Delivery and retrieval system for a medical device

Abstract

A medical system including a tether handle assembly configured to exert a driving force on a tether head assembly using an elongate body. The elongate body is configured to exert the driving force when an actuation member of the tether handle assembly is in an actuation position and cease or fail to exert the driving force when the actuation member is in a rest position. The handle assembly includes a lock member having a blocking position, a clearing position, and a locking position. The lock member is configured to block the actuation member from the actuation position in the blocking position. The lock member is configured to allow the actuation member to position in the actuation position in the clearing position. The lock member is configured to lock the actuation member in the actuation position in the locking position.

Description

DELIVERY AND RETRIEVAL SYSTEM FOR A MEDICAL DEVICE

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 580,956, filed 6 September 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] Various types of implantable medical devices have been implanted for treating or monitoring one or more conditions of a patient. Such implantable medical devices may be adapted to allow medical devices to monitor and / or treat conditions or functions relating to heart, muscle, nerve, brain, stomach, endocrine organs or other organs and their related functions. The implantable medical devices may be implanted at target locations selected to detect a physiological condition of the patient and / or deliver one or more therapies. For example, implantable medical devices may be delivered to locations within an atrium or ventricle of a heart to sense intrinsic cardiac signals and deliver pacing or antitachyarrhythmia shock therapy.

[0004] Some implantable medical devices are sized to be completely implanted within one of the chambers of the heart and / or another anatomical volume of the patient to detect a physiological condition and / or deliver one or more therapies. Such implantable medical devices may utilize delivery and / or retrieval systems to allow a clinician to navigate the implantable medical device (e.g., through vasculature of the patient) to the target location, and / or to retrieve the implantable medical device from the patient. In some examples, the implantable medical device may include one or more anchoring components intended to engage tissues at the target location (e.g., for implantation) and / or disengage from tissue at the target location (e.g., for retrieval).SUMMARY

[0005] In an example, a medical system comprises a tether head assembly configured to establish an engagement configuration to engage an implantable medical device and establish a disengagement configuration to disengage from the implantable medical device, the tether head assembly configured to transition between the engagementconfiguration and the disengagement configuration in response to a driving force exerted on the tether head assembly; a handle assembly including a housing defining an inner volume, the handle assembly including an actuation member having an actuation position and a rest position, and the handle assembly including a lock member having a blocking position, a clearing position, and a locking position; and an elongate body including a proximal body portion coupled to the handle assembly and extending into the inner volume, the elongate body including a distal body portion opposite the proximal body portion, wherein the distal body portion is configured to exert the driving force on the tether head assembly, wherein the actuation member is configured to cause the distal body portion to exert the driving force on the tether head assembly when the actuation member is in the actuation position and cease exerting the driving force on the tether head assembly when the actuation member is in the rest position, wherein the lock member in the blocking position is configured to prevent the actuation member from positioning in the actuation position, wherein the lock member in the clearing position is configured to permit the actuation member to position in the actuation position, and wherein the lock member in the locking position is configured to prevent the actuation member from transitioning from the actuation position to the rest position.

[0006] In an example, a method comprises blocking, using a lock member in a blocking position, an actuation member from transitioning from a rest position to an actuation position, wherein the lock member is configured to prevent the actuation member from positioning in the actuation position when the lock member is in the blocking position, wherein the lock member is configured to permit the actuation member to position in the actuation position when the lock member is in a clearing position, and wherein the lock member is configured to prevent the actuation member from transitioning from the actuation position to the rest position when the lock member is in a locking position; transitioning the lock member from the blocking position to the clearing position; positioning, with the lock member in the clearing position, the actuation member in the actuation position; exerting, using the actuation member in the actuation position, a driving force on a tether head assembly, wherein the actuation member is configured to cause a distal body portion of an elongate body to exert the driving force on the tether head assembly when the actuation member is in an actuation position and configured to cause the distal body portion to cease exerting the driving force on the tether headassembly when the actuation member is in a rest position, wherein a proximal body portion opposite the distal body portion is coupled to a handle assembly supporting the locking member and the actuation member, wherein the proximal body portion extends through an inner volume defined by the handle assembly, and wherein the tether head assembly is configured to transition between an engagement configuration to engage an implantable medical device and a disengagement configuration to disengage from the implantable medical device in response to the driving force exerted on the tether head assembly; positioning, with the actuation member in the actuation position, the lock member in a locking position, wherein the lock member is configured to prevent the actuation member from transitioning from the actuation position to the rest position in the locking position.

[0007] The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.BRIEF DESCRIPTION OF DRAWINGS

[0008] FIG. 1 is a conceptual drawing illustrating portions of patient anatomy including potential implant sites for an implantable medical device (IMD).

[0009] FIG. 2 is a plan drawing illustrating an example medical device delivery system for delivering an IMD to a location within a heart.

[0010] FIG. 3 is a conceptual drawing illustrating, in conjunction with tissue of a heart, a distal portion of the example medical device delivery system of FIG. 2 carrying an example IMD.

[0011] FIG. 4A is a plan view of a distal portion of an example tether assembly and an IMD, where a distal portion of the tether head assembly is outlined.

[0012] FIG. 4B is a cross-sectional view of the distal portion of the tether head assembly and a portion of the IMD of FIG. 4A, with the cross-section taken along line A— A of FIG. 4A.

[0013] FIG. 4C is a cross-sectional view of the distal portion of the tether head assembly and the portion of the IMD of FIG. 4A and FIG. 4B with the tether head assembly in a disengagement configuration, with the cross-section taken along line A — A of FIG. 4A.

[0014] FIG. 4D is a cross-sectional view of the distal portion of the tether head assembly and the portion of the IMD of FIG. 4 A, FIG. 4B, and FIG. 4C with the tether head assembly in an engagement configuration, with the cross-section taken along line A— A of FIG. 4A.

[0015] FIG. 5A is schematic diagram of a tether handle assembly with an actuation member in a rest position and a lock member in a blocking position.

[0016] FIG. 5B is a schematic diagram of the tether handle assembly of FIG. 5A with the actuation member in the rest position and the lock member in a clearing position.

[0017] FIG. 5C is a schematic diagram of the tether handle assembly of FIG. 5A and FIG. 5B with the actuation member in an actuation position and the lock member in the clearing position.

[0018] FIG. 5D is a schematic diagram of the tether handle assembly of FIG. 5A, FIG. 5B, and FIG. 5C with the actuation member in the actuation position and the lock member in a locking position.

[0019] FIG. 6 is a perspective view of a tether handle assembly with an actuation member in a rest position and a lock member in a blocking position.

[0020] FIG. 7 is a cross-section view of the tether handle assembly of FIG. 6, with the cross-section taken along line B-B of FIG. 6.

[0021] FIG. 8 is a perspective view of the tether handle assembly of FIG. 6 and FIG. 7 with the actuation member in the rest position and the lock member in a clearing position.

[0022] FIG. 9 is a perspective view of the tether handle assembly of FIG. 6, FIG. 7, and FIG. 8 with the actuation member in an actuation position and the lock member in a locking position.

[0023] FIG. 10 is a cross-section view of the tether handle assembly of FIG. 9, with the cross-section taken along line B-B of FIG. 6.

[0024] FIG. 11 A is a perspective view of a tether head assembly.

[0025] FIG. 1 IB is an exploded view of the tether head assembly of FIG. 11 A.

[0026] FIG. 11C is a perspective view of an example inner retainer.

[0027] FIG. 1 ID is a perspective view of the inner retainer of FIG. 11C and an example outer retainer.

[0028] FIG. 12A is an exploded view of a tether head assembly.

[0029] FIG. 12B is a perspective view of a portion of the tether head assembly of FIG.12A.

[0030] FIG. 12C is a perspective view of an example inner retainer and example outer retainer of the tether head assembly of FIG. 12A and FIG. 12B.

[0031] FIG. 12D is a cross-section view of the tether head assembly of FIG. 12A, FIG, 12B, and FIG. 12C, with the cross-section taken along line C — C of FIG. 12B.

[0032] FIG. 13 is a schematic block diagram of an IMD.

[0033] FIG. 14 illustrates an example technique for operating a tether handle assembly.DETAILED DESCRIPTION

[0034] This disclosure describes a medical system configured to deliver, position, and / or retrieve an implantable medical device (“IMD”) within an anatomical volume (e.g., a chamber of a heart) within a patient. In general, this disclosure is directed to examples of medical system including tether assemblies and techniques of using such tether assemblies. The medical system includes a tether head assembly configured to engage with and / or disengage from a medical device, e.g., an intracardiac device. Additionally, or alternatively, the medical system includes a tether handle assembly including one or more components configured to transmit a driving force to the tether head assembly via an elongate body (e.g., a pull wire) to cause the tether head assembly to engage with and / or disengage from the medical device. In examples, the tether head assembly is configured to engage the medical device in an engagement configuration and configured to disengage from the medical device in a disengagement configuration. The tether handle assembly may be configured to transmit the driving force via the elongate body and / or cease transmitting the driving force via the elongate body to cause the tether head assembly to transition between the engagement configuration and the disengagement configuration.

[0035] In examples, the tether head assembly is configured to define an aperture to receive an attachment member of the medical device. The tether head assembly may be configured to define a passageway leading to the aperture, such that the attachment member may be received within the aperture via the passageway. In examples, the tether head assembly is configured to vary a size of the passageway to engage with and / or disengage from the medical device. For example, in the engagement configuration, the tether head assembly may be configured such that the passageway is too narrow to permit the attachment member to pass through the passageway to exit (and / or enter) the aperture.In the disengagement configuration, the tether head assembly may be configured such that the passageway is wide enough to permit the attachment member to pass through the passageway to exit (and / or enter) the aperture.

[0036] Hence, as the medical device and tether head assembly transit through vasculature to a target site within a patient, the attachment member may be positioned within the aperture with the tether head assembly in the engagement configuration, such that the attachment member is substantially trapped within the aperture. In proximity to the target site, with the tether head in the engagement configuration, the tether head assembly may transfer driving forces (e.g., axial driving forces and / or rotational torques) to the medical device via the attachment member to engage the medical device with tissue, disengage the medical device from tissue, reposition and / or relocate the medical device, and / or for other reasons. The tether head assembly may transition from the engagement configuration to the disengagement configuration to disengage from the medical device (e.g., to allow the attachment member to exit the aperture via the passageway). For example, with the medical device engaged with tissue and / or otherwise repositioned, the tether head assembly may transition to the disengagement configuration such that movement of the tether head assembly relative to the medical device causes the attachment member to exit the aperture via the passageway, allowing withdrawal of the tether head assembly from the vasculature as the medical device remains implanted at the target site.

[0037] Likewise, the tether head assembly may be configured to capture a medical device to remove and / or reposition the medical device within vasculature. For example, with the tether head assembly in the disengagement configuration, the tether head assembly may be moved relative to the medical device to cause the attachment member to enter the aperture via the passageway. The tether head assembly may transition from the disengagement configuration to the engagement configuration to substantially trap the attachment member within the aperture. With the tether head in the engagement configuration, the tether head assembly may transfer driving forces (e.g., axial driving forces and / or rotational torques) to the medical device via the attachment member to disengage the medical device from tissue, engage the medical device with tissue, reposition and / or relocate the medical device, and / or for other reasons. The tether head assembly may subsequently transition to the disengagement configuration such thatmovement of the tether head assembly relative to the medical device causes the attachment member to exit the aperture via the passageway.

[0038] The tether head assembly is configured to transition between the engagement configuration and the disengagement configuration (e.g., from the engagement configuration to the disengagement configuration) in response to a driving force exerted on the tether head assembly. The medical system further includes an elongate body (e.g., a pull wire) configured to exert the driving force on the tether head assembly. In examples, the elongate body includes a distal portion (“distal body portion”) configured to exert the driving force on the tether head assembly and a proximal portion (“proximal body portion”) opposite the distal body portion. The proximal body portion may be coupled (e.g., mechanically coupled) to the tether handle assembly.

[0039] The tether handle assembly may be configured to exert a driving force on the proximal body portion to cause the distal body portion to exert the driving force on the tether head assembly. In examples, the tether handle assembly includes an actuation member operable by a clinician and configured to cause the tether handle assembly to exert the driving force on the proximal body portion, which may then transfer the driving force to the distal body portion. Hence, in examples, the medical system is configured such that a clinician may control the exertion of driving force on the tether head assembly using the actuation member, such that the clinician may control the transitioning of the tether head assembly between the engagement configuration and the disengagement configuration.

[0040] In examples, the tether handle assembly includes a housing (“handle housing”) defining an inner volume. The proximal body portion may extend through the inner volume. In examples, the proximal body portion defines a proximal end of the elongate body (“proximal body end”) coupled to the handle housing and / or otherwise configured to remain stationary relative to the handle housing.

[0041] As used herein, when the elongate body exerts a driving force on the tether head assembly, this may refer to a force sufficient to cause the tether head assembly to depart from the engagement configuration and / or disengagement configuration, and / or transition between the engagement configuration and the disengagement configuration. In examples, the driving force may refer to a difference between a first force exerted on the tether head assembly by the elongate member when an actuation member is in an actuationposition and a second force exerted on the tether head assembly when the actuation member is in a rest position. It is understood that the medical system may be configured such that the elongate body exerts other forces either intentional or incidental on the tether head assembly instead of or in addition to the driving force.

