMD 200. In some examples, a clinician may manipulate the medical device system 100 to reach the target implantation site 102. For example, with the IMD loaded therein, the clinician may guide the delivery tool 106 upward through the inferior vena cava (IVC) and into the RA. In some examples, other pathways or techniques may be used to guide the delivery tool 106 to other target implantation sites within the patient's body.

[0030] Figure 2AThis is a conceptual plan view illustrating a relatively compact IMD 200 including a fixing component 202. The IMD 200 includes a housing 204 extending along a longitudinal axis 206 from a proximal end 214 to a distal end 215. The housing 204 may be formed of a biocompatible and biostable metal such as titanium. In some examples, the housing 204 may include a hermetically sealed housing. The housing 204 may include a non-conductive coating, and the return electrode 211 is defined as the uncoated portion of the housing 204. The IMD 200 may include any suitable dimensions. In some examples, the outer diameter of the IMD 200 (e.g., the outer diameter of the housing 204) may be between about 10 French (Fr) and about 30 Fr, such as about 20 Fr.

[0031] The IMD 200 may contain electronic circuitry including one or more of sensing circuitry (e.g., for sensing cardiac signals), therapeutic delivery circuitry (e.g., for generating cardiac pacing pulses), and processing circuitry for controlling the functionality of the IMD 200, and may include a first miniature lead 208. The first miniature lead 208 may terminate within a distal electrode 210. For example, the miniature lead 208 may include a conductor, such as a conductive material, extending through a non-conductive sheath (such as a polytetrafluoroethylene (PTFE) coating or a polyetheretherketone (PEEK) tube), with a portion of the conductor exposed at electrode 210. The electronic circuitry may be configured to generate and deliver therapeutic electrical pulses via the first electrode 210 to tissue adjacent to the miniature lead 208, through which it reaches a return electrode 211. The miniature lead 208 may be spaced apart from a distal end 215 of the housing 204, for example, connected to the sensing and therapeutic delivery circuitry via a conductor of a hermetically sealed through-hole assembly (not shown).

[0032] In some examples, the IMD 200 includes a retrieval structure 212 that is fixedly attached to the proximal end 214 of the housing 204. The retrieval structure 212 may be configured to temporarily tether the IMD 200 to a delivery catheter or retrieval catheter, such as delivery tool 106. In some examples, the retrieval structure 212 may be configured to be coupled to a tethering assembly, such as the tethering assembly described in U.S. Patent Application No. 62 / 844,674 entitled “TETHER ASSEMBLIES FOR MEDICAL DEVICE DELIVERYSYSTEMS,” the entire contents of which are incorporated herein by reference.

[0033] The IMD 200 includes a second miniature lead 216. The second miniature lead 216 may be similar to the first miniature lead 208 in at least some respects. For example, the second miniature lead 216 may include a conductor, such as a conductive material, extending through a non-conductive sheath (such as a PTFE-coated or PEEK tube), a portion of which is exposed at the second electrode 218. The first miniature lead 208 may act in conjunction with the second miniature lead 216 for bipolar pacing and sensing, and / or the first miniature lead 208 and the second miniature lead 216 may each act independently with the return electrode 211 for unipolar pacing and sensing of different selected tissues. In some examples, an insulating layer, such as medical-grade polyurethane, parylene, or silicone, may be used to cover the housing 204. In some examples, the insulating layer may define the second electrode 218, for example, by removing a portion of the insulating layer to expose the metallic surface of the housing 204. The second electrode 218 may be used in conjunction with the first miniature lead 208 and / or the second miniature lead 216 for unipolar pacing and / or sensing.

[0034] The fixation component 202 includes a plurality of rake teeth 220 (“rake teeth 220”). The rake teeth 220 may be configured to maintain contact between the miniature wires 208 and 216 and tissue at the target implantation site (e.g., target implantation site 102). Figure 2A As illustrated, rake teeth 202 include penetrating rake teeth 220A, protective rake teeth 220B, and supporting rake teeth 220C. Rake teeth 220 may include one or more segments. For example, rake teeth 220 may include an elastically deformable material pre-defined as one or more curved segments and one or more optional substantially straight segments. For example, penetrating rake teeth 220A may include a pre-defined curvature 228, protective rake teeth 220B may include a pre-defined curvature 230, and supporting rake teeth 220C may include a pre-defined curvature 232. In some examples, rake teeth 220 may define a band shape configured to deform along a plane perpendicular to the longitudinal axis 206 and resist torsion outside that plane. In some examples, the rake teeth 220 may include two or more curved segments (e.g., steering knuckles), as described in U.S. Patent Application No. 62 / 825,233, entitled “Fixation Components for Implantable Medical Devices,” the entire contents of which are incorporated herein by reference. For example, the supporting rake teeth 220C may be the same as or substantially similar to the rake teeth described in U.S. Patent Application No. 62 / 825,233.

[0035] The rake teeth 220 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 forces applied to the IMD 200 in the proximal direction when the retainer 202 engages with tissue at the target site 102. In some examples, the target deflection stiffness may be selected such that the rake teeth 220 can deflect a predetermined amount to achieve visualization of the rake teeth 220 under fluorescence microscopy. In some examples, the target deflection stiffness may be in the range of about 0.2 N to about 0.8 N, such as about 0.3 N to about 0.6 N. Deployment stiffness may be included in the distance from the distal opening 108 of the delivery tool 106 to the retainer 202. Figure 1 The target deployment stiffness is a measure of the force exerted by the rake tooth 220 as it moves from the deformed configuration to the undeformed configuration after the rake tooth 202 has been deployed such that the free distal end (e.g., free distal end 352) penetrates the pectinate muscle PM. In some examples, the target deployment stiffness may be in the range of about 0.6 N to about 1.2 N.

[0036] Figures 2B to 2F Different views of the IMD 200 are shown. In some examples, such as... Figure 2B and Figure 2D As illustrated, the penetrator rake teeth 220A may define an orifice 236. The orifice 236 may be configured to control the deployment stiffness or deflection stiffness of the penetrator rake teeth 220A. For example, the orifice 236 may define a shear stress reduction region configured to reduce shear stress in the penetrator rake teeth 220A during bending (such as when bending into a deformable configuration) or during a pull or drag test. In some examples, at least a portion of the first miniature conductor 208 may extend through the orifice 236. By extending through the orifice 236, the first miniature conductor 208 may be adjustable. For example, a delivery conduit member may be configured to grip the portion of the first miniature conductor 208 extending through the orifice 236 before or after the deployment of the IMD 200. After the IMD 200 is deployed, a delivery conduit can be used to adjust the amount of the portion of the first miniature wire 208 extending through the orifice 236 to control the amount of the miniature wire 208 extending beyond the distal end 223 of the penetrator rake tooth 220A or the distal end 225 of the protector rake tooth 220B. In some examples, the penetrator rake tooth 220A may include other features configured to control the deployment stiffness or deflection stiffness of the penetrator rake tooth 220A or to interact with other components of the IMD 200. For example, the penetrator rake tooth 220A may define an additional orifice or one or more recesses configured to control the deployment stiffness or deflection stiffness of the penetrator rake tooth 220A, or the first miniature wire 208 may be slidably engaged therein during deployment.

