Tether assembly for a medical device delivery system

Abstract

In some examples, a tether head assembly of a delivery system includes an inner retainer and an outer retainer defining an aperture. A tether head assembly of a delivery system includes an inner retainer and an outer retainer defining an aperture including a receptacle configured to receive an attachment member of a medical device, a passageway, and a recess. The inner retainer is movable within the recess between a second position in which the passageway is sized to receive the attachment member and a first position in which the passageway is sized to prevent passage of the attachment member. A tether handle assembly defines a channel, a force transmitter within the channel, a slidable member partially received within a first end of the channel, and a button partially received within a second end of the channel.

Description

Technical Field

[0001] The present disclosure relates generally to medical devices and, more particularly, to systems for delivering medical devices. Background Art

[0002] Some types of implantable medical devices (IMDs), such as pacemakers or implantable cardioverter-defibrillator systems, can be used to provide cardiac sensing and therapy to a patient through one or more electrodes. As an example, some IMDs include an implantable pulse generator that includes a housing that encloses electronic components, and the implantable pulse generator can be configured to be implanted subcutaneously in the patient's chest or within a chamber of the patient's heart. An IMD with a pulse generator configured to be implanted within a chamber of the heart can be referred to as an intracardiac device or a leadless implantable medical device. A medical device delivery system that includes a delivery catheter can be used to deliver an intracardiac device intravenously to an implantation site within the patient's heart and release the device after the device has been secured at the implantation site. The medical device delivery system can then be withdrawn from the patient. Summary of the Invention

[0003] In general, the present disclosure relates to examples of tether assemblies for medical device delivery systems and to techniques for using such tether assemblies. An example tether assembly may include a distal tether head assembly configured to releasably hold a medical device, such as an attachment member of an intracardiac device. Additionally or alternatively, the tether assembly of a medical device delivery system may include a tether handle assembly configured to hold the proximal end of a pull wire of the tether assembly. The tether handle assembly includes one or more components (e.g., an actuator) configured to transmit a force to the tether head assembly via the pull wire. The techniques may include applying a force to the actuator of the tether handle assembly to move the pull wire, thereby achieving removal of the attachment member from the tether head assembly at a treatment site.

[0004] The tether head assembly may include an inner retainer and an outer retainer. The outer retainer may define an aperture comprising: a container configured to receive an attachment member of a medical device; and a passage extending proximally from a distal end of the outer retainer to the container. The aperture may further include a groove extending proximally from the distal end of the outer retainer to at least the container.

[0005] The inner retainer can be movable between a first position and a second position. When the inner retainer is in the first position, the distal portion of the inner retainer can be partially received in the recess and extend into the passageway, thereby narrowing the passageway. Thus, the passageway can be sized to prevent the attachment member from passing therethrough when the inner retainer is in the first position, such as to prevent the attachment member from passing from the container when the attachment member is loaded onto the tether assembly during a medical procedure for delivering the medical device. When the inner retainer is in the second position, the inner retainer does not narrow the passageway, and thus, the passageway can be sized to accommodate the attachment member of the medical device when the medical device is being loaded onto or released from the tether assembly.

[0006] The inner retainer can be biased to the first position.When the proximal movement of the pull wire is interrupted and / or when the attachment member has passed through the passageway and is received within the receptacle defined by the outer member, the resiliently compressible member of the tether head assembly can expand and apply a distal force to the inner retainer, thereby moving the inner retainer from the second position to the first position.

[0007] In other examples, the tether head assembly configured to hold the attachment member of the medical device may include a retainer or other such component that is not biased back to such a first position. The action of loading the medical device onto such other tether assemblies before delivery to the patient's heart may require two people (e.g., clinicians). The first person may be required to hold the medical device in place while the second person opens the tether head assembly, such as by moving the pull line of the tether assembly proximally to move the internal retainer from the first position of the tether assembly "closed" to the second position of the tether assembly "open". The first person can then load the attachment member of the medical device onto the tether head assembly (e.g., by placing the attachment member in a container defined by the tether head assembly), and the second person can move the pull line distally to return the tether head assembly to the first position and keep the attachment member within the container. Using two people to load the medical device onto the tether assembly may increase the time and complexity of the medical procedure for delivering the medical device and / or may increase the possibility of contamination of the medical device or other objects in the surgical area.

[0008] The example tether head assembly described herein can enable one person, rather than two, to load a medical device onto the tether head assembly. For example, biasing the inner retainer to the first position can enable a clinician to hold the tether head assembly with one hand and simply press the attachment member into the passage defined by the outer retainer, thereby causing the inner retainer to move to the second position as the elastically compressible member of the tether head assembly is compressed as the attachment member moves through the passage to the container. The biasing of the inner retainer toward the first position provided by the elastically compressible member can enable the clinician to release their grip on the medical device once the attachment member is received within the container, thereby allowing the inner retainer to return to the first position.

[0009] In this way, the tether assemblies described herein can reduce the time and complexity associated with procedures for delivering medical devices. In some instances, the tether assemblies described herein can reduce the likelihood of contamination of the medical device or other objects within the surgical field by reducing the number of people touching the medical device and the tether assembly. In some instances, the tether assemblies described herein can provide one or more advantages to the functionality, reliability, robustness, manufacturability, and cost associated with such tether assemblies.

[0010] In some instances, a tether handle assembly as described herein can be used in combination with a tether head assembly and a common pull line as described herein. As an example, a tether assembly can include a tether head assembly, a pull line, and a tether handle assembly attached to the proximal end of the pull line. The tether handle assembly can include an actuator configured to cause proximal movement of the pull line, which enables the attachment member to be removed from the tether head assembly. Applying a force to the actuator can cause proximal movement of the pull line, which can enable the medical device to be released from the tether head assembly at a treatment site in the patient's body (e.g., within the patient's heart). The force applied to the actuator can be a distal force, such as a button push. In such instances, one or more components of the tether handle assembly can be configured to convert the distal force applied to the actuator into a proximal force applied to the pull line.

[0011] Examples of tether handle assemblies of a tether assembly of a medical device delivery system in which the medical device can be released from the tether assembly by converting a distal force into a proximal force can provide one or more advantages. In some instances, a clinician may find applying a distal force (i.e., a push force) to a button or slidable member to release the medical device more intuitive and / or otherwise easier to use than some other tether handle assembly configurations. In some instances, when using a tether handle assembly configured to release a medical device from the tether assembly by a distal force relative to other actuator configurations, the clinician is less likely to accidentally release the medical device.

[0012] Any such tether handle assembly may include one or more components configured to reduce the likelihood of accidental release of the medical device from the tether assembly, such as a locking member or a cover. Additionally or alternatively, any of the handle assemblies described herein may enable sensing of electrical signals through an electrical path comprising the medical device and one or more components of the tether assembly comprising the tether handle assembly, which may help enable a clinician to determine delivery and positioning of the medical device relative to the target tissue, attachment of the medical device to the target tissue, and how much force to apply to an actuator of the tether handle assembly to release the medical device from the tether assembly.

[0013] In some other examples, the tether assembly of the medical device delivery system may not be reusable, such as in other examples where the tether assembly comprises a string or other such component that is looped through the medical device and then cut after the medical device is secured at the treatment site. In such other examples, a new tether assembly and / or medical device delivery system can therefore be packaged with each medical device. Packaging the medical device delivery system and / or tether assembly with the medical device may be associated with shelf life considerations, such as in examples where the medical device comprises a drug eluting component that may have an expiration date.

[0014] The example tether assemblies described herein can be sterilizable and reusable, at least in part because they can be released from a medical device without being cut. In some instances, the tether assembly can be packaged separately from the medical device, such as when the medical device may include a drug-eluting component with a limited shelf life. In such instances, packaging the tether assembly separately from the medical device can alleviate shelf life concerns regarding the tether assembly.

[0015] Thus, the example tether assemblies described herein may enable a person to load a medical device onto the tether assembly, may be more intuitive for a clinician to operate than some other example tether assemblies, may reduce the likelihood of accidental deployment of a medical device, may enable a clinician to determine the placement of a medical device at a treatment site within a patient's body (e.g., within a patient's heart), and / or may enable a clinician to monitor electrical signals from a distal portion of the medical device and / or delivery system during an implantation procedure.

[0016] In one example, a tether assembly of a medical device delivery system includes a pull wire and a tether head assembly, the pull wire defining a proximal end and a distal end. The tether head assembly includes an inner retainer, the inner retainer including a proximal portion and a distal portion, wherein the inner retainer is coupled to the distal end of the pull wire and extends distally from the distal end of the pull wire; and an outer retainer, the outer retainer including a proximal portion and a distal portion, the proximal portion defining a channel configured to receive the inner retainer, the distal portion defining an orifice. The orifice includes: a container configured to receive an attachment member of a medical device; a passage extending proximally from the distal end defined by the outer retainer to the container, wherein the passage is narrower than the container; and a groove extending proximally from the distal end of the outer retainer to at least the container, wherein the depth of the groove is less than the thickness of the distal portion of the inner retainer. The inner retainer is movable between a first position in which the distal portion of the inner retainer is partially received in the groove and extends into the passageway, thereby narrowing the passageway, and a second position in which the distal portion of the inner retainer is positioned proximal to the passageway.

[0017] In another example, a tether assembly of a medical device delivery system includes a tether handle assembly comprising: a housing defining a curved channel defining a first end and a second end; a force transmitter received within the curved channel; a slidable member received within the housing such that a portion of the slidable member is received within the channel at the first end of the channel; and a button defining a proximal surface and including a distal portion received within the channel at the second end of the channel, wherein the button surrounds at least the proximal portion of the slidable member. The tether assembly further includes a pull wire defining a proximal end and a distal end, wherein the proximal end of the pull wire is received within the housing and retained by the slidable member. The button is configured to move from a first position to a second position in response to a distal force applied to the button, thereby causing the force transmitter to move toward the first end of the curved channel, so that the force transmitter applies a proximal force to the portion of the sliding member housed in the channel, and the proximal force causes the sliding member and the pull wire to move proximally.

[0018] In another example, a method for using a tether assembly of a medical device delivery system includes positioning the tether head assembly of the tether assembly at a treatment site of a patient with an attachment member of a medical device received within a container of the tether head assembly, the tether head assembly being configured to releasably retain the attachment member of the medical device. The tether head assembly includes an inner retainer including a proximal portion and a distal portion, wherein the inner retainer is coupled to and extends distally from the distal end of a pull wire of the medical device delivery system; and an outer retainer including a proximal portion and a distal portion, the proximal portion defining a channel configured to receive the inner retainer, the distal portion defining an orifice. The aperture includes a receptacle configured to receive the tether member of the medical device, a passageway extending proximally from a distal end of the outer retainer to the receptacle, wherein the passageway is narrower than the receptacle, and a groove extending proximally from the distal end of the outer retainer to at least the receptacle, wherein a depth of the groove is less than a thickness of the distal portion of the inner retainer. Positioning the tether head assembly includes positioning the tether head assembly with the inner retainer in a first position in which the distal portion of the inner retainer is partially received in the groove and extends into the passageway, thereby narrowing the passageway, wherein the passageway is sized to prevent the attachment member from passing therethrough when the inner retainer is in the first position. The method further includes applying a force to an actuator of the tether assembly to cause proximal movement of the pull wire, the proximal movement of the pull wire causing the inner retainer to move from the first position to a second position, in which the distal portion of the inner retainer is positioned proximal to the passageway, wherein the passageway is sized to receive the attachment member of the medical device when the inner retainer is in the second position, thereby allowing the attachment member of the medical device to pass from the container through the passageway. The method further includes moving the tether assembly proximally with the inner retainer in the second position to remove the attachment member of the medical device from the tether head assembly, thereby delivering the medical device to the treatment site.

[0019] In another example, a tether assembly of a medical device delivery system includes a tether handle assembly, the tether handle assembly comprising: a housing; a first slidable member defining a first aperture and housed within the housing; a second slidable member housed within the first aperture and defining a second aperture; and at least one gear housed within the aperture defined by the first slidable member and configured to mechanically engage the first slidable member and the second slidable member. The tether assembly further includes a pull wire defining a proximal end and a distal end, wherein the proximal end of the pull wire is housed within the housing and retained by the second slidable member. The first slidable member is configured to move distally in response to application of a distal force to the first slidable member, and when the first slidable member moves distally, the at least one gear causes the second slidable member and the pull wire to move proximally.