[0042] The tether head assembly may be configured to hold (e.g., position in) one of the engagement configuration or the disengagement configuration as the elongate body exerts the driving force on the tether head assembly. For example, when the elongate body exerts the driving force on the tether head assembly and causes the tether head assembly to transition from a first configuration (e.g., one of the engagement configuration or the disengagement configuration) to a second configuration (e.g., the other of the engagement configuration or the disengagement configuration), the tether head assembly may be configured to hold the second configuration as long as the elongate body continues to exert the driving force on the tether head assembly.

[0043] In examples, the tether head assembly is biased to the first configuration (e.g., the engagement configuration). For example, the tether head assembly may be configured to transition from the second configuration (e.g., the disengagement configuration) to the first configuration when the elongate body ceases to exert the driving force on the tether head assembly. Stated similarly, the tether head assembly may be biased such that, in the absence of the driving force exerted on the tether head assembly, the tether head assembly tends to assume the first configuration. In some examples, the tether head assembly includes an elastic member configured to cause the tether head assembly to assume the first configuration in the absence of the driving force exerted by the elongate body.

[0044] Hence, the medical system is configured such that a clinician may control the configuration and / or configuration transitions of the tether head assembly through operation of the actuation member. For example, the clinician may cause the tether head assembly to transition to and / or hold the second configuration (e.g., the disengagement configuration) by operating the actuation member such that the elongate body exerts the driving force on the tether head assembly. The clinician may cause the tether head assembly to transition to and / or hold the first configuration (e.g., the engagement configuration) by operating the actuation member such that the elongate body to ceases or otherwise fails to exert the driving force on the tether head assembly.

[0045] In examples, the actuation member is configured to assume (e.g., position in) an actuation position and a rest position. The actuation member may be configured to cause the elongate body to exert the driving force on the tether head assembly in the actuation position. The actuation member may be configured to cause the elongate body to cease exerting and / or fail to exert the driving force on the tether head assembly in the rest position. The actuation member may be configured to cause the tether head assembly to transition between the engagement configuration and the disengagement configuration when the actuation member transitions between the actuation position and the rest position.

[0046] In examples, the tether handle assembly includes an actuation elastic member configured to bias the actuation member in the rest position. For example, actuation elastic member may be configured to drive the actuation member from the actuation position to the rest position. In examples, the actuation member defines an actuation operator (e.g., a push button) configured to drive the actuation member from the rest position to the actuation position (e.g., to overcome the actuation elastic member) when an actuating force is exerted (e.g., by a clinician) on the actuation operator. Hence, the medical system may be configured such that the actuating force on the actuation member (e.g., exerted by a clinician) overcomes the actuation elastic member to drive the actuation member from the rest position to the actuation position, such that the elongate body exerts the driving force on the tether head assembly (e.g., causing the tether head assembly to assume the disengagement configuration). The medical system may be configured such that, in the absence of the actuating force on the actuation member, the actuation elastic member drives the actuation member to the rest position, such that the elongate body fails to exert the driving force on the tether head assembly (e.g., causing the tether head assembly to assume and / or remain in the engagement position).

[0047] The tether handle assembly may include a lock member configured to prevent and / or permit a positioning of the actuation member. In examples, the tether handle assembly is configured such that a repositioning of the lock member (e.g., by a clinician) is required prior to transitioning the actuation member between the rest position and actuation position. Hence, the tether handle assembly may be configured such that repositioning the actuation member (e.g., to cause the tether head assembly to transition from the engagement configuration to the disengagement configuration, or vice-versa) firstrequires a repositioning of the lock member. The necessary positioning of the lock member in preparation for repositioning the actuation member may reduce and / or eliminate inadvertent transitions of the tether head assembly between the engagement configuration and the disengagement configuration, and / or reduce and / or eliminate a need for a clinician to maintain an actuating force on the actuation member in order to retain the tether head assembly in a given configuration.

[0048] The lock member may be configured to assume a blocking position, a clearing position, and a locking position. In the blocking position, the lock member may be configured to prevent the actuation member from positioning in the actuation position. For example, in the blocking position, the lock member may be configured to prevent the actuation member from transitioning from the rest position to the actuation position such that, for example, the tether head assembly remains in an engagement configuration. In the clearing position, the lock member may be configured to permit the actuation member to position in the actuation position. Hence, the tether handle assembly may be configured such that repositioning the actuation member from the rest position to the actuation position requires initially repositioning the lock member from the blocking position to the clearing position.

[0049] In examples, the tether handle assembly includes a lock elastic member configured to bias the lock member toward the blocking position. The lock member may define a lock operator (e.g., a second push button) configured to drive the lock member to the clearing position from the blocking position (e.g., to overcome the lock elastic member) when a locking force is exerted (e.g., by a clinician) on the lock operator. Hence, the tether handle assembly may be configured such that, in order to position the actuation member in the actuation position (to, e.g., place the tether head assembly in the disengagement configuration), a clinician must initially exert the locking force on the lock operator to reposition the lock member from the blocking position to the clearing position.

[0050] The lock member, when in the locking position, may be configured to prevent the actuation member from transitioning from the actuation position to the rest position. In examples, the lock elastic member is configured to drive the lock member toward the locking position from the clearing position. Thus, when the actuation member is in the actuation position and the locking force on the lock operator ceases (e.g., is ceased by a clinician), the lock elastic member may drive the lock member from the clearing positionto the locking position, such that the lock member prevents the actuation member (e.g., under the influence of the actuation elastic member) from returning to the rest position. The tether handle assembly is configured such that an exertion of locking force on the lock operator may drive the lock member from the locking position back to the clearing position, such that the actuation member may return to the rest position from the actuation position.

[0051] Thus, the tether handle assembly is configured such that a repositioning of the lock member is necessary in order to alter a position of the actuation member. For example, in order to reposition the actuation member from the rest position to the actuation position (to, e.g., transition the tether head assembly from the engagement configuration to the disengagement configuration), the lock member must first be positioned from the blocking position to the clearing position. The lock member must be held (e.g., by the exertion of a locking force from a clinician) in the clearing position against the action of the lock elastic member as the actuation member is repositioned to the actuation position (e.g., by the exertion of an actuation driving force by the clinician). To cause the actuation member to remain in the actuation position (e.g., against the actuation elastic member tending to cause a return to the rest position), the locking force on the lock member must be reduced and / or eliminated (e.g., by the clinician) to allow the lock elastic member to drive the lock member from the clearing position to the locking position.

[0052] Once the actuation member is in the actuation position and the lock member is in the locking position, return of the actuation member to the rest position requires an exertion of a locking force on the locking member to drive the locking member from the locking position to the clearing position (e.g., against the action of the lock elastic member), such that the actuation elastic member may drive the actuation member from the actuation position to the rest position. The necessary positioning of the lock member in preparation for repositioning the actuation member may reduce and / or eliminate inadvertent transitions of the tether head assembly between the engagement configuration and the disengagement configuration, and / or reduce and / or eliminate a need for a clinician to maintain an actuating force on the actuation member in order to retain the tether head assembly in a given configuration.

[0053] In examples, the actuation member is configured to substantially deflect the elongate body to cause the elongate body to exert the driving force on the tether head assembly. The deflection of the elongate body may increase the tension in the elongate body, causing the distal body portion coupled to the tether head assembly to exert the driving force on the tether head assembly. For example, the elongate body may be configured to define a rest path from the proximal body portion to the distal body portion when the actuation member is in the rest position (e.g., when the elongate body is not exerting the driving force on the tether head assembly). The elongate body may be configured to define an actuation path from the proximal body portion to the distal body portion when the actuation member is in the actuation position (e.g., when the elongate body is exerting the driving force on the tether head assembly). The actuation member may be configured to cause the elongate body to substantially deflect from the rest path to the actuation path when the actuation member transitions from the rest position to the actuation position. The medical system may be configured such that the elongate body returns to the rest path when the actuation member transitions from the actuation position to the rest position. In examples, the elastic element of the tether head assembly or another elastic element causes the elongate body to return to the rest path.

[0054] In examples, the medical system includes a tether. The tether head assembly may be configured to couple to a distal portion of the tether (“distal tether portion”). The tether handle assembly may be configured to couple a proximal portion of the tether (“proximal tether portion”). In examples, the tether defines a lumen having a proximal opening in the proximal tether portion and a distal opening in the distal tether portion. The elongate body may extend through the lumen (e.g., from the proximal tether opening to the distal tether opening). The tether may be configured to transfer an axial force (e.g., in the distal direction or the proximal direction) from the tether handle assembly to the tether head assembly and / or transfer a rotational torque from the tether handle assembly to the tether head assembly.

[0055] The tether handle assembly may include one or more additional components configured to reduce a possibility of accidental release of the medical device from the tether assembly, such as one or more locks and / or covers. Additionally, or alternatively, the tether handle assembly may enable sensing of electrical signals via an electrical path including the medical device and one or more components including the tether handleassembly, which may help enable a clinician to determine positioning of the delivery and medical device relative to target tissue, attachment of the medical device to target tissue, and how much driving force to apply to an actuator of a tether handle assembly to enable release the medical device from the tether assembly. In examples, the tether handle assembly is configured such that the actuation member may be positioned using a first finger of a human hand (e.g., a thumb) as the lock member is positioned using a second finger of the human hand (e.g., an index finger).

[0056] FIG. 1 is a conceptual drawing illustrating portions of patient anatomy including potential implant sites for an implantable medical device (“IMD”). For example, an IMD may be implanted on or within heart 1 of a patient, such as within an appendage 2 of a right atrium (RA), within a coronary vein (CV) via a coronary sinus ostium (CSOS), or in proximity to an apex 3 of a right ventricle (RV). In other examples, an IMD may be implanted on other portions of heart 1 or implanted in locations other than heart 1, such as any suitable implant site in a body of the patient.

[0057] FIG. 2 is a plan drawing illustrating an example medical device delivery system 4 for delivering an IMD (not shown in FIG. 1) to a location within heart 1. Although described herein in the context of delivering an IMD into the vasculature, e.g., heart 1, the devices, systems, and techniques of this disclosure may be used to deliver an IMD to any anatomical location.

[0058] Medical device delivery system 4 may include an introducer 5, a delivery catheter system 6, and a medical system 12. Introducer 5 is an elongated member defining an interior lumen. Introducer 5 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. Delivery catheter system 6 may be configured to be inserted through the lumen of introducer 5 to deliver an IMD within the vasculature. Delivery catheter system 6 may includes a delivery catheter 9, a handle 7, and a device cup 8. Handle 7 may be disposed at a proximal end of delivery catheter 9, and may include one or more elements (such as buttons, switches, etc.) configured to control the motion of the distal end of delivery catheter 9 and release of the IMD from device cup 8, as examples.

[0059] Device cup 8 may be disposed at a distal end of delivery catheter 9. Device cup 8 includes a body (e.g., a hollow, cylindrical body) configured to house and support anIMD (e.g., IMD 10 described with respect to FIG. 3) while the IMD is being implanted within a vasculature of a patient. For example, a physician may insert the distal end of delivery catheter system 6, including device cup 8, through the lumen of introducer 5, which is disposed within a vasculature of a patient. Once device cup 8 has extended through the distal end of introducer 5 and reached an implant site within the patient, the physician may release the IMD from a distal opening 11 of device cup 8 and withdraw delivery catheter system 6 proximally through introducer 5.

[0060] Medical system 12 may extend through a lumen defined by delivery catheter system 6, e.g., including handle 7 and delivery catheter 9. In examples, medical system 12 includes a tether 20, a tether handle assembly 13, and a tether head assembly (e.g., tether head assembly 18 (FIG. 3)). In examples, handle assembly is disposed (e.g., coupled to) a proximal end of tether 20. In examples, tether head assembly 18 is disposed (e.g., coupled to) a distal end of tether 20. Medical system 12 may include an elongate body (e.g., elongate body 34 (FIG. 4B)) extending from tether handle assembly 13 to tether head assembly 18 through a lumen defined by tether 20. In examples, handle 7 is configured to impart a force in the distal direction D and / or the proximal direction P to tether 20. Tether 20 may be configured to impart a force in the distal direction D and / or the proximal direction P to the tether head assembly. In examples, handle 7 is configured to impart a torque around an axis defined by tether 20 to tether 20. Tether 20 may be configured to impart a torque around the axis defined by tether 20 to the tether head assembly.

[0061] Medical system 12 may be of sufficient length that a clinician may manipulate tether handle assembly 13 to advance tether head assembly 18 out of distal opening 11 of device cup 8. In some examples, with tether head assembly 18 outside of device cup 8, a clinician may attach an IMD to tether head assembly 18 as described herein. The clinician may then load the IMD into device cup 8 via distal opening 11, and advance delivery catheter system 6, with medical system 12 and the IMD therein, through introducer 5 and into the vasculature.

[0062] FIG. 3 illustrates device cup 8 pressed against tissue 15 at the implant site of heart 1. When a clinician is satisfied with the positioning of device cup 8 with respect to tissue 15, the clinician may advance IMD 10 towards distal opening 11 using medical system 12. For example, the clinician may advance IMD 10 towards distal opening 1 Iwhen a longitudinal axis of device cup 8 is generally orthogonal to a plane defined bytissue 15, and / or when device cup 8 is pressed sufficiently against / into tissue 15 such that fixation members 16 of IMD 10 will deploy into the tissue. The clinician may advance IMD 10 toward distal opening 11 using handle assembly 13 to advance medical system 12 distally relative to delivery catheter system 6. Fixation members 16 may be configured to embed into tissue 15, and in some cases pull IMD 10 through distal opening 11 of device cup 8, when advanced through the distal opening 11. While IMD 10 is shown having fixation members 16 that includes a plurality of tine structures, IMD 10 may include any other suitable fixation structure or structures instead of or in addition to the plurality of tine structures, such as, for example, a screw-shaped fixation structure (helix) that may be rotated into tissue 15.

