WO2025093977A1

WO2025093977A1 - Tether assemblies for medical device delivery systems

Info

Publication number: WO2025093977A1
Application number: PCT/IB2024/060136
Authority: WO
Inventors: Brian P. COLIN
Original assignee: Medtronic Inc
Current assignee: Medtronic Inc
Priority date: 2023-10-31
Filing date: 2024-10-16
Publication date: 2025-05-08
Anticipated expiration: 2026-04-30

Abstract

A tether handle assembly including: a first element coupled to a proximal end of a pull shaft and including: an elongated body; one or more first features; and a second element configured to retain the elongated body, the second element comprising: a housing defining a recess; and one or more second features disposed within the recess, wherein the first element is configured to rotate to transition between a locked orientation and an unlocked orientation, wherein in the locked orientation, the one or more first features are configured to interface with the one or more second features to inhibit movement of the first element relative to the second element, wherein in the unlocked orientation, the first element is configured to move along the longitudinal axis relative to the second element and impart a force along the pull shaft.

Description

TETHER ASSEMBLIES FOR MEDICAL DEVICE DELIVERY SYSTEMS

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63/594,611, filed October 31, 2023, the entire content of which is incorporated herein by reference.

TECHNICAL FIELD

[0002] This disclosure relates generally to medical devices, and, more particularly, to systems for delivering medical devices.

BACKGROUND

[0003] Some types of implantable medical devices (IMDs), such as cardiac pacemakers or implantable cardioverter defibrillators systems, may be used to provide cardiac sensing and therapy for a patient via one or more electrodes. Some IMDs include an implantable pulse generator that includes a housing that encloses electronic components, which may be configured to be implanted subcutaneously in the chest of the patient or within a chamber of a heart of the patient, as examples. IMDs having a pulse generator that is configured to be implanted within a chamber of the heart may be referred to as an intracardiac device or a leadless implantable medical device. A medical device delivery system including a delivery catheter may be used to deliver an intracardiac device transvenously to an implant site within a heart of a patient and release the device after the device has been fixed at the implant site. The medical device delivery system then may be withdrawn from the patient.

SUMMARY

[0004] In general, this disclosure is directed to systems, devices, and methods for inserting a medical device into body of a patient via a medical device delivery system. The medical device delivery system may include a tether assembly including a tether handle assembly and a tether head assembly. The tether head assembly and the tether handle assembly may be coupled via a pull shaft. The medical device (e.g., an intracardiac device) may be releasably coupled to the tether head assembly. A clinician may actuate the tether handle assembly to cause tether head assembly to release the medical device, e.g., within the body of the patient. Tether handle assemblies described herein may include a first element configured to interface with a second element. The clinician may manipulate first element to cause the tether handle assembly to retain or release a medical device. The clinician may rotate the first element form a locked orientation to an unlocked orientation relative to the second element and move the first element in the unlocked orientation to manipulate the tether head assembly to release or retain the medical device.

[0005] The devices, systems, and methods described herein may provide several advantages over other tether assemblies for medical device delivery system. The tether assemblies described herein require the clinician to manipulate the tether handle assembly in two separate motions to release the medical device (e.g., by rotation of the first element to the unlocked orientation and by movement of the first element in the unlocked orientation). The requirement for two separate motions may inhibit unintended release of the medical device from the medical device delivery system within the patient and simplifies the process of releasing the medical device. In some examples described herein, features on the first element and the second element on the tether handle assembly may restrict the range of movement and/or rotation of the first element relative to the second element, which may facilitate consistent and repeatable movement of the first element relative to the second element to manipulate the tether head assembly. In some examples, the restriction of the range of rotation reduces torque applied on the tether head assembly from the tether handle assembly, thereby inhibiting torquing of the tether assembly.

[0006] In some examples, this disclosure describes a tether assembly of a medical device delivery system, the tether assembly comprising: a tether head assembly; and a tether handle assembly coupled to the tether head assembly via a pull shaft, the tether handle assembly comprising: a first element coupled to a proximal end of the pull shaft, the first element comprising: a movable body; one or more first features disposed on the movable body of the first element; and a second element configured to retain at least a portion of the movable body of the first element, the second element comprising: a housing defining a recess sized to receive the at least the portion of the elongated body; and one or more second features disposed within the recess, wherein the first element is configured to rotate about a longitudinal axis of the tether handle assembly to transition between a locked orientation and an unlocked orientation, wherein when the first element is in the locked orientation relative to the second element, the one or more first features are configured to interface with the one or more second features to inhibit movement of the first element relative to the second element along the longitudinal axis, wherein when the first element is in the unlocked orientation relative to the second element, the first element is configured to move along the longitudinal axis relative to the second element and impart a force along the pull shaft, and wherein the tether head assembly is configured to release a medical device in response to the force along the pull shaft.

[0007] In some examples, this disclosure describes a method comprising: advancing a tether head assembly of a tether assembly and a medical device to a target location within a body lumen of a patient, wherein an attachment member of the medical device is retained between an outer retainer and an inner retainer of the tether head assembly; implanting the medical device within tissue of the patient at the target location; rotating a first element of a tether handle assembly relative to a second element of the tether handle assembly from a locked orientation to an unlocked orientation, wherein the tether handle assembly is coupled to the tether head assembly via a pull shaft, wherein at least a portion of an movable body of the first element is disposed within a recess defined by a housing of the second element, and wherein one or more first features disposed on the movable body interface with one or more second features within the recess to inhibit movement of the first element relative to the second element along a longitudinal axis of the tether handle assembly when the first element is in the locked orientation; and retracting the first element proximally relative to the second element along the longitudinal axis when the first element is in the unlocked orientation to cause the pull shaft to retract the inner retainer proximally and release the attachment member of from the tether head assembly. [0008] In some examples, this disclosure describes a tether handle assembly comprising: a first element coupled to a proximal end of a pull shaft, the first element comprising: a movable body; one or more first features disposed on the movable body; and a second element configured to retain at least a portion of the movable body of the first element, the second element comprising: a housing defining a recess sized to receive the at least the portion of the movable body; and one or more second features disposed within the recess, wherein the first element is configured to rotate about the longitudinal axis to transition between a locked orientation and an unlocked orientation, wherein when the first element is in the locked orientation relative to the second element, the one or more first features are configured to interface with the one or more second features to inhibit movement of the first element relative to the second element along a longitudinal axis of the tether handle assembly, wherein when the first element is in the unlocked orientation relative to the second element, the first element is configured to move along the longitudinal axis relative to the second element and impart a proximal force along the pull shaft.

[0009] 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 apparatus and methods described in detail within the accompanying drawings and description below. Further details of one or more examples are set forth in the accompanying drawings and the description below.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 is a conceptual diagram illustrating portions of patient anatomy including potential implant sites for an implantable medical device (IMD).

[0011] FIG. 2 is a conceptual diagram illustrating an example medical device delivery system for delivering an IMD to a location within a heart.

[0012] FIG. 3A is a conceptual diagram illustrating an example tether head assembly of the example medical device delivery system of FIG. 2.

[0013] FIG. 3B is a cross-sectional diagram illustrating a cross-sectional view of the example tether head assembly of FIG. 3A, the cross-section being taken along line A-A of FIG. 3A.

[0014] FIG. 4 is a cross-sectional diagram illustrating a cross-sectional view of the example tether head assembly of FIG. 3A with an inner retainer of the tether head assembly in a retracted position, the cross-section being taken along line A-A of FIG. 3A. [0015] FIG. 5 is a cross-sectional diagram illustrating a cross-sectional view of the example tether head assembly of FIG. 3A with the inner retainer of the tether head assembly in an extended position, the cross-section being taken along line A-A of FIG. 3A.

[0016] FIG. 6A is a conceptual diagram illustrating an example tether handle assembly of the example medical device delivery system of FIG. 2 in a locked orientation.