[0020] In another example, a tether assembly of a medical device delivery system includes a tether handle assembly comprising a housing, a slidable member within the housing, and a plunger coupled to the slidable member and extending distally from the slidable member. The tether assembly further includes a pull wire defining a proximal end and a distal end, wherein the proximal end of the pull wire is received within the housing and retained by the slidable member. The plunger is configured to move from a first position to a second position in response to a proximal force applied to the plunger, the proximal force causing the slidable member and the pull wire to move proximally.

[0021] In another example, a method for using a tether assembly of a medical device delivery system includes positioning the tether head assembly of the tether assembly at a treatment site of a patient with an attachment member of a medical device housed within a container of the tether head assembly, the tether head assembly being configured to releasably retain the attachment member of the medical device. The method further includes: applying a force in a distal direction to an actuator of a tether handle assembly of the tether assembly to cause proximal movement of the pull wire, the proximal movement of the pull wire causing the tether head assembly to open; and, with the tether head assembly open, moving the tether assembly proximally to remove the attachment member of the medical device from the tether head assembly, thereby delivering the medical device to the treatment site.

[0022] This summary is intended to provide an overview of the subject matter described in this disclosure. It is not intended to provide an exclusive or exhaustive explanation of the devices and methods described in detail in the following figures and description. Further details of one or more examples are set forth in the figures and the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a conceptual diagram illustrating a portion of a patient's anatomy including a potential implantation site for an implantable medical device (IMD);

[0024] Figure 2 is a plan view of an example medical device delivery system illustrating positioning for delivering an IMD into the heart;

[0025] Figure 3 is shown with an example IMD Figure 2 A conceptual illustration of an example medical device delivery system with a distal portion coupled to cardiac tissue;

[0026] Figure 4A is a plan view of a distal portion of an example tether assembly including a tether head assembly and a pull wire, wherein the distal portion of the tether head assembly is outlined;

[0027] Figure 4B yes Figure 4A an exploded plan view of a distal portion of an example tether assembly depicting an outline of a distal portion of an inner retainer of the tether head assembly;

[0028] Figure 4C yes Figure 4B a plan view of the distal portion of the inner retainer outlined in FIG.

[0029] Figure 4D yes Figure 4A a plan view of a distal portion of the tether head assembly outlined in FIG;

[0030] Figure 5A is with Figure 3 Side view of the IMD combined with Figures 4A-4D a side view of a distal portion of an example tether assembly with the tether head assembly and the IMD disconnected;

[0031] Figure 5B yes Figure 5A A cross-sectional view of a highlighted portion of the proximal portion of the tether head assembly and the IMD, wherein the cross-section is taken in a plane parallel to the longitudinal axis of the tether head assembly and the longitudinal axis of the IMD. Figure 5A The line AA is intercepted;

[0032] Figure 5C yes Figure 5A a cross-sectional view of a device including a highlighted portion of the tether head assembly and a proximal portion of the IMD, wherein the inner retainer is in the second position and the attachment member of the IMD is within a receptacle defined by the outer retainer;

[0033] Figure 5Dyes Figure 5A a cross-sectional view of a device including a highlighted portion of a tether head assembly and a proximal portion of an IMD, wherein an attachment member of the IMD is held by an inner retainer in a first position within a receptacle defined by an outer retainer;

[0034] Figure 6A is an exploded view of a distal portion of another example tether assembly including a tether head assembly and a pull wire, depicting Figure 6A a profile of a distal portion of an inner retainer of the tether head assembly;

[0035] Figure 6B yes Figure 6A a plan view of the distal portion of the inner retainer outlined in FIG.

[0036] Figure 6C It is stored in Figure 6A The outer retainer of the tether head assembly Figure 6B a plan view of a distal portion of an inner retainer;

[0037] Figure 6D yes Figure 6A Example tether head assembly and Figure 3 a cross-sectional view of a proximal portion of an IMD, wherein the cross-section is taken along a plane parallel to the longitudinal axis of the tether head assembly and the longitudinal axis of the IMD;

[0038] Figure 7 is a functional block diagram showing an example configuration of an IMD;

[0039] Figure 8 is demonstrated for use Figures 4A-6D A flowchart of an example technique for an example tether assembly;

[0040] Figure 9A is a plan view of an example tether handle assembly of a proximal portion of another example tether assembly;

[0041] Figure 9B yes Figure 9A an exploded plan view of the tether handle assembly;

[0042] Figures 10A-10D yes Figure 9A and 9B A side view of a tether handle assembly with a portion of the housing of the tether handle assembly removed, the side view illustrating Figure 9A and 9B The example tether assembly's force transmitter, slidable member, and pull wire move in response to a button of the tether handle assembly moving from a first position to a second position;

[0043] Figures 11A-11Jyes Figure 9A and 9B A plan view of components of a tether handle assembly of an example tether assembly illustrating an example technique for assembling the tether handle assembly;

[0044] Figures 12A-12E is a plan view of another example tether handle assembly of a tether assembly including a cover for a button;

[0045] Figure 13A and 13B is a plan view of a proximal end of another example tether assembly including another example tether handle assembly;

[0046] Figure 13C yes Figure 13A and 13B an exploded plan view of an example tether handle assembly;

[0047] Figure 13D and 13E yes Figures 13A-13C a plan view of an example tether handle assembly with portions of a housing removed, the plan view illustrating movement of a plurality of gears, a second slidable member, and a pull wire of the example tether handle assembly in response to movement of the first slidable member of the tether handle assembly from a first position to a second position;

[0048] Figure 14 is a flow chart illustrating an example technique for using a medical device delivery system including a tether assembly, the tether assembly including Figures 9A-13E The described tether handle assembly and Figures 4A-6D The described tether head assembly;

[0049] Figure 15A is a side view of another example tether assembly including another example tether handle assembly;

[0050] Figure 15B yes Figure 15A an exploded plan view of the tether handle assembly;

[0051] Figures 15C-15E yes Figure 15A and 15B a perspective view of the tether handle assembly with portions of the housing removed, the perspective view illustrating different positions of the locking member and plunger of the tether handle assembly;

[0052] Figure 16A is an exploded plan view of another example tether handle assembly;

[0053] Figure 16B yes Figure 14A is a cross-sectional view of an example tether handle assembly;

[0054] Figure 17A is an exploded plan view of another example tether handle assembly;

[0055] Figure 17B yes Figure 17A a cross-sectional view of an example tether handle assembly; and

[0056] Figure 17C yes Figure 17A A plan view of the collar portion of the plunger of an example tethered handle assembly. DETAILED DESCRIPTION

[0057] In general, the present disclosure describes an example medical device delivery system. Such a medical device delivery system may include a tether assembly comprising a tether head assembly, a tether handle assembly, and a pull line. The tether head assembly is attached to the pull line and is configured to releasably hold an attachment member of a medical device (e.g., an intracardiac device). In some instances, the tether handle assembly is configured to hold the pull line attached to the tether head assembly. The tether handle assembly may include an actuator configured to transmit force to the tether head assembly through the pull line and be capable of removing the attachment member of a medical device from the tether head assembly at a treatment site in a patient's body. Although example tether assemblies are generally described herein as being configured for delivering implantable medical devices (IMDs), it should be understood that any of the example tether assemblies described herein may alternatively be configured for delivering other types of medical devices.

[0058] Figure 1 is a conceptual diagram illustrating a portion of a patient's anatomy including potential implantation sites for an IMD. For example, an IMD can be implanted on or within a patient's heart 1, such as within an appendage 2 of the right atrium (RA), within a coronary vein (CV) via the coronary sinus ostium (CSOS), or near the apex 3 of the right ventricle (RV). In other examples, the IMD can be implanted at other locations within the heart 1 or in a location other than the heart 1, such as at any suitable implantation site within the patient's body.

[0059] Figure 2 is demonstrated for the IMD ( Figure 1 1 , a plan view of an example medical device delivery system 4 for delivery (not shown) to a location within heart 1. Although described herein in the context of delivering an IMD to the vasculature, such as heart 1, the devices, systems, and techniques of the present disclosure may be used to deliver an IMD to any anatomical location.

[0060] System 4 includes an introducer 5, a delivery catheter 6, and a tether assembly 12. The introducer 5 is an elongated member defining an interior lumen. The introducer 5 is configured to be inserted into a patient's vasculature by a physician to provide a rigid passage through the interior lumen through which a medical instrument, device, or other therapy is inserted.

[0061] Delivery catheter 6 is configured to be inserted through the lumen of introducer 5 to deliver the IMD within the vasculature. Delivery catheter 6 includes an elongated shaft 9, a handle 7, and a device cup 8. As an example, handle 7 is disposed at the proximal end of shaft 9 and may include one or more elements (e.g., buttons, switches, etc.) configured to control movement of the distal end of shaft 9 and release of the IMD from device cup 8.

[0062] The device cup 8 is disposed at the distal end of the shaft 9. The device cup 8 includes a housing configured to receive and support the IMD (e.g., regarding Figure 3 10). For example, a physician can insert the distal end of a delivery catheter 6 containing a device cup 8 through the lumen of an introducer 5 positioned within the patient's vasculature. Once the device cup 8 has extended through the distal end of the introducer 5 and reached the implantation site within the patient, the physician can release the IMD from the distal opening 11 of the device cup 8 and withdraw the delivery catheter 6 proximally through the introducer 5.

[0063] The tether assembly 12 extends through the lumen-defined delivery catheter, which includes, for example, a handle 7 and a shaft 9. The tether assembly 12 comprises an elongated body 20, a tether handle assembly 13 at the proximal end of the elongated body 20, and a tether head assembly 18 at the distal end of the elongated body 20. Figure 3 Pull Wire( Figure 2 1 and 2. The tether handle assembly 13 (not shown) may extend from the tether handle assembly 13 to the tether head assembly 18 through the lumen defined by the elongated body 20.

[0064] Tether assembly 12 can be of sufficient length so that a clinician can manipulate tether handle assembly 13 to advance tether head assembly 18 out of distal opening 11 of cup 8. As described herein, in some examples, a clinician can attach an IMD to tether head assembly 18 with tether head assembly 18 outside of cup 8. The clinician can then load the IMD into cup 8 through distal opening 11 and advance delivery catheter 6 with tether assembly 12 and the IMD therein through introducer 5 and into the vasculature.

[0065] Figure 3is a conceptual diagram illustrating a distal portion of an example medical device delivery system 4 carrying an example IMD 10 in engagement with tissue 15 of a heart 1. The IMD 10 may be a pacemaker device having a housing 80 containing electronic components suitable for performing various pacing functions. However, an IMD configured to deliver other types of electrotherapy to a patient may be suitable for use with the delivery system 4. The IMD 10 may include an attachment member 14 at its proximal end and a securing member 16 at its distal end. The tether head assembly 18 may be configured to receive and retain the attachment member 14, as described below with respect to FIG. Figures 4A-5D Further discussion.

[0066] In some examples, IMD 10 can include a hermetically sealed housing 80 defining a proximal end 82 and a distal end 84. Housing 80 can contain a pulse generator and an associated power supply (not shown), as well as electrodes 86, which can be positioned at distal end 84 of housing 80 and which can be electrically coupled to the pulse generator of IMD 10 via a hermetically sealed feedthrough assembly (not shown). Housing 80 can be formed from any suitable biocompatible and biostable metal. For example, housing 80 can be formed from titanium and can be covered with an insulating layer (e.g., medical-grade polyurethane, parylene, or silicone). In some examples, IMD 10 can include housing electrodes 88, which can be formed by removing portions of the insulating layer to expose a metal surface defined by housing 80. In such examples, housing electrodes 88 of IMD 10 can function in conjunction with electrodes 86, such as for bipolar pacing and sensing.