[0037] In some examples, such as Figure 2EAs illustrated, the protector rake teeth 220B may define an orifice 238. The protector rake teeth 220B and the second miniature wire 216 may be configured such that, in the deployed configuration, at least the second electrode 218 may protrude through the orifice 238. For example, the protector rake teeth 220B may define additional orifices or one or more recesses configured to control the deployment stiffness or deflection stiffness of the protector rake teeth 220B, or the second miniature wire 216 may be slidably engaged therein during deployment.

[0038] Figure 3 This is a conceptual diagram illustrating an IMD 200 implanted at a target implantation site 102. Rake teeth 220 may define a deformable preset curvature configured to position miniature leads 208 and 216 at selected tissue sites within the target implantation site 102. The target implantation site 102 includes a portion of the right atrial RA wall, such as an atrioventricular septum having an atrial surface 103 and a ventricular surface 105. In other examples, the target implantation site 102 may include other tissues within the patient's body. When deployed at the target implantation site 102, the rake teeth 220 have deployment stiffness that allows the respective rake teeth to penetrate selected tissue at the target implantation site 102. For example, the IMD 200 may be secured at the target implantation site 102 by the rake teeth 220 of a fixation member 202 that penetrates the myocardium (such as a pectinate layer). The rake teeth 220 are configured to be positioned at the distal opening 108 through the delivery tool 106 (…). Figure 1 The spring load is released when the rake tooth 202 unfolds outward, allowing the free distal end of the rake tooth 202 (e.g., the free distal end 223 of the penetrator rake tooth) to penetrate the myocardium. It should be noted that alternative suitable implantation sites for the fixation component 202 can be along any suitable surface of the heart or other tissues within the patient's body. By controlling the unfolding stiffness, the rake tooth 220 can have improved tissue fixation, including control over the penetration depth and the amount of tissue engagement in the lateral direction.

[0039] Figure 4A and Figure 4B This is a conceptual diagram illustrating an exemplary fixing member 302. Except for the differences described herein, fixing member 302 may be identical to fixing member 202 as substantially similar. For example, fixing member 302 includes rake teeth 320. The rake teeth 320 are illustrated in an unfolded (e.g., undeformed) configuration.

[0040] The fixing member 302 includes a base 303. The base 303 may define a longitudinal axis 307 of the fixing member 302. When the base 303 is mounted around the distal end 215 of the device housing 204 such that the periphery of the fixing member 302 extends around the housing 204, the longitudinal axis 307 is generally along the longitudinal axis 206 of the IMD 200. Figure 2A )alignment.

[0041] like Figure 4B As illustrated, rake teeth 320 are spaced apart from each other around the periphery of base 303. Base 303 may have any suitable inner and outer diameter. In some examples, base 303 may have an inner diameter ranging from about 0.1 inches (2.54 mm) to about 0.3 inches (7.62 mm) (such as 0.20 inches (5.08 mm)) and an outer diameter ranging from about 0.11 inches (2.794 mm) to about 0.31 inches (7.874 mm) (such as about 0.21 inches (5.334 mm)). In some examples, the retaining member 302 may be mounted to the distal end 202 of device housing 204 in the same or substantially similar manner as described in U.S. Patent No. 10,099,050B2 (filed January 19, 2017), which is incorporated herein by reference in its entirety. In some examples, the mounting component 302 may include separately formed rake teeth 320, which are individually mounted to the distal end 202 of the device housing 204 (e.g., not integrated with the base 303).

[0042] The rake teeth 320 may comprise any suitable, elastically deformable, biocompatible material. In some examples, the rake teeth 320 may comprise a hyperelastic material, such as a nickel-titanium alloy. For example, the fixation member 302 may be cut from a medical-grade nickel-titanium alloy tube that meets the chemical, physical, mechanical, and metallurgical requirements of ASTM F2063 and has a wall thickness of approximately 0.005 inches (0.127 mm). In this way, the rake teeth 320 may be integrally formed with the base 303, and each rake tooth in the rake teeth 320 may have a constant thickness “t” of approximately 0.005 inches ± 0.001 inches (0.127 mm ± 0.0254 mm). In some examples, after cutting the tube or otherwise forming the fixation member 302, the rake teeth 320 may be shaped into a predetermined configuration by bending and holding the rake teeth 320 while performing heat treatment according to methods known to those skilled in the art.

[0043] like Figure 4AAs illustrated, the penetrator rake tooth 320A may include a proximal segment 350, a curved segment 351, and a distal segment 352. Each of the proximal segment 350, the curved segment 351, and the distal segment 352 may include any suitable length. In some examples, the length of the penetrator rake tooth 320A may range from about 2 mm to about 15 mm, such as from about 4 mm to about 10 mm. The proximal segment 350 is fixedly attached to the base 303. The proximal segment 350 extends in a first direction d1. In some examples, the first direction d1 may be substantially parallel to the longitudinal axis 307. In some examples, the first direction d1 may be angled relative to the longitudinal axis 307, such as between about 0 degrees and about 5 degrees. The curved segment 351 may include a deformable preset curvature. The curved segment 351 extends laterally from the proximal segment 350 across the longitudinal axis 307 to the distal segment 352. In some examples, the bending segment 351 may include a single radius ranging from about 0.06 inches (1.520 mm) to about 0.08 inches (2.032 mm) (such as about 0.067 inches ± 0.010 inches (1.7018 mm ± 0.254 mm)). In some examples, the bending segment 351 may include more than one bending segment.

[0044] The distal segment 352 may include a substantially straight section terminating at a distal end 323. The distal end 323 of the penetrator rake tooth 320A may include a sharp shape. In some examples, the sharp shape may include a shape that tapers sufficiently to a point or edge that pierces or cuts tissue. In some examples, the sharp shape may include a pointed shape, such as a needle shape. In some examples, the sharp shape may include a blade shape that tapers to a sharp edge, a short blade tip, a forked tip, a double short fork tip, or a double short fork tip with a curved cutting surface. In some examples, the shape of the distal end 323 of the penetrator rake tooth 320A may be at least partially based on the spreading force of the penetrator rake tooth 320A. For example, a penetrator rake tooth 320A with a smaller spreading force may require a sharper distal end 323 to achieve tissue penetration compared to a penetrator rake tooth 320A with a larger spreading force that may have a relatively less sharp distal end 323 to achieve tissue penetration. In this way, the selected shape of the distal end 223 can improve tissue penetration, reduce the spreading force required to penetrate the tissue, and / or better control the depth of tissue penetration compared to other distal ends.

[0045] The distal segment 352 may be oriented by the curved segment 351 such that the distal segment 352 extends substantially in direction d2 within the manufacturing limits. In some examples, the angle between d1 and d2... It can be within a range of approximately 35 degrees to 145 degrees relative to the longitudinal axis 307, such as approximately 90 degrees or approximately 135 degrees.