[0017] FIG. 6B is a conceptual diagram illustrating a first element of the tether handle assembly of FIG. 6A. [0018] FIG. 7A is a cross-sectional diagram illustrating a cross-sectional view of the tether handle assembly of FIG. 6A, the cross-section being taken along line B-B of FIG. 6A.

[0019] FIG. 7B is a cross-sectional diagram illustrating a cross-sectional view of another example of the tether handle assembly of FIG. 6A, the cross-section being taken along line B-B of FIG. 6A.

[0020] FIG. 8A is a conceptual diagram illustrating the tether handle assembly of FIG. 6A in an unlocked orientation.

[0021] FIG. 8B is a conceptual diagram illustrating a front view of the tether handle assembly of FIG. 8A.

[0022] FIG. 9A is a cross-sectional diagram illustrating a cross-sectional view of the tether handle assembly of FIG. 6A in the unlocked orientation and at a distal position, the cross-section being taken along line B-B of FIG. 6A.

[0023] FIG. 9B is a cross-sectional diagram illustrating a cross-sectional view of the tether handle assembly of FIG. 6A in the unlocked orientation and at a proximal position, the cross-section being taken along line B-B of FIG. 6A.

[0024] FIG. 9C is a cross-sectional diagram illustrating a cross-sectional view of the tether handle assembly of FIG. 6A in the locked orientation and at the proximal position, the cross-section being taken along line B-B of FIG. 6A.

[0025] FIG. 10 is a flow chart illustrating an example process of implanting a medical device within a patient via the medical device delivery system of FIG. 2.

[0026] FIG. 11 is a flow chart illustrating an example process of manipulating the tether head assembly of the medical device delivery system of FIG. 2 via the tether handle assembly of the medical device delivery system.

DETAILED DESCRIPTION

[0027] In general, this disclosure describes example medical device delivery systems. Such medical device delivery systems may include a tether assembly comprising a tether head assembly, and tether handle assembly, and a pull shaft (e.g., a pull wire). The tether head assembly is attached to the pull shaft and configured to releasably retain an attachment member of a medical device (e.g., an intracardiac device). In some examples, a tether handle assembly is configured to retain the pull shaft attached to the tether head assembly. The tether handle assembly may include an actuator configured to transmit force to the tether head assembly via the pull shaft and enable removal of the attachment member of a medical device from the tether head assembly at a treatment site within a patient. Although the example tether assemblies are generally described herein as being configured for delivering an implantable medical device (IMD), it should be understood that any of the example tether assemblies described herein alternatively may be configured for delivering other types of medical devices.

[0028] FIG. 1 is a conceptual drawing illustrating portions of patient anatomy including potential implant sites for an IMD. For example, an IMD may be implanted on or within heart 100 of a patient, such as within an appendage 102 of a right atrium (RA), within a coronary vein (CV) via a coronary sinus ostium (CSOS), or in proximity to an apex 104 of a right ventricle (RV). In other examples, an IMD may be implanted on other portions of heart 100 or implanted in locations other than heart 100, such as any suitable implant site in a body of the patient.

[0029] FIG. 2 is a plan drawing illustrating an example medical device delivery system 202 for delivering an IMD (not shown in FIG. 1) to a location within heart 100. Although described herein in the context of delivering an IMD into the vasculature, e.g., heart 100, the devices, systems, and techniques of this disclosure may be used to deliver an IMD to any anatomical location.

[0030] System 202 includes an introducer 204, a delivery catheter 206 and a tether assembly 216. Introducer 204 is an elongated member defining an interior lumen.

Introducer 204 is configured to be inserted, such as by a physician, into a vasculature of a patient to provide a rigid channel, via the interior lumen, through which to insert a medical instrument, a device, or other therapy.

[0031] Delivery catheter 206 is configured to be inserted through the lumen of introducer 204 to deliver an IMD within the vasculature. Delivery catheter 206 includes an elongated shaft 212, a handle 208, and a device cup 210. Handle 208 is disposed at a proximal end of shaft 212, and may include one or more elements (such as buttons, switches, etc.) configured to control the motion of the distal end of shaft 212 and release of the IMD from device cup 210, as examples.

[0032] Device cup 210 is disposed at a distal end of shaft 212. Device cup 210 includes a hollow cylindrical body configured to house and support an IMD while the IMD is being implanted within a vasculature of a patient. For example, a physician may insert the distal end of delivery catheter 206, including device cup 210, through the lumen of introducer 204, which is disposed within a vasculature of a patient. Once device cup 210 has extended through the distal end of introducer 204 and reached an implant site within the patient, the physician may release the IMD from a distal opening 214 of device cup 210 and withdraw delivery catheter 206 proximally through introducer 204.

[0033] Tether assembly 216 extends through a lumen defined delivery catheter, e.g., including handle 208 and shaft 212. Tether assembly 216 includes an elongate body 220, a tether handle assembly 218 at a proximal end of elongate body 220, and a tether head assembly (not shown in FIG. 2) at a distal end of elongate body 220. A pull shaft (not shown in FIG. 2) may extend from tether handle assembly 218 to the tether head assembly through a lumen defined by elongate body 220.

[0034] Tether assembly 216 may be of sufficient length that a clinician may manipulate tether handle assembly 218 to advance the tether head assembly out of distal opening 214 of cup 210. In some examples, with the tether head assembly outside of cup 210, a clinician may attach an IMD to the tether head assembly as described herein. The clinician may then load the IMD into cup 210 via distal opening 214, and advance delivery catheter 206, with tether assembly 216 and the IMD therein, through introducer 204 and into the vasculature.

[0035] FIG. 3A is a conceptual diagram illustrating an example tether head assembly 302 of system 202 of FIG. 2. FIG. 3A illustrates a distal portion 216A of tether assembly 216 with the components of tether assembly 216 in an assembled configuration, including tether head assembly 302 at a distal end of tether assembly 216 along longitudinal axis 301. Elongate body 220 may include a shaft defining a lumen (not shown) in which a portion of a pull shaft 310 is received. Tether head assembly 302 may include inner retainer 318, an outer retainer 320, and a sheath 302. Components of tether assembly 216 may be separately formed of any suitable material. In some examples, one or more of pull shaft 310, inner retainer 318, outer retainer 320, sheath 312, and/or one or more layers of elongate body 220 may be formed of an electrically conductive material, which may help enable testing of placement of an IMD during a procedure to deliver the IMD. One or more components of tether assembly 216 may be manufactured via a technique such as metal injection molding or any other suitable technique. [0036] Inner retainer 218 may be coupled to pull shaft 310 and extends distally of from a distal end of pull shaft 310. A distal portion of outer retainer 320 defines an aperture that includes a receptacle dimensioned to receive an attachment member of the IMD and a passageway. The passageway may extend from a distal end defined by outer retainer 320 proximally to the receptacle and may be narrower than the receptacle.

[0037] A proximal portion of outer retainer 320 may define a channel configured to receive inner retainer 318. Inner retainer 318 may be received within outer retainer 320 in a first position in which a distal portion of inner retainer 318 extends into the passageway, as shown in FIG. 3 A. When inner retainer 318 is in the first position (alternatively referred to herein as the “extend position”), the passageway may be dimensioned to prevent passage of the attachment member of the IMD through the passageway (e.g., the passageway is too narrow to allow passage of the attachment member).

[0038] Proximal movement of pull shaft 310 may cause movement of inner retainer 36 from the first position to a second position (alternatively referred to herein as the “retracted position”) in which inner retainer 318 does not extend into the passageway. Additionally, or alternatively, an application of force to inner retainer 318, e.g., a distal end of inner retainer 318, by the attachment member may cause inner retainer 318 to move from the first position to the second position. With inner retainer 318 in the second position, the passageway may be dimensioned to receive the attachment member. Inner retainer 318 and outer retainer 320 may be received within sheath 312, and more particularly a cavity defined by sheath 312, which may help retain inner retainer 318 within outer retainer 320 and couple outer retainer 320 to elongate body 312.