[0067] Figure 3 The distal cup 8 of the delivery catheter 6 is shown pressed against tissue 15 at the implantation site of the heart 1. When the clinician is satisfied with the positioning of the cup 8 relative to the tissue 15, e.g., the longitudinal axis of the cup 8 is generally orthogonal to the plane defined by the tissue 15 and the cup 8 is sufficiently pressed against / into the tissue 15 such that the fixation member 16 of the IMD 10 will deploy into the tissue, the clinician can advance the IMD 10 toward the distal opening using the tether assembly 12, e.g., by advancing the tether assembly 12 distally relative to the delivery catheter 6 using the tether assembly handle 13. The fixation member 16 can be configured to embed in the tissue 15 and, in some cases, pull the IMD 10 through the distal opening 11 of the cup when advanced through the distal opening. Although IMD 10 is shown having fixation member 16 including a plurality of tine structures, it should be understood that IMD 10 may include one or more other suitable fixation structures, such as a helical fixation member (helix) that can be rotated into tissue at the implantation site.

[0068] IMD 10 can temporarily remain attached to tether assembly 12 via attachment member 14 and tether head assembly 18 while being secured to tissue 15 via fixation member 16. Thus, a clinician can be able to test the fixation of IMD 10 at the implant site and / or, if necessary, remove IMD 10 from the implant site and return it to cup 8 for repositioning at a more suitable site. Once satisfied with the implantation of IMD 10, the clinician can detach tether head assembly 18 from attachment mechanism 14 and move tether assembly 12 proximally as described in more detail below, and then withdraw delivery catheter 6 and tether assembly 12 from the patient through introducer 5.

[0069] For example, the tether assembly 12 may include Figures 4A-5D A pull line (not shown) is discussed in further detail. Such a pull line may be attached at its distal end to the tether head assembly 18 and at its proximal end to the tether handle assembly 13, as discussed below. Figures 9A-17C Examples of the tether head assembly and the tether handle assembly are discussed. A clinician can apply force to an actuator of the tether handle assembly to move the tether head assembly 18 from a closed position, in which the attachment member 14 is retained within the tether head assembly 18, to an open position, in which the attachment member 14 can be removed from the tether head assembly 18. With the tether head assembly 18 in the open position, the clinician can move the tether assembly 12 proximally to remove the attachment member 14 from the tether head assembly 18, thereby securing the IMD 10 at the treatment site.

[0070] The clinician may secure attachment member 14 to tether head assembly 18 by pressing attachment member 14 of IMD 10 into the passageway defined by tether head assembly 18, thereby opening tether head assembly 18 from a first (e.g., closed) position to a second (e.g., open) position and advancing attachment member 14 through the passageway until tether member 14 is received within the receptacle defined by tether head assembly 18, as described below with respect to Figures 4A-5D This can be accomplished by a single clinician, whereas in some other example medical device delivery systems, two clinicians may be required to secure the IMD's attachment member to the tether assembly. Thus, tether assembly 12 can reduce the time and complexity associated with the procedure for delivering IMD 10. In some examples, tether head assembly 18 can reduce the likelihood of contamination of medical devices or other objects within the surgical field by reducing the number of people who touch IMD 10 and tether head assembly 18 relative to such other tether assemblies.

[0071] As described herein, a clinician can secure attachment member 14 of IMD 10 to tether head assembly 18 while performing a medical procedure for delivering IMD 10. Furthermore, the clinician can release IMD 10 from tether head assembly 18 without having to cut a portion of tether assembly 12. In some instances, tether head assembly 18 can thus reduce or eliminate disadvantages that may be associated with other types of tether mechanisms, such as tension associated with pulling on such other tether mechanisms (e.g., a string loop or similar material), potential twisting or binding of such other tether mechanisms, and the like. The reusability of tether assembly 12 can alleviate shelf life concerns regarding tether assembly 12, delivery system 4, and IMD 10, such as in instances where IMD 10 includes a drug-eluting component with a limited shelf life. For example, when packaged separately from IMD 10, tether assembly 12 and / or delivery system 4 may not necessarily be associated with a limited shelf life.

[0072] During delivery of IMD 10 to a treatment site via delivery system 4, a clinician can advance cup 8 into contact with tissue 15 of heart 1 before engaging fixation member 16 with tissue 15 of heart 1. The clinician can then determine whether cup 8 and IMD 10 are properly positioned at the implant site before engaging fixation member 16 with tissue 15 of heart 1. In some instances, the clinician can determine whether cup 8 and IMD 10 are properly positioned relative to heart 2 based on impedance or other electrical signals sensed through an electrical path that includes IMD 10 (e.g., housing 80 or electrode 88), attachment member 14, and one or more components of tether assembly 12 (e.g., one or more components of tether head assembly 18). In addition to the IMD, another electrode of the electrical path can be a reference electrode attached to or within the patient but positioned external to cup 8. In some instances, a relatively high impedance can indicate that cup 8 is positioned flush with tissue 15 of heart 1 and at a sufficient depth within the tissue, as may be desired for proper fixation. After fixation member 16 and IMD 10 are deployed from cup 8, with IMD 10 secured to tissue 15, the impedance or electrical signal can also indicate the quality of fixation of IMD 10 to tissue, for example, based on changes in impedance during a “drag test,” in which a clinician pulls on tether assembly 12 while it is attached to IMD 10 and IMD 10 is secured to tissue 15. Some examples may employ any of the techniques for testing the spatial relationship of a cup and / or IMD to tissue and techniques for testing fixation of an IMD to tissue described in U.S. patent application Ser. No. 16 / 146,391, filed on September 28, 2018, by Medtronic, Inc., and entitled “Impedance-Based Verification of Delivery of Implantable Medical Devices.”

[0073] Figures 4A-6D An example of a distal portion of a tether assembly including an example tether head assembly is shown. Figures 4A-6D Although not described herein, the delivery system may be used to deliver other appropriately configured medical devices.

[0074] Figure 4A 1 is a plan view of the distal portion of the tether assembly 12 with the components of the tether assembly 12 in an assembled configuration, with the distal portion of the tether head assembly 18 outlined. Figure 4B 1 is an exploded plan view of the distal portion of the tether assembly 12 , outlining the distal portion of the inner retainer 36 of the tether head assembly 18 . Figure 4C yes Figure 4B 1 and 2. A plan view of the distal portion of the inner retainer 36 is outlined in FIG. Figure 4D yes Figure 4A FIG. 2 is a plan view of the distal portion of the tether head assembly 18 outlined in FIG.

[0075] like Figure 4A As shown in , the elongated body 20 can include a shaft defining an inner lumen (not shown) in which a portion of the pull wire 34 is received. The tether head assembly 18 can include an inner retainer 36, an outer retainer 38, and a sheath 40. The components of the tether assembly 12 can be individually formed from any suitable material. In some instances, one or more of the pull wire 34, the inner retainer 36, the outer retainer 38, the sheath 40, and / or one or more layers of the elongated body 20 can be formed from a conductive material, which can facilitate achieving the desired effect as described above with respect to Figure 3 The placement of IMD 10 discussed is tested during a procedure for delivering IMD 10. One or more components of tether assembly 12 may be manufactured by techniques such as metal injection molding or any other suitable technique.

[0076] The inner retainer 36 can be coupled to the pull wire 34 and extend distally from a distal end (not shown) of the pull wire 34. The distal portion 56 of the outer retainer 38 defines the aperture 42, as shown in FIG. Figure 4B , the aperture includes a receptacle 44 sized to receive the attachment member 14 of the IMD 10 and a passageway 46. The passageway 46 may extend proximally from a distal end 48 defined by the outer retainer 38 to the receptacle 44 and may be narrower than the receptacle 44.

[0077] The proximal portion 54 of the outer retainer 38 can define a channel (not shown) configured to receive the inner retainer 36. The inner retainer 36 can be received within the outer retainer 38 in a first position in which the distal portion 52 of the inner retainer 36 extends into the passageway 46, as shown in FIG. Figure 4A and 4D When the inner retainer 36 is in the first position, the passageway 46 can be sized to prevent the attachment member 14 of the IMD 10 from passing therethrough (eg, too narrow to allow the attachment member 14 to pass therethrough).

[0078] Proximal movement of the pull wire 34 can move the inner retainer 36 from the first position to a second position in which the inner retainer 36 does not extend into the passageway 46. Additionally or alternatively, applying a force to the inner retainer 36 (e.g., a distal end of the inner retainer 36) via the attachment member 14 of the IMD 10 can move the inner retainer 36 from the first position to the second position. When the inner retainer 36 is in the second position, the passageway 46 can be sized to accommodate the tether member 14. The inner retainer 36 and the outer retainer 38 can be housed within the sheath 40, and more specifically, within the cavity 64 defined by the sheath 40, which can help retain the inner retainer 36 within the outer retainer 38 and couple the outer retainer 38 to the elongated body 20.

[0079] In some examples, the configuration of inner retainer 36 and outer retainer 38 can substantially isolate the function of retaining attachment member 14 of IMD 10 to tether head assembly 18 from that of pull wire 34 or another element of the handle assembly extending to tether assembly 12. For example, the path length of pull wire 34 and / or shaft 20 can change as tether assembly 12 is navigated through a tortuous portion of a patient's vasculature. In some other example medical device delivery systems in which the tether assembly relies on the pull wire to retain the attachment member within the tether head assembly, such changes in the path length of the pull wire and / or shaft can cause a loss of contact between the pull wire and the attachment member, thereby adversely affecting retention of the attachment member during delivery.

[0080] In the examples of tether assembly 12 and other tether assemblies described herein, changes in the path length of the pull wire 34 and / or shaft 20 of the tether assembly 12 may not significantly move the inner retainer 36 proximally or distally. For example, the sheath 40 and / or the resiliently compressible member 60 can help reduce or prevent proximal movement of the inner retainer 36 when the path length of the pull wire 34 and / or shaft 20 changes during navigation through tortuous vasculature. In this way, substantial isolation of the IMD retention function within the tether head assembly 18 can help maintain retention of the attachment member 14 as the tether assembly 12 is navigated through tortuous vasculature.

[0081] exist Figure 4B In FIG, the distal portion of the inner retainer 36 is outlined, and in FIG. Figure 4C The portion of the inner retainer 36 is shown in more detail in FIG. Figure 4B , the inner retainer 36 can include a proximal portion 50 and a distal portion 52. The outer retainer 38 can include a proximal portion 54 and a distal portion 56. The proximal portion 54 of the outer retainer 38 can define a channel (not shown) sized to receive the proximal portion 50 of the inner retainer 36. The distal portion 56 of the outer retainer 38 can define the orifice 42. In some examples, the orifice 42 can further include a groove 58 extending proximally from the distal end 48 of the outer retainer 38 to at least the receptacle 44. The groove 58 can be partially defined by the distal portion 56 of the outer retainer 38 and can have a depth that is less than the thickness of the distal portion 52 of the inner retainer 36. The amount by which the thickness of the distal portion 52 of the inner retainer 36 exceeds the depth of the groove 58 can correspond to the distance that the inner retainer 36 extends into the passageway 46, for example, transverse to the longitudinal axis defined by the inner retainer 36.

[0082] Figure 4B Further shown is an elastically compressible member 60 that can be housed within a cavity 64 defined by the sheath 40, the cavity being proximal to the inner retainer 36, for example, in abutting relationship therewith. The elastically compressible member 60 can be formed of a suitably elastically compressible material, such as a polymer. The elastically compressible member 60 can define an inner cavity 62 through which the distal portion of the pull wire 34 can extend and attach to the more distally positioned inner retainer 36. In some instances, the elastically compressible member 60 can be configured to bias the inner retainer 36 to a first position. For example, the elastically compressible member 60 can define a longitudinal axis that can correspond to the longitudinal axis of the tether assembly 18. Axial expansion of the elastically compressible member 60 relative to the longitudinal axis causes the elastically compressible member 60 to apply a distal force to the inner retainer 36, thereby moving the inner retainer 36 from the second position to the first position.