[0063] IMD 10 may, for a time, remain coupled to (e.g., engaged with) medical system 12 while fixed to tissue 15 by fixation members 16. For example, an attachment member 14 of IMD 10 may be coupled to tether head assembly 18. Thus, the clinician may be able to test the fixation of IMD 10 at the implant site and / or remove IMD 10 from the implant site (e.g., and back into device cup 8) for repositioning at a more suitable site, if necessary. Once satisfied with the implantation of IMD 10, the clinician can separate tether head assembly 18 from attachment member 14 and move medical system 12 proximally to withdraw delivery catheter system 6 and medical system 12 from the patient through introducer 5. For example, tether handle assembly 13 may be configured to cause tether head assembly 18 to move from an engagement configuration, in which attachment member 14 is retained within tether head assembly 18, to a disengagement configuration, in which attachment member 14 may be released from tether head assembly 18. With tether head assembly 18 in the disengagement configuration, the clinician may proximally move medical system 12 to remove attachment member 14 from tether head assembly 18, leaving IMD 10 fixed at the treatment site.

[0064] In some examples, the clinician may determine whether device cup 8 and IMD 10 is properly positioned relative to heart 2 based on an impedance or other electrical signal sensed via an electrical path including IMD 10 (e.g., an IMD housing 81 or an IMD electrode 89), attachment member 14, and one or more components of medical system 12 (e.g., one or more components of tether head assembly 18). In addition to the IMD, another electrode of the electrical path may be a reference electrode attached to the patient, or inside the patient but located outside of device cup 8. In some examples, relativelyhigher impedance may be indicative of device cup 8 being positioned flush against, and with adequate depth in, tissue 15 of heart 1, which may be desirable for proper fixation. After deployment of fixation members 16 and IMD 10 from device cup 8, with IMD 10 fixed to tissue 15, an impedance or electrical signal may also indicate the quality of the fixation of IMD 10 to tissue, e.g., based on variations of the impedance during a “tug test” in which a clinician pulls on medical system 12 while attached to IMD 10 and while IMD 10 is fixed to tissue 15.

[0065] In examples, a clinician may secure attachment member 14 of IMD 10 to tether head assembly 18 by pressing attachment member 14 into a passageway defined by tether head assembly 18. In some examples, this may be accomplished by one clinician instead of two or more which may be required in some other example medical device delivery systems. Thus, medical system 12 may reduce the time and complexity associated with a procedure to deliver IMD 10. In some examples, tether head assembly 18 may reduce a possibility of contamination of the medical device or other objects within the surgical field, relative to such other tether assemblies, by reducing the number of people that touch IMD 10 and tether head assembly 18.

[0066] In addition, the clinician may release IMD 10 from tether head assembly 18 without cutting a portion of medical system 12. In some examples, tether head assembly 18 thus may reduce or eliminate drawbacks that may be associated with other types of tether mechanisms, such as tension associated with pulling on such other tether mechanisms (e.g., a loop of string or similar material), potential twisting or binding of such other tether mechanisms, or the like. The re-usability of medical system 12 may mitigate shelf life considerations with respect to medical system 12, medical device delivery system 4, and IMD 10, such as in examples in which IMD 10 includes a drug eluting component with a finite shelf life. For example, medical system 12 and / or medical device delivery system 4 may not necessarily be associated with a finite shelf life when packaged separately from IMD 10.

[0067] As discussed, tether head assembly 18 is configured to assume an engagement configuration to engage IMD 10 and assume a disengagement configuration to disengage from IMD 10. Tether head assembly 18 may be configured to transition between the engagement configuration and the disengagement configuration when elongate body 34 exerts a driving force on tether head assembly 18. Tether head assembly 18 may beconfigured to transition between the engagement configuration and the disengagement configuration when elongate body 34 exerts a driving force on tether head assembly 18. In examples, tether head assembly 18 is configured to vary and / or alter one or more dimensions of a passageway into an aperture when tether head assembly transitions between the engagement configuration and the disengagement configuration. Tether head assembly 18 may be configured to transition between the engagement configuration and the disengagement configuration when elongate body 34 exerts a force on tether head assembly 18.

[0068] For example, FIG. 4A is a side view of a distal portion of medical system 12 including tether head assembly 18, in conjunction with a side view of IMD 10, where tether head assembly 18 is displaced from IMD 10. FIG. 4B is a cross-sectional view of tether head assembly 18 and IMD 10, with tether head assembly 18 defining an aperture 42 and a passageway 46 into aperture 42, and IMD 10 including attachment member 14. In FIG. 4B, tether head assembly 18 is in the engagement configuration, and attachment member 14 is displaced from aperture 42. FIG. 4C is a cross-sectional view of tether head assembly 18 and IMD 10, with tether head assembly 18 in the disengagement configuration, and attachment member 14 is within aperture 42. FIG. 4D is a cross- sectional view of tether head assembly 18 and IMD 10, with tether head assembly 18 in the engagement configuration, and attachment member 14 within aperture 42. In FIG. 4B, 4C, and 4D, the cross-section is taken along line A — A of FIG. 4A in a plane parallel to a longitudinal axis LT of tether head assembly 18.

[0069] Tether head assembly 18 may be configured such that attachment member 14 may be received within aperture 42 via passageway 46. Tether head assembly 18 may be configured to vary a size of passageway 46 to engage with and / or disengage from IMD 10. For example, in FIG. 4B, with tether head assembly 18 in the engagement configuration, tether head assembly 18 is configured to cause passageway 46 to be too narrow to permit attachment member 14 to pass through passageway 46, substantially preventing attachment member 14 from entering aperture 42. In FIG. 4C, with tether head assembly 18 in the disengagement position, tether head assembly 18 is configured to widen passageway 46, such that attachment member 14 may pass through passageway 46 into aperture 42. In FIG. 4D, and with attachment member 14 within aperture 42, tether head assembly has returned to the engagement configuration (e.g., narrowing passageway 46),such that attachment member 14 is substantially trapped within aperture 42. With tether head assembly 18 in the engagement configuration and attachment member 14 within aperture 42 as illustrated in FIG. 4D, tether head assembly may return to the disengagement configuration of FIG. 4C to permit attachment member 14 to exit aperture 42.

[0070] In examples, tether head assembly 18 includes an outer retainer 38 and an inner retainer 36. Outer retainer 38 may at least partially define aperture 42 and passageway 46. For example, a body 39 of outer retainer 38 (“outer retainer body 39”) may at least partially define a boundary of aperture 42 and / or a boundary of passageway 46. In examples, passageway 46 extends from a distal end 63 of outer retainer 38 (“outer retainer distal end 63”) and opens into aperture 42. In examples, outer retainer distal end 63 and / or passageway 46 is distal to aperture 42. A body 37 of inner retainer 36 (“inner retainer body 37”) may be configured to alter the width of passageway 46 (e.g., to cause the passageway to widen or narrow). For example, inner retainer body 37 may be configured to move (e.g., in the proximal direction P and / or the distal direction D) relative to outer retainer body 39 to alter the width of passageway 46. In examples, inner retainer body 36 is configured to move in the proximal direction P relative to outer retainer body 39 when tether head assembly 18 transitions from the engagement configuration to the disengagement configuration (e.g., when tether head assembly 18 widens passageway 46). Inner retainer body 36 may be configured to move in the distal direction D relative to outer retainer body 39 when tether head assembly 18 transitions from the disengagement configuration to the engagement configuration (e.g., when tether head assembly 18 narrows passageway 46).

[0071] Tether head assembly 18 may be configured to transition between the engagement configuration and the disengagement configuration when elongate body 34 exerts a driving force F (FIG. 4C) on tether head assembly 18 (e.g., on inner retainer body 37). In examples, tether head assembly 18 includes an elastic member 60 configured to exert a member force FE (FIGS. 4B-4D) on a portion of tether head assembly 18 (e.g., on inner retainer body 37), and elongate body 34 is configured to overcome member force FE when elongate body 34 exerts driving force F. In examples, elastic member 60 is configured to cause tether head assembly 18 to assume the first configuration (e.g., one of the engagement configuration or the disengagement configuration) when elastic member 60 exerts member force FE. Elongate body 34 may be configured to cause tether headassembly 18 to assume the second configuration (e.g., the other of the engagement configuration or the disengagement configuration) when elongate body 34 exerts driving force F. In some examples, elastic member 60 is configured to cause tether head assembly 18 to assume the engagement configuration when elastic member 60 exerts member force FE in the absence of elongate body 34 exerting driving force F, and elongate body 34 is configured to cause tether head assembly 18 to assume the disengagement configuration when elongate body 34 exerts driving force F and overcomes member force FE.

[0072] In examples, elastic member 60 is configured to define an first length LI when tether head assembly 18 is in the first configuration, and define a second length L2 when tether head assembly 18 is the second configuration. For example, as depicted in FIG. 4B, elastic member 60 may define first length LI when tether head assembly is in the engagement configuration. As depicted in FIG. 4C, elastic member 60 may define second length L2 when tether head assembly 18 is in the disengagement configuration. In examples, first length LI and second length L2 are substantially parallel to the distal direction D and / or the proximal direction P. In some examples, first length LI and second length L2 define a shortest length between a distal end 59 of elastic member 60 (“elastic member distal end 59) and a proximal end 61 of elastic member 60 (“elastic member proximal end 61”) opposite elastic member distal end 59. In some examples, first length LI and second length L2 define a length measured along elastic member 60 between elastic member distal end 59 and elastic member proximal end 61. In examples, elastic member 60 is configured such that member force FE increases as elastic member transitions from first length LI to second length L2. In some examples, elastic member 60 may be configured such that member force FE increases as elastic member transitions from second length L2 to first length LI.

[0073] In examples, a distal portion 35 of elongate body 34 (“distal body portion 35”) exerts driving force F on tether assembly 18. Elongate body 34 may include a proximal portion (e.g., proximal body portion 78 (FIG. 5 A)) coupled to handle assembly 13. Elongate body may be configured such that increasing a tension of proximal body portion 78 causes distal body portion 35 to exert driving force F on tether head assembly 18. In examples, tether handle assembly 13 is configured to increase the tension of proximal body portion 78, such that distal body portion 35 exerts driving force F.

[0074] In examples, tether head assembly 18 is configured to define an aperture 42 to receive attachment member 14 of IMD 10. Tether head assembly 18 may be configured to define a passageway 46 leading to aperture 42, such that attachment member 14 may be received within aperture 42 via passageway 46. Tether head assembly 18 may be configured to vary a size of passageway 46 to engage with and / or disengage from IMD 10. For example, in the engagement configuration, tether head assembly 18 may be configured to cause passageway 46 to be too narrow to permit attachment member 14 to pass through passageway 46, substantially preventing attachment member 14 from exiting (and / or entering) aperture 42. In the disengagement configuration, tether head assembly 18 may be configured to cause passageway 46 to be wider than in the engagement configuration, such that attachment member 14 may pass through passageway 46 to exit (and / or enter) aperture 42.

[0075] Tether handle assembly 13 is configured to exert driving force F on tether head assembly and / or cease exerting driving force F on tether head assembly 18 to control a configuration of tether head assembly. Tether handle assembly 13 may configured such that a clinician may cause tether handle assembly 13 to exert and / or cease exerting driving force F on tether head assembly 18. Tether handle assembly 13 is configured to substantially lock into a configuration exerting driving force F and / or substantially lock into a configuration which ceases and / or fails to exert driving force F on tether head assembly 18, such that tether head assembly 18 substantially maintains one of the engagement configuration or the disengagement configuration until a locking member is operated (e.g., by a clinician). In examples, handle assembly 13 is configured to cause elongate body 34 to exert driving force F and / or cease exerting or fail to exert driving force F based on the position of an actuation member and a lock member.

[0076] For example, FIG. 5A is a schematic illustration of handle assembly 13 including elongate body 34, with an actuation member 70 in a rest position and a lock member 72 in a blocking position. In the rest position, actuation member 70 is configured to cause elongate body 34 to cease exerting or fail to exert driving force F on tether head assembly 18. Lock member 72 is in the blocking position. In the blocking position, lock member 72 prevents actuation member 70 from transitioning from the rest position to the actuation position. Hence, with lock member 72 in the blocking position, movement of actuation member 70 to the actuation position (e.g., to exert driving force F on tether headassembly 18) requires first moving lock member 72 to a position other than the blocking position. Actuation member 70 may be defined by a body 71 of actuation member 70 (“actuator member body 71”). Lock member 72 may be defined by a body 73 of lock member 72 (“lock member body 73”)

[0077] FIG. 5B is a schematic illustration of handle assembly 13 with actuation member 70 in the rest position and lock member 72 in a clearing position (e.g., moved from the blocking position of FIG. 5A). In the clearing position, and although FIG. 5B depicts actuation member 70 remaining in the rest position for clarity, lock member 72 permits a transition of actuation member 70 from the rest position to the actuation position. Hence, with lock member 72 in the clearing position, movement of actuation member 70 to the actuation position (e.g., to exert driving force F on tether head assembly 18) is permitted by lock member 72.

[0078] FIG. 5C is a schematic illustration of handle assembly 13 with actuation member 70 in an actuation position and lock member 72 in the clearing position. In contrast to FIG. 5B, actuation member 70 has transitioned from the rest position to the actuation position to cause elongate body 34 to exert driving force F on tether head assembly 18.