[0046] The protector rake tooth 320B may include a proximal section 354, a curved section 355, and a distal section 356. Each of the proximal section 354, the curved section 355, and the distal section 356 may include any suitable length. The proximal section 354 is fixedly attached to the base 303. As discussed above, the proximal section 354 extends in a first direction d1. The curved section 355 may include a deformable preset curvature. The curved section 355 extends laterally from the proximal section 354 outward from the longitudinal axis 307 to the distal section 356. In some examples, the curved section 355 may include a single radius in the range of about 0.06 inches (1.520 mm) to about 0.08 inches (2.032 mm) (such as about 0.067 inches ± 0.010 inches (1.7018 mm ± 0.254 mm)). In some examples, the curved section 355 may include more than one curved section. The distal section 356 may include a substantially straight section terminating at the distal end 325. The distal end 325 of the protector rake tooth 323 may include any suitable shape, such as a rounded shape or a pointed shape. As discussed above, the distal section 356 may be oriented by the curved section 355 such that the distal section 356 extends substantially in direction d2.

[0047] The support rake tooth 320C may include a proximal section 358, a curved section 359, and a distal section 360. Each of the proximal section 358, the curved section 359, and the distal section 360 may include any suitable length. The proximal section 358 is fixedly attached to the base 303. As discussed above, the proximal section 358 extends in a first direction d1. The curved section 359 may include a deformable preset curvature. The curved section 359 extends laterally from the proximal section 358 outward from the longitudinal axis 307 to the distal section 360. In some examples, the curved section 355 may include a single radius ranging from about 0.06 inches (1.520 mm) to about 0.08 inches (2.032 mm) (such as about 0.067 inches ± 0.010 inches (1.7018 mm ± 0.254 mm)). In some examples, the curved section 355 may include more than one curved section. The distal section 360 may include a substantially straight section terminating at the distal end 327. The distal end 327 supporting the rake tooth 320C may include any suitable shape, such as a rounded or pointed shape. The distal section 360 may be oriented by the curved section 359 such that the distal section 360 extends substantially in direction d3 within the manufacturing limits.

[0048] The shape (e.g., deformable preset curve) and width of each tooth in the rake 320, as well as the hyperelastic stiffness of the nickel-titanium alloy in some examples, provide the rake 320 with sufficient spring force and structural stiffness to engage tissue so as to secure the IMD 200 at the implantation site when unfolded by the delivery tool 106, as described in more detail below. For example, refer to Figure 4B The penetrator rake teeth 320A have a proximal width "W" in the range of approximately 0.020 inches (0.508 mm) to approximately 0.1 inches (2.54 mm), such as approximately 0.06 inches (1.520 mm). P In some examples, the rake tooth 320 may have a substantially constant width along its length (e.g., constant or nearly constant within the limits of common manufacturing tolerances). For example, the proximal section 358, the curved section 359, and the distal section 360 supporting the rake tooth 320C may have substantially constant widths. In some examples, the width of the rake tooth 320 may taper towards the respective distal end. For example, the width of the penetrator rake tooth 320A may taper from the proximal width W... P The width tapers from approximately 0.1 inch (2.54 mm) at the proximal end to approximately 0.024 inches (0.6 mm) at the distal end. In some examples, the cone shape of the penetrator rake 320A can be selected and shaped to provide tissue penetration up to a selected width of the cone. For example, the penetrator rake 320A can taper from a proximal width of W... P The width tapers from approximately 0.59 inches (1.5 mm) at the initial position to approximately 0.020 inches (0.508 mm) at the distal width, and is configured to penetrate tissue to a width of approximately 0.028 inches (0.7 mm). In some examples, the tapered portion of a corresponding rake tooth in rake tooth 320 may include multiple cones, each having a corresponding maximum width and a corresponding minimum width. Generally, the tapered portion increases the flexibility of the corresponding rake tooth relative to the non-tapered portion. In this way, one or more cones can be used to selectively control deployment stiffness, deflection stiffness, and / or tissue penetration depth. In some examples, the width of rake tooth 220 may be selected to provide a radiopaque density, which facilitates visualization during and after the implantation procedure using fluorescence examination.

[0049] In some examples, excluding the tapered portion, the rake teeth 320 may include cuts, engravings, embossings, or other variations in the thickness of the rake teeth 320. For example, the penetrator rake teeth 320A includes apertures 336A and 336B. Apertures 336A and 336B may include any suitable shape, length, and / or width. Similarly, the protector rake teeth 320B may include aperture 338. In some examples, cuts, engravings, embossings, or other variations in the thickness of the rake teeth 320 may be configured to increase the flexibility of selected portions of the rake teeth 320 relative to other portions of the rake teeth 320. For example, apertures 336A and 336B may increase the flexibility of the curved section 351 of the penetrator rake teeth 320A. By increasing the flexibility of selected portions of the respective rake teeth 320, the respective rake teeth may have reduced unfolding stiffness and / or deflection stiffness after forming a predetermined curvature, compared to rake teeth without cuts, engravings, embossings, or other variations in thickness.

[0050] In some examples, the rake teeth of the stationary component may include two or more curved sections to generate target deflection stiffness and target deployment stiffness. Figures 5A to 5D This is a conceptual diagram illustrating an exemplary fixing member 502, which includes a protector rake tooth 520B having multiple curved sections. Except for the differences described herein, fixing member 502 may be related to the above references. Figures 2A to 4B The fixing components 202 and / or 302 discussed are identical or substantially similar. For example, fixing component 502 includes a base 503 from which rake teeth 520 extend and are spaced apart from each other around the periphery of the base 503. The base 503 may define a longitudinal axis 507 of fixing component 502, which in some examples may be substantially along the longitudinal axis 206 of IMD 200 (…). Figure 2A Alignment. The penetrator rake teeth 520A and the protector rake teeth 520B are aligned at an angle of approximately 45 degrees. Extending laterally outward from the longitudinal axis 507.

[0051] like Figure 5A As illustrated, the protector rake tooth 520B includes a proximal section 554, a first curved section 555A, a second curved section 555B, a third curved section 555C, and a distal section 556. The proximal section 520B is fixedly attached to the base 503. The size of each of the proximal section 554, the first curved section 555A, the second curved section 555B, the third curved section 555C, and the distal section 556 can be set and shaped to enable the protector rake tooth 520B to have target deflection stiffness and / or target deployment stiffness.

[0052] The first bending segment 555A, the second bending segment 555B, and the third bending segment 555C may include corresponding deformable preset curvatures. For example, the first bending segment 555A extends laterally from the longitudinal axis 507 outward from the proximal segment 554 to the second bending segment 555B. In some examples, the first bending segment 555A may include a single radius ranging from about 0.02 inches (0.508 mm) to about 0.08 inches (2.032 mm) (such as 0.06 inches (1.520 Bmm)). The second bending segment 555B extends laterally from the first bending segment 555A toward the longitudinal axis 507 to the third bending segment 555C. In some examples, the second bending segment 555B may include a single radius ranging from about 0.02 inches (0.508 mm) to about 0.08 inches (2.032 mm) (such as 0.06 inches (1.520 Bmm)). The third bending segment 555C extends laterally from the second bending segment 555B outward from the longitudinal axis 507 to the distal segment 556. In some examples, the third bending segment 555C may include a single radius ranging from about 0.02 inches (0.508 mm) to about 0.1 inches (2.54 mm), such as 0.08 inches (2.032 mm).