[0039] In some examples, the configuration of inner retainer 318 and outer retainer 320 may substantially isolate the function of retaining the attachment member of the IMD to tether head assembly 302, rather than pull shaft 310 or another element that extends to tether handle assembly 218. For example, as tether assembly 216 is navigated through curved portions of patient vasculature, the path lengths of pull shaft 310 and/or elongate body 220 may change.

[0040] In the example of tether assembly 216 and other tether assemblies described herein, changes in path length of pull shaft 310 and/or elongate body 220 of tether assembly 216 may not cause substantial proximal or distal movement of inner retainer 318. For example, sheath 312 and/or an elastically-compressible member may help reduce or prevent proximal movement of inner retainer 318 as path lengths of pull shaft 310 and/or elongate body 220 change during navigation of curved vasculature. In this manner, the substantial isolation of the IMD retention function within tether head assembly 302 may help maintain retention of the attachment member as tether assembly 216 is navigated through curved vasculature.

[0041] FIG. 3B is a cross-sectional diagram illustrating a cross-sectional view of tether head assembly 302 of FIG. 3A, the cross-section being taken along line A-A of FIG. 3A. FIG. 3B illustrates tether head assembly 302 with inner retainer 318 in an extended position 300A. Tether head assembly 302 may be disposed at distal end 216A of tether assembly 216, e.g., at a distal end of elongated body 220 of tether assembly 216. Pull shaft 310 extends through a lumen 308 defined by elongate body 220 and into cavity 313 defined by sheath 312. Elastically-compressible member 322, proximal portion 328 of inner retainer 318, and proximal portion 330 of outer retainer 320 are disposed within cavity 313, with a distal portion 332 of elastically-compressible member 322 and proximal portion 328 of inner retainer 318 received within a channel defined by proximal portion 330 of outer retainer 320. Pull shaft 310 extends through lumen 324 defined by elastically-compressible member 322, and is connected to inner retainer 318, e.g., fixedly received within proximal portion 328 of inner retainer 318. Various components of delivery system 202 and tether assembly 216 may be connected by any of a variety of techniques, such as welding, crimping, threading, reflowing, bonding, adhesives, or friction fits.

[0042] Distal portion 319 of inner retainer 318 extends into distal portion 321 of outer retainer 320 to contribute to the definition of receptacle 314. In the illustrated extended position 300A of inner retainer 318, distal portion 319 of inner retainer 318 also extends into passageway 316 to reduce the size of passageway 316 such that a thickness or depth of passageway 316 is smaller than a thickness of attachment member 304 of IMD 305. In the illustrated extended position 300A of inner retainer 318, distal portion 319 of inner retainer 318 may be disposed within a groove defined by distal portion 321 of outer retainer 320, as described herein. In the illustrated extended position 300A of inner retainer 318, elastically-compressible member 322 may be in a relaxed, or lower kinetic energy state. [0043] As illustrated in FIG. 3B, attachment member 304 of IMD 305 may be included as part of a structure that provides a variety of features supporting a variety of functions related to delivery and retrieval of IMD 10. In the illustrated example, attachment member 304 is formed within, and joined to a housing of IMD 305, by a shroud structure 303. In the illustrated example, attachment member 304 comprises a pin (also referred to as a strut) that is welded or otherwise fixedly attached to shroud structure 303. Attachment member 304 provides an elongate holding surface that is spaced apart from a proximal end of the housing of IMD 305 and that extends along a length substantially orthogonal to a longitudinal axis of IMD 305.

[0044] Shroud structure 303 may define a cavity with an opening and attachment member 304 may span and be exposed at the opening. Attachment member 304 may be welded at either end to opposing sides of shroud structure 303. Distal portion 321 of outer retainer 320 may be configured to enter or otherwise interact with shroud structure 303 when attachment member 304 is received within passageway 316 and receptacle 314. The configuration of shroud structure 303 and distal portion 321 of outer retainer 320 may selectively inhibit or allow relative motion of IMD 305 and tether assembly 216 in a variety of directions. It should be understood that shroud structure 303 and attachment member 304 are provided for example only, and that a variety of other attachment members may be configured to be attached to tether assembly 216 as described herein. [0045] FIG. 4 is a cross-sectional diagram illustrating a cross-sectional view of tether head assembly 302 of FIG. 3 A with an inner retainer 318 of tether head assembly 302 in a retracted position 300B, the cross-section being taken along line A-A of FIG. 3 A. FIG. 4 illustrates inner retainer 318 in retracted position 300B and attachment member 304 within receptacle 314 defined by the outer retainer 320. Inner retainer 318 may transition between extended position 300A and retracted position 300B within channel 408 defined by proximal portion 330 of outer retainer 320. Inner retainer 318 may be moved to retracted position 300B by a proximally directed force 402 along longitudinal axis 301 of tether head assembly 302. The proximally directed force may be provided by a pulling force from pull shaft 310 or a pushing force on distal end 326 of inner retainer 318 as attachment member 304 is pushed through passageway 316 and into receptacle 314. Inner retainer 318 may travel within groove 406 defined by outer retainer 320 as inner retainer 318 transitions between extended position 300A and retracted position 300B. As illustrated in FIG. 4, movement of inner retainer 318 to retracted position 300B may compress elastically-compressible member 322, e.g., such that distal portion 332 is no longer located within channel 408. In the compressed state, elastically-compressible member 322 may have higher kinetic energy to be released by expanding in the direction of longitudinal axis 301, thereby moving inner retainer 318 from retracted position 300B to extended position 300 A illustrated in FIG. 3B.

[0046] FIG. 5 is a cross-sectional diagram illustrating a cross-sectional view of tether head assembly 302 of FIG. 3 A with inner retainer 318 of tether head assembly 302 in extended position 300A, the cross-section being taken along line A-A of FIG. 3A. FIG. 5 illustrates attachment member 304 held within receptacle 314 defined by outer retainer 320 by inner retainer 318 being in extended position 300A. Inner retainer 318 may transition from retracted position 300B to extended position 300A in response to a distal acting force 502 along longitudinal axis 301 (e.g., along push wire 310). Receptacle 314 is configured, e.g., sized and shaped, to retain attachment member 304 while allowing distal portion 319 of inner retainer 318 to move past attachment member 304, e.g., through passageway 314. As illustrated in FIG. 5, at least portion 504 of distal portion 319 of inner retainer 318 may contact attachment member 304 when attachment member 304 is positioned within receptable 314, e.g., when inner retainer 318 is in extended position 300A. As described herein, portion 504 may secure attachment member 304 within receptacle 314 and help ensure substantially constant physical contact between attachment member 304 and at least portion 504 of inner retainer 318. The physical contact between attachment member 304 and inner retainer 318 enabled by portion 504 may provide substantially constant electrical contact for conduction of electrical signals, e.g., for impedance monitoring, from IMD 305 to a proximal portion of tether assembly 216.

[0047] FIG. 6A is a conceptual diagram illustrating an example of tether handle assembly 218 of system 202 of FIG. 2 in a locked orientation 600A. Tether handle assembly 218 may define a proximal portion of tether assembly 216. Tether handle assembly 218 may include a first element 602 and a second element 604. First element 602 may be at least partially disposed within a recess defined by second element 604. Second element 604 may be distal to first element 602 along longitudinal axis 601. Second element 604 may contact first element 602 at a first end and elongate body 220 at an opposite end. Pull shaft 310 may extend through elongate body 220 and second element 604 into first element 602. First element 602 may include one or more first features disposed on first element 602. Second element 604 may include one or more second features disposed within the recess defined by second element 604. The one or more first features and the one or more second features may interface to maintain tether handle assembly 218 in locked orientation 600A.