[0083] In this manner, resiliently compressible member 60 can act as a spring to bias inner retainer 36 to the first position. Biasing inner retainer 36 to the first position can provide one or more advantages, such as enabling a clinician to load IMD 10 onto tether head assembly 18 without necessarily requiring assistance from another clinician. When tether assembly 12 is in the assembled configuration, for example Figure 4AAs shown in FIG, the elastically compressible member 60 can be housed within the sheath 40. In this way, the sheath 40 can provide a stop against which the elastically compressible member 60 can be compressed during movement of the inner retainer 36 from the first position to the second position.

[0084] Figure 4B The forms of the elastically compressible member 60 shown in the figures are examples. In other examples, other forms of elastically compressible members can be used to provide the functions described herein with respect to the elastically compressible member 60. For example, the elastically compressible member can be in the form of a coil or a spring. Additionally, the elastically compressible member can be formed from a variety of materials such as polymers or metals.

[0085] Figure 4C yes Figure 4B FIG. 5 is a plan view of the distal portion 52 of the inner retainer 36, which is outlined in FIG. Figure 4C , the distal portion 52 of the inner retainer 36 can define a first portion 70, a second portion 72, and a third portion 74. The first portion 70 can include the distal end of the inner retainer 36 and can have a first thickness. The second portion 72 can be proximal to the first portion 70 and can have a second thickness that is greater than the first thickness of the first portion 70. The third portion 74 can extend between the first portion 70 and the second portion 72 and can gradually decrease in thickness from the first thickness of the first portion 70 to the second thickness of the second portion 72. In this manner, the gradually decreasing thickness of the third portion 74 can define a "sloping" surface from the proximal portion 70 toward the second portion 72 and the container 44.

[0086] When the attachment member 14 of the IMD 10 is received in the receptacle 44 (e.g., when the inner retainer 36 is in the first position), the ramped surface defined by the third portion 74 may help ensure substantially constant physical contact between the attachment member 14 and at least the third portion 74 of the inner retainer 36. Figure 5D The physical contact between the attachment member 14 and the inner retainer 36 via the third portion 74 is illustrated in and discussed further in detail.

[0087] In some examples, internal retainer 36 and attachment member 14 can be electrically conductive. In such examples, ensuring substantially constant physical contact between attachment member 14 and internal retainer 36 during the method of delivering IMD 10 can serve as an electrical connection and / or can help reduce electrical noise that might otherwise be caused by intermittent contact between attachment member 14 and internal retainer 36. Such reduction in electrical noise can help determine whether IMD 10 is properly positioned and / or attached relative to tissue of heart 1 during electrical testing of IMD 10 before it is released from tether head assembly 18 at the implant site.

[0088] Figure 4D 38 when the inner retainer 36 is in the first position. The embodiment illustrates how the distal portion 52 of the inner retainer 36 can be received within a groove 58 defined by the distal portion 56 of the outer retainer 38. In some examples, the groove 58 can extend proximally from the distal end 48 of the outer retainer 38 toward the receptacle 44. In some examples, the groove 58 can extend proximally past the receptacle 44 toward the proximal portion 54 of the outer retainer 38. In any such example, the groove 58 can help provide support for the distal portion 52 of the inner retainer 36, such as by reducing the likelihood of the distal portion 52 bending laterally during loading of the attachment member 14 of the IMD 10 into the receptacle 44 or other use of the tether assembly 12. In this manner, the groove 58 can help maintain the mechanical integrity and functionality of the tether assembly 12 during one or more uses, thereby contributing to the durability of the tether assembly 12.

[0089] Figure 5A is a side view of a distal portion of tether assembly 12 including tether head assembly 18 in conjunction with a side view of IMD 10, wherein tether head assembly 18 and IMD 10 are disconnected. Figure 5B is the proximal portion of the tether head assembly 18 and the IMD 10 Figure 5A 10, wherein the cross section is taken along a plane parallel to the longitudinal axis of the tether head assembly 18 and the longitudinal axis of the IMD 10. Figure 5A The line AA is intercepted. Figure 5C The distal portion of the tether head assembly 18 and the proximal portion of the IMD 10 Figure 5A 1 is a cross-sectional view of a highlighted portion of FIG, but with the inner retainer 36 in the second position and the attachment member 14 within the receptacle 44 defined by the outer retainer 38. Figure 5D The distal portion of the tether head assembly 18 and the proximal portion of the IMD 10 are included. Figure 5A1 is a cross-sectional view of a highlighted portion of FIG. 1 , but with the attachment member 14 retained by the inner retainer 36 in the first position within the receptacle 44 defined by the outer retainer 38 .

[0090] Figure 5A and 5B IMD 10 is shown detached from tether assembly 12, which may be the case before IMD 10 is loaded onto tether assembly 12 or after IMD 10 has been implanted at the desired tissue site. Figure 5A and 5B , attachment member 14 of IMD 10 is not received within tether head assembly 18 of tether assembly 12 .

[0091] Figure 5B The sheath 40 of the tether head assembly 18 is shown attached to the distal end of the elongated member 20 of the tether assembly 12. The pull wire 34 extends through the lumen defined by the elongated member 20 and into the cavity 64 ( Figure 4B The resiliently compressible member 60, the proximal portion 50 of the inner retainer 36, and the proximal portion 54 of the outer retainer 38 are disposed within the cavity 64, wherein the distal portion 66 of the resiliently compressible member 60 and the proximal portion 50 of the inner retainer 36 are received in the channel 68 defined by the proximal portion 54 of the outer retainer 38 ( Figure 5C ). The pull wire 34 extends through the inner lumen 62 defined by the resiliently compressible member 60 and is connected to the inner retainer 36, for example, being fixedly received within the proximal portion 50 of the inner retainer 36. The various components of the delivery system 12 and the tether assembly 18 can be connected by any of a variety of techniques, such as welding, crimping, threading, reflowing, bonding, adhesive bonding, or friction fitting.

[0092] 4. The distal portion 52 of the inner retainer 36 extends into the distal portion 56 of the outer retainer 38 to help define the receptacle 44. In the illustrated first position of the inner retainer 36, the distal portion 52 of the inner retainer 36 also extends into the passageway 46 to reduce the size of the passageway such that the thickness or depth of the passageway is less than the thickness of the attachment member 14 of the IMD 10. In the illustrated first position of the inner retainer 36, the distal portion 52 of the inner retainer 36 can be seated within the recess 58 defined by the distal portion 56 of the outer retainer 38 as described herein. In the illustrated first position of the inner retainer 36, the resiliently compressible member 60 can be in a relaxed or lower kinetic energy state.

[0093] like Figure 5CAs shown in the middle, the attachment member 14 of the IMD 10 can be included as part of a structure that provides support for delivering and retrieving the IMD 10 in connection with various features that provide various functions. In the illustrated example, the attachment member 14 is formed within a housing 80 of the IMD 10 and is connected to the housing by a shroud structure 90. In the illustrated example, the attachment member 14 includes a pin (also referred to as a post) that is welded or otherwise fixedly attached to the shroud structure 90. The attachment member 14 provides an elongated retention surface that is spaced apart from the housing proximal end 82 of the housing 80 and extends along a length that is substantially orthogonal to the longitudinal axis of the IMD 10.

[0094] The shroud structure 90 can define a cavity having an opening, and the attachment member 14 can span the opening and be exposed at the opening. The attachment member 14 can be welded to opposite sides of the shroud structure 90 at either end. The distal portion 56 of the outer retainer 38 can be configured to enter the shroud structure 90 or otherwise interact with the shroud structure when the attachment member 14 is received within the passage 46 and the receptacle 44. The configuration of the shroud structure 90 and the distal portion 56 of the outer retainer 38 can selectively prevent or allow relative movement of the IMD 10 and tether assembly in multiple directions. It should be appreciated that the shroud structure 90 and attachment member 14 are provided for example purposes only, and various other attachment members can be configured to attach to a tether assembly as described herein.

[0095] Figure 5C The inner retainer 36 in the second position and the attachment member 14 within the receptacle 44 defined by the outer retainer 38 are shown. The inner retainer 36 can be moved to the second position by a proximal directed force. The proximal directed force can be provided by a pulling force from the pull wire 34 or a pushing force on the distal end 65 of the inner retainer 36 as the attachment member 14 is pushed through the passage 46 and into the receptacle 44. As shown, the movement of the inner retainer 36 to the second position has compressed the elastically compressible member 60, for example such that the distal portion 66 is no longer positioned within the channel 68 defined by the proximal portion 54 of the outer retainer 38. Figure 5B As shown, the movement of the inner retainer 36 to the second position has compressed the elastically compressible member 60, for example such that the distal portion 66 is no longer positioned within the channel 68 defined by the proximal portion 54 of the outer retainer 38.

[0096] When in this compressed state, the elastically compressible member 60 can have a higher potential energy that is released by expanding in the direction of its longitudinal axis, as shown in the expanded or relaxed state shown in Figure 5B and 5D thereby moving the inner retainer 36 from the second position shown in Figure 5D and 5D to the first position shown in Figure 5DThe attachment member 14 is shown held within the receptacle 44 defined by the outer retainer 38 by the inner retainer 36 in the first position. The receptacle 44 is configured, e.g., sized and shaped, to hold the attachment member 14 while allowing the distal portion 52 of the inner retainer 36 to move past the attachment member, e.g., through the passage 46. As shown in Figure 6A When the attachment member is positioned within the receptacle 44, e.g., when the inner retainer 36 is in the first position, at least a third portion 74 of the distal portion 52 of the inner retainer 36 can contact the attachment member 14 of the IMD 10. As described herein, the third portion 74 can secure the attachment member 14 within the receptacle 44 and help ensure substantially constant physical contact between the attachment member 14 and the at least third portion 74 of the inner retainer 36. The physical contact between the attachment member 14 and the inner retainer 36 ensured by the third portion 74 can provide substantially constant electrical contact for electrical signal conduction from the IMD 10 to the proximal portion of the tether assembly 12, e.g., for impedance sensing.

[0097] Figure 6B is an exploded view of a distal portion of another example tether assembly 112 including another example tether assembly 118 and a pull wire 134, with the profile of a distal portion 152 of an inner retainer 136 of the tether assembly 118 depicted. Figure 6A is a plan view of the profiled portion of Figure 6C is a plan view of the profiled portion of Figure 6D is a plan view of the distal portion 152 of the inner retainer 136 housed within the outer retainer 38 of the tether assembly 118. Figures 4A-5D is a cross-sectional view of the tether assembly 118 and a proximal portion of the IMD 10, with the cross-section taken along a plane parallel to the longitudinal axis of the tether assembly and the longitudinal axis of the IMD. The tether assembly 112 and the tether assembly 118 can be substantially similar to the tether assembly 12 and the tether assembly 18 described above with respect to Figures 4A-5D , e.g., components of the tether assembly 112 and the tether assembly 118 having the same reference numerals as components in the tether assembly 12 and the tether assembly 18 can be configured and function as described with respect to Figures 6A-6D .

[0098] In the example of Figures 4A-5D , the inner retainer 136 is substantially similar to the inner retainer 36 described above with respect to Figure 6DThe inner retainer 36 is different from the inner retainer 36 described. Similar to the inner retainer 36, the inner retainer 136 includes a proximal portion 150 that is received in the channel defined by the proximal portion 54 of the outer retainer 38. The inner retainer 136 also includes a distal portion 152 that is supported by the groove 58 defined by the distal portion 56 of the outer retainer 38. Similar to the inner retainer 36, when the inner retainer 136 is in the first position and the resiliently compressible member 60 is in its relaxed state, the distal portion 152 of the inner retainer 136 extends into the aperture 42 to reduce the size of the passageway 46.

[0099] However, the distal portion 152 of the inner retainer 136 does not include portions having different thicknesses, such as the similar portions 70, 72, and 74 of the distal portion 52 of the inner retainer 36. In some examples, the distal portion 152 defines a substantially constant thickness along its length. The attachment member 14 can apply a force to the distal end 65 of the inner retainer 136 and move the inner retainer 136 to the second position when the resiliently compressible member 60 is compressed, thereby allowing the attachment member 14 to pass through the passageway 46 and into the container 44. Figures 6A-6D , the inner retainer 136 can return to the first position, for example, in response to longitudinal expansion of the resiliently compressible member 60, to retain the attachment member 14 in the receptacle 44. However, the distal portion 152 may not include an inclined or elevated surface for contacting the attachment member 14, such as provided by the portion 74 of the distal portion 52 of the inner retainer 36.