[0053] In some examples, the protector rake tooth 520B may also include one or more straight sections between the first curved section 555A and the second curved section 555B or between the second curved section 555B and the third curved section 555C. These one or more straight sections may include lengths ranging from about 0.01 inches (0.254 mm) to about 0.1 inches (2.54 mm).

[0054] like Figure 5B As illustrated, the rake teeth 520 are spaced apart from each other around the periphery of the base 503. In some examples, the support rake teeth 520C can be spaced apart from each other at any suitable angle Φ, such as an angle in the range of about 60 degrees to 120 degrees, such as 90 degrees. In some examples, the approximately 45-degree spacing between the support rake teeth 520C and the protector rake teeth 520B (e.g., 90 degrees relative to each other) can improve the fixation of the IMD (e.g., IMD 200) by increasing the amount of tissue engaged by the support rake teeth 520C when the penetrator rake teeth 520A and the protector rake teeth 520B are deviated from perpendicularity relative to selected tissue at the target implantation site.

[0055] In some examples, the corresponding curved section extends to or almost extends to the corresponding distal end of the corresponding rake tooth. Figure 6This is a conceptual diagram illustrating an exemplary fixing member 602, which includes a protector rake tooth 620A having multiple curved sections. Except for the differences described herein, fixing member 602 may be related to the above-referenced... Figures 2A to 5D The fixing components 202, 302, and / or 502 discussed are identical or substantially similar. For example, fixing component 602 includes a base 603 from which rake teeth 620 extend and are spaced apart from each other around the periphery of the base 603. The base 603 may define a longitudinal axis 607 of fixing component 602, which in some examples may be substantially along the longitudinal axis 206 of IMD 200 (…). Figure 2A Alignment. The penetrator rake teeth 620A and the protector rake teeth 620B are aligned at an angle of approximately 80 degrees. Extending laterally outward from the longitudinal axis 607. In addition, the third curved section 655C of the protector rake tooth 620C extends to the distal section 656, which is almost at the distal end 625.

[0056] In some examples, the stationary component may include one or more guide rake teeth. Figure 7A and Figure 7B This is a conceptual diagram illustrating an exemplary fixing member 702 including guide rake teeth. Except for the differences described herein, fixing member 702 may be referenced above. Figures 2A to 6 The fixing components 202, 302, 502, and / or 602 discussed are identical or substantially similar. For example, fixing component 702 includes a base 703 from which rake teeth 720 extend. Rake teeth 720 include penetrating rake teeth 720A, protector rake teeth 720B, support rake teeth 720C, and guide rake teeth. Guide rake teeth may be spaced from protector rake teeth 720B at an angle ranging from about 80 degrees to about 90 degrees. In some examples, guide rake teeth may include a non-sharp distal end. In some examples, guide rake teeth may be used during deployment to determine and / or control the orientation of the IMD (e.g., IMD 200). For example, guide rake teeth may have a length greater than other rake teeth, such as penetrating rake teeth 720B. During deployment, guide rake teeth may extend ahead of other rake teeth to form a distal opening 108 of the delivery conduit 106. In this manner, clinicians can partially deploy the IMD 200 before deploying the penetrator rake teeth 720A and / or the support rake teeth 720C to provide clinicians with visual indication of the orientation of the IMD 200, for example, via fluorescein microscopy. In some examples, the guide rake teeth may contact selected tissue at the target implantation site before deploying the penetrator rake teeth 720A. By contacting selected tissue at the target implantation site before deploying the penetrator rake teeth 720A, the guide rake teeth can orient the IMD such that the penetrator rake teeth 720A are substantially perpendicular to the selected tissue.

[0057] In some examples, the fixed component may include one or more unfolded rake teeth. Figure 8A and Figure 8B This is a conceptual diagram illustrating an exemplary fixing member 802 including deployed rake teeth 820D. Except for the differences described herein, the fixing member 802 may be referenced above. Figures 2A to 7B The fixation components 202, 302, 502, 602, and / or 702 discussed are identical or substantially similar. For example, fixation component 802 includes a base 803 from which rake teeth 820 extend. Rake teeth 820 include penetrating rake teeth 820A, protective rake teeth 820B, supporting rake teeth 820C, and deploying rake teeth 820D. Deploying rake teeth 820D may be spaced from penetrating rake teeth 720A at an angle ranging from about 20 degrees to about 90 degrees. In some examples, deploying rake teeth 820D may include a non-sharp distal end. Deploying rake teeth are configured to increase the deploying force of IMD 200 to, for example, improve tissue penetration of penetrating rake teeth 820A and / or supporting rake teeth 820C during deployment. In some examples, rake teeth may include guiding rake teeth (e.g., guiding rake teeth 720A) and deploying rake teeth 820A. In this way, deploying rake teeth 820A can be added to the fixed component 802 to achieve the selected deploying force.

[0058] Figure 9 This is a conceptual diagram illustrating a partial cross-sectional view of an exemplary medical device system 100 including a delivery tool 106 and an IMD 200. For illustrative purposes, the distal end of the delivery tool 106 is enlarged relative to the handle 410. Additionally, while reference is made to the reference... Figures 2A to 3 The description of the fixed component 202 is used to describe the medical device system 100, but in other examples, the medical device system 100 may include other fixed components.

[0059] During use, the IMD 200 is loaded into the delivery tool 106 for deployment to a target implantation site (e.g., target implantation site 102). The delivery tool 106 includes a handle 410, an elongated outer member 430, and an elongated inner member 420 extending within a cavity 435 of the outer member 430. The inner member 420 includes a distal end 422 configured to engage the IMD 200 by abutting a proximal end 214 of the housing 204 (e.g., as shown in a cross-section). The entire IMD 200 can be loaded within a tubular sidewall 432, which defines, for example, the distal portion of the outer member cavity 430 already loaded therein, by pulling the IMD 200 through a distal opening 108 of the cavity with the proximal end 214 of the housing forward. In some examples, when the IMD 200 is loaded into the cavity 435, the inner surface 434 of the tubular sidewall 432 engages the rake teeth 220 of the fixing member 202 to deform the rake teeth 220 (according to arrow L), and then each of the rake teeth 220 of the loaded IMD 200 is kept in a deformable configuration, such as a spring-loaded configuration.

[0060] The handle 410 may be configured to control the movement of the delivery tool 106 and / or the deployment of the IMD 200. Clinicians may position the medical device system 100 by advancing the delivery tool 403 through a patient's blood vessel, for example, from the femoral vein entry point and upwards through the inferior vena cava (IVC). Figure 1 The delivery tool 106 may include articulation features to facilitate navigation of the distal portion of the delivery tool 106. For example, the internal member 420 of the delivery tool 106 may include a pull cable assembly (not shown) integrated into the internal member and coupled to another control member 411 of the handle 410, which causes the internal member 420 and the external member 430 to bend along their distal portions when moved in accordance with arrow A.