[0079] FIG. 5D is a schematic illustration of handle assembly 13 with actuation member 70 in the actuation position and lock member 72 in a locking position. In the locking position, lock member 72 substantially prevents transition of actuation member 70 from the actuation position to the rest position. Hence, with lock member 72 in the locking position, return of actuation member 70 to the actuation position (e.g., to cease exertion of driving force F on tether head assembly 18) requires first moving lock member 72 to a position other than the locking position (e.g., may require returning lock member 72 to the clearing position of FIG. 5B and 5C).

[0080] Tether handle assembly 13 includes a housing 74 (“handle housing 74”) at least partially surrounding an inner volume 76 of tether handle assembly 13. A proximal portion 78 of elongate body 34 (“proximal body portion 78”) may extend through inner volume 76. In examples, proximal body portion 78 defines a proximal end portion 80 of elongate body 34 (“proximal end portion 80”) configured to remain stationary relative to handle housing 74. For example, proximal end portion 80 may be attached to and / or mechanically coupled to handle housing 74. In examples, handle housing 74 supports an anchoringstructure 75 configured to cause proximal end portion 80 to remain substantially stationary relative to handle housing 74. In examples, proximal end portion 80 is attached and / or coupled (e.g., mechanically coupled) to anchoring structure 75.

[0081] Proximal body portion 78 is configured to cause distal body portion 35 to exert driving force F on tether head assembly 18 when tether handle assembly 13 increases a tension in proximal body portion 78. Proximal body portion 78 may be configured to transmit a tensile force arising from the increased tension to distal body portion 35, causing distal body portion 35 to exert driving force F. In examples, actuation member 70 is configured to increase the tension in proximal body portion 78. For example, actuation member 70 may be configured to cause a first tensile force Fl in proximal body portion 78 when actuation member 70 is in the rest position (FIG. 5A, FIG. 5B), and configured to cause a second tensile force F2 greater than first tensile force Fl in proximal body portion 78 when actuation member 70 is in the actuation position (FIG. 5C, FIG. 5D).

[0082] In examples, elongate body 34 may be configured to define a rest path from proximal body portion 78 to distal body portion 35 when elongate body 34 ceases or fails to exert driving force F on tether head assembly 18. In some examples, as depicted in FIG. 5 A and FIG. 5B, elongate body 34 may be configured define the rest path when actuation member 70 is in the rest position. Proximal body portion 78 may be configured to experience first tensile force Fl when elongate body 34 defines the rest path. First tensile force Fl may arise from, for example, a tension (or lack thereof) experienced by elongate body 34 as a result of mechanical coupling to one or more other components of medical system 12, such as elastic member 60, handle housing 74, and / or other components. For example, first tensile force Fl may be at least partially caused by member force FE from elastic member 60 acting on distal body portion 35 and the coupling of proximal end portion 80 to handle housing 74 (e.g., when elastic member 60 defines first length LI). In some examples, as depicted in FIG. 5a, the rest path defined by elongate body 34 may be a substantially linear path. In other examples, the rest path defined by elongate body 34 may be a curved or curvilinear path.

[0083] Elongate body 34 may be configured to define an actuation path from proximal body portion 78 to distal body portion 35 when elongate body 34 exerts driving force F on tether head assembly 18. In some examples, as depicted in FIG. 5C and FIG. 5D, elongate body 34 may be configured define the actuation path when actuation member 70 is in theactuation position. Proximal body portion 78 may be configured to experience second tensile force F2 (greater than first tensile force Fl) when elongate body 34 defines the actuation path. Proximal body portion 78 is configured to transmit second tensile force F2 to distal body portion 35 to cause distal body portion 35 to exert driving force F (e.g., in a direction opposite second tensile force F2) on tether head assembly 18. In examples, elongate body 34 is a flexible body (e.g., such as a wire or other thin member) configured to flex and / or bend in response to a force imparted on the flexible body.

[0084] Second tensile force F2 may result from, for example, an increased tension experienced by elongate body 34 as a result of an actuator force FA transmitted to elongate body 34 by actuation member 70 and / or an increase in the member force FE exerted by elastic member 60. For example, elongate body 34 may be configured to cause and / or allow elastic member 60 to define first length LI (FIG. 4B) when elongate body 34 defines the rest path. Elongate body 34 may be configured to cause and / or allow elastic member 60 to define second length L2 (FIG. 4C) when elongate body 34 defines the actuation path. Second tensile force F2 (with elongate body 34 defining the actuation path) may be greater than the first tensile force Fl (with elongate body 34 defining the rest path) due at least in part to the increase in spring member force FE as actuation member 70 exerts actuation force FA and elastic member 60 transitions from first length LI to second length L2.

[0085] Actuation member 70 (e.g., actuator member body 71) may be configured to cause elongate body 34 to transition from the rest path to the actuation path. In examples, actuation member 70 is configured to deflect elongate body 34 from the rest path to the actuation path. Hence, actuation member 70 may be configured to cause elongate body 34 to exert driving force F on tether head assembly 18 and / or cause elongate body 34 to cease or fail to exert driving force F on tether head assembly 18. In examples, actuation member 70 is configured to cause elongate body 34 to define the rest path when actuation member 70 is in the rest position (FIG. 5A, FIG. 5B). Actuation member 70 may be configured to cause elongate body 34 to define the actuation path when actuation member 70 is in the actuation position (FIG. 5C, FIG. 5D).

[0086] In examples, actuation member 70 (e.g., actuation member body 71) is configured to move relative to handle housing 74 when actuation member 70 transitions between the rest position and the actuation position. In some examples, actuation member70 may be configured to translate in a substantially linear direction relative to handle housing 74 when actuation member 70 transitions between the rest position and the actuation position. In examples, actuation member 70 defines and / or includes an actuation operator 82 configured to receive an actuating force (e.g., from a clinician). Actuation member 70 may be configured to move relative to handle housing 74 when the actuating force is exerted on actuation operator 82 to, for example, transition from the rest position to the actuation position, such that elongate body 34 transitions from the rest path to the actuation path. In some examples, actuation member 70 is configured to move relative to handle housing 74 in a travel direction DA when actuation member 70 transitions from the rest position to the actuation position.

[0087] In examples, actuation member 70 includes an inner portion 84 (“actuation inner portion 84”) and an outer portion 86 (“actuation outer portion 86”). Actuation member body 71 may define actuation inner portion 84 and / or actuation outer portion 86. Actuation member 70 may be configured to substantially extend through handle housing 74 (e.g., an opening in handle housing 74) such that actuation inner portion 84 remains substantially within inner volume 76 when actuation member 70 moves relative to handle housing 74. In some examples, actuation member 70 is configured such that actuation outer portion 86 (or a portion thereof) remains outside of inner volume 76 at least when actuation member 70 is in the rest position. In examples, actuation operator 82 is supported by and / or comprises a portion of actuation outer portion 86. In examples, actuation inner portion 84 is configured to cause elongate body 34 to transition from the rest path to the actuation path when actuation member 70 transitions from the actuation position to the rest position.

[0088] Actuation member 70 (e.g., actuation inner portion 84) may be configured to impart force FA to elongate body 34 to cause elongate body 34 to transition from the rest path to the actuation path. For example, actuation member 70 (e.g., actuation member body 71) may define a bearing surface 85 configured to exert force FA on proximal body portion 80 when actuation member 70 is in the actuation position. Bearing surface 85 may be configured to contact proximal body portion 80 at least when actuation member 70 is in the actuation position. In examples, bearing surface 85 comprises at least some portion of a boundary defined by actuation member body 71 and defining a slot, channel, or passage through actuation member body 71. Elongate body 34 may be configured such thatproximal body portion 80 passes through the slot, channel, or passage when actuation member 70 is in the actuation position and / or the rest position. In examples, actuation operator 82 is configured to transfer an actuating force imparted on actuation operator 82 (e.g., by a clinician) to actuation inner portion 84 (e.g., via actuation outer portion 86) to cause actuation inner portion 84 to exert actuation force FA on proximal body portion 78.

[0089] Actuation outer portion 86 may extend from handle housing 74 to a lesser or greater degree than that depicted in FIGS. 5A-5D. Actuation member 70 may be configured such that actuation operator 82 extends from, is substantially flush with, or is slightly recessed from an exterior surface 83 of tether head assembly 18 when actuation member 70 is in the actuation position. Exterior surface 83 may be an exterior surface (e.g., a surface outside of inner volume 79) defined by handle housing 74. Further, tether handle assembly 13 may include one or more additional components configured to reduce a possibility of accidental exertion of an actuation force on actuation member 70 (e.g., actuation operator 82), such as one or more locks and / or covers configured to prevent movement of actuation operator 82 and / or actuation member 70 relative to handle housing 74 (e.g., exterior surface 83) unless, for example, the locks and / or covers are positioned to permit the relative movement.

[0090] Tether handle assembly 13 may include an actuation elastic member 88 configured to bias actuation member 70 in the rest position. In examples, actuation elastic member 88 is configured to drive actuation member 70 from the actuation position to the rest position. For example, actuation elastic member 88 may be configured to exert a force FS (e.g., an actuating spring force) on actuation member 70 (e.g., actuation member body 71) which biases actuation member 70 in the rest position. Actuation member 70 may be configured to overcome force FS when an actuating force is exerted (e.g., by a clinician) on actuation operator 82, such that the actuating force causes actuation member 70 to transition from the rest position to the actuation position.

[0091] Although depicted in FIGS. 5A-5D as extending substantially parallel and displaced from actuation member body 71 for clarity, actuation elastic member 88 may be located anywhere and / or act on any portion of actuation member 70. In examples, actuation elastic member 88 is located within inner volume 76. Actuation elastic member 88 may be located anywhere and / or act on any portion of actuation member 70 sufficientto cause actuation elastic member to exert force FS on actuation member 70 (e.g., actuation member body 71).

[0092] In examples, actuation elastic member 88 includes a first end 90 (“actuation elastic member first end 90”) and a second end 92 (“actuation elastic member second end 92”) substantially opposite actuation elastic member first end 90. Actuation elastic member first end 90 may be coupled (e.g., mechanically coupled) to handle housing 74. Actuation elastic member second end 92 may be coupled (e.g., mechanically coupled) to actuation member 70. In examples, actuation elastic member 88 is configured to define a length LAI from actuation elastic member first end 90 to actuation elastic member second end 92 when actuation member 70 is in the rest position. Actuation elastic member 88 may be configured to define a length LA2 from actuation elastic member first end 90 to actuation elastic member second end 92 when actuation member 70 is in the actuation position. Actuation elastic member 88 may be configured to exert force FS on actuation member 70 when actuation elastic member 88 transitions from defining the length LA2 to defining the length LAI. In some examples, actuation elastic member 88 is configured such that force FS increases as elastic member transitions from length LAI to length LA2. In some examples, actuation elastic member 88 is configured such that force FS increases as elastic member transitions from length LA2 to length LAL In some examples, length LAI and / or length LA2 are substantially parallel to travel direction DA.

[0093] In some examples, the length LAI is greater than the length LA2 (e.g., when actuation elastic member 88 is configured to behave similar to a compression spring). In some examples, the length LAI is less than the length LA2 (e.g., when actuation elastic member 88 is configured to behave similar to a tension spring). Actuation elastic member 88 may be configured to drive actuation member 70 from the actuation position to the rest position when actuation elastic member 88 transitions from defining length LA2 to defining length LAL Actuation member 70 may be configured to drive actuation elastic member 88 from defining the length LAI to defining the length LA2 when actuation member 70 transitions from the rest position to the actuation position. In some examples, length LAI and length LA2 define a shortest length between actuation elastic member first end 90 and actuation elastic member second end 92. In some examples, length LAI and length LA2 define a length measured along actuation elastic member 88 between actuation elastic member first end 90 and actuation elastic member second end 92. In someexamples, actuation elastic member 88 is configured such that force FS increases as actuation elastic member transitions from length LAI to length LA2. In some examples, actuation elastic member 88 may be configured such that member force FE increases as elastic member transitions from length LA2 to length LAI.

[0094] Lock member 72 is configured to prevent and / or permit a positioning of actuation member 70. Tether handle assembly 13 may be configured such that a repositioning of lock member 72 (e.g., by a clinician) is required prior to transitioning the actuation member from the rest position to the actuation position and / or from the actuation position to the rest position. The necessary positioning of lock member 72 in preparation for repositioning actuation member 70 may reduce and / or eliminate inadvertent transitions of the tether head assembly 18 between the engagement configuration and the disengagement configuration, and / or reduce and / or eliminate a need for a clinician to maintain an actuating force on actuation operator 82 in order to retain tether head assembly 18 in a given configuration.

[0095] Lock member 72 is configured to assume a blocking position, a clearing position, and a locking position. In the blocking position, as depicted in FIG. 5A, lock member 72 is configured to prevent actuation member 70 from positioning in the actuation position. For example, lock member 72 may be configured such that, in the blocking position, lock member 72 substantially prevents movement of actuation member 70 relative to handle housing 74. Lock member 72 may be configured such that, in the blocking position, lock member 72 substantially prevents actuation member 70 from causing proximal body portion 78 to transition from a rest path to an actuation path (such that, for example, elongate body 34 is substantially prevented from exerting driving force F on tether head assembly 18).

[0096] In examples, in the blocking position (FIG. 5A), lock member 72 is configured to exert a force FB on actuation member 70 to prevent actuation member 70 from moving to the actuation position. In some examples, in the blocking position, lock member 72 is configured to contact actuation member 70 to prevent actuation member 70 from moving to the actuation position. For example, a body 98 of lock member 72 (“lock member body 73”) may define a blocking portion 96 configured to exert the force FB on actuation member 70 when lock member 72 is in the blocking position. Lock member 72 may be configured such that, with lock member in the blocking position, actuation member 70encounters blocking portion 96 when actuation member 70 travels and / or attempts to travel in the travel direction DA from the rest position to the actuation position.