[0100] Figure 6D Also shown are different couplings of the pull wire 134 and the inner retainer 136, followed by couplings of the pull wire 34 to the inner retainer 36. Specifically, the pull wire 134 includes a curved distal portion 176. The proximal portion 150 of the inner retainer 136 defines a notch or other corresponding feature configured to receive the curved distal portion 176 ( Figures 6A-6D ). When the pull wire 134 is actuated, the distal portion 176 can bear against the proximal portion 150 to move the inner retainer 136 from the first position to the second position. In some examples, Figure 7 The coupling of the pull wire 134 and the internal retainer 136 shown in FIG. 1 may allow for some relative movement between these structures, for example, in response to bending and length changes of the pull wire 134 during the implantation procedure.

[0101] Figure 7 is a functional block diagram illustrating an example configuration of IMD 10. Figure 3As shown, IMD 10 includes processing circuitry 220, sensing circuitry 222, therapy delivery circuitry 224, sensor 226, communication circuitry 228, and memory 230. In some examples, memory 230 includes computer-readable instructions that, when executed by processing circuitry 220, cause IMD 10 and processing circuitry 220 to perform the various functions attributed herein to IMD 10 and processing circuitry 220. Memory 230 may include any volatile, nonvolatile, magnetic, optical, or electrical media, such as random access memory (RAM), read-only memory (ROM), nonvolatile RAM (NVRAM), electrically erasable programmable ROM (EEPROM), flash memory, or any other digital media.

[0102] Processing circuitry 220 may include fixed-function circuitry and / or programmable processing circuitry. Processing circuitry 220 may include any one or more of the following: a microprocessor, a controller, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or equivalent discrete or analog logic circuitry. In some examples, processing circuitry 220 may include multiple components such as any combination of one or more microprocessors, one or more controllers, one or more DSPs, one or more ASICs, or one or more FPGAs, as well as other discrete or integrated logic circuitry. The functionality attributed to processing circuitry 220 herein may be embodied in software, firmware, hardware, or any combination thereof.

[0103] In some examples, processing circuitry 220 may receive corresponding values ​​of a plurality of cardiac sensing parameters, cardiac therapy parameters (e.g., cardiac pacing parameters), and / or electrode vectors via communication circuitry 228 (e.g., from an external device). Processing circuitry 220 may store such parameters and / or electrode vectors in memory 130.

[0104] The therapy delivery circuitry 224 and sensing circuitry 222 are electrically coupled to electrodes 232, which may correspond to electrodes 86 and 88 ( Figure 8 and 5A ). Processing circuitry 220 is configured to control therapy delivery circuitry 224 to generate and deliver electrical therapy to heart 2 via electrodes 132. The electrical therapy may include, for example, pacing pulses or any other suitable electrical stimulation. Processing circuitry 220 may control therapy delivery circuitry 224 to deliver electrical stimulation therapy via electrodes 232 according to one or more therapy parameter values ​​that may be stored in memory 230. In some examples, therapy delivery circuitry 224 may include a capacitor, a current source, and / or a regulator.

[0105] Additionally, processing circuitry 220 is configured to control sensing circuitry 222 to monitor signals from electrodes 232 in order to monitor the electrical activity of heart 2. Sensing circuitry 222 may include circuitry for acquiring electrical signals, such as filters, amplifiers, and analog-to-digital circuitry. The electrical signals acquired by sensing circuitry 222 may include intrinsic and / or paced cardiac electrical activity, such as atrial depolarization and / or ventricular depolarization. Sensing circuitry 222 may filter, amplify, and digitize the acquired electrical signals to generate raw digital data. Processing circuitry 220 may receive the digitized data generated by sensing circuitry 222. In some examples, processing circuitry 120 may perform various digital signal processing operations on the raw data, such as digital filtering. In some examples, in addition to sensing circuitry 222, IMD 10 may optionally include sensors 226, which may be, for example, one or more pressure sensors and / or one or more accelerometers. Communications circuitry 228 may include any suitable hardware (eg, an antenna), firmware, software, or any combination thereof for communicating with another device, eg, external to the patient.

[0106] Figures 4A-5D is demonstrated for use Figures 6A-6D The tether assembly 12 and Figures 4A-5D Flowchart of an example technique for the tether assembly 112 of FIG. Figure 8 The tether assembly 12 and the tether head assembly 18 are described in the context of Figures 6A-6D The example techniques are provided herein, but the example techniques should not be construed as being so limiting, but rather may be applied using Figure 8

[0026] Methods of tethering the tether assembly 112 and tether head assembly 118, or any other tether assembly configured in accordance with the techniques of this disclosure.

[0107] Figure 2 An example technique includes coupling 240 the tether head assembly 18 of the tether assembly 12 to the attachment member 14 of the IMD 10. For example, the clinician can grasp the tether head assembly 18 with one hand and press the attachment member 14, for example, against the distal end 65 of the inner retainer 36, into the passage 46 defined by the outer member 38, thereby causing the inner retainer 36 to move to the second position as the attachment member 14 moves through the passage 46 to the receptacle 44 and as the elastically compressible member 60 is compressed. Once the attachment member 14 is received within the receptacle 44, the clinician can release his or her grip on the IMD 10 to allow the inner retainer 36 to return to the first position by the biasing of the inner retainer 36 to the first position provided by the elastically compressible member 60.

[0108] With attachment member 14 housed within receptacle 44, the clinician can then position IMD 10, attached to tether head assembly 18, at a treatment site (e.g., within heart 1) in the patient (242). In some instances, delivery catheter 9 is advanced to, for example, the position described above with respect to Figures 9A-11J and 3 When the treatment site is described, the delivery catheter can carry IMD 10 and tether assembly 12 within it. In some examples, the clinician can determine whether IMD 10 is properly positioned relative to heart 1 based on an impedance signal sensed through an electrical path including one or more components of IMD 10, attachment member 14, and tether member 12 (e.g., inner retainer 36 of tether head assembly 18 and / or one or more other components). The clinician can then advance fixation member 16 into tissue of heart 1 to secure IMD 10 at the implantation site (244).

[0109] Once the clinician is satisfied with the positioning and fixation of the IMD 10 relative to the tissue of the heart 1, the clinician can separate the attachment member 14 of the IMD 10 from the tether head assembly 18. For example, the clinician can move the pull wire 34 proximally, such as by applying a force to an actuator of the tether handle assembly attached to the proximal end of the pull wire 34, to move the inner retainer 36 from the first position to the second position (246). With the inner retainer 36 in the second position, the clinician can move the tether assembly 12 proximally to remove the attachment member 14 from the tether head assembly 18 (248). For example, the proximal movement of the tether assembly 12 when the inner retainer 36 is in the second position can enable the attachment member 14 to pass from the container 44 through the passage 46 and out the distal end 48 of the outer retainer 38.

[0110] Figure 9A A proximal portion of another example tether assembly 250 including a tether handle assembly 252 is shown. Figure 9B is a plan view of the tether handle assembly 252, and Figure 9A FIG is an exploded plan view of the tether handle assembly 252. Figures 3-6D As shown in FIG, the tether handle assembly 252 can be coupled to the proximal end of the elongated member 254 of the tether assembly 250, which can correspond to and be substantially similar to Figure 3. In some examples, tether handle assembly 252 can be a handle assembly of a tether assembly that includes either tether head assembly 18 or 118. In some such examples, tether head assembly 18 or 118 can be coupled to elongated body 254 in a manner similar to how tether head assembly 18 or 118 can be coupled to elongated body 20 as described above. The tether head assembly and tether handle assembly described herein can be used in any suitable combination with each other as part of a tether assembly. Therefore, the example combinations of tether head assembly and tether handle assembly described are exemplary and should not be construed as limiting.

[0111] Tether handle assembly 252 includes a housing 258. A pull wire (not shown) can extend through elongated member 254 and can include a proximal end housed within housing 258 of tether handle assembly 252. Tether handle assembly 252 can further include a button 260 defining a proximal surface 262. Button 260 can be configured to cause proximal movement of the pull wire when a distally directed force is applied to proximal surface 262 of button 260. Proximal movement of the pull wire can enable inner retainer 36 or 136 to move from a first position to a second position, e.g., to remove attachment member 14 of IMD 10 from tether head assembly 18 or 118 as described herein.

[0112] Housing 258 of tether handle assembly 252 can include a shroud 264 that extends proximally of proximal surface 262 of button 260 such that proximal surface 262 is recessed within housing 258. Thus, shroud 264 can help reduce the likelihood of inadvertent application of distal force to proximal surface 262, which can help reduce the likelihood of inadvertent deployment of IMD 10 during a procedure for delivering IMD 10.

[0113] Tether handle assembly 252 can further include a strain relief member 266 attached to housing 258 at a distal end 268 defined by housing 258. A pull wire of tether assembly 250 can extend through elongated member 254 and be housed within strain relief member 266. In addition to providing strain relief for elongated member 254 and the pull wire as it enters distal end 268 of housing 258, strain relief member 266 can also facilitate sensing of impedance signals or electrical testing of IMD 10 during delivery at a treatment site.

[0114] In some examples, strain relief member 266 can be electrically conductive and electrically coupled to conductive elements of elongated body 254. In such examples, strain relief member 266 can enable sensing of an impedance signal or other electrical signal sensed through an electrical path including IMD 10, attachment member 14, inner retainer 36 or 136, other conductive components of tether head assembly 18 or 118, elongated member 254, and strain relief member 266. For example, a clinician can couple a conductive clip or similar connector from a device external to the patient to strain relief member 266 during an implant procedure to effectively electrically couple the external device to housing 80 of IMD 10. A return electrode can be attached to the patient and coupled to the external device to provide a return path.

[0115] As mentioned above about Figure 9B As discussed, based on the impedance signal sensed via this electrical pathway, a clinician can determine whether cup 8 and / or IMD 10 are properly positioned relative to tissue 15 of heart 1 and / or whether IMD 10 is properly secured to the tissue via securement member 16. In this way, strain relief member 266 can help enable a clinician to determine whether IMD 10 is properly placed at a treatment site.

[0116] like Figure 9B As shown in FIG, the interior of the housing 258 can define at least a portion of a curved channel 270 that defines a first end 272 and a second end 274. In the example shown, an intermediate portion 276 of the curved channel 270 between the first end 272 and the second end 274 can be separately formed and positioned within the housing 258 during assembly of the handle assembly 252, for example, for each manufacturing operation of the curved channel 270. The tethered handle assembly 252 can further include a force transmitter 278 received within the curved channel 270. In the example shown, the force transmitter 278 includes a plurality of balls (e.g., ball bearings) or other similar objects that are movable through the channel 270. However, other suitable objects configured to be received within and movable through the channel 270 can be used in place of or in addition to the plurality of balls.

[0117] The tether handle assembly 252 can further include a slidable member 280 received within the housing 258 such that a channel portion 282 of the slidable member 280 is received within the channel 270 at the first end 272 of the channel 270. Figures 10A-10D, a proximal end 286 of the pull wire 284 can extend from the elongated member 254, through the strain relief member 266, and be housed within the housing 258. The proximal end 286 of the pull wire 284 is attached to the slidable member 280. In the illustrated example, the proximal end 286 of the pull wire 284 is housed within an anchor member 288, which can retain the proximal end 286 of the pull wire 284 to the slidable member 280, thereby attaching the proximal end 286 of the pull wire 284 to the slidable member 280.

[0118] The button 260 can include an elongated distal portion 290 received at the second end 274 within the channel 270. The distal portion 290 of the button 260 can be configured to move the force transmitter 278 toward the first end 272 within the channel 270 and into contact with the channel portion 282 of the slidable member 280. For example, when the button 260 moves from the first position to the second position in response to application of a distal force to the proximal surface 262 of the button (e.g., by a clinician pressing the button), the distal portion 290 of the button 260 can contact the force transmitter 278 and move it through the channel 270 toward the first end 272. Because the force transmitter 278 contacts the portion 282 of the slidable member 280 received within the channel 270, the force transmitter 278 applies a proximal force to the channel portion 282 and, therefore, to the slidable member 280. This proximal force causes the slidable member 278 and the pull wire 284 to move proximally. In this manner, channel 270 and force transmitter 278 can be configured to translate a distally directed force applied to proximal surface 262 of button 260 into a proximal force applied to slidable member 280 and pull wire 284. In some instances, a clinician may find applying a distally directed force (i.e., a pushing force) to button 260 to release IMD 10 to be more intuitive and / or otherwise easier to use than with some other handle assembly configurations.