[0048] FIG. 6B is a conceptual diagram illustrating first element 602 of tether handle assembly 218 of FIG. 6A. First element 602 may include a handle 606 and a movable body 608 extending from handle 606. Movable body 608 may be an elongated body. Movable body 608 may be disposed within the recess defined by second element 604. In some examples, as illustrated in FIG. 6B, the one or more first features may include one or more channels disposed within movable body 608. The one or more channels may include one or more first channels 610A, 610B (alternatively referred to herein as “first channels 610”) and one or more second channels 612. Longitudinally adjacent first channels 610 may be connected by second channels 612. Channels 610, 612 may extend from an outer surface of movable body 608 radially inwards and may define reduced-width regions along movable body 608.

[0049] FIG. 7A is a cross-sectional diagram illustrating a cross-sectional view of tether handle assembly 218 of FIG. 6A, the cross-section being taken along line B-B of FIG. 6A. FIG. 7B is a cross-sectional diagram illustrating a cross-sectional view of another example of tether handle assembly 218 of FIG. 6A, the cross-section being taken along line B-B of FIG. 6A. FIGS. 7A and 7B illustrate tether handle assembly 218 in locked orientation 600A.

[0050] Second element 604 may define a recess 702. For example, a housing defining second element 604 may include an inner surface defining recess 702. Recess 702 may be sized to receive movable body 608 of first element 602. First element 602 (e.g., movable body 608 of first element 602) may be partially disposed within recess 702. Pull shaft 310 may extend from first element 602 and into elongate body 220 of tether assembly 216. Pull shaft 310 may be affixed to one or more of movable body 608 or handle 606 of tether assembly 216.

[0051] In some examples, as illustrated in FIG. 7A, a proximal end 708 of pull shaft 310 may be affixed within handle 606 via a fixation feature 706. Fixation feature 706 may include, but are not limited to, a set screw, a bolt, a clamp, or the like. In some examples, as illustrated in FIG. 7B, one or more of movable body 608 or handle 606 may be formed from two or more pieces 707A, 707B (collectively referred to herein as “pieces 707”). Pieces 707 may be affixed to each other to form one or more of handle 606 or movable body 608. When affixed, pieces 707 may affix proximal end 708 of pull shaft 310 within first element 602, e.g., by applying compressive force on proximal end 708 of pull shaft 310.

[0052] As compared to use of fixation feature 706 to affix pull shaft 310 to first element 602, fixation of pull shaft 310 to first element 602 via pieces 707 may inhibit or reduce unintended application of tensile forces on pull shaft 310 along longitudinal axis 601. Insertion of fixation feature 706 within handle 606 may unintentionally apply a tensile force on pull shaft 310, thereby putting pull shaft 310 in tension while tether assembly 216 is in a default state. Reduction or elimination of unintended tensile forces on pull shaft 310 may reduce forces acting on pull shaft 310 along longitudinal axis 601 when pull shaft 310 is in the default state and/or may increase responsiveness of tether head assembly 302 to forces applied by a clinician to tether handle assembly 218.

[0053] First element 602 may include one or more first features disposed on movable body 608 of first element 602. In some examples, wherein movable body 608 is partially disposed within recess 702, the one or more first features may be disposed on a portion of movable body 608 configured to be disposed within recess 702. In some examples, as illustrated in FIG. 7A, the one or more first features may include channels 610, 612 disposed on an outer surface of movable body 608. In some examples, as illustrated in FIG. 7B, the one or more first features includes one or more protrusions 712 extending radially away from the outer surface of movable body 608.

[0054] Second element 604 may include one or more second features disposed within recess 702. In some examples, as illustrated in FIG. 7A, the one or more second features include one or more protrusions 704 extending into recess 702. Protrusion(s) 704 may be removably or permanently disposed within recess 702. For example, protrusion(s) 704 may include bolts or screws configured to be removably inserted into recess 702 to define the one or more second features. In some examples, as illustrated in FIG. 7B the one or more second features include one or more channels disposed along an inner surface of second element 604 defining recess 702. The one or more channels may include one or more first channels 710A, 710B (alternatively referred to herein as “first channels 710”) and one or more second channels connecting longitudinally adjacent first channels.

[0055] The one or more first features of first element 602 may interface with the one or more second features of second element 604 to inhibit movement of first element 602 relative to second element 604 along longitudinal axis 601 when tether handle assembly 218 is in locked orientation 600A. Inhibition of movement of first element 602 in locked orientation 600A may inhibit unintended application of force (e.g., of force 402, force 502) along pull shaft 310 This may inhibit unintended release of IMD 303 from tether head assembly 302 via unintended transition of inner retainer 318 from extended position 300A to retracted position 300B. Instead, the clinician may be required to first transition tether handle assembly from locked orientation 300 A to unlocked orientation 300B prior to moving first element 602 relative to second element 604 along longitudinal axis 601, e.g., to release IMD 305 from tether head assembly 302.

[0056] In some examples, as illustrated in FIG. 7A, protrusion(s) 704 interfaces with channels 610 to inhibit movement of first element 602 while tether handle assembly 218 is in locked orientation 600A. For example, protrusion(s) 704 may interface with sidewalls of channels 610 to inhibit movement of first element 602. In some examples, as illustrated in FIG. 7B, protrusions(s) 712 interfaces with channels 710 to inhibit movement of first element 602 while tether handle assembly 218 is in locked orientation 600A. For example, protrusion(s) 712 may interface with sidewalls of channels 710 to inhibit movement of first element 602 while tether handle assembly 218 is in locked orientation 600A. While FIGS. 7A and 7B illustrate first and second features as protrusions and channels, other example tether handle assemblies may include any other features which, when circumferentially aligned, may interface with each other to inhibit longitudinal movement of one or more of first element 602 or second element 604.

[0057] FIG. 8 A is a conceptual diagram illustrating tether handle assembly 218 of FIG. 6A in an unlocked orientation 600B. FIG. 8B is a conceptual diagram illustrating a front view of tether handle assembly 218 of FIG. 8 A. The clinician may rotate first element 602 around longitudinal axis 601 and relative to second element 604 to orient tether handle assembly 218 in unlocked orientation 600B. The clinician may apply rotational force 802 first element 602 (e.g., to handle 606 of first element 602) to cause first element 602 to rotate relative to second element 604 to unlocked orientation 600B. The first and second features on first element 602 and second element 604, respectively, may be shaped to facilitate rotation of first element 602 in a single direction (e.g., clockwise or counterclockwise) or in either direction.

[0058] In some examples, over-rotation of first element 602 relative to second element 604 (e.g., rotation of first element 602 around longitudinal axis 601 by more than 90 degrees) may cause first element 602 to impart torque on pull shaft 310 and, consequently, on tether head member 302. The first and second features of tether handle assembly 218 may be shaped to restrict rotation of first element 602 (e.g., in a single direction, in either direction) to less than or equal to a threshold angle, e.g., to reduce an amount of torque first elements 604 imparts on pull shaft 310 during transition to unlocked orientation 600B. The threshold angle may be 90 degrees, as illustrated in FIG. 8B, or may be another angle between 0 degrees and 180 degrees (e.g., 30 degrees, 45 degrees, 120 degrees, 135 degrees).

[0059] When tether handle assembly 218 is in unlocked orientation 600B, the clinician may apply rotational force 802 on first element 602 (e.g., on handle 606 of first element 602) to rotate first element 602 back to locked orientation 600A. Rotational force 802 required to transition first element 602 back to locked orientation 600A may have a same amplitude and/or a direction of rotation as rotational force 802 required to transition first element 602 from locked orientation 600A to unlocked orientation 600B. For example, the clinician may rotate first element 602 about longitudinal axis 601 in a first direction to orient tether handle assembly 218 in unlocked orientation 600B and may rotate first element 602 about longitudinal axis 601 in a same or different direction to return tether handle assembly to locked orientation 600B.