[0097] In the clearing position, as depicted in FIG. 5B, lock member 72 is configured to permit actuation member 70 to position in the actuation position (e.g., to transition from the rest position to the actuation position). Lock member 72 may be configured such that, in the clearing position, lock member 72 permits actuation member 70 to cause proximal body portion 78 to transition from the rest path to the actuation path. For example, when lock member 72 transitions from the blocking position to the clearing position, lock member 72 may be configured to cause blocking portion 96 to move relative to handle housing 74 and / or actuation member 70. Lock member 72 may cause the movement of blocking portion 96 such that actuation member 70 does not encounter blocking portion 96 when actuation member 70 travels and / or attempts to travel in the travel direction DA from the rest position to the actuation position.

[0098] In examples, in the clearing position (FIG. 5B), lock member 72 is configured such a variable displacement DL between actuation member 70 and lock member 72 (e.g., lock member body 73) is present at least until actuation member 70 positions in the actuation position. In examples, actuation member 70 is configured to travel over the variable displacement DL as actuation member 70 transitions to the actuation position. Actuation member 70 and / or lock member 72 may be configured such that variable displacement DL decreases as actuation member 70 transitions from the rest position to the actuation position. In some examples, variable displacement DL is substantially parallel to travel direction DA.

[0099] In examples, lock member 72 (e.g., lock member body 73) defines a clearing portion 102 configured to permit actuation member 70 to position in the actuation position when lock member 72 is in the clearing position. In some examples, clearing portion 102 is a receptacle defined by lock member body 73 and configured receive actuation member 70 when actuation member 70 transitions to and / or positions in the actuation position. Lock member 72 may be configured such that variable displacement DL defines a displacement between actuation member 70 and a boundary of clearing portion 102. In some examples, with lock member 72 in the clearing position, clearing portion 102 is configured to permit actuation member 70 to position in and / or transition to the actuation position when actuation member 70 travels in the travel direction AD. In examples, whenlock member 72 transitions from the blocking position to the clearing position, lock member body 73 is configured to displace blocking portion 96 from a path defined by travel direction DA and insert clearing portion 102 into the path defined by travel direction DA. Lock member 72 (e.g., lock member body 73), may be configured such that a linear translation of lock member 72 (e.g., in the proximal direction P or distal direction D) relative to handle housing 74 displaces blocking portion 96 from the path defined by travel direction DA and inserts clearing portion 102 into the path defined by travel direction DA, such that actuation member 70 may position in and / or transition to the actuation position.

[0100] As an example, FIG. 5C depicts lock member 72 in the clearing position and actuation member 70 having transitioned from the rest position of FIG. 5B to the actuation position of FIG. 5C. The displacement of blocking portion 102 from the path of actuator 70 defined by travel direction DA permits actuation member 70 to position in the actuation position and exert force FA on proximal body portion 78. The exertion of force FA on proximal body portion 78 causes distal body portion 35 to exert driving force FD on tether head assembly 18. Hence, lock member 72 may be configured such that, with lock member 72 in the blocking position (FIG. 5A), blocking portion 96 positions to exert force FB to prevent actuation member 70 from positioning in the actuation position, and, with lock member 72 in the clearing position (FIG. 5B, FIG. 5C), clearing portion 102 positions to receive actuation member 70, such that actuation member 70 may position in the actuation position.

[0100] In the locking position, as depicted in FIG. 5D, lock member 72 is configured to prevent actuation member 70 from transitioning from the actuation position to the rest position. Lock member 72 may be configured such that, in the locking position, lock member 72 (e.g., lock member body 73) and / or tether handle assembly 13 exerts a force FL on actuation member 70 to substantially prevent actuation member 70 from transitioning from the actuation position to the rest position. Force FL may be a reaction force exerted by lock member 72 in response to force FS exerted on actuation member 70 by actuation elastic member 88. Tether handle assembly 13 may be configured such that lock member 72, in the locking position, maintains actuation member 70 in the actuation position when the actuation force on actuation operator 82 ceases (e.g., is ceased by a clinician). Stated similarly, tether head assembly 18 may be configured such that lock member 72, in the locking position, exerts force FL to overcome (e.g., counteract) forceFS, such that actuation member 70 remains in the actuation position even in the absence of the actuation force on actuation operator 82.

[0101] Thus, tether handle assembly 13 may be configured such that, with actuation operator 70 in the actuation position and lock operator 72 in the locking position, a clinician may cease the exertion of force on actuation operator 82 and allow lock member 72 to prevent return to actuation member 70 to the rest position. Hence, once actuation member 70 is in the actuation position and causing elongate body 34 to exert driving force F to transition tether head assembly 18 from a first configuration (e.g., the engagement configuration) to a second configuration (e.g., the disengagement configuration), tether handle assembly 13 may retain tether head assembly in the second configuration as long as lock member 72 remains in the locking position (e.g., regardless of the presence or absence of an actuating force on actuation operator 82). Tether handle assembly 13 may be configured such that positioning lock member 72 in the clearing position (FIG. 5C) from the locking position (FIG. 5D) causes lock member to cease the exertion of force FL, and allows force FS to return actuation member 70 to the rest position.

[0102] In examples, when lock member 72 is in the locking position and actuation member 70 is in the actuation position, lock member 72 and / or tether handle assembly 13 is configured to couple (e.g., mechanically couple) with actuation member 70 to substantially prevent actuation member 70 from transitioning from the actuation position to the rest position. For example, tether handle assembly 13 may define a lock member feature 106 and an actuation member feature 104. Tether handle assembly 13 may be configured such that actuation member 70 is substantially prevented from transitioning from the actuation position to the rest position when lock member feature 106 couples with actuation member feature 104. In some examples, lock member feature 106 is configured to mechanically couple with actuation member feature 104 to substantially prevented actuation member 70 from transitioning from the actuation position to the rest position. In some examples, lock member feature 106 is configured to couple with actuation member feature 104 using another type of coupling which causes lock member 72 and / or tether handle assembly 13 to exert force FL on actuation member 70, such as magnetic coupling and / or other types of coupling.

[0103] Lock member feature 106 may be configured to mechanically mate with actuation member feature 104. In some examples, lock member 72 (e.g., lock memberbody 73) defines lock member feature 106 and / or actuation member 70 (e.g., actuation member body 71) defines actuation member feature 104. In some examples, actuation inner portion 84 defines actuation member feature 104. Tether handle assembly 13 may be configured such that lock member feature 106 and actuation member feature 104 position within inner volume 76 at least when lock member feature 106 couples with actuation member feature 104.

[0104] In examples, lock member feature 106 defines one of a recess or a protrusion and actuation member feature 104 defines the other of the recess or the protrusion. Lock member feature 106 and actuation member feature 104 may be configured such that the recess receives the protrusion when lock member 72 is in the locking position and actuation member 70 is in the actuation position. For example, when lock member 72 transitions from the clearing position to the locking position, lock member 72 and / or actuation member 70 may be configured to cause the recess to receive the protrusion. In some examples, lock member feature 106 and / or actuation member feature 104 may be configured to substantially prevent actuation member 70 from transitioning from the actuation position to the rest position when lock member feature 106 is coupled to and / or in sliding contact with actuation member feature 104.

[0105] As discussed, tether handle assembly 13 may be configured such that positioning lock member 72 in the clearing position (FIG. 5C) from the locking position (FIG. 5D) allows actuation member 70 to return to the rest position from the actuation position. In examples, lock member 72 is configured to generate a displacement between lock member feature 106 and actuation member feature 104 when lock member 72 transitions from the locking position to the clearing position. The displacement may cause lock member to cease the exertion of force FL, such that force FS exerted by actuation elastic member 88 may return actuation member 70 to the rest position.

[0106] Hence, tether handle assembly 13 may be configured such that repositioning actuation member 70 (e.g., to cause tether head assembly 18 to transition from the engagement configuration to the disengagement configuration, or vice-versa) first requires a repositioning of lock member 72. The necessary positioning of lock member 72 in preparation for repositioning actuation member 70 may reduce and / or eliminate inadvertent transitions of tether head assembly 18 between the engagement configuration and the disengagement configuration, and / or reduce and / or eliminate a need for a clinicianto maintain an actuating force on actuation operator 82 in order to retain tether head assembly 18 in a given configuration.

[0107] Lock member 72 may be configured to move relative to handle housing 74 when lock member 72 transitions from one of blocking position, the clearing position, or the locking position to another of the blocking position, the clearing position, or the locking position. In examples, lock member 72 may be configured to translate in a substantially linear direction relative to handle housing 74 (e.g., in the proximal direction P and / or the distal direction D). Lock member 72 may include and / or define lock operator 108 configured to receive a locking force (e.g., from a clinician). Lock member 72 may be configured to move relative to handle housing 74 when the locking force is exerted on lock operator 108 to, for example, transition from the blocking position to the clearing position, such that blocking portion 96 permits actuation member 70 to position in the actuation position. In examples, lock member 72 is configured to move relative to handle housing 74 in a direction substantially perpendicular to the travel direction DA when lock member 72 transitions from one of blocking position, the clearing position, or the locking position to another of the blocking position, the clearing position, or the locking position.

[0108] In examples, lock member 72 includes an inner portion 110 (“lock inner portion 110”) and an outer portion 112 (“lock outer portion 112”). Lock member 72 may be configured to substantially extend through handle housing 74 (e.g., an opening in handle housing 74) such that such that lock inner portion 110 remains substantially within inner volume 76 when lock member 72 moves relative to handle housing 74. In some examples, lock member 72 is configured such that lock outer portion 112 remains outside of inner volume 76 at least when lock member 72 is in the blocking position. In examples, lock operator 108 is supported by and / or a portion of lock outer portion 112. In examples, lock inner portion 110 defines clearing portion 102 and / or lock member feature 106. Lock inner portion 110 may be configured to impart force FL to actuation member 70 to substantially prevent actuation member 70 from transitioning from the actuation position to the rest position. In examples, actuation operator 82 is configured to transfer a locking force imparted on lock operator 108 (e.g., by a clinician) to lock inner portion 110 (e.g., via lock outer portion 112 to cause lock inner portion 110 to transition from the blocking position to the clearing position.

[0109] Lock outer portion 112 may extend from handle housing 74 to a lesser or greater degree than that depicted in FIGS. 5A-5D. Lock member 72 may be configured such that lock operator 108 extends from, is substantially flush with, or is slightly recessed from an exterior surface 109 of tether head assembly 18 when lock member 72 is in the lock position and / or the clearing position. Exterior surface 109 may be an exterior surface (e.g., a surface outside of inner volume 79) defined by handle housing 74. Further, tether handle assembly 13 may include one or more additional components configured to reduce a possibility of accidental exertion of a locking force on lock member 72 (e.g., lock operator 108), such as one or more locks and / or covers configured to prevent movement of lock operator 108 and / or lock member 72 relative to handle housing 74 (e.g., exterior surface 109) unless, for example, the locks and / or covers are positioned to permit the relative movement.

[0110] Tether handle assembly 13 may include a lock elastic member 114 configured to bias lock member 72 in and / or toward the blocking position. For example, lock elastic member 114 may be configured to bias lock member 72 in a direction from the clearing position (FIG. 5B, FIG. 5C) to the blocking position (FIG. 5A). In examples, lock elastic member 114 is configured to drive lock member 72 from the clearing position to the blocking position (e.g., when actuation member 70 is in the rest position). For example, lock elastic member 114 may be configured to exert a force FP (e.g., a locking spring force) on lock member 72 which biases lock member 72 in the blocking position when actuation member 70 is in the rest position. Lock member 72 may be configured to overcome force FP when a locking force is exerted (e.g., by a clinician) on lock operator 108, such that the locking force causes lock member 72 to transition from the blocking position to the clearing position.

[0111] Lock elastic member 114 may be configured to drive lock member 72 from the clearing position (FIG. 5B, FIG. 5C) to the locking position (FIG. 5D). For example, when lock member 72 is in the clearing position and actuation member 70 is in the actuation position (FIG. 5C), and when the locking force on lock operator 108 is ceased (e.g., when a clinician ceases to exert the locking force), lock elastic member 114 may exert force FP to drive lock member 72 to the locking position. Hence, with actuation member 70 in the actuation position and lock member 72 driven to the locking position by lock elastic member 114, tether handle assembly is configured to maintain tether head assembly 18 ina given configuration (e.g., the disengagement configuration) when a clinician ceases exertion of an actuation force on actuation operator 82 and exertion of a locking force on locking operator 108.

[0112] In examples, lock elastic member 114 is configured cause lock member feature 106 to couple with actuation member feature 104 when actuation member 70 is in the actuation position. For example, when lock member 72 is in the clearing position and actuation member 70 is in the actuation position (FIG. 5C), lock elastic member 114 may be configured to exert force FP such that lock member feature 106 couples with actuation member feature 104 (as depicted in FIG. 5D). In examples, when lock member feature 106 defines one of a protrusion or a recess and actuation member feature 104 defines the other of the protrusion of the recess, lock elastic member 114 may be configured such that force FP tends to maintain the protrusion within the recess and / or causes the protrusion to insert with the recess.