[0119] In some examples, the tethered handle assembly 252 can further include an elastically compressible member 292, such as a spring, positioned within the housing 258 proximal to the slidable member 280, which, in some examples, can help control the movement of the slidable member 280. When the handle assembly 252 is in the assembled configuration, the button 260 can surround at least a proximal portion of the elastically compressible member 292. Proximal movement of the slidable member 280 can axially compress the elastically compressible member 292 relative to its longitudinal axis. In some examples, the elastically compressible member 292 can help control the proximal movement of the slidable member 280 as the slidable member 280 moves proximally within the housing 258. Additionally or alternatively, the elastically compressible member 292 can be configured to bias the slidable member 280 and / or the button 260 to their respective first positions, such as their positions when the button 260 is not pushed distally inward relative to the housing 258, as described with respect to Figure 9B As shown and described above, when the physician releases button 260, pull wire 284 can be moved distally by elastically compressible member 292 to help return tether head assembly 18 or 118 to the closed configuration, such as, in some examples, to return inner retainer 36 or 136 to the first position. Some example tether assemblies may include both an elastically compressible member in the handle assembly, such as elastically compressible member 292, and an elastically compressible member in the head assembly, such as elastically compressible member 60, while other tether assemblies may include only one of the elastically compressible members, for example, to provide the functionality of returning the tether head assembly to the closed configuration, such as, for example, returning the inner retainer to the first position.

[0120] In some instances, such as Figure 9A As shown in FIG, the housing 258 may include a removable cover portion 296 that may facilitate manufacture of the tethered handle assembly 252. The tethered handle assembly 252 may further include an elastically stretchable band 294 that may be configured to be placed over distal portions of the housing 258 and cover 296 to help hold the components of the handle assembly 252 in place. Figures 10A-10D In the assembled configuration shown in .

[0121] Figure 9A yes Figure 10A and 9B 25. A side view of the tether handle assembly 252 with portions of the housing 258 removed illustrates the force transmitter 278, the slidable member 280, and the pull wire 284 responsive to the button 260 being moved from the first position 300 ( Figure 10D ) moves to the second position 302 ( Figures 10B-10D). The first position 300 can be the “original” or uncompressed position of the button 260. The second position 302 can be the compressed or recessed position of the button 260. The resiliently compressible member 292 can bias the button 260 to the first position 300.

[0122] like Figure 9B As shown in FIG, when the button 260 is pushed inwardly into the shield 264 with a distal force in the direction of arrow 304, the distal portion 290 of the button 260 moves distally in the direction of arrow 304 within the channel 270. As the distal portion 290 moves distally within the channel 270, the distal portion 290 moves the force transmitter 278 within the channel toward the first end 272 ( Figure 10B ) is pushed. In this way, force transmitter 278 transmits the distal force from button 260 to a proximal force in the direction of arrow 306 against channel portion 282 of slidable member 280. In response to the proximal force, slidable member 280 and attached pull wire 284 can move proximally in the direction of arrow 306, which can cause tether head member 18 or 118 to open at the distal end of the tether assembly as described herein.

[0123] like Figures 11A-11J , the housing 258 and the button 260 can include features configured to interact, e.g., abut, when the button 260 is in the second position 302. Such features can prevent the button 260 from moving further distally beyond the second position 302. In the example shown, the housing 258 defines an internal shoulder 308, and the button 260 includes a distal protrusion 310.

[0124] As the button 260 moves in the distal direction 304 from the first position 300 to the second position 302 and the slidable member 280 correspondingly moves in the proximal direction 306, the elastically compressible member 292 compresses between the button 260 and the slidable member 280, thereby storing potential energy. When the physician releases the button 260, the elastically compressible member 292 can expand longitudinally, thereby releasing the stored energy and moving the button 260 and the slidable member 280 in directions 306 and 304, respectively, until the button 260 is once again in the first position 300. As the slidable member 280 moves distally in the direction 304, the pull wire 284 can also move distally to help return the tether head assembly 18 or 118 to the closed configuration, for example, in some examples, returning the inner retainer 36 or 136 to the first position.

[0125] Figure 9A yes Figure 11A and 9BFIG. 2 is a plan view of components of the tether handle assembly 252 of the tether assembly 250, illustrating an example technique for assembling the tether handle assembly 252. Figure 11B , the pull wire 284 extends out of the proximal end of the elongated member 254 and passes through the strain relief member 266 at the proximal end of the elongated member 254. An anchor member 288 can be formed on or attached to the proximal end 286 of the pull wire 284.

[0126] like Figure 11C , the housing 258 can define a receptacle 320 configured to receive the strain relief member 266 and a channel 322 configured to receive the pull wire 284. The anchor member 288 can be positioned on an end of the channel 322 opposite the strain relief member 266. This configuration, including securing the strain relief member 266 within the receptacle 320 of the housing 258, can provide strain relief for the connection of the elongated member 254 to the handle assembly 252.

[0127] Figure 11D Insertion of the intermediate portion 276 is shown to complete the curved channel 270 , which also closes the channel 322 . Figure 11E The slidable member 280 is shown inserted into the housing 258. The slidable member 280 can define a feature (not shown) configured to receive the anchor member 288, thereby coupling the pull wire 284 to the slidable member 280.

[0128] Figure 11F The resiliently compressible member 292 is shown inserted into the housing 258, and Figure 11F The button 260 is shown inserted into the housing 258. The slidable member 280 and the button 260 may include features for retaining the resiliently compressible member 292 therebetween. Figure 11G Also shown is a distal portion 290 of the button 260 inserted at the second end 274 of the channel 270 .

[0129] Figure 11H The force transmitter 278 is shown inserted into the channel 270 between the distal portion 290 of the button 260 and the channel portion 282 of the slidable member 280. Figure 11I A removable cover 296 is shown attached to the housing 258, and Figure 11I An elastically stretchable band 294 is shown positioned over distal portions of the housing 258 and cover 296 to help retain the components of the tether handle assembly 252 in the assembled configuration. Figures 12A-12E and 11JIt is also shown that the housing 258 can define features to aid in the usability of the handle assembly 252 , such as a recess 324 and a ridge 326 , which can assist a physician in orienting and gripping the tethered handle assembly 252 .

[0130] Figures 9A-11J is a plan view of another example tether handle assembly 352. The tether handle assembly 352 may be used with respect to Figures 9A-11J The described tether handle assembly 252 is substantially similar. For example, components of the tether handle assembly 352 that have the same reference numerals as components of the tether handle assembly 252 may be similar to those described with respect to FIG. Figure 12E Configure and function as described.

[0131] Unlike tether handle assembly 252, tether handle assembly 352 includes a cover 354 for button 260 ( Figure 12D Housing 358 of tether handle assembly 352, such as shroud portion 364 thereof, may define a recess 370 configured to allow a user's finger to access tabs 372 formed on cover 354 to move cover 354 away from button 260. Cover 354 may be included on tether handle assembly 352 to reduce the likelihood of accidentally pressing button 260 and deploying IMD 10 during an implantation procedure for IMD 10 using tether handle assembly 352.

[0132] The strap 376 may connect the cover 354 to the collar 374. For example, Figure 12D As shown in FIG, the loop 374 and the strap 376 can be configured to keep the cover 354 attached to the tether handle assembly 352 when the cover 354 is moved away from the button 260. For example, as shown in FIG. Figure 12D and 12E , the band 376 can be configured to space the cover 354 from the proximal opening of the shroud portion 364 to facilitate user access to the proximal surface 262 of the button 260 when the cover 354 is moved. The cover 354, the collar 374, and the band 376 can be formed of any material, such as a polymer, and can be formed from a single piece of material, for example, molded as a single piece of material. The shroud portion 364 and / or other portions of the housing 358 can be configured with corresponding features for receiving the collar 374 and the band 376, for example, to secure them to the tether handle assembly 352 and provide a substantially uniform outer surface for the tether handle assembly 352.

[0133] like Figure 12E and 12E As shown in FIG, the cover 354 may include a plug portion 378 having a reduced diameter. Figure 13A, the proximal opening of the shroud portion 364 can define an enlarged diameter shelf 380 configured to receive the plug portion 378. The plug portion 378 and the shelf 380 can be configured to interact to secure the cover 354 within the proximal opening of the shroud portion 364, for example, by a friction fit, threading, or other attachment mechanism.

[0134] Figure 13C and 13B is a plan view of the proximal end of another example tether assembly 412 including another example tether handle assembly 452 coupled to the proximal end of an elongated member 454. Figure 13D is an exploded plan view of the tether handle assembly 452. Figures 3-6D and 13E is a plan view of tether handle assembly 452 with portions of housing 458 of tether handle assembly 452 removed to illustrate an example arrangement, interaction, and movement of the components of tether handle assembly 452 during use.

[0135] The elongated member 454 of the tether assembly 412 may correspond to and be substantially similar to Figure 13C . In some examples, tether handle assembly 452 can be a handle assembly of a tether assembly that includes either tether head assembly 18 or 118. In some such examples, tether head assembly 18 or 118 can be coupled to elongated body 454 in a manner similar to how tether head assembly 18 or 118 can be coupled to elongated body 20 as described above. The tether head assembly and tether handle assembly described herein can be used in any suitable combination with each other as part of a tether assembly. Therefore, the example combinations of tether head assembly and tether handle assembly described are exemplary and should not be construed as limiting.

[0136] exist Figure 13C In the example shown, housing 458 includes two housing portions 458A and 458B. Housing portions 458A and 458B can be press-fitted together or otherwise connected during assembly of tether handle assembly 452 to form housing 458, for example, after the components of tether handle assembly 452 described herein are appropriately arranged. In some examples, housing portions 458A and 458B can be molded components of plastic or another polymer.

[0137] Pull Wire 484( Figures 4A-6D) can extend through the elongated member 454 and can include a proximal end 486 housed within the housing 458 of the tether handle assembly 452. The tether handle assembly 452 can further include a button 460 defining a proximal surface 462 and configured to cause proximal movement of the pull wire 484 when a distal force is applied to the proximal surface 462 of the button 460. Proximal movement of the pull wire 484 can enable the inner retainer 36 or 136 to move from a first position to a second position, for example, as described herein with respect to Figure 13C Removal of attachment member 14 of IMD 10 from tether head assembly 18 or 118 is described.

[0138] Tether handle assembly 452 can further include a strain relief member 466 attached to housing 458 at a distal end of housing 458. Elongated member 454 can be attached to strain relief member 466 and pull wire 484 can be housed within strain relief member 466. In addition to providing strain relief for elongated member 454 and pull wire 484 with the elongated member attached to housing 458 and the pull wire entering the housing, strain relief member 466 can also be electrically conductive and facilitate sensing of impedance signals or electrical testing of IMD 10 during delivery at a treatment site, as described above with respect to strain relief member 266.

[0139] like Figure 7 As shown in , button 460 includes a bracket 470 within a housing that defines internal teeth 472 that are configured to interact with corresponding teeth of gears 474A and 474B (collectively referred to as "gears 474"). Button 460 can be machined and / or molded. The tether handle assembly 452 further includes a slidable member 480 that includes teeth 482 on opposite sides of the slidable member. The teeth 482 of the slidable member 480 are configured to interact with the teeth of gear 474. The slidable member 480 defines a longitudinal lumen through which the distal end 486 of the pull wire 484 extends and into which a distal portion of a sleeve 488 can be inserted. Sleeve 488 can be used to attach the pull wire 484 to the slidable member 480 by defining an inner cavity to accommodate the proximal end 486 of the pull wire 484. The proximal end 486 of the pull wire 484 may be secured by welding, crimping, capping, bonding, and / or using an anchoring member (e.g., Figure 13D B's anchor member 288) is fixed to the sleeve 488 as an example.