[0060] FIG. 9A is a cross-sectional diagram illustrating a cross-sectional view of tether handle assembly 218 of FIG. 6 A in unlocked orientation 600B and having first element 602 at a distal position, the cross-section being taken along line B-B of FIG. 6A. At the distal position, movable body 608 may be a at a distalmost position within recess 702. Protrusion(s) 704 may interface with a proximal-most channel of first channels 610 (e.g., first channel 610B, as illustrated in FIG. 9A) to inhibit further distal movement of movable body 608 within recess 702. When first element 602 is at the distal position, first element 602 may cause tether head assembly 302 to maintain inner retainer 318 in extended position 300A. In some examples, the clinician maintains first element 602 at the distal position to inhibit unintended movement of inner retainer 318 from extended position 300A to retracted position 300B, thereby releasing attachment member 304 from within receptacle 314.

[0061] Tether handle assembly 218 may be in either locked orientation 600A or unlocked orientation 600B while first element 602 is at the distal position. When tether handle assembly 218 is in locked orientation 600A, protrusions(s) 704 may interface with first channel 610B to inhibit proximal movement of first element 602 from the distal position. For example, protrusion(s) 704 may be circumferentially offset from second channel 612 to inhibit movement of protrusion(s) 704 between first channels 610 connected by second channel 612. When tether handle assembly 218 is in locked orientation 600A, protrusion(s) 704 may, in response to a force along longitudinal axis 601, interface with sidewalls of first channel 610B to inhibit movement (e.g., proximal movement) of movable body 608 along longitudinal axis 601.

[0062] The clinician may rotate first element 602 about longitudinal axis 601 to place tether handle assembly 218 in unlocked orientation 600B. As previously described above, the clinician may rotate first element 602 via application of rotational force 802 on first element 602 (e.g., on handle 606 of first element 602).

[0063] When tether handle assembly 218 is in unlocked orientation 600B, first features on first element 602 may not interface with second elements on second element 604, thereby facilitating longitudinal movement of first element 602 relative to second element 604. For example, as illustrated in FIG. 9A, when tether handle assembly 218 is in unlocked orientation 600B, second channel 612 is circumferentially aligned with protrusion(s) 704. Second channel 612 may be sized to receive protrusion(s) 704 and allow movement of protrusion(s) 704 between one of first channels 610 (e.g., first channel 610B) and another of first channels 610 (e.g., first channel 610A) via second channel 612. [0064] FIG. 9B is a cross-sectional diagram illustrating a cross-sectional view of tether handle assembly 218 of FIG. 6 A in unlocked orientation 600B with first element 602 at a proximal position, the cross-section being taken along line B-B of FIG. 6A. When tether handle assembly 218 is in unlocked orientation 600B, the clinician may withdraw first element 602 within recess 702 from the distal position to the proximal position via application of force 804 to first element 602 (e.g., to handle 606 of first element 602). Force 804 may be along longitudinal axis 601 (e.g., proximally along longitudinal axis 601).

[0065] In response to force 804, movable body 608 may travel proximally along longitudinal axis 601 to the proximal position. Since tether handle assembly 218 is in unlocked orientation 600B, the first and second features on first and second element 602, 604 may not interface to inhibit movement of movable body 608. For example, as illustrated in FIG. 9B, protrusion(s) 704 may travel between first channels 610 via second channels 612, thereby facilitating movement of movable body 608 to the proximal position.

[0066] The proximal position of first element 602 may correspond to inner retainer 318 of tether head assembly 302 in retracted position 300B. For example, proximal movement of first element 602 to the proximal position may cause first element 602 to apply force 402 on inner retainer 318, thereby causing inner retainer 318 to retract from extended position 300A to retracted position 300B. A distance between the distal position and the proximal position for first element 602 may be less than, the same as, or greater than, a length of travel of inner retainer 318 from extended position 300A to retracted position 300B.

[0067] The first and second features of first and second elements 602, 604 may interface to inhibit proximal travel of first element 602 past the proximal position. In the example illustrated in FIG. 9B, protrusion(s) 704 interface with a sidewall of first channel 610A to inhibit further proximal movement of first element 602 past the proximal position. Restriction of movement of first element 602 between the distal position and the proximal position may increase controllability of tether head assembly 302 via tether handle assembly 218 and may simplify control of tether head assembly 302 via tether handle assembly 218. For example, the restriction of movement of first element 602 by protrusion(s) 704, first channels 610, and second channel 612 may facilitate repeatable and uniform movement of inner retainer 381 within tether head assembly 302.

[0068] FIG. 9C is a cross-sectional diagram illustrating a cross-sectional view of tether handle assembly 218 of FIG. 6A in locked orientation 600Cand at the proximal position, the cross-section being taken along line B-B of FIG. 6A. Once first element 602 is at the proximal position within recess 702, the clinician may apply rotational force 802 to first element 602 to transition tether handle assembly 218 from unlocked orientation 600B to locked orientation 600C. The clinician may transition tether handle assembly 218 to locked orientation 600C to inhibit unintended movement of first element 602 out of the proximal position (e.g., towards or to the distal position), thereby inhibiting unintended movement of inner retainer 318 from retracted position 600B within tether head assembly 302.

[0069] When the clinician rotates first element 602 to locked orientation 600B, the first and second features are oriented to interface with each other and inhibit longitudinal movement of first element 602. For example, as illustrated in FIG. 9C, when the clinician rotates first element 602 to locked orientation 600B, protrusion(s) 702 are circumferentially offset from second channels 612 (not shown in FIG. 9C), thereby inhibit movement of protrusion(s) 702 between first channels 610 (e.g., between first channel 610A and first channel 610B).

[0070] FIGS. 9A-9C illustrate an example process of manipulating first element 602 to transition from the distal position to the proximal position, e.g., to release IMD 305 from tether head assembly 302 or to allow access to receptacle 314. The clinician may perform the example process illustrated in FIGS. 9A-9C in reverse order to transition first element 602 from the proximal position to the distal position, e.g., to secure IMD 305 to tether head assembly 302 or to restrict access to receptacle 314. Some example processes of operating the example medical device system described herein are discussed in greater detail below.

[0071] FIG. 10 is a flow chart illustrating an example process of implanting a medical device (e.g., IMD 305) within a patient via system 202 of FIG. 2. Although the example process illustrated in FIG. 10 is primarily described with reference to an intracardiac medical device, the example process, devices, and systems described herein may be used for other medical device and/or for implantation of medical devices to other locations within the patient.

[0072] A clinician may navigate tether head assembly 302 and IMD 305 to a target location within the patient (902). IMD 305 and tether assembly 216 may be carried within delivery catheter 206 as it is advanced to the treatment site. The clinician may advance a distal end of delivery catheter 206 to the treatment site via handle 208 connected to shaft 212 of delivery catheter 206. The clinician may determine whether IMD 305 is properly positioned relative to the target location based on an impedance signal sensed via an electrical path including IMD 305, attachment member 304, and one or more components of tether assembly 216 (e.g., inner retainer 318 and/or or one or more other components of tether head assembly 302). In some examples, the clinician determines whether IMD 305 is properly positioned at the target location via one or more imaging techniques including, but is not limited to, fluoroscopy.

[0073] The clinician may implant IMD 305 within tissue at the target location (904). During navigation of delivery catheter 206 to the target location, IMD 305 may be retained within device cup 210 of delivery catheter 206. Once the clinician determines that IMD 305 is properly positioned at the target location, the clinician may advance IMD 305 distally out of device cup 210 via tether assembly 216. For example, the clinician may apply a distal force along tether assembly 216 via tether handle assembly 218 to push tether head assembly 302 and IMD 305 at least partially out of distal opening 214 of device cup 210.