[0113] Although depicted in FIGS. 5A-5D as extending substantially parallel to and acting on an end of lock member body 73 for clarity, lock elastic member 114 may be located anywhere and / or act on any portion of lock member 72. In examples, lock elastic member 114 is located within inner volume 76. Lock elastic member 114 may be located anywhere and / or act on any portion of lock member 72 sufficient to cause lock elastic member 114 to exert force FP on lock member 72 (e.g., lock member body 73).

[0114] In examples, lock elastic member 114 includes a first end 116 (“lock elastic member first end 116”) and a second end 118 (“lock elastic member second end 118”) substantially opposite lock elastic member first end 116. Lock elastic member first end 116 may be coupled (e.g., mechanically coupled) to handle housing 74. Lock elastic member second end 118 may be coupled (e.g., mechanically coupled) to lock member 72. In examples, lock elastic member 114 is configured to define a length LL1 from lock elastic member first end 116 to lock elastic member second end 118 when lock member 72 is in the locking position. Lock elastic member 114 may be configured to define a length LL2 from lock elastic member first end 116 to lock elastic member second end 118 when lock member 72 is in the clearing position. Lock elastic member 114 may be configured to define a length LL3 from lock elastic member first end 116 to lock elastic member second end 118 when lock member 72 is in the locking position.

[0115] Lock elastic member 114 may be configured to exert force FP on lock member 72 when lock elastic member 114 transitions from defining the length LL2 or LL3 to defining the length LL1. In some examples, actuation elastic member 88 is configured such that force FP increases as elastic member transitions from length LL1 to one of length LL2 or length LL3. In some examples, lock elastic member 114 is configured such that force FP increases as elastic member transitions from one of length LL2 or length LL3 to length LL1. In some examples, length LL1, length LL2, and / or length LL3 are substantially parallel to travel direction DA.

[0116] In some examples, the length LL1 is greater than the length LL2 and / or the length LL3 (e.g., when lock elastic member 114 is configured to behave similar to a compression spring). In some examples, the length LL1 is less than the length LL2 and / or the length LL3 (e.g., when lock elastic member 114 is configured to behave similar to a tension spring). Lock elastic member 114 may be configured to drive lock member 72 from the clearing position to the locking position when lock elastic member 114 transitions from defining length LL2 to defining length LL3. Lock elastic member 114 may be configured to drive lock member 72 from the clearing position to the blocking position when lock elastic member 114 transitions from defining length LL2 to defining length LL1. Lock member 72 (e.g., locking member body 73) may be configured to drive lock elastic member 114 from defining the length LL1 to defining the length LL2 when lock member 72 transitions from the blocking position to the clearing position. Lock member 72 (e.g., locking member body 73) may be configured to drive lock elastic member 114 from defining the length LL3 to defining the length LL2 when lock member 72 transitions from the locking position to the clearing position.

[0117] In some examples, length LL1, length LL2, and length LL3 define a shortest length between lock elastic member first end 116 and lock elastic member second end 118. In some examples, length LL1, length LL2, and length LL3 define a length measured along lock elastic member 114 between lock elastic member first end 116 and lock elastic member second end 118. In some examples, lock elastic member 114 is configured such that force FP increases as lock elastic member 114 transitions from length LL1 to length LL2 or length LL3 . In some examples, lock elastic member 114 is configured such that force FP increases as lock elastic member 114 transitions from length LL2 or length LL3 to length LL1.

[0118] Thus, in some examples, tether handle assembly 13 is configured such that a repositioning of lock member 72 is necessary in order to alter a position of actuation member 70. For example, in order to reposition actuation member 70 from the rest position to the actuation position (to, e.g., transition tether head assembly 18 from the engagement configuration to the disengagement configuration), lock member 72 should first be positioned from the blocking position to the clearing position. Lock member 72 should be held (e.g., by the exertion of a locking force on lock operator 108) in the clearing position against the action of lock elastic member 114 as actuation member 70 is repositioned to the actuation position (e.g., by the exertion of an actuation driving force on actuation operator 82). To cause actuation member 70 to remain in the actuation position (e.g., against force FS by actuation elastic member 88), the locking force on lock operator 108 should be reduced and / or eliminated to allow lock elastic member 114 to drive lock member 72 from the clearing position to the locking position. To return actuation member 70 to the rest position from the actuation position, lock member 72 may be returned to the clearing position to allow actuation elastic member 88 to drive actuation member 70 to the rest position.

[0119] FIG. 6 is a perspective view illustrating tether handle assembly 13, with actuation member 70 in the rest position and lock member 72 in the blocking position and portions of handle housing 74 shown in cross-section. FIG. 7 is a cross-sectional plan view of tether handle assembly 13. The cross-sections of FIG. 6 and FIG. 7 are taken in a cutting plane B-B which passes through longitudinal axis LT and is parallel to the page in FIG. 7. With actuation member 70 in the rest position, proximal body portion 78 defines the rest path within inner volume 76, such that elongate body experiences first tensile force Fl (FIG. 5A, FIG. 5B). In the blocking position, blocking portion 96 substantially prevents (e.g., blocks) actuation member 70 from traveling in travel direction DA from the rest position to the actuation position.

[0120] Lock elastic member 114 is configured to exert force FP on lock member body 73 to substantially maintain lock member 72 in the blocking position. In some examples, lock elastic member 114 exerts force FP on lock member body 73 when lock member 72 is in the blocking position. In some examples, lock elastic member 114 is in a substantially relaxed condition and exerts minimal or substantially no force on lock member body 73 when lock member 72 is in the blocking position, but begins to exert force FP as lockmember 72 transitions from the blocking position to the clearing position. Actuation elastic member 88 is configured to exert force FS on actuation member body 71 to substantially maintain actuation member 70 in the rest position. In some examples, actuation elastic member 88 exerts force FS on actuation member body 71 when actuation member 71 is in the rest position. In some examples, actuation elastic member 88 is in a substantially relaxed condition and exerts minimal or substantially no force on actuation member body 71 when actuation member 70 is in the rest position, but begins to exert force FS as actuation member 70 transitions from the rest position to the actuation.

[0121] FIG. 8 is a perspective view illustrating tether handle assembly 13 with actuation member 70 in the rest position and lock member 72 in the clearing position. Portions of handle housing 74 are shown in cross-section, with the cross-section taken in the cutting plane B-B. In the clearing position, lock member 72 displaces blocking portion 96 and clearing portion 102 such that travel of actuation member 70 in travel direction DA from the rest position to the actuation position is permitted. Lock member 72 may be configured to transition from the blocking position to the clearing position when locking force LF is exerted (e.g., by a clinician) on lock operator 108 to overcome force FP exerted by lock elastic member 114. With lock member 72 in the clearing position, actuation member 70 may be configured to transition from the rest position to the actuation position when actuation force FA is exerted (e.g., by a clinician) on actuation operator 82 to overcome force FS exerted by actuation elastic member 88.

[0122] FIG. 9 is a perspective view illustrating tether handle assembly 13 with actuation member 70 in the actuation position and lock member 72 in the locking position, with portions of handle housing 74 shown in cross-section. FIG. 10 is a cross-sectional plan view of tether handle assembly 13. The cross-sections of FIG. 9 and FIG. 10 are taken in the cutting plane B-B, which is parallel to the page in FIG. 10. With actuation member 70 in the actuation position, proximal body portion 78 defines the actuation path within inner volume 76, such that elongate body experiences second tensile force F2 (FIG. 5C, FIG. 5D) and elongate body 34 exerts driving force F on tether head assembly 18. With lock member 72 in the locking position, lock elastic member 114 causes and / or maintains lock member feature 106 (FIGS. 5A-5D) coupled with actuation member feature 104. The coupling of lock member feature 106 and actuation member feature 104causes lock member 72 to exerts force FL on actuation member 70 and counteract force FS exerted by actuation elastic member 88.

[0123] FIG. 11A is a perspective view of a tether head assembly 18 with the components of tether head assembly 18 in an assembled configuration, where a distal portion of a tether head assembly 18 is outlined. FIG. 1 IB is an exploded view of the distal portion of tether assembly 18, where a distal portion of inner retainer 36 is outlined. FIG. 11C is a perspective view of the distal portion of inner retainer 36 outlined in FIG.1 IB. FIG. 1 ID is a perspective view of the distal portion of tether head assembly 18 outlined in FIG. 11 A.

[0124] As illustrated in FIG. 11 A, tether 20 may define a lumen 21 (“tether lumen 21”) in which a portion of elongate body 34 is received. Tether head assembly 18 may include inner retainer 36, outer retainer 38, and a sheath 40. Components of medical system 12 may be separately formed of any suitable material. In some examples, one or more of elongate body 34, inner retainer 36, outer retainer 38, sheath 40, and / or one or more layers of tether 20 may be formed of an electrically conductive material, which may help enable testing of placement of IMD 10 during a procedure to deliver IMD 10. One or more components of medical system 12 may be manufactured via a technique such as metal injection molding or any other suitable technique.

[0125] Inner retainer 36 may be coupled to elongate body 34 (e.g., distal body portion 35). In examples, inner retainer 36 extends distally from elongate body 34. A distal portion 56 of outer retainer 38 may define aperture 42 and passageway 46. Passageway 46 may extend from outer retainer distal end 48 proximally to aperture 42.

[0126] A proximal portion 54 of outer retainer 38 may define a channel (not shown) configured to receive inner retainer 36. Inner retainer 36 may be received within outer retainer 38 in a first position in which a distal portion 52 of inner retainer 36 extends into passageway 46, as shown in FIGS. 11A and 1 ID. When inner retainer 36 is in the first position, passageway 46 may be dimensioned to prevent passage of attachment member 14 of IMD 10 (e.g., passageway 46 is too narrow to allow passage of attachment member 14).

[0127] Proximal movement of elongate body 34 (e.g., caused by driving force F) may cause movement of inner retainer 36 from the first position to a second position in which inner retainer 36 does not extend into passageway 46. Additionally, or alternatively, an application of driving force F to inner retainer 36, e.g., a distal end of inner retainer 36, byattachment member 14 of IMD 10 may cause inner retainer 36 to move from the first position to the second position. With inner retainer 36 in the second position, passageway 46 may be dimensioned to receive attachment member 14. Inner retainer 36 and outer retainer 38 may be received within sheath 40, and more particularly a cavity 64 defined by sheath 40, which may help retain inner retainer 36 within outer retainer 38 and couple outer retainer 38 to tether 20.

[0128] In some examples, the configuration of inner retainer 36 and outer retainer 38 may substantially isolate the function of retaining attachment member 14 of IMD 10 to tether head assembly 18, rather than elongate body 34 or another element that extends to tether handle assembly 13. For example, as medical system 12 is navigated through curved portions of patient vasculature, the path lengths of elongate body 34 and / or tether 20 may change. In some other example medical device delivery systems in which a tether assembly relies on a pull wire to retain an attachment member within the tether head assembly, such changes in path lengths of a pull wire and / or tether may cause a loss of contact between the pull wire and the attachment member, thereby adversely affecting retention of the attachment member during delivery.

[0129] In the example of medical system 12 and other tether assemblies described herein, changes in path length of elongate body 34 and / or tether 20 of medical system 12 may substantially limit and / or eliminate substantial proximal or distal movement of inner retainer 36 (e.g., relative to outer retainer 38). For example, sheath 40 and / or elastic member 60 may help reduce or prevent proximal movement of inner retainer 36 as path lengths of elongate body 34 and / or tether 20 change during navigation of curved vasculature. In this manner, the substantial isolation of the IMD retention function within tether head assembly 18 may help maintain retention of attachment member 14 as medical system 12 is navigated through curved vasculature.

[0130] In FIG. 1 IB a distal portion of inner retainer 36 is outlined, and that portion of inner retainer 36 is illustrated in greater detail in FIG. 11C. As shown in FIG. 1 IB, inner retainer 36 may include a proximal portion 50 and a distal portion 52. Outer retainer 38 may include a proximal portion 54 and a distal portion 56. Proximal portion 54 of outer retainer 38 may define a channel (not shown) dimensioned to receive proximal portion 50 of inner retainer 36. Distal portion 56 of outer retainer 38 may at least in part define aperture 42. In some examples, aperture 42 may further include a groove 58 extendingfrom outer retainer distal end 48 proximally at least to aperture 42. Groove 58 may be partially defined by distal portion 56 of outer retainer 38 and may have a depth that is less than a thickness of distal portion 52 of inner retainer 36. A value by which the thickness of distal portion 52 of inner retainer 36 exceeds the depth of groove 58 may correspond to a distance that inner retainer 36 extends, e.g., transverse to a longitudinal axis defined by inner retainer 36, into passageway 46.

[0131] FIG. 11B further illustrates elastic member 60, which is receivable within cavity 64 defined by sheath 40 proximal of, e.g., in an abutting relationship with, inner retainer 36. Elastic member 60 may be formed of a suitably elastically-compressible material, such as a polymer. Elastic member 60 may define a lumen 62 through which a distal portion of elongate body 34 may extend and be attached to more distally located inner retainer 36. In some examples, elastic member 60 may be configured to bias inner retainer 36 to the first position. For example, elastic member 60 may be configured such that an axial expansion of elastic member 60 (e.g., in the distal direction D) causes elastic member 60 to apply a distally-directed force to inner retainer 36, thereby causing inner retainer 36 to move from the second position to the first position.

[0132] In this manner, elastic member 60 may function as a spring that biases inner retainer 36 to the first position. Biasing of inner retainer 36 to the first position may provide one or more advantages, such as enabling a clinician to load IMD 10 onto tether head assembly 18 without necessarily requiring the assistance of another clinician. Elastic member 60 may be received within sheath 40 when medical system 12 is in an assembled configuration, e.g., shown in FIG. 11 A. In this manner, sheath 40 may provide a backstop against which elastic member 60 may be compressed during movement of inner retainer 36 from the first position to the second position.