[0140] Tether handle assembly 452 further includes resiliently compressible members 492A, 492B, and 492C (collectively, "resiliently compressible members 492"), such as springs, within housing 458. The longitudinal lumen defined by slidable member 480 houses resiliently compressible member 492C, which inhibits proximal movement of pull wire 484 when button 460 is pushed distally.

[0141] Figure 13D and 13E is a side view of the tether handle assembly 452 with the housing portion 458A removed, showing the bracket 470, gear 474, slidable member 480, and pull wire 484 in response to the button 460 being moved from the first position ( Figure 13E ) moves to the second position ( Figure 13D ) and move. Figure 13E The first position shown in may be the “original” or uncompressed position of button 460 . Figure 13D The second position shown in FIG4 may be a compressed or recessed position of the button 460. The resiliently compressible members 492A and 492B may bias the button 460 to the first position.

[0142] like Figure 13D and 13E As shown in FIG, when button 460 is pushed inwardly with a distal force in the direction of arrow 494, bracket 470 moves distally in the direction of arrow 494 within housing 458. As bracket 470 moves distally, teeth 472 rotate gear 474. When gear 474 rotates against teeth 482 of slidable member 480, slidable member 480 moves proximally in the direction of arrow 496 and pushes pull wire 484 connected to slidable member 480 proximally in the direction of arrow 496. In this way, gear 474 transfers the distal force from button 460 to a proximal force in the direction of arrow 496, in response to which pull wire 484 can move proximally in the direction of arrow 496, which can cause tether head member 18 or 118 to open at the distal end of tether assembly 412 in the manner described herein.

[0143] When the button 460 is moved in the distal direction 494 from the first position ( Figure 13E ) moves to the second position ( Figure 14), the elastically compressible members 492A and 492B compress between the button 460 and the features of the housing 458, thereby storing potential energy. When the physician releases the button 460, the elastically compressible members 492A and 492B can expand longitudinally, thereby releasing the stored energy and causing the button 460 and the slidable member 480 to move in directions 496 and 494, respectively, until the button 460 is once again in the first position. As the slidable member 480 moves distally in direction 494, the pull wire 484 can also move distally to help return the tether head assembly 18 or 118 to the closed configuration, for example, in some examples, returning the inner retainer 36 or 136 to the first position.

[0144] Figures 9A-13E is a flow chart illustrating an example technique for using a tether assembly including a tether assembly as described with respect to Figures 4A-6D The described tether handle assembly and Figures 4A-5D The described tether head assembly. Although in the context Figures 9A-11J The tether head assembly 18 and Figure 14 The tether handle assembly 252 is described in Figures 6A-6D The example techniques are described herein, but the example techniques should not be construed as being so limited, but rather may be applied to the use of Figures 12A-12E The tether head assembly 118, Figure 8 Methods of tethering handle assemblies 352 and 452 or any other tether head assembly or tether handle assembly configured in accordance with the techniques of this disclosure.

[0145] and Figure 14 The example technique is similar to Figure 14 An example technique includes positioning 242 an IMD 10 attached to a tether head assembly 18 at a treatment site (e.g., a treatment site within heart 1) of a patient with attachment member 14 housed within receptacle 44. In some examples, a clinician may determine whether IMD 10 is properly positioned relative to heart 1 based on an impedance signal sensed through an electrical path including IMD 10, attachment member 14, one or more components of tether head assembly 18, the elongated member, and strain relief member 266. The clinician may then advance fixation member 16 into tissue of heart 1 to secure IMD 10 at the implantation site (244).

[0146] Once satisfied with the positioning and fixation of IMD 10 relative to the tissue of heart 1, the clinician can separate attachment member 14 of IMD 10 from tether head assembly 18. Figure 15AIn the example of FIG, the clinician pushes the proximal surface 262 (500) of the button 260 of the tether handle assembly 252 distally. The tether handle assembly 252 converts the distal force into a proximal force to move the pull wire 282 proximally and open the tether head assembly 18 (502). For example, the distal portion 290 of the handle 260 can move distally in the channel 270 and push the force transmitter 278 through the channel 270 against the channel portion 282 of the slidable member 280, which can move the slidable member 280 in the proximal direction. The pull wire 284 connected to the slidable member 280 is therefore moved in the proximal direction.

[0147] In other examples, distal movement of the bracket 470 of the button 460 rotates the gear 474. The rotation of the gear 474 causes the slidable member 480 to which the pull wire 484 is connected to move proximally. In either case, with the tether head assembly 18 open, the clinician can move the tether assembly 12 proximally to remove the attachment member 14 from the tether head assembly 18 (248).

[0148] Figure 15B is a side view of another example tether assembly 550 including another example tether handle assembly 552. Figures 15C-15E is an exploded plan view of the tether assembly 550 and the tether handle assembly 552. Figure 15A is a perspective view of tether handle assembly 552 with portion 596 of housing 558 removed, illustrating different positions of locking member 570 and plunger 560 of tether handle assembly 552 during use.

[0149] like Figures 3-6D As shown in FIG, the tether handle assembly 552 can be coupled to the proximal end of the elongated member 554 of the tether assembly 550, which can correspond to and be substantially similar to Figures 4A-6D . In some examples, tether handle assembly 552 can be a tether handle assembly of a tether assembly that includes either tether head assembly 18 or 118. In some such examples, tether head assembly 18 or 118 can be coupled to elongated body 554 in a manner similar to how tether head assembly 18 or 118 can be coupled to elongated body 20 as described above. The tether head assembly and tether handle assembly described herein can be used in any suitable combination with one another as part of a tether assembly. Thus, the example combinations of tether head assembly and tether handle assembly described are exemplary and should not be construed as limiting.

[0150] The tether handle assembly 552 includes a housing 558. The pull wire 584 can extend through the elongated member 554 and can include a proximal end housed within the housing 558 of the tether handle assembly 552. The tether handle assembly 552 can further include a plunger 560 configured to cause proximal movement of the pull wire when the user pulls on the pull wire. Proximal movement of the pull wire can enable the inner retainer 36 or 136 to move from a first position to a second position, for example, as described with respect to FIG. Figure 15A Removal of attachment member 14 of IMD 10 from tether head assembly 18 or 118 is described.

[0151] The tether handle assembly 552 can further include a strain relief member 566 attached to the housing 558 at the distal end of the housing 558. The elongated member 554 can be attached to the strain relief member 566 and the pull wire 584 can be housed within the strain relief member 566. In addition to providing strain relief for the elongated member 554 and the pull wire 584 with the elongated member attached to the housing 558 and the pull wire entering the housing, the strain relief member 566 is also electrically conductive and can facilitate sensing of impedance signals or electrical testing of the IMD 10 during delivery at a treatment site, as described herein with respect to the strain relief member 266.

[0152] In the example shown, the housing 558 includes a removable cover portion 596 that can facilitate manufacture of the handle assembly 552. The handle assembly 552 can further include an elastically stretchable band 594 that can be configured to be placed over distal portions of the housing 558 and cover 596 to help hold the components of the tethered handle assembly 552 in place. Figure 15B In the assembled configuration shown in .

[0153] like Figure 15B As shown in FIG, the tether handle assembly 552 includes a locking member 570. The locking member 570 includes opposing buttons 572A and 572B (collectively referred to as "buttons 572"). The locking member 570 also defines a keyhole 574. The tether handle assembly 552 further includes a slidable member 576 that includes a protrusion 578. As long as the protrusion 578 is aligned with the keyhole 574 defined by the locking member 570, the slidable member 576 can slide through the internal channel defined by the locking member 570. Figures 15C-15E, a proximal end 586 of the pull wire 584 can extend from the elongated member 554, through the strain relief member 566, and be housed within the housing 558. The proximal end 586 of the pull wire 584 is attached to the slidable member 576. In the illustrated example, the proximal end 586 of the pull wire 584 is housed within an anchor member 588, which can retain the proximal end 586 of the slidable member 576, thereby attaching the pull wire 584 to the slidable member 576.

[0154] The plunger 560 can include a plug 562 received within a collar 564. The collar 564 defines an internal passage configured to receive a proximal portion of the slidable member 576 including the bayonet locks 580. The plug 562 can be inserted into the internal passage of the collar 564 between the bayonet locks 580 to push the bayonet locks outward and attach the plunger 560 to the slidable member 576.

[0155] In some examples, the tether handle assembly 552 can further include an elastically compressible member 592, such as a spring, positioned between the inner surface of the housing 558 on one end and the enlarged diameter portion 582 of the slidable member 576 on the opposite end. Proximal movement of the slidable member 576 can axially compress the elastically compressible member 592 relative to its longitudinal axis. In some examples, the elastically compressible member 592 can help control the proximal movement of the slidable member 576 as the slidable member 576 moves proximally in response to a user pulling the plunger 560. Additionally or alternatively, the elastically compressible member 592 can be configured to bias the slidable member 576 and / or the plunger 560 to their respective first positions, such as their positions when the plunger 560 has not been pulled. Thus, when the physician releases the plunger 560, the pull wire 584 can be moved distally by the resiliently compressible member 592 to help return the tether head assembly 18 or 118 to the closed configuration, such as, in some instances, returning the inner retainer 36 or 136 to the first position.

[0156] Figure 15C is a perspective view of tether handle assembly 552 with portion 596 of housing 558 removed, illustrating different positions of locking member 570 and plunger 560 of tether handle assembly 552 during use. Figure 15D Both the locking member 570 and the plunger 560 are shown in their first or "home" position. In the first position, the protrusion 578 of the slidable member 576 is not aligned with the keyhole 574 of the locking member 570. Therefore, the plunger 560 is prevented from being pulled distally to its second position.

[0157] Figure 15ELocking member 570 is shown in its second position such that protrusion 578 of slidable member 576 is not aligned with keyhole 574 of locking member 570. A user can move locking member 570 to the second position by pressing button 572A of locking member 570 to move locking member 570 transverse to the longitudinal axis of tether handle assembly 552. For example, after deploying IMD 10, a user can move locking member 570 back to the first position by pressing button 572B. Notably, in the first and second positions of locking member 570, button 572B is more accessible to the user than button 572A, for example to prevent accidental unlocking and deployment of the IMD.

[0158] Figure 16A The locking member 570 is shown in its second position and the plunger 560 has been pulled to its second position. Pulling the plunger 560 to its second position causes the pull wire 584 to move proximally and compress the elastically compressible member 592, thereby storing potential energy. When the physician releases the plunger 560, the elastically compressible member 592 can expand longitudinally, thereby releasing the stored energy and moving the plunger 560 and the slidable member 576 distally. As the slidable member 576 moves distally, the pull wire 584 can also move distally to help return the tether head assembly 18 or 118 to the closed configuration, for example, in some instances, returning the inner retainer 36 or 136 to the first position.

[0159] Figure 14 is an exploded plan view of another example tether handle assembly 652. Figures 15A-15E B is a cross-sectional view of the tether handle assembly 652. The tether handle assembly 652 can be substantially similar to that described above with respect to FIG. Figures 15A-15E For example, components of tether handle assembly 652 having the same reference numerals as components in tether handle assembly 552 may be as described with respect to FIG. Figure 16B Configure and function as described.

[0160] Plunger 660 differs from plunger 560 in that collar 664 defines an aperture 665. Removable housing portion 696 and slidable member 676 also define apertures 697 and 678, respectively. Apertures 697, 665, and 678 align to define a passageway for receiving the lower portion of locking member 670 of tether handle assembly 652 within housing 558. Locking member 670 includes a lower post 674 receivable within a longitudinal lumen defined by resiliently compressible member 675, which biases locking member 670 into a locked position. Locking member 670 further defines an entrance 672 that acts as a keyhole for locking member 670. When locking member 670 is pressed downward and into the unlocked position, thereby compressing resiliently compressible member 675, entrance 672 aligns with a distal edge 667 of aperture 665 defined by collar 664. The alignment of the inlet 672 and the distal edge 667 allows the plunger 660 to be pulled proximally. Figure 17A Locking member 670 is shown in an unlocked position, wherein inlet 672 and distal edge 667 are misaligned and plunger 670 is prevented from being pulled proximally, eg, to open the tether head member and release the IMD.