[0061] In some examples, the proximal end of the outer member 430 may be coupled to the control member 412 of the handle 410, allowing the entire outer member 430 to move relative to the inner member 420 via the control member 412. For example, when positioning the medical device system 100 near the target implantation site 102 ( Figure 1 After selecting the implantation site, the clinician can retract the outer member 430 relative to the IMD 200 and the inner member 420 as indicated by arrow W, thereby releasing the spring-loaded fixation member 202 to deploy the IMD 200 outward through the distal opening 108, such that the rake teeth 220 engage the selected tissue to secure the IMD 200 at the implantation site. Alternatively, the delivery tool 106 may be configured such that the clinician can push the inner member 420 relative to the outer member 430 to push the IMD 200 outward through the distal opening 108 for deployment. The length of the outer member 430 between the handle 410 and the distal opening 108 may be between approximately 100 cm and approximately 120 cm. Suitable construction details for a delivery tool like the delivery tool 106 are described in U.S. Patent 9,526,522 to Wood et al., which is incorporated herein by reference in its entirety.

[0062] The penetrator rake 220A is configured to penetrate or cut selected tissue to form a puncture. The protector rake 220B is configured to protect the first miniature lead 208 during deployment. In some examples, during deployment from the delivery catheter 106, the penetrator rake 220A may initially penetrate selected tissue on the atrial surface 103 to form a puncture. Furthermore, the protector rake 220B may push the first miniature lead 208 toward the penetrator rake 220A, thereby guiding the miniature lead 208 and the protector rake 220B into the puncture. For example, the protector rake 220B may push the first miniature lead 208 toward the penetrator rake 220A by applying force to the first miniature lead 208 in the direction of the penetrator rake 220A during and / or after deployment. By pushing the first miniature wire 208 toward the penetrator rake tooth 220A, the protector rake tooth 220B can reduce unwanted displacement of the first miniature wire 208 and / or reduce mechanical damage to the first miniature wire 208 (e.g., when the first miniature wire 208 exits the delivery conduit 106). Upon further deployment of the retaining member 202, the penetrator rake tooth 220A and the protector rake tooth 220B can return from the deployment configuration, as... Figure 3 The diagram shows that, in its deployed configuration, a first miniature lead 208 extends distally between the penetrator rake teeth 220A and the protector rake teeth 220B. In this manner, the first miniature lead 208 extends from the distal end 215 of the housing 204 of the IMD 200 to reach selected target tissue, such as tissue near the ventricular surface 105. A second miniature lead 216 can be advanced against tissue at the atrial surface 103 via the penetrator rake teeth 220A and the protector rake teeth 220B, and optionally the support rake teeth 220C. In this manner, the IMD 200 can be configured to penetrate the atrioventricular septum to achieve pacing and / or sensing at the ventricular surface 105 via the first electrode 210 and at the atrial surface 103 via the second electrode 218.

[0063] In some examples, after deployment at the target implantation site 102, the deflection stiffness of the rake teeth 220 allows clinicians to confirm that the rake teeth 220 are adequately secured to the patient's tissue. For example, a pull test or drag test can be performed under fluorescence microscopy to confirm that the rake teeth 220 have engaged with the tissue, thereby confirming proper implantation of the IMD 200. This pull or drag test may involve a clinician pulling or dragging the deployed IMD 200 and observing the movement of the rake teeth 220 to determine whether the rake teeth 220 are engaged in the tissue, such as the rake teeth 220 embedded in the tissue deflecting or bending when the deployed IMD 200 is pulled or dragged. By controlling the deflection stiffness, the rake teeth 220 can have a flexibility that allows clinicians to more easily confirm improved tissue engagement.

[0064] The fixed components described herein can be manufactured using any suitable technology. Figure 10 This is a flowchart illustrating an exemplary method for manufacturing the fixed component 202. Although referenced from the reference... Figures 2A to 2F The illustrated fixed component 202 is used to describe the... Figure 10 The technology illustrated in the figure can be used to manufacture other fixed components, such as references. Figures 4A to 8B The described fixing components 302, 502, 602, 702 and / or 802 and references Figure 3 The described fixing component 202. Alternatively, other techniques may be used to manufacture the fixing component 202 and / or the fixing component 202.

[0065] exist Figure 10 The technique illustrated includes forming a base 203 (1002) that defines the longitudinal axis 207 of the fixing member 202. In some examples, forming the base 203 may include cutting a conduit, such as a metal conduit, a nickel-titanium alloy conduit, or a stainless steel conduit, to define the base 203. Forming the base 203 may include pre-processing or post-processing steps, such as grinding, coating, heat-treating, or polishing the substrate defining the base 203.

[0066] exist Figure 10 The technique illustrated also includes forming rake teeth 220 (1004) extending from and spaced apart from the base 203. In some examples, the base 203 and the rake teeth 220 may be integrally formed. For example, the base 203 and the rake teeth 220 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 203 and the rake teeth 220 from a single conduit may include removing material from the single conduit to define the base 203 and the rake teeth 220. In some examples, removing material from the single conduit may include one or more of the following: machining, chemical etching, laser etching, stamping, or waterjet cutting. In some examples, forming the rake teeth 220 may include forming one or more cones on one or more of the rake teeth 220. For example, forming one or more cones may include any of the above techniques for removing material from the single conduit. In some examples, one or more cones may be formed while removing material from the single conduit.

[0067] In some examples, forming the rake teeth 220 may include bending each of the rake teeth 220 to define one or more curved sections (e.g., see reference above). Figure 5A and Figure 5BThe first bending section 555A, the second bending section 555B, and the third bending section 555C are described. In some examples, each curve of the rake tooth 520 and / or each rake tooth 520 may be bent individually or simultaneously, for example, by using a jig configured to bend one or more curves on one or more rake teeth 220. After bending (and maintaining) the rake tooth 220, forming the rake tooth 220 may also include heat-treating the bent rake tooth 220 such that the rake tooth 220 maintains the bent configuration. For example, heat-treating the bent rake tooth 220 may cause the microstructure of the material of the rake tooth 220 to take on a configuration such that the resting state of the rake tooth 220 (e.g., without the application of external force) is the bent configuration.

[0068] In some examples, forming the rake teeth 220 may also include sharpening the distal ends of the rake teeth 220. For example, forming the penetrator rake teeth 220A may include laser etching the distal ends 223 to define infinite or nearly infinitely sharp edges (within the tolerances of common manufacturing processes).

[0069] In some examples, forming the rake teeth 220 may also include forming one or more cuts, engravings, embossings, or other variations in the thickness of the rake teeth 220. For example, other variations in the thickness of the cuts, engravings, embossings, or rake teeth 220 may be formed by laser etching or chemical etching.