[0133] The form of elastic member 60 illustrated in FIG. 1 IB is an example. In other examples, other forms may be used to provide the functionality described with respect to elastic member 60 herein. For example, an elastic member 60 may take the form of a coil or spring. Additionally, elastic member 60 may be formed from a variety of materials, such as polymers or metals.

[0134] As illustrated in FIG. 11C, distal portion 52 of inner retainer 36 may define a first portion 67, a second portion 69, and a third portion 77. First portion 67 may include the distal end of inner retainer 36 and may have a first thickness. Second portion 69 maybe proximal to first portion 67 and may have a second thickness that is greater than the first thickness of first portion 67. Third portion 77 may extend between first portion 67 and second portion 69 and may taper in thickness from the first thickness of first portion 67 to the second thickness of second portion 69. In this manner, the tapered thickness of third portion 77 may define a “ramp” surface from first portion 67 toward second portion 69 (and, e.g., aperture 42 when inner retainer 36 is in the first position). When attachment member 14 of IMD 10 is received in passageway 46 and inner retainer 36 is in the first position, the ramp surface defined by third portion 77 may help ensure substantially constant physical contact between attachment member 14 and at least third portion 77 of inner retainer 36 (e.g., as illustrated in FIG. 5D).

[0135] In some examples, inner retainer 36 and attachment member 14 may be electrically conductive. In such examples, ensuring substantially constant physical contact between attachment member 14 and inner retainer 36 during a method of delivering IMD 10 may enable use as an electrical connection and / or may help reduce electrical noise that otherwise may be caused by intermittent contact between attachment member 14 and inner retainer 36. A reduction in such electrical noise may help enable determination of whether IMD 10 is properly positioned and / or affixed relative to tissue of heart 1 during electrical testing of IMD 10 prior to release of IMD 10 from tether head assembly 18 at the implant site.

[0136] FIG. 1 ID illustrates a manner in which distal portion 52 of inner retainer 36 may be received within groove 58 defined by distal portion 56 of outer retainer 38 when inner retainer 36 is in the first position. In some examples, groove 58 may extend proximally past aperture 42 toward proximal portion 54 of outer retainer 38. In any such examples, groove 58 may help provide support to distal portion 52 of inner retainer 36, such as by reducing a possibility of distal portion 52 being bent sideways during loading of attachment member 14 of IMD 10 into receptable 44, or other use of medical system 12. In this manner, groove 58 may help maintain the mechanical integrity and functionality of medical system 12 during one or more uses, thereby contributing to the durability of medical system 12.

[0137] FIG. 12A is an exploded view of a distal portion of medical system 12 including another example tether assembly 118 and a pull wire 134, where a distal portion 152 of an inner retainer 136 of tether head assembly 118 is outlined. FIG. 12B is aperspective view of the outlined portion of FIG. 6 A, including distal portion 152 of inner retainer 136 in conjunction with a distal portion 176 of pull wire 134. FIG. 12C is a perspective view of distal portion 152 of inner retainer 136 received within an outer retainer 38 of tether head assembly 118. FIG. 12D is a cross-sectional view of tether head assembly 118 and a proximal portion of IMD 10, where the cross-section is taken along a plane parallel to a longitudinal axis of the tether head assembly and a longitudinal axis of the IMD. Except as noted herein, medical system 12 and tether head assembly 118 may be substantially similar to medical system 12 and tether head assembly 18 described herein.

[0138] In the example of FIGS. 12A-12D, inner retainer 136 includes a proximal portion 150 received in a channel defined by a proximal portion 54 of outer retainer 38. Inner retainer 136 also includes a distal portion 152 that is supported by groove 58 defined by distal portion 56 of outer retainer 38. Distal portion 152 of inner retainer 136 may extends into aperture 42 to reduce a size of passageway 46 when inner retainer 136 is in the first position and elastic member 60 is in its relaxed state.

[0139] In examples, distal portion 152 defines a substantially constant thickness along its length. Attachment member 14 may apply force to distal end 65 of inner retainer 136 and move inner retainer 136 to the second position as elastic member 60 is compressed, thereby allowing attachment member 14 to pass through passageway 46 and into aperture 42. Inner retainer 136 may return to the first position, e.g., in response to longitudinal expansion of elastic member 60, to retain attachment member 14 in aperture 42.

[0140] In examples, pull wire 134 includes a bent distal portion 176. Proximal portion 150 of inner retainer 136 may defines a notch or other corresponding feature configured to receive bent distal portion 176. When pull wire 134 is actuated, distal portion 176 may bear against proximal portion 150 to move inner retainer 136 from the first position to the second position. In some examples, the coupling of pull wire 134 and inner retainer 136 may allow some relative movement between these structures, e.g., in response to bending and changes in length of pull wire 134 during an implant procedure.

[0141] Referring to FIGS. 4A-4D, FIGS. 4A and 4B illustrate IMD 10 detached from medical system 12, as may be the case prior to loading IMD 10 onto medical system 12 or after IMD 10 has been implanted at a desired tissue site. In particular, in FIGS. 4A and 4B, attachment member 14 of IMD 10 is not received within tether head assembly 18 ofmedical system 12. FIG. 4B illustrates sheath 40 of tether head assembly 18 attached to the distal end of tether 20 of medical system 12. Elongate body 34 may extend through a lumen defined by tether 20 and into cavity 64 defined by sheath 40. Elastic member 60, proximal portion 50 of inner retainer 36, and proximal portion 54 of outer retainer 38 may be disposed within cavity 64, with a distal portion 66 of elastic member 60 and proximal portion 50 of inner retainer 36 received within a channel 68 defined by proximal portion 54 of outer retainer 38. Elongate body 34 may extend through lumen 62 defined by elastic member 60, and may be connected to inner retainer 36, e.g., fixedly received within proximal portion 50 of inner retainer 36. Various components of delivery system 12 and tether assembly 18 may be connected by any of a variety of techniques, such as welding, crimping, threading, reflowing, bonding, adhesives, or friction fits.

[0142] Distal portion 52 of inner retainer 36 may extend into distal portion 56 of outer retainer 38 to contribute to the definition of aperture 42. In the illustrated first position of inner retainer 36, distal portion 52 of inner retainer 36 also extends into passageway 46 to reduce the size of the passageway such that a thickness or depth of the passageway is smaller than a thickness of attachment member 14 of IMD 10. In the illustrated first position of inner retainer 36, distal portion 52 of inner retainer 36 may be disposed within groove 58 defined by distal portion 56 of outer retainer 38, as described herein. In the illustrated first position of inner retainer 36, elastic member 60 may be in a relaxed, or lower kinetic energy state.

[0143] As illustrated in FIG. 4B, attachment member 14 of IMD 10 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 14 is formed within, and joined to IMD housing 81 of IMD 10 by a shroud structure 153. In the illustrated example, attachment member 14 comprises a pin (also referred to as a strut) that is welded or otherwise fixedly attached to shroud structure 153. Attachment member 14 may provide an elongate holding surface that is spaced apart from a housing proximal portion 154 of IMD housing 81 and that extends along a length substantially orthogonal to a longitudinal axis of IMD 10.

[0144] Shroud structure 153 may define a cavity with an opening and attachment member 14 may span and be exposed at the opening. Attachment member 14 may be welded at either end to opposing sides of shroud structure 153. Distal portion 56 of outerretainer 38 may be configured to enter or otherwise interact with shroud structure 153 when attachment member 14 is received within passageway 46 and aperture 42. The configuration of shroud structure 153 and distal portion 56 of outer retainer 38 may selectively inhibit or allow relative motion of IMD 10 and tether assembly in a variety of directions. It should be understood that shroud structure 153 and attachment member 14 are provided for example only, and that a variety of other attachment members may be configured to be attached to tether assemblies as described herein.

[0145] FIG. 4C illustrates inner retainer 36 in the second position and attachment member 14 within aperture 42 defined by the outer retainer 38. Inner retainer 36 may be moved to the second position by driving force F provided by elongate body 34 or by a pushing driving force on distal end 65 of inner retainer 36 as attachment member 14 is pushed through passageway 46 and into aperture 42. When in this compressed state, elastic member 60 may have higher kinetic energy to be released by expanding in the direction of its longitudinal axis to the expanded or relaxed state illustrated in FIGS. 4B and 4D, thereby moving inner retainer 36 from the second position to the first position illustrated in FIGS. 4B and 4D. FIG. 5D illustrates attachment member 14 held within aperture 42 defined by outer retainer 38 by inner retainer 36 being in the first position. Aperture 42 and / or passageway 46 are configured, e.g., sized and shaped, to retain attachment member 14 while allowing distal portion 52 of inner retainer 36 to move past attachment member 14, e.g., through passageway 46. As illustrated in FIG. 4D, at least third portion 77 of distal portion 52 of inner retainer 36 may contact attachment member 14 of IMD 10 when the attachment member is positioned within aperture 42, e.g., when inner retainer 36 is in the first position. As described herein, third portion 77 may secure attachment member 14 within aperture 42 and help ensure substantially constant physical contact between attachment member 14 and at least third portion 77 of inner retainer 36. The physical contact between attachment member 14 and inner retainer 36 enabled by third portion 77 may provide substantially constant electrical contact for conduction of electrical signals, e.g., for impedance monitoring, from IMD 10 to a proximal portion of medical system 12.

[0146] FIG. 13 is a functional block diagram illustrating an example configuration of IMD 10. IMD 10 may include processing circuitry 220, sensing circuitry 222, therapy delivery circuitry 224, sensors 226, communication circuitry 228, and memory 230. Insome examples, memory 230 includes computer-readable instructions that, when executed by processing circuitry 220, cause IMD 10 and processing circuitry 220 to perform various functions attributed to IMD 10 and processing circuitry 220 herein. Memory 230 may include any volatile, non-volatile, magnetic, optical, or electrical media, such as a random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), electrically-erasable programmable ROM (EEPROM), ferroelectric RAM (FRAM), flash memory, or any other digital media.

[0147] Processing circuitry 220 may include fixed function circuitry and / or programmable processing circuitry. Processing circuitry 220 may include any one or more of 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 functions attributed to processing circuitry 220 herein may be embodied as software, firmware, hardware or any combination thereof.

[0148] In some examples, processing circuitry 220 may receive (e.g., from an external device), via communication circuitry 228, a respective value for each of a plurality of cardiac sensing parameters, cardiac therapy parameters (e.g., cardiac pacing parameters), and / or electrode vectors. Processing circuitry 220 may store such parameters and / or electrode vectors in memory 130. Therapy delivery circuitry 224 and sensing circuitry 222 are electrically coupled to electrodes 232, which may correspond to an electrode 91, IMD electrode 89, and / or other electrodes supported by IMD 10. Processing circuitry 220 is configured to control therapy delivery circuitry 224 to generate and deliver electrical therapy to heart 2 via electrodes 132. 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, which may be stored in memory 230. Therapy delivery circuitry 224 may include capacitors, current sources, and / or regulators, in some examples.

[0149] In addition, processing circuitry 220 is configured to control sensing circuitry 222 to monitor signals from electrodes 232 in order to monitor electrical activity of heart2. Sensing circuitry 222 may include circuits that acquire electrical signals, such as filters, amplifiers, and analog-to-digital circuitry. Electrical signals acquired by sensing circuitry 222 may include intrinsic and / or paced cardiac electrical activity, such as atrial depolarizations and / or ventricular depolarizations. 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 optionally may include sensors 226, which may one or more pressure sensors and / or one or more accelerometers, as examples. Communication circuitry 228 may include any suitable hardware (e.g., an antenna), firmware, software, or any combination thereof for communicating with another device, e.g., external to the patient.

[0150] IMD housing 81 may enclose processing circuitry 220 and / or other circuitry within medical system 12. IMD housing 81 may be configured to fluidly isolate processing circuitry 220 and / or other circuitry from an environment in contact with an exterior surface of IMD housing 81. In examples, IMD housing 81 is configured to hermetically seal an enclosure defined by IMD 10 and holding processing circuitry 220 and / or other circuitry. IMD housing 81 may be configured to define shapes that are easily accepted by the patient's body while minimizing patient discomfort. For example, IMD housing 81 may define a substantially cylindrical shape with cylindrical sidewalls. In other examples, IMD housing 81 may define substantially rectangular or other non- cylindrical shapes. IMD housing 81 may define shapes in which corners and edges are designed with relatively large radii, in order to present a housing having smoothly contoured exterior surfaces. In examples, attachment member 14 is coupled to IMD housing 81.

[0151] In some other examples, a tether head assembly 18 and / or other portions of medical system 12 may not be re-usable, such as in other examples in which tether head assembly 18 includes a string or other such component that is looped through a medical device and then cut after the medical device is fixed at a treatment site. In such other examples, a new tether assembly and / or medical device delivery system thus may be packaged with each medical device. Packaging a medical device delivery system and / ortether assembly with a medical device may be associated with shelf-life considerations, such as in examples in which the medical device includes a drug-eluting component that may have an expiration date. In some examples, tether head assembly 18 and / or other portions of medical system 12 may be sterilizable and re-usable, at least in part because tether head assembly 18 can be released from the medical device (e.g., IMD 10) without being cut. In some examples, tether head assembly 18 and / or one or more other portions of medical system 12 may be packaged separately from the medical device, such as examples in which the medical device may include a drug eluting component that has a finite shelf life. In such instances, packaging tether head assembly 18 and / or the one or more other portions of medical system 12 separately from the medical device may mitigate shelf life considerations with respect to tether head assembly 18 and / or the one or more other portions of medical system 12.