[0161] Figure 17B is an exploded plan view of another example tether handle assembly 752. Figure 17C is a cross-sectional view of tether handle assembly 752 . Figures 15A-15E is a plan view of the collar portion 764 of the plunger 760 of the tether handle assembly 752. Except as noted herein, the tether handle assembly 752 can be substantially similar to the tether handle assembly 752 described above with respect to FIG. Figures 15A-15E For example, components of tether handle assembly 752 having the same reference numerals as components in tether handle assembly 552 may be as described with respect to FIG. Figure 17B Configure and function as described.

[0162] The plunger 760 differs from the plunger 560 in that the collar 764 includes a cantilevered locking mechanism 770. Additionally, the housing 758 defines an aperture 759 configured to receive a button portion 774 of the locking mechanism 770 when in the locked position. The button portion 774 is coupled to the collar 764 by an arm portion 772 that biases the button portion 774 into the locked position, as shown. ​ When button portion 774 is received in aperture 759 of housing 758, the user is prevented from pulling plunger 760 proximally and releasing IMD 10. The user can press button portion 774 into housing 758, thereby unlocking cantilevered locking mechanism 770 and allowing the user to pull plunger 760 proximally (thereby pulling pull wire 784) and releasing IMD 10.

[0163] The following examples illustrate the techniques described herein.

[0164] Example 1: A tether assembly of a medical device delivery system, the tether assembly including a tether handle assembly, the tether handle assembly including: a shell defining a curved channel, the curved channel defining a first end and a second end; a force transmitter received within the curved channel; a slidable member received within the shell such that a portion of the slidable member is received within the channel at the first end of the channel; and a button defining a proximal surface and including a distal portion received within the channel at the second end of the channel, wherein the button surrounds at least a proximal portion of the slidable member. The tether assembly further includes a pull wire defining a proximal end and a distal end, wherein the proximal end of the pull wire is housed within the housing and retained by the slidable member, wherein the button is configured to move from a first position to a second position in response to application of a distal force to the button, thereby causing the force transmitter to move toward the first end of the curved channel, so that the force transmitter applies a proximal force to the portion of the slidable member housed within the channel, the proximal force causing the slidable member and the pull wire to move proximally.

[0165] Example 2: A tether assembly according to Example 1, wherein the tether handle assembly further includes an elastically compressible member that defines a longitudinal axis and is housed within the housing proximal to the slidable member, wherein the button surrounds at least a proximal portion of the elastically compressible member, and wherein proximal movement of the slidable member compresses the elastically compressible member relative to the longitudinal axis.

[0166] EXAMPLE 3 The tether assembly of example 1 or 2, further comprising a tether head assembly attached to the distal end of the pull wire, wherein the tether head assembly is configured to releasably retain an attachment member of a medical device.

[0167] Example 4: The tether assembly of example 3, wherein the proximal movement of the pull wire effects removal of the attachment member from the tether head assembly.

[0168] Example 5: The tether assembly of example 4, wherein the proximal movement of the pull wire effects removal of the attachment member from the tether head assembly by at least increasing a passage defined by the tether head assembly from a first thickness to a second thickness greater than the first thickness.

[0169] Example 6: A tether assembly according to any one of Examples 1 to 5, wherein the shell defines a proximal end and a distal end, the system further includes a strain relief member defining an inner cavity, wherein the pull wire is housed within the inner cavity defined by the strain relief member, and wherein the strain relief member is attached to the shell at the distal end of the shell.

[0170] Example 7: The tether assembly of Example 6, further comprising an elongated body defining a proximal end, a distal end, and an inner lumen, wherein a portion of the pull wire is received within the elongated body.

[0171] Example 8: The tether assembly of Example 7, wherein the elongated body and the strain relief member are electrically conductive.

[0172] Example 9: A tether assembly according to any one of Examples 1 to 8, wherein the shell defines a proximal end and a distal end, wherein the button defines a proximal surface that is located distal to the proximal end of the shell when the button is in the first position, and wherein applying the distal force to the button includes applying the distal force to the proximal surface.

[0173] Example 10: The tether assembly of any of Examples 1-9, wherein the force transmitter comprises a plurality of balls.

[0174] Example 11: A tether assembly according to any one of Examples 1 to 10, wherein the tether handle assembly further includes a locking member, which is movable from a first position to a second position, in which the locking member restricts actuation of the button and in which the locking member does not restrict actuation of the button.

[0175] Example 12: The tether assembly of Example 11, wherein the housing defines a proximal end, and wherein the locking member includes a cover that extends over the proximal end of the housing when the locking member is in the first position.

[0176] Example 13: The tether assembly of Example 11, wherein the housing defines a longitudinal axis, and wherein the locking member includes a movable pin that physically prevents axial movement of the button relative to the longitudinal axis when the movable pin is in the first position.

[0177] Example 14: A tether assembly of a medical device delivery system, the tether assembly including a tether handle assembly, the tether handle assembly comprising: a housing; a first slidable member defining a first aperture and housed within the housing; a second slidable member housed within the first aperture and defining a second aperture; and at least one gear housed within the aperture defined by the first slidable member and configured to mechanically engage the first and second slidable members. The tether assembly further includes a pull wire defining a proximal end and a distal end, wherein the proximal end of the pull wire is housed within the housing and retained by the second slidable member, wherein the first slidable member is configured to move distally in response to application of a distal force to the first slidable member, and when the first slidable member moves distally, the at least one gear causes the second slidable member and the pull wire to move proximally.

[0178] Example 15: The tether assembly of Example 14, wherein the housing defines a channel, and wherein the pull wire is at least partially received within the channel.

[0179] Example 16: A tether assembly according to Example 14 or 15, wherein the first orifice defines a plurality of first teeth and the second orifice defines a plurality of second teeth, and wherein the gear is configured to mechanically engage the first slidable member and the second slidable member by mechanically engaging at least one first tooth of the plurality of first teeth and at least one second tooth of the plurality of second teeth.

[0180] Example 17: A tether assembly for a medical device delivery system, the tether assembly comprising a handle assembly, the handle assembly comprising: a housing; a slidable member received within the housing; and a plunger coupled to and extending distally from the slidable member. The tether assembly further comprises a pull wire defining a proximal end and a distal end, wherein the proximal end of the pull wire is received within the housing and retained by the slidable member, wherein the plunger is configured to move from a first position to a second position in response to application of a proximal force to the plunger, the proximal force causing the slidable member and the pull wire to move proximally.

[0181] Example 18: A tether assembly according to Example 17, wherein the tether handle assembly further includes an elastically compressible member that defines a longitudinal axis and is housed within the housing, wherein the elastically compressible member surrounds at least a proximal portion of the slidable member, and wherein proximal movement of the slidable member compresses the elastically compressible member relative to the longitudinal axis.

[0182] Example 19: A tether assembly according to Example 17 or 18, wherein the tether handle assembly further includes a locking member that is movable from a first position to a second position, wherein the locking member restricts actuation of the plunger in the first position and wherein the locking member does not restrict actuation of the plunger in the second position.

[0183] Example 20: The tether assembly of Example 19, wherein the housing defines a longitudinal axis, and wherein the locking member comprises a movable pin that physically prevents axial movement of the plunger relative to the longitudinal axis when the movable pin is in the first position.

[0184] Example 21: A tether assembly according to Example 20, wherein the movable pin defines an orifice and the slidable member is received within the orifice, and wherein the movable pin physically prevents axial movement of the plunger relative to the longitudinal axis when the movable pin is in the first position by at least physically preventing axial movement of the slidable member relative to the longitudinal axis.

[0185] Example 22: A method for using a tether assembly of a medical device delivery system, the method comprising: positioning the tether head assembly of the tether assembly at a treatment site of a patient with an attachment member of a medical device housed within a container of the tether head assembly, the tether head assembly being configured to releasably retain the attachment member of the medical device; applying force in a distal direction to an actuator of a tether handle assembly of the tether assembly to cause proximal movement of the pull wire, the proximal movement of the pull wire causing the tether head assembly to open; and moving the tether assembly proximally to remove the attachment member of the medical device from the tether head assembly with the tether head assembly open, thereby delivering the medical device to the treatment site.

[0186] Example 23: A method according to Example 22, wherein the tether handle assembly includes a shell defining a proximal end and a distal end, wherein the actuator includes a button defining a proximal surface, the proximal surface being located distal to the proximal end of the shell when the button is in the first position, and wherein applying the force includes applying the force to the proximal surface.

[0187] Example 24: A method according to Example 22 or 23, wherein the tether handle assembly includes a locking member, and the method further includes moving the locking member from a first position to a second position, wherein the locking member restricts actuation of the actuator, and wherein the locking member does not restrict actuation of the actuator.

[0188] Various aspects of the disclosure have been described. These and other aspects are within the scope of the following claims.

Claims

1. A tether assembly for a medical device delivery system, the tether assembly comprising: A tether handle assembly, the tether handle assembly comprising: a housing defining a curved channel, the curved channel defining a first end and a second end; a force transmitter housed in the curved channel; a slidable member received within the housing such that a portion of the slidable member is received within the channel at the first end of the channel; and a button defining a proximal surface and including a distal portion received within the channel at the second end of the channel, wherein the button surrounds at least a proximal portion of the slidable member; and a pull wire defining a proximal end and a distal end, wherein the proximal end of the pull wire is received within the housing and retained by the slidable member, The button is configured to move from a first position to a second position in response to applying a distal force to the button, thereby causing the force transmitter to move toward the first end of the curved channel, so that the force transmitter applies a proximal force to the portion of the sliding member housed in the channel, and the proximal force causes the sliding member and the pull wire to move proximally.

2. A tether assembly according to claim 1, wherein the tether handle assembly further includes an elastically compressible member, which defines a longitudinal axis and is housed within the housing proximal to the sliding member, wherein the button surrounds at least a proximal portion of the elastically compressible member, and wherein proximal movement of the sliding member compresses the elastically compressible member relative to the longitudinal axis.

3. The tether assembly of claim 1 or 2, further comprising a tether head assembly attached to the distal end of the pull wire, wherein the tether head assembly is configured to releasably retain an attachment member of a medical device.

4. The tether assembly of claim 3, wherein the proximal movement of the pull wire effects removal of the attachment member from the tether head assembly.

5. The tether assembly of claim 4, wherein the proximal movement of the pull wire effects removal of the attachment member from the tether head assembly by at least increasing a passageway defined by the tether head assembly from a first thickness to a second thickness greater than the first thickness.

6. A tether assembly according to claim 1, wherein the shell defines a proximal end and a distal end, the system further includes a strain relief member defining an inner cavity, wherein the pull wire is received within the inner cavity defined by the strain relief member, and wherein the strain relief member is attached to the shell at the distal end of the shell.

7. The tether assembly of claim 6, further comprising an elongated body defining a proximal end, a distal end, and an inner lumen, and wherein a portion of the pull wire is received within the elongated body.

8. The tether assembly of claim 7, wherein the elongated body and the strain relief member are electrically conductive.

9. A tether assembly according to claim 1, wherein the shell defines a proximal end and a distal end, wherein the button defines a proximal surface, the proximal surface being located distal to the proximal end of the shell when the button is in the first position, and wherein applying the distal force to the button includes applying the distal force to the proximal surface.

10. The tether assembly of claim 1, wherein the force transmitter comprises a plurality of balls.

11. The tether assembly of claim 1 , wherein the tether handle assembly further comprises a locking member that is movable from a first position to a second position, wherein the locking member restricts actuation of the button in the first position and does not restrict actuation of the button in the second position.

12. The tether assembly of claim 11, wherein the housing defines a proximal end, and wherein the locking member includes a cover that extends over the proximal end of the housing when the locking member is in the first position.

13. The tether assembly of claim 11, wherein the housing defines a longitudinal axis, and wherein the locking member includes a movable pin that physically prevents axial movement of the button relative to the longitudinal axis when the movable pin is in the first position.

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