[0074] The clinician may cause one or more fixation features IMD 305 to puncture and affix IMD 305 to the tissue at the target location. Fixation features may include, but are not limited to, tines, coiled elongated bodies (e.g., helical coils), or the like. In some examples, the clinician causes the one or more fixation features to expand and secure IMD 305 to the tissue. In some examples, the clinician advances the one or more fixation features into the tissue to secure IMD 305 to the tissue. In such examples, the clinician may rotate tether handle assembly 218 to cause IMD 305 to rotate and advance the one or more features into the tissue. The clinician may rotate tether handle assembly 218 (e.g., about longitudinal axis 601) while maintaining first element 602 and second element 604 in locked orientation 600A.

[0075] The clinician may rotate first element 602 of tether handle assembly 218 relative to second element 604 from locked orientation 600A to unlocked orientation 600B (906). In some examples, once the clinician determines that IMD 305 is secured to the tissue at the target location, the clinician rotates tether handle assembly 218 to unlocked orientation 600B. When tether handle assembly 218 is in locked orientation 600A, first features (e.g., channels 610, 612, protrusion(s) 712) on first element 602 interface with second features (e.g., protrusion(s) 702, channels 710) on second element 604 to inhibit longitudinal movement of first element 602 relative to second element 604. The clinician may rotate first element 602 to unlocked orientation 600B to facilitate longitudinal movement of first element 602 relative to second element 604, e.g., to detach IMD 305 from tether assembly 216.

[0076] The clinician may apply rotational force 802 to handle 606 cause first element 602 to rotate to unlocked orientation 600B. The clinician may apply rotational force 802 to handle 606 in either clockwise direction or counterclockwise direction. In some examples, the clinician applies rotational force 802 to first element 602 in a single, specific direction to cause first element 602 to rotate. The clinician may rotate first element 602 until the clinician determines (e.g., visually, tactilely) determines that tether handle assembly 218 is in unlocked orientation 600B. In some examples, one or more of first features or second features may be shaped to inhibit rotation of first element 602 relative to second element 604 beyond unlocked orientation 600B, e.g., to inhibit over-rotation of first element 602 and unintended application of torque on pull shaft 310 of tether assembly 216. For example, one or more of first channels 610 or channels 710 may be only extend partially around movable body 608 or the inner surface of second element 604, respectively, to limit a maximum angle of rotation of first element 602. When the clinician rotates first element 602 to unlocked orientation 600B, the first and second features may no longer interface to inhibit longitudinal movement of first element 602 relative to second element 605.

[0077] The clinician may retract first element 602 proximally relative to second element 604 (908). In some examples, as illustrated in FIGS. 3A-5, while attachment member 304 of IMD 305 is disposed within receptacle 314 of tether head assembly 302, inner retainer 318 of tether head assembly 302 may restrict passageway 316 leading to receptacle 314 when inner retainer 318 is at extended position 300A, e.g., to inhibit passage of attachment member 304 out of receptacle 314. By inhibiting passage of attachment member 304 out of receptacle 314, inner retainer 318 secures IMD 305 to tether head assembly 302.

[0078] Once IMD 305 is affixed to target location within the patient, the clinician may detach tether assembly 216 from IMD 305 and remove tether assembly 216 from within the body of the patient. The clinician may proximally refract first element 602 from distal position to a proximal position within recess 702 of second element 604. Retraction of first element 602 to the distal position may transmit a proximal force 402 along pull shaft 310 to inner retainer 318, thereby causing inner retainer 318 to retract from extended position 300A to retracted position 300B. When inner retainer 318 is in retracted position 300B, passageway 316 may be unobstructed by inner retainer 318 and may be sized to facilitate movement of attachment member 304 out of receptacle 314 through passageway 316. [0079] The clinician may release tether head assembly 302 from IMD 305 (910). The clinician may retract tether head assembly 302 proximally to cause tether head assembly 302 to release IMD 305. In some examples, the clinician proximally retracts tether assembly 216 to cause attachment member 304 to exit receptacle 314 via passageway 316. Once attachment member 304 exits passageway 316 of tether head assembly 302, IMD 305 is separated from tether head assembly 302. In some examples, the clinician may rotate first element 602 to locked orientation 600A in the proximal position prior to retracting tether assembly 216, e.g., to inhibit unintended longitudinal movement of inner retainer 318 within tether head assembly 302 while tether head assembly 302 detaches from IMD 305.

[0080] FIG. 11 is a flow chart illustrating an example process of manipulating tether head assembly 302 of system 202 of FIG. 2 via tether handle assembly 218 of system 202. Although the example process illustrated in FIG. 11 is primarily described with reference to an intracardiac medical device, the example process, devices, and systems described herein may be used for other medical device and/or for implantation of medical devices to other locations within the patient.

[0081] A clinician may rotate first element 602 of tether handle assembly 218 relative to second element 604 from locked orientation 600A to unlocked orientation 600B (1002). The clinician may retract first element 602 proximally relative to second element 604 to cause inner retainer 318 within tether head assembly 302 to retract from a first position (e.g., extended position 300A) to a second position (e.g., retracted position 300B) (1004). The clinician may rotate and retract first element 602 in accordance with other example processes previously discussed herein.

[0082] The clinician may position attachment member 304 of IMD 305 in receptacle 314 within tether head assembly (1006). When inner retainer 318 is in retracted position 300B, passageway 316 may be sized to facilitate passage of attachment member 304 of IMD 305 into receptacle 314. The clinician may insert attachment member 304 through passageway 316 until attachment member 304 is disposed within receptacle 314. In some examples, movement of attachment member 304 into receptacle 304 causes inner retainer 38 to retract from extended position 300A to retracted position 300B, e.g., in response to contact between attachment member 304 and distal end 326 of inner retainer 318. For example, the clinician may hold tether head assembly 302 in one hand and press attachment member 304 into passageway 316 defined by outer retainer 308, e.g., against distal end 326 of inner retainer 318, thereby moving inner retainer 318 to the retracted position 300B as attachment member 304 moves through passageway 316 to receptacle 314 and as elastically-compressible member 322 is compressed.

[0083] The clinician may advance first element 602 distally relative to second element 604 to cause inner retainer 318 to advance to the first position (1008). In some examples, inner retainer 318 may return from retracted position 300B to extended position 300A under spring pressure, via the biasing of inner retainer 318 to extended position 300A provided by elastically-compressible member 322. The distal movement of inner retainer 318 to extended position 300A may cause first element 602 to advance from the proximal position to the distal position. In some examples, the clinician manually advances movable body 608 of first element 602 into recess 702 of second element 604 until first element 602 is at the distal position. One or more of first features or second features may inhibit further movement of first element 602 into recess 702 beyond the distal position. When first element 602 is at the distal position, inner retainer 318 is at extended position 300A within tether head assembly 302 and narrows passageway 316 to restrict exit of attachment member 304 from within receptacle 314, thereby securing IMD 305 to tether head assembly 302.

[0084] The clinician may rotate first element 602 relative to second element 604 from unlocked orientation 600B to locked orientation 600C (1010). Once tether handle assembly 218 is in locked orientation 600C, two separate actions are required to cause tether head assembly 302 to release IMD 305. The clinician may need to rotate first element 602 to unlocked orientation 600B and then retract first element 602 from within recess 702 of second element 604 to allow attachment member 204 to exit receptacle 314 of tether head assembly 302. The requirement of the two separate actions may inhibit unintended detachment of IMD 305 from tether assembly 216 during the implantation process for IMD 305.

[0085] The following examples are illustrative of the techniques described herein.