[0070] Figure 11A and Figure 11B This is a conceptual diagram illustrating the distal ends 1123A and 1123B of exemplary corresponding penetrator rake teeth 1120A and 1120B. The distal ends of the penetrator rake teeth may include a sharp shape selected to provide penetration of selected tissue in response to a spreading force. Measurement of the selected shape of the curve may include manufacturing tolerances, such as common manufacturing tolerances in the machining of medical device components. Figure 11AThe illustration shows that the distal end 1123A of the penetrator rake teeth 1120A includes forked tips. In some examples, the gap 1129A between the tips of the forked tips may have a radius ranging from about 0.005 inches (0.127 mm) to about 0.015 inches (0.381 mm) or about 0.01 inches (0.254 mm). The tips of the forks may extend substantially parallel or distally at an angle 1131A, such as between about 5 degrees and about 15 degrees or about 7 degrees. In some examples, the width 1133A of the distal end 1123A may range from about 0.04 inches (1.016 mm) to about 0.12 inches (3.048 mm) or about 0.06 inches (1.524 mm). In some examples, the front surfaces 1125A and 1127A (e.g., the distal surface) may taper into a blade shape, such as a dagger blade. In some examples, the front surfaces 1125A and 1127A may taper from the proximal portion to the distal end within a range of about 180 degrees to about 300 degrees or at an angle of about 281 degrees 1135A.

[0071] like Figure 11B The illustration shows that the distal end 1123B of the penetrator rake tooth 1120B includes a forked tip with curved points. In some examples, the gap 1129B between the points of the forked tip may have a radius ranging from about 0.005 inches (0.127 mm) to about 0.015 inches (0.381 mm) or about 0.01 inches (0.254 mm). The fork points may extend substantially parallel or distally at an angle 1131B, such as ranging from about 15 degrees to about 25 degrees or about 19 degrees. In some examples, the length of the fork points may range from about 0.02 inches (1.016 mm) to about 0.05 inches (3.048 mm) or about 0.038 inches (0.9652 mm). In some examples, the width 1133B of the distal end 1123A may range from about 0.04 inches (1.016 mm) to about 0.1 inches (3.048 mm), such as about 0.033 inches (0.8382 mm). In some examples, the front surfaces 1125B and 1127B may taper into a blade shape, such as a curved dagger blade.

[0072] The following clauses illustrate the exemplary topics described herein.

[0073] Clause 1. A fixation component for an implantable medical device (IMD), the fixation component comprising: a base defining a longitudinal axis of the fixation component, wherein the base is fixedly attached to the IMD, the IMD having a proximal end and a distal end aligned along the longitudinal axis; and a plurality of rake teeth extending from the base and spaced apart from each other, the plurality of rake teeth including: a penetrator rake tooth, the penetrator rake tooth including: a proximal segment of the penetrator rake tooth, the proximal segment of the penetrator rake tooth being fixedly attached to the base and extending from the base in a first direction; a curved segment of the penetrator rake tooth, the curved segment of the penetrator rake tooth defining a deformable predetermined curvature of the penetrator rake tooth and extending laterally from the proximal segment of the penetrator rake tooth and across the longitudinal axis; and a distal segment of the penetrator rake tooth, the penetrator rake tooth having a proximal segment extending from the proximal segment of the penetrator rake tooth and across the longitudinal axis; and a distal segment of the penetrator rake tooth, the penetrator rake tooth having a proximal segment extending from the proximal segment of the penetrator rake tooth and extending across the longitudinal axis. The distal segment of the rake tooth extends from the curved segment of the penetrating rake tooth and terminates at a sharp distal end, wherein the sharp distal end is configured to penetrate tissue to form a puncture; and the protector rake tooth includes: a proximal segment of the protector rake tooth, the proximal segment of the protector rake tooth being fixedly attached to the base and extending from the base in a first direction; a curved segment of the protector rake tooth, the curved segment of the protector rake tooth defining a deformable predetermined curvature of the protector rake tooth and extending laterally outward from the longitudinal axis from the proximal segment of the protector rake tooth; and a distal segment of the protector rake tooth, the distal segment of the protector rake tooth extending from the curved segment of the protector rake tooth and terminating at a non-sharp distal end, wherein the protector rake tooth is configured to allow the non-sharp distal end to pass through the puncture.

[0074] Clause 2. The fixing component as described in Clause 1, wherein the distal section of the protector rake tooth is configured to push the small wire of the IMD toward the penetrator rake tooth when in a deformed configuration.

[0075] Clause 3. The fixing component as described in Clause 1 or 2, wherein the length of the penetrator rake teeth is in the range of about 4 mm to about 10 mm.

[0076] Clause 4. The fixing component according to any one of Clauses 1 to 3, wherein the width of the penetrator rake teeth gradually tapers from a first width in the proximal section to a second width smaller than the first width in the distal section.

[0077] Clause 5. The fixing component according to any one of Clauses 1 to 4, wherein the distal section of the protector rake tooth is configured to push the small wire of the IMD toward the penetrator rake tooth when in a deformed configuration, and wherein, when unfolded from the deformed configuration to an undeformed configuration, the penetrator rake tooth is configured to pierce tissue, and the protector rake tooth is configured to push the small wire into the piercing element in the tissue.

[0078] Clause 6. The fixing component according to any one of Clauses 1 to 5, wherein the deformable preset curvature of the penetrator rake teeth comprises a plurality of curves, each of the plurality of curves defining a corresponding radius.

[0079] Clause 7. The fixing component as described in Clause 6, wherein the curved section of the penetrator rake teeth further includes at least one straight section located between two of the multiple curves.

[0080] Clause 8. The fixing component according to Clause 6 or 7, wherein at least a first curve of the plurality of curves of the penetrator rake teeth defines a first radius, and a second curve of the plurality of curves of the penetrator rake teeth defines a second radius different from the first radius.

[0081] Clause 9. The fixing component according to any one of Clauses 1 to 8, wherein the deformable preset curvature of the protector rake teeth comprises a plurality of curves, each of the plurality of curves defining a corresponding radius.

[0082] Clause 10. The fixing component as described in Clause 9, wherein the curved section of the protector rake teeth further includes at least one straight section located between two of the multiple curves.

[0083] Clause 11. The fixing component according to Clause 9 or 10, wherein at least a first curve of a plurality of curves of the penetrator rake teeth defines a first radius, and a second curve of a plurality of curves of the penetrator rake teeth defines a second radius different from the first radius.

[0084] Clause 12. The fixing component according to any one of Clauses 1 to 11, wherein the plurality of rake teeth further includes one or more supporting rake teeth, wherein the one or more supporting rake teeth are configured to engage when in the unfolded configuration.

[0085] Clause 13. The fixing component as described in Clause 12, wherein the one or more support rake teeth are positioned on the base at approximately 45 degrees from the protector rake teeth.

[0086] Clause 14. The fixing component according to any one of Clauses 1 to 13, wherein the plurality of rake teeth further includes one or more guide rake teeth, the one or more guide rake teeth being configured to perform at least one of the following operations: controlling or indicating the orientation of the fixing component during deployment.