[0086] Example 1: a tether assembly of a medical device delivery system, the tether assembly comprising: a tether head assembly; and a tether handle assembly coupled to the tether head assembly via a pull shaft, the tether handle assembly comprising: a first element coupled to a proximal end of the pull shaft, the first element comprising: a movable body; one or more first features disposed on the movable body of the first element; and a second element configured to retain at least a portion of the movable body of the first element, the second element comprising: a housing defining a recess sized to receive the at least the portion of the elongated body; and one or more second features disposed within the recess, wherein the first element is configured to rotate about a longitudinal axis of the tether handle assembly to transition between a locked orientation and an unlocked orientation, wherein when the first element is in the locked orientation relative to the second element, the one or more first features are configured to interface with the one or more second features to inhibit movement of the first element relative to the second element along the longitudinal axis, wherein when the first element is in the unlocked orientation relative to the second element, the first element is configured to move along the longitudinal axis relative to the second element and impart a force along the pull shaft, and wherein the tether head assembly is configured to release a medical device in response to the force along the pull shaft.

[0087] Example 2: the tether assembly of example 1, wherein the one or more first features comprise two or more channels extending at least partially around a circumference of the elongated body, and wherein the one or more second features comprise one or more protrusions extending into the recess.

[0088] Example 3: the tether assembly of example 1, wherein the one or more first features comprise one or more protrusions extending radially away from an outer surface of the elongated body, and wherein the one or more second features comprise two or more channels extending along an inner surface of the housing, wherein the inner surface defines the recess.

[0089] Example 4: the tether assembly of any of examples 2 and 3, wherein the two or more channels are longitudinally offset along the longitudinal axis.

[0090] Example 5 : the tether assembly of any of examples 2-4, wherein the one or more protrusions are configured to be disposed within the at least one channel of the two or more channels when the first element is in the locked orientation, and wherein the one or more protrusions are configured to travel between channels of the two or more channels when the first element is in the unlocked orientation.

[0091] Example 6 : the tether assembly of example 5, where the two or more channels comprises two or more first channels, wherein longitudinally adjacent first channels of the two or more first channels are connected via a second channel, and wherein when the first element is in the unlocked orientation, the one or more protrusions are configured to travel between longitudinally adjacent first channels of the two or more first channels via the second channel.

[0092] Example 7: the tether assembly of any of examples 2-6, wherein the tether head assembly comprises: an outer retainer defining a passageway configured to receive an attachment member of the medical device; and an inner retainer at least partially disposed within the passageway, wherein the inner retainer is coupled to a distal end of the pull shaft, and wherein the inner retainer is configured to transition between a first position and a second position in response to the force along the pull shaft.

[0093] Example 8: the tether assembly of example 7, wherein when the inner retainer is in the first position, the passageway the inner retainer narrows a width of the passageway and inhibits travel of the attachment member out of the passageway, wherein when the inner retainer is in the second position, the inner retainer increases the width of the passageway to facilitate travel of the attachment member into the passageway.

[0094] Example 9 : the tether assembly of any of examples 7 and 8, wherein a first channel of the two or more channels corresponds to the first position of the inner retainer, and wherein a second channel of the two or more channels corresponds to the second position of the retainer, wherein the second channel is proximal to the first channel.

[0095] Example 10: the tether assembly of example 9, wherein the inner retainer travels a specific distance between the first position and the second position, and wherein the first channel and the second channel are separated by at least the specific distance.

[0096] Example 11: the tether assembly of any of examples 2-10, wherein when the one or more protrusions are disposed within at least one channel of the two or more channels, the one or more protrusions interface with one or more side walls of the at least one channel to inhibit longitudinal movement of the first element relative to the second element.

[0097] Example 12: the tether assembly of any of examples 1-9, wherein the second element extends distal to the elongated body, wherein the first element further comprises a handle attached to and disposed proximally of the elongated body, and wherein the first element is configured to transition between the locked orientation and the unlocked orientation in response to rotation of the handle about the longitudinal axis.

[0098] Example 13: the tether assembly of example 12, wherein the proximal end of the pull shaft is coupled to the handle.

[0099] Example 14: the tether assembly of example 13, wherein the handle comprises a first piece and a second piece, wherein the proximal end of the pull shaft is disposed between the first piece and the second piece, and wherein the pull shaft is affixed to the handle via a compressive force between the first piece and the second piece.

[0100] Example 15: the tether assembly of any of examples 1-14, wherein the one or more first features are configured to interface with the one or more second features to limit rotation of the first element relative to the second element to less than or equal to an angle of rotation.

[0101] Example 16: the tether assembly of example 15, wherein the angle of rotation is 90 degrees.

[0102] Example 17: the tether assembly of any of examples 1-16, wherein the pull shaft comprises a pull wire.

[0103] Example 18: the tether assembly of any of examples 1-17, wherein the movable body comprises an elongated body.

[0104] Example 19: a method comprising: advancing a tether head assembly of a tether assembly and a medical device to a target location within a body lumen of a patient, wherein an attachment member of the medical device is retained between an outer retainer and an inner retainer of the tether head assembly; implanting the medical device within tissue of the patient at the target location; rotating a first element of a tether handle assembly relative to a second element of the tether handle assembly from a locked orientation to an unlocked orientation, wherein the tether handle assembly is coupled to the tether head assembly via a pull shaft, wherein at least a portion of an movable body of the first element is disposed within a recess defined by a housing of the second element, and wherein one or more first features disposed on the movable body interface with one or more second features within the recess to inhibit movement of the first element relative to the second element along a longitudinal axis of the tether handle assembly when the first element is in the locked orientation; and retracting the first element proximally relative to the second element along the longitudinal axis when the first element is in the unlocked orientation to cause the pull shaft to retract the inner retainer proximally and release the attachment member of from the tether head assembly.

[0105] Example 20: the method of example 19, wherein retracting the first element proximally to cause the pull shaft to retract the inner retainer proximally comprises: retracting the first element proximally to cause the pull shaft to retract the inner retainer proximally from a first position to a second position, wherein in the first position, the inner retainer is configured to inhibit movement of the attachment member out of a passageway defined by the outer retainer and the inner retainer, and wherein in the second position, the inner retainer is configured to allow movement of the attachment member out of the passageway.

[0106] Example 21: the method of example 20, further comprising: rotating the first element from the locked orientation to the unlocked orientation; retracting the first element proximally relative to the second element to cause the inner retainer to retract proximally from the first position to the second position; inserting the attachment member of the medical device into the passageway when the inner retainer is in the second position; advancing the first element distally relative to the second element along the longitudinal axis to cause the inner retainer to advance distally from the second position to the first position; and rotating the first element from the unlocked orientation to the locked orientation.

[0107] Example 22: the method of any of examples 19-21, wherein the one or more first features comprise two or more channels extending at least partially around a circumference of the elongated body, and wherein the one or more second features comprise one or more protrusions extending into the recess.

[0108] Example 23: the method of any of examples 19-21, wherein the one or more first features comprise one or more protrusions extending radially away from an outer surface of the elongated body, and wherein the one or more second features comprise two or more channels extending along an inner surface of the housing, wherein the inner surface defines the recess.

[0109] Example 24: the method of any of examples 22 and 23, wherein the two or more channels comprises two or more first channels, wherein longitudinally adjacent first channels of the two or more first channels are connected by a second channel, wherein rotating the first element from the locked orientation to the unlocked orientation circumferentially aligns the one or more protrusions with the second channel, and wherein retracting the first element proximally relative to the second element causes the one or more protrusions to travel between longitudinally adjacent first channels via the second channel.

[0110] Example 25: the method of any of examples 22-24, wherein a first channel of the two or more channels corresponds to the first position, wherein a second channel of the two or more channels corresponds to the second position, and wherein the second channel is proximal to the first channel.

[0111] Example 26: the method of example 25, wherein retracting the first element proximally to cause the inner retainer to retract proximally from the first position to a second position comprises: retracting the first element proximally to cause the inner retainer to retract proximally by a specific distance, and wherein the first channel and the second channel are separated at least the specific distance.

[0112] Example 27: the method of any of examples 19-26, wherein the one or more first features is configured to interface with one or more second features to limit rotation of the first element relative to the second element to less than or equal to an angle of rotation.

[0113] Example 28: the method of example 27, wherein the angle of rotation is 90 degrees.

[0114] Example 29: the method of any of examples 19-28, wherein the pull shaft comprises a pull wire.

[0115] Example 30: a tether handle assembly comprising: a first element coupled to a proximal end of a pull shaft, the first element comprising: a movable body; one or more first features disposed on the movable body; and a second element configured to retain at least a portion of the movable body of the first element, the second element comprising: a housing defining a recess sized to receive the at least the portion of the movable body; and one or more second features disposed within the recess, wherein the first element is configured to rotate about the longitudinal axis to transition between a locked orientation and an unlocked orientation, wherein when the first element is in the locked orientation relative to the second element, the one or more first features are configured to interface with the one or more second features to inhibit movement of the first element relative to the second element along a longitudinal axis of the tether handle assembly, wherein when the first element is in the unlocked orientation relative to the second element, the first element is configured to move along the longitudinal axis relative to the second element and impart a proximal force along the pull shaft.

[0116] Example 31: the tether handle assembly of example 30, wherein the proximal force is configured to cause a tether head assembly coupled to a distal end of the pull shaft to release a medical device.

[0117] Example 32: the tether handle assembly of any of examples 30 and 31, wherein the one or more first features comprise two or more channels extending at least partially around a circumference of the movable body, and wherein the one or more second features comprise one or more protrusions extending into the recess.

[0118] Example 33: the tether handle assembly of any of examples 30 and 31, wherein the one or more first features comprise one or more protrusions extending radially away from an outer surface of the movable body, and wherein the one or more second features comprise two or more channels extending along an inner surface of the housing, wherein the inner surface defines the recess.

[0119] Example 34: the tether handle assembly of any of examples 32 and 33, wherein the one or more protrusions are configured to be disposed within the at least one channel of the two or more channels when the first element is in the locked orientation, and wherein the one or more protrusions are configured to travel between channels of the two or more channels when the first element is in the unlocked orientation.

[0120] Example 35: the tether handle assembly of example 34, where the two or more channels comprises two or more first channels, wherein longitudinally adjacent first channels of the two or more first channels are connected via a second channel, and wherein when the first element is in the unlocked orientation, the one or more protrusions are configured to travel between longitudinally adjacent first channels of the two or more first channels via the second channel.

[0121] Example 36: the tether assembly of any of examples 30-35, wherein the second element is distal to the movable body, wherein the first element further comprises a handle attached to and disposed proximally of the movable body, and wherein the first element is configured to transition between the locked orientation and the unlocked orientation in response to rotation of the handle about the longitudinal axis. [0122] Example 37: the tether assembly of example 36, wherein the proximal end of the pull shaft is coupled to the handle.

[0123] Example 38: the tether assembly of example 37, wherein the handle comprises a first piece and a second piece, wherein the proximal end of the pull shaft is disposed between the first piece and the second piece, and wherein the pull shaft is affixed to the handle via a compressive force between the first piece and the second piece.

[0124] Example 39: the tether assembly of any of examples 30-38, wherein the one or more first features is configured to interface with the one or more second features to limit rotation of the first element relative to the second element to less than or equal to an angle of rotation.

[0125] Example 40: the tether assembly of example 39, wherein the angle of rotation is 90 degrees.

[0126] Example 41: the tether assembly of any of examples 30-40, wherein the pull shaft comprises a pull wire.

[0127] Example 42: the tether assembly of any of examples 30-41, wherein the movable body comprises an elongated body.

[0128] Various aspects of the disclosure have been described. These and other aspects are within the scope of the following claims.

Claims

WHAT IS CLAIMED IS:

1. A tether assembly of a medical device delivery system, the tether assembly comprising: a tether head assembly; and a tether handle assembly coupled to the tether head assembly via a pull shaft, the tether handle assembly comprising: a first element coupled to a proximal end of the pull shaft, the first element comprising: a movable body; one or more first features disposed on the movable body of the first element; and a second element configured to retain at least a portion of the movable body of the first element, the second element comprising: a housing defining a recess sized to receive the at least the portion of the elongated body; and one or more second features disposed within the recess, wherein the first element is configured to rotate about a longitudinal axis of the tether handle assembly to transition between a locked orientation and an unlocked orientation, wherein when the first element is in the locked orientation relative to the second element, the one or more first features are configured to interface with the one or more second features to inhibit movement of the first element relative to the second element along the longitudinal axis, wherein when the first element is in the unlocked orientation relative to the second element, the first element is configured to move along the longitudinal axis relative to the second element and impart a force along the pull shaft, and wherein the tether head assembly is configured to release a medical device in response to the force along the pull shaft.

2. The tether assembly of claim 1, wherein the one or more first features comprise two or more channels extending at least partially around a circumference of the elongated body, and wherein the one or more second features comprise one or more protrusions extending into the recess.

3. The tether assembly of claim 1, wherein the one or more first features comprise one or more protrusions extending radially away from an outer surface of the elongated body, and wherein the one or more second features comprise two or more channels extending along an inner surface of the housing, wherein the inner surface defines the recess.

4. The tether assembly of any of claims 2 and 3, wherein the two or more channels are longitudinally offset along the longitudinal axis.

5. The tether assembly of any of claims 2-4, wherein the one or more protrusions are configured to be disposed within the at least one channel of the two or more channels when the first element is in the locked orientation, and wherein the one or more protrusions are configured to travel between channels of the two or more channels when the first element is in the unlocked orientation.

6. The tether assembly of claim 5, where the two or more channels comprises two or more first channels, wherein longitudinally adjacent first channels of the two or more first channels are connected via a second channel, and wherein when the first element is in the unlocked orientation, the one or more protrusions are configured to travel between longitudinally adjacent first channels of the two or more first channels via the second channel.

7. The tether assembly of any of claims 2-6, wherein the tether head assembly comprises: an outer retainer defining a passageway configured to receive an attachment member of the medical device; and an inner retainer at least partially disposed within the passageway, wherein the inner retainer is coupled to a distal end of the pull shaft, and wherein the inner retainer is configured to transition between a first position and a second position in response to the force along the pull shaft.

8. The tether assembly of claim 7, wherein when the inner retainer is in the first position, the passageway the inner retainer narrows a width of the passageway and inhibits travel of the attachment member out of the passageway, wherein when the inner retainer is in the second position, the inner retainer increases the width of the passageway to facilitate travel of the attachment member into the passageway.

9. The tether assembly of any of claims 7 and 8, wherein a first channel of the two or more channels corresponds to the first position of the inner retainer, and wherein a second channel of the two or more channels corresponds to the second position of the retainer, wherein the second channel is proximal to the first channel.

10. The tether assembly of any of claims 2-9, wherein when the one or more protrusions are disposed within at least one channel of the two or more channels, the one or more protrusions interface with one or more side walls of the at least one channel to inhibit longitudinal movement of the first element relative to the second element.

11. The tether assembly of any of claims 1-9, wherein the second element extends distal to the elongated body, wherein the first element further comprises a handle attached to and disposed proximally of the elongated body, and wherein the first element is configured to transition between the locked orientation and the unlocked orientation in response to rotation of the handle about the longitudinal axis.

12. The tether assembly of claim 11, wherein the proximal end of the pull shaft is coupled to the handle.

13. The tether assembly of claim 12, wherein the handle comprises a first piece and a second piece, wherein the proximal end of the pull shaft is disposed between the first piece and the second piece, and wherein the pull shaft is affixed to the handle via a compressive force between the first piece and the second piece.

14. The tether assembly of any of claims 1-13, wherein the one or more first features are configured to interface with the one or more second features to limit rotation of the first element relative to the second element to less than or equal to an angle of rotation.

15. The tether assembly of claim 14, wherein the angle of rotation is 90 degrees.