[0087] Clause 15. The fixing component as described in Clause 14, wherein the one or more guide rake teeth are positioned on the base at approximately 180 degrees from the protector rake teeth.

[0088] Clause 16. The fixing member according to any one of Clauses 1 to 15, wherein the plurality of rake teeth further includes one or more deploying rake teeth configured to increase the deploying force of the fixing member.

[0089] Clause 17. The fixing component as described in Clause 16, wherein the unfolding rake tooth is positioned on the base at approximately 45 degrees from the penetrator rake tooth.

[0090] Clause 18. The fixing component according to any one of Clauses 1 to 17, wherein the distal section of the protector rake tooth is configured to push the miniature wire of the IMD toward the penetrator rake tooth when in a deformed configuration, and wherein the protector rake tooth is configured to protect the miniature wire when the IMD is loaded into the delivery conduit.

[0091] Clause 19. The fixation component according to any one of Clauses 1 to 18, wherein the tissue includes myocardial tissue, and wherein the penetrator rake teeth are configured to penetrate at least one of the atrial septum, ventricular septum, or atrioventricular septum.

[0092] Clause 20. The fixing member according to any one of Clauses 1 to 19, wherein the penetrator rake teeth define a metal strip configured to deform along a plane perpendicular to the longitudinal axis and resist torsion outside the plane.

[0093] Clause 21. The fixing member according to any one of Clauses 1 to 20, wherein the penetrator rake tooth defines an orifice disposed between the proximal end and the distal end of the penetrator rake tooth.

[0094] Clause 22. The fixing component according to Clause 21, wherein the distal section of the protector rake tooth is configured to push a small wire of the IMD toward the penetrator rake tooth when in a deformed configuration, wherein the small wire includes an elongated member extending from a proximal end mounted near the distal end of the IMD to the distal end, wherein at least a portion of the small wire between the proximal and distal ends of the IMD extends through the orifice, and wherein this portion of the small wire is configured to adjust the position of the electrode relative to the penetrator rake tooth or the protector rake tooth.

[0095] Clause 23. The fixing component according to any one of Clauses 1 to 22, wherein the distal section of the penetrator rake tooth extends from the curved section of the penetrator rake tooth at an angle ranging from about 45 degrees to about 135 degrees relative to the longitudinal axis.

[0096] Clause 24. An implantable medical device (IMD) comprising: a housing extending along a longitudinal axis from a proximal end to a distal end; an elongated miniature wire extending from a proximal end of the miniature wire mounted near the distal end of the housing to a distal end of the miniature wire, wherein the distal end of the miniature wire includes a first electrode; a second electrode mounted near the distal end of the housing; and a fixing member comprising: a base defining a longitudinal axis of the fixing member, wherein the base is fixedly attached to the IMD, the IMD having a proximal end and a distal end aligned along the longitudinal axis; and a plurality of rake teeth extending from the base and spaced apart from each other, the plurality of rake teeth including: a penetrator rake tooth including: a proximal segment of the penetrator rake tooth fixedly attached to the base and extending from the base in a first direction; and a curved segment of the penetrator rake tooth, the curved segment of the penetrator rake tooth... The segment defines the deformable predetermined curvature of the penetrator rake tooth and extends laterally from the proximal segment of the penetrator rake tooth and across the longitudinal axis; and the distal segment of the penetrator rake tooth, the distal segment of the penetrator rake tooth extending from the curved segment of the penetrator rake tooth and terminating at a sharp distal end, wherein the sharp distal end is configured to penetrate tissue to form a puncture; and the protector rake tooth, the protector rake tooth including: the proximal segment of the protector rake tooth, the proximal segment of the protector rake tooth being fixedly attached The device includes: a bent section of the protector rake tooth that defines a deformable preset curvature of the protector rake tooth and extends laterally outward from the longitudinal axis from the proximal section of the protector rake tooth; and a distal section of the protector rake tooth that extends from the bent section of the protector rake tooth and terminates at a non-sharp distal end, wherein the protector rake tooth is configured such that the non-sharp distal end passes through the puncture.

[0097] Clause 25. The IMD as described in Clause 24, wherein the distal section of the protector rake tooth is configured to push the small conductor of the IMD toward the penetrator rake tooth when in a deformed configuration.

[0098] Clause 26. The IMD as described in Clause 24 or 25, wherein the miniature conductor includes a first miniature conductor, wherein the IMD further includes a second miniature conductor extending from a proximal end of the second miniature conductor mounted near the distal end of the housing to a distal end of the second miniature conductor including the second electrode, the second miniature conductor including a deflection member having a deformable preset curvature.

[0099] Clause 27. The IMD as described in Clause 26, wherein, in its undeformed configuration, the deflection member causes the second electrode to extend laterally outward from the longitudinal axis.

[0100] Clause 28. The IMD as described in Clause 26 or 27, wherein the elongated body of the second electrode defines a notch configured to reduce shear stress in at least a portion of the elongated body of the second electrode when the deflection member causes the second electrode of the deformed configuration to extend laterally outward from the longitudinal axis into the undeformed configuration.

[0101] Clause 29. An IMD as described in any of Clauses 24 to 28, wherein the protector rake teeth define the orifice size to allow the second electrode to extend through the orifice when the protector rake teeth and the second electrode are in an undeformed configuration.

[0102] Clause 30. An IMD as described in any of Clauses 24 to 29, wherein the first electrode is configured to perform at least one of the following operations: delivering stimulation therapy to the ventricles of the heart or sensing cardiac signals of the ventricles of the heart when the IMD is implanted in the atrium of the heart.

[0103] Clause 31. An IMD as described in any of Clauses 24 to 30, wherein the second electrode is configured to perform at least one of the following operations: delivering stimulation therapy to the atrium of the heart or sensing cardiac signals of the atrium of the heart when the IMD is implanted in the atrium of the heart.

[0104] Clause 32. The IMD as described in any of Clauses 24 to 31, wherein the fixing component includes the fixing component as described in any of Clauses 2 to 23.

[0105] Clause 33. A medical device system comprising: an implantable medical device (IMD), the IMD including: a housing extending along a longitudinal axis from a proximal end to a distal end; an elongated miniature wire extending from a proximal end of a miniature wire mounted near the distal end of the housing to a distal end of the miniature wire, wherein the distal end of the miniature wire includes a first electrode; a second electrode mounted near the distal end of the housing; and a fixing member including a base and a plurality of rake teeth. The base is located near the distal end of the housing, and the plurality of rake teeth are fixedly attached to each other at intervals around the periphery of the distal end of the housing; and a delivery tool includes a tubular sidewall defining an inner cavity into which an IMD can be loaded, wherein the inner cavity has a distal opening through which the IMD can be deployed, wherein the plurality of rake teeth includes: a penetrator rake tooth, the penetrator rake tooth including: a proximal segment of the penetrator rake tooth, the proximal segment of the penetrator rake tooth being fixedly attached to the base and extending from the base in a first direction. Extension; a curved section of the penetrator rake tooth, the curved section defining a deformable predetermined curvature of the penetrator rake tooth and extending laterally from the proximal section of the penetrator rake tooth and across the longitudinal axis; and a distal section of the penetrator rake tooth, the distal section extending from the curved section of the penetrator rake tooth and terminating at a sharp distal end, wherein the sharp distal end is configured to penetrate tissue to form a puncture; and a protector rake tooth, the protector rake tooth comprising: the proximal section of the protector rake tooth, the protector The proximal section of the rake tooth is fixedly attached to the base and extends from the base in a first direction; the curved section of the protector rake tooth defines a deformable preset curvature of the protector rake tooth and extends laterally outward from the longitudinal axis from the proximal section of the protector rake tooth; and the distal section of the protector rake tooth extends from the curved section of the protector rake tooth and terminates at a non-sharp distal end, wherein the protector rake tooth is configured such that the non-sharp distal end passes through the puncture.

[0106] Clause 34. A medical device system pursuant to Clause 33, wherein the IMD includes an IMD pursuant to any one of Clauses 24 to 32.

[0107] Clause 35. A method of forming a fixing member for an IMD, the method comprising: forming a base defining a longitudinal axis of the fixing member; and forming a plurality of rake teeth extending from the base and spaced apart from each other, the plurality of rake teeth including: a penetrating rake tooth, the penetrating rake tooth including: a proximal section of the penetrating rake tooth fixedly attached to the base and extending from the base in a first direction; a curved section of the penetrating rake tooth defining a deformable predetermined curvature of the penetrating rake tooth and extending laterally from the proximal section of the penetrating rake tooth and across the longitudinal axis; and a distal section of the penetrating rake tooth extending from the curved section of the penetrating rake tooth. And terminates at a sharp distal end, wherein the sharp distal end is configured to penetrate tissue to form a puncture; and a protector rake tooth comprising: a proximal section of the protector rake tooth, the proximal section of the protector rake tooth being fixedly attached to the base and extending from the base in a first direction; a curved section of the protector rake tooth, the curved section of the protector rake tooth defining a deformable predetermined curvature of the protector rake tooth and extending laterally outward from the longitudinal axis from the proximal section of the protector rake tooth; and a distal section of the protector rake tooth, the distal section of the protector rake tooth extending from the curved section of the protector rake tooth and terminating at a non-sharp distal end, wherein the protector rake tooth is configured to allow the non-sharp distal end to pass through the puncture.

[0108] Clause 36. The method according to Clause 35, wherein forming the plurality of rake teeth further includes sharpening the distal ends of the penetrator rake teeth.

[0109] Clause 37. The method described in Clause 35 or 36, wherein forming a plurality of rake teeth further includes forming at least one of the following in the penetrator rake teeth or protector rake teeth: cut, engraving, imprinting, or variation in the thickness of the respective rake teeth.

[0110] Clause 38. The method described in any of Clauses 35 to 37, wherein the fixing component includes the fixing component described in any of Clauses 2 to 23.

[0111] Various examples of this 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. A fixation component for an implantable medical device, the fixation component comprising: A base defining the longitudinal axis of the fixation member, wherein the base is fixedly attached to the implantable medical device having a proximal end and a distal end aligned along the longitudinal axis; and A plurality of rake teeth, the plurality of rake teeth extending from the base and spaced apart from each other, the plurality of rake teeth comprising: Penetrator rake teeth, the penetrator rake teeth comprising: The proximal section of the penetrator rake tooth is fixedly attached to the base and extends from the base in a first direction; The curved section of the penetrator rake tooth defines a deformable predetermined curvature of the penetrator rake tooth and extends laterally from the proximal section of the penetrator rake tooth and across the longitudinal axis; and The distal section of the penetrator rake tooth, the distal section of the penetrator rake tooth extending from the curved section of the penetrator rake tooth and terminating at a sharp distal end, wherein the sharp distal end is configured to penetrate tissue to form a puncture; and Protector rake teeth, the protector rake teeth comprising: The proximal section of the protector rake teeth is fixedly attached to the base and extends from the base in the first direction; The curved section of the protector rake tooth defines a deformable preset curvature of the protector rake tooth and extends laterally outward from the longitudinal axis from the proximal section of the protector rake tooth; and The distal section of the protector rake tooth extends from the curved section of the protector rake tooth and terminates at a non-sharp distal end, wherein the protector rake tooth is configured to allow the non-sharp distal end to pass through the puncture, and wherein the distal section of the protector rake tooth is configured to push a small lead of the implantable medical device toward the penetrator rake tooth when in a deformed configuration.

2. The fixing component according to claim 1, wherein the length of the penetrator rake teeth is in the range of 4 mm to 10 mm.

3. The fixing component according to claim 1 or 2, wherein the width of the penetrator rake teeth gradually tapers from a first width at the proximal section to a second width at the distal section that is smaller than the first width.

4. The fixing component according to claim 1 or 2, wherein the distal section of the protector rake tooth is configured to push the small wire of the implantable medical device toward the penetrator rake tooth when in a deformed configuration, and wherein, When unfolded from the deformed configuration to the undeformed configuration, the penetrator rake teeth are configured to pierce the tissue, and the protector rake teeth are configured to push the small wire into the piercing element in the tissue.

5. The fixing component according to claim 1, wherein the deformable preset curvature of the penetrator rake teeth comprises a plurality of curves, each of the plurality of curves defining a corresponding radius.

6. The fixing component according to claim 5, wherein the curved section of the penetrator rake teeth further includes at least one straight section located between two of the plurality of curves.

7. The fixing component according to claim 5 or 6, wherein at least a first curve of the plurality of curves of the penetrator rake teeth defines a first radius, and a second curve of the plurality of curves of the penetrator rake teeth defines a second radius different from the first radius.

8. The fixing component according to claim 1, wherein the deformable preset curvature of the protector rake teeth comprises multiple curves, each of the multiple curves defining a corresponding radius.

9. The fixing component according to claim 8, wherein the curved section of the protector rake teeth further includes at least one straight section located between two of the plurality of curves.

10. The fixing member according to claim 8 or 9, wherein at least a first curve of the plurality of curves of the penetrator rake teeth defines a first radius, and a second curve of the plurality of curves of the penetrator rake teeth defines a second radius different from the first radius.

11. The fixing component according to claim 1 or 2, wherein the plurality of rake teeth further includes one or more supporting rake teeth, wherein the one or more supporting rake teeth are configured to engage the tissue when in the unfolded configuration.

12. The fixing component according to claim 11, wherein the one or more support rake teeth are positioned on the base at a 45-degree angle from the protector rake teeth.

13. The fixing member according to claim 1 or 2, wherein the plurality of rake teeth further comprises one or more guide rake teeth, the one or more guide rake teeth being configured to perform at least one of the following operations: controlling or indicating the orientation of the fixing member during deployment.

14. The fixing component according to claim 13, wherein the one or more guide rake teeth are positioned on the base at a distance of 180 degrees from the protector rake teeth.

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