[0152] Although the example tether head assembly 18 and / or one or more other portions of medical system 12 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.

[0153] As used here, when a first portion of a system (e.g. medical system 12) is substantially parallel to a second portion of or an axis defined by the system, this may mean the first portion is parallel or nearly parallel to the second portion or the axis to the extent permitted by manufacturing tolerances. In some examples, when the first portion is substantially parallel to the second portion or the axis, this may mean a first vector defined by the first component of the system defines an angle of less than 10 degrees, in some examples less than 5 degrees, and in some examples less than 1 degree, with a second vector defined by the second component or the axis. When a first portion of the system is substantially perpendicular to a second portion of or an axis defined by the system, this may mean the first portion is perpendicular or nearly perpendicular to the second portion or the axis to the extent permitted by manufacturing tolerances. In some examples, when the first portion is substantially perpendicular to the second portion or the axis, this may mean that the first vector defined by the first component of the system defines an angle of at least 80 degrees, in some examples at least 85 degrees, and in some examples at least 89 degrees, with the second vector defined by the second component.

[0154] As used here, when a first portion of a system (e.g. medical system 12) supports a second portion of the system, this means that when the second portion causes a first force to be exerted on the first portion, the first portion causes a second force to be exerted on the second portion in response to the first force. The first force and / or second force may be a contact driving force and / or an action-at-a-distance driving force. For example, first force and / or second force may be mechanical driving force, a magnetic driving force, a gravitational driving force, or some other type of driving force. The first portion of the system may be a portion of the system or a portion of a component of the system. The second portion of the system may be another portion of the system or another portion of the same component or a different component. In some examples, when the first portion of the system supports the second portion of the system, this may mean the second portion is mechanically supported by and / or mechanically connected to the first portion.

[0155] A technique for conducting a signal to a receptacle volume of a receptacle device is illustrated in FIG. 14. Although the technique is described mainly with reference to medical system 12 of FIGS. 1-13, the technique may be applied to other medical systems in other examples.

[0156] The technique includes blocking, using a lock member 72 in a blocking position, an actuation member 70 from transitioning from a rest position to an actuation position (1402). In examples, a lock elastic member 114 exerts a force FP on a lock member body 73 of lock member 72 to substantially retain lock member 72 in the blocking position. An actuation elastic member 88 may exerts a force FS on an actuation member body 71 of actuation member 70 which tends to cause actuation member 70 to remain in the actuation position. In examples, a handle housing 74 of a tether handle assembly 13 supports actuation elastic member 88 and lock elastic member 114. A blocking portion 96 of lock member body 73 may exert a force FB on actuation member body 71 to substantially prevent actuation member 70 from transitioning from the rest position to the actuation position. A proximal body portion 78 of an elongate body 34 may define a rest path within an inner volume 76 defined by handle housing 74 when actuation member 70 is in the rest position.

[0157] The technique includes transitioning lock member 72 from the blocking position to a clearing position (1404). Lock member 72 may move relative to handlehousing 74 when lock member 72 transitions from the blocking position to the clearing position. In examples, a lock force LF imparted to a lock operator 108 overcomes force FP to cause lock member 72 to transition from the blocking position to the clearing position. Lock member 72 may move blocking portion 96 relative to handle housing 74 when lock member 72 transitions to the clearing position. In examples, lock member 72 moves a clearing portion 102 of lock member 72 relative to handle housing 74 when lock member 72 transitions to the clearing position.

[0158] The technique includes positioning actuation member 70 in the actuation position when lock member 72 is positioned in the clearing position (1406). Actuation member 70 may move relative to handle housing 74 when actuation member 70 transitions from the rest position to the actuation position. In examples, an actuation force FA imparted to an actuation operator 82 overcomes force FS to cause actuation member 70 to transition from the rest position to the actuation position.

[0159] Proximal body portion 78 may define an actuation path within inner volume 76 when actuation member 70 is in the actuation position. In examples, actuation member body 71 transfers at least some portion of the force FA to displace proximal body portion 78 from the rest path to the actuation path. Proximal body portion 78 increase a tension force (e.g., from first tension force Fl to second tenson force F2) when proximal body portion 78 transitions from the rest path to the actuation path. Second tension force F2 may cause a distal body portion 35 of elongate body 34 to exert a driving force F on a tether head assembly 18.

[0160] The technique includes positioning, with actuation member 70 in the actuation position, lock member 72 in a locking position (1408). Lock member 72 may substantially prevent actuation member 70 from transitioning from the actuation position to the rest position when lock member 72 is in the locking position. In examples, lock member 72 imparts a force FL on actuation member 70 (e.g., actuation member body 71) to substantially prevent actuation member 70 from transitioning from the actuation position to the rest position. Lock member 72 may impart force FL using a lock member feature 106. In examples, lock member feature 106 couples to an actuation member feature 106 when lock member imparts force FL. Locking member feature 106 may impart force FL to actuation member feature 104. The technique may include ceasing force LF on lock operator 108 when actuation member 70 is in the actuation position such that lock elasticmember 114 causes lock member feature 106 to couple with actuation member feature 104. The technique may include ceasing force FA on actuation operator 82 when lock member feature 106 couples with actuation member feature 104.

[0161] In examples, the technique includes exerting force LF on lock operator 108 to transition lock member 72 from the locking position to the clearing position when actuation member 70 is in the actuation position. The technique may include uncoupling lock member feature 106 and actuation member feature 104 when lock member 72 transitions from the locking position to the clearing position. In examples, with lock member 72 in the clearing position, elastic member 88 drives actuation member 70 to the rest position using force FS. The technique may include ceasing force LF on lock operator 108 to allow lock elastic member 114 to drive lock member 72 from the clearing position to the blocking position when actuation member 70 is in the rest position.

[0162] Various examples of the disclosure have been described. Any combination of the described systems, operations, or functions is contemplated. These and other examples are within the scope of the following claims.

[0163] Example 1. A medical system comprising: a tether head assembly configured to establish an engagement configuration to engage an implantable medical device and establish a disengagement configuration to disengage from the implantable medical device, the tether head assembly configured to transition between the engagement configuration and the disengagement configuration in response to a driving force exerted on the tether head assembly; a handle assembly including a housing defining an inner volume, the handle assembly including an actuation member having an actuation position and a rest position, and the handle assembly including a lock member having a blocking position, a clearing position, and a locking position; and an elongate body including a proximal body portion coupled to the handle assembly and extending into the inner volume, the elongate body including a distal body portion opposite the proximal body portion, wherein the distal body portion is configured to exert the driving force on the tether head assembly, wherein the actuation member is configured to cause the distal body portion to exert the driving force on the tether head assembly when the actuation member is in the actuation position and cease exerting the driving force on the tether head assembly when the actuation member is in the rest position, wherein the lock member in the blocking position is configured to prevent the actuation member from positioning inthe actuation position, wherein the lock member in the clearing position is configured to permit the actuation member to position in the actuation position, and wherein the lock member in the locking position is configured to prevent the actuation member from transitioning from the actuation position to the rest position.

[0164] Example 2. The medical system of Example 1, wherein: the elongate body is configured to define an actuation path from the proximal body portion to the distal body portion when the distal body portion exerts the driving force on the tether head assembly, the elongate body is configured to define a rest path from the proximal body portion to the distal body portion when the distal body portion ceases to exert the driving force on the tether head assembly, and the actuation member is configured to cause the proximal body portion to define the actuation path in the actuation position and configured to cause the proximal body portion to define the rest path in the rest position.

[0165] Example 3. The medical system of Example 2, wherein the elongate body is configured to define the actuation path within the inner volume and configured to define the rest path within the inner volume.

[0166] Example 4. The medical system of Example 2 or Example 3, wherein the actuation member is configured to deflect the elongate body from the rest path to the actuation path when the actuation member transitions from the rest position to the actuation position.

[0167] Example 5. The medical system of any of Examples 1-4, further comprising an actuation elastic member configured to drive the actuation member from the actuation position to the rest position.

[0168] Example 6. The medical system of Example 5 wherein: the lock member, in the locking position, is configured to engage the actuation member to prevent the actuation elastic member from driving the actuation member from the actuation position to the rest position, and the lock member, in the clearing position, is configured to disengage from the actuation member to permit the actuation elastic member to drive the actuation member from the actuation position to the rest position.

[0169] Example 7. The medical system of Example 6, wherein the lock member is configured to engage the actuation member within the inner volume.

[0170] Example 8. The medical system of any of Examples 1-7, further comprising a lock elastic member configured to drive the lock member from the lockingposition to the blocking position.

[0171] Example 9. The medical system of Example 8, wherein the lock elastic member is configured to drive the lock member from the clearing position to the locking position.

[0172] Example 10. The medical system of Example 8 or Example 9, wherein the lock elastic member is configured to drive the lock member from the clearing position to the blocking position.

[0173] Example 11. The medical system of any of Examples 8-10, wherein: the actuation member, in the actuation position, is configured to engage the lock member to prevent the lock elastic member from driving the lock member from the locking position to the blocking position, and the actuation member, in the rest position, is configured to disengage from the lock member to permit the lock elastic member to drive the lock member from the locking position to the blocking position.

[0174] Example 12. The medical system of Example 11, wherein the actuation member is configured to engage the lock member within the inner volume.

[0175] Example 13. The medical system of any of Examples 1-12, wherein the actuation member defines an actuation operator accessible from outside the inner volume of the handle assembly, wherein the actuation operator is configured to cause the actuation member to transition from the rest position to the actuation position.

[0176] Example 14. The medical system of Example 13, wherein: the actuation operator is configured to receive an actuating force to cause the actuation member to transition from the rest position to the actuation position, the actuation elastic member of claim 5 is configured to exert an actuating spring force on the actuation member to drive the actuation member from the actuation position to the rest position, and wherein the actuation member is configured to transfer the actuating force to the actuation elastic member to overcome the actuating spring force when the actuation member transitions from the rest position to the actuation position.

[0177] Example 15. The medical system of any of Examples 1-14, wherein the lock member defines a lock operator accessible from outside the inner volume of the handle assembly, wherein the lock operator is configured to cause the lock member to transition from the blocking position to the clearing position.

[0178] Example 16. The medical system of Example 15, wherein: the lockoperator is configured to receive a locking force to cause the lock member to transition from the blocking position to the clearing position, the lock elastic member of claim 10 is configured to exert a locking spring force on the lock member to drive the lock member from the clearing position to the blocking position, and wherein the lock member is configured to transfer the locking force to the lock elastic member to overcome the locking spring force when the lock operator transitions from the blocking position to the clearing position.

[0179] Example 17. The medical system of any of Examples 1-16, wherein the tether head assembly includes an elastic member configured to exert a member force on the distal body portion, wherein the member force is opposite the driving force on the tether head assembly exerted by the distal body portion.

[0180] Example 18. The medical system of Example 17, wherein the elastic member is configured to cause the elongate body to transition from the first path of claim 2 to the second path of claim 2 using the member force when the actuation member transitions from the actuation position to the rest position.

[0181] Example 19. The medical system of any of Examples 1-18, wherein the tether head assembly defines an aperture, wherein the aperture is configured to receive an attachment member of the implantable medical device in the engagement configuration, and wherein the aperture is configured to trap the attachment member in the disengagement configuration.

[0182] Example 20. The medical system of Example 19, wherein the tether head assembly is configured to transition from the disengagement configuration to the engagement configuration when the elongate body exerts the driving force on the tether head assembly.

[0183] Example 21. The medical system of any of Examples 1-20, wherein the medical system defines a distal direction from the handle assembly to the tether head assembly and a proximal direction opposite the distal direction.

[0184] Example 22. The medical system of Example 21, further comprising a tether, wherein the tether head assembly is coupled to a distal portion of the tether, and wherein the handle assembly is coupled to a proximal portion of the tether.

[0185] Example 23. The medical system of Example 21 or Example 22, wherein the tether defines a lumen having a proximal opening and a distal opening distal to theproximal opening, and wherein the elongate body extends through the lumen from the proximal opening to the distal opening.

[0186] Example 24. The medical system of any of Examples 21-23, wherein the tether is configured to transfer a first force to the tether head assembly in the distal direction when the first force is exerted on the handle assembly in the distal direction, and wherein the tether is configured to transfer a second force to the tether head assembly in the proximal direction when the second force is exerted on the handle assembly in the proximal direction.

[0187] Example 25. The medical system of Example 24, wherein the actuation operator of claim 14 is configured to receive the actuating force in a direction substantially perpendicular to at least one of the distal direction or the proximal direction.

[0188] Example 26. The medical system of any of Examples 22-25, wherein the tether is configured to transfer a torque to the tether head assembly when the torque is exerted on the handle assembly, and wherein the tether head assembly is configured to transfer the torque to the implantable medical device when the tether head assembly engages the implantable medical device.

[0189] Example 27. The medical system of any of Examples 21-26, wherein the elongate body is configured to exert the driving force on the tether head assembly in the proximal direction.

[0190] Example 28. A method, comprising: blocking, using a lock member in a blocking position, an actuation member from transitioning from a rest position to an actuation position, wherein the lock member is configured to prevent the actuation member from positioning in the actuation position when the lock member is in the blocking position, wherein the lock member is configured to permit the actuation member to position in the actuation position when the lock member is in a clearing position, and wherein the lock member is configured to prevent the actuation member from transitioning from the actuation position to the rest position when the lock member is in a locking position; transitioning the lock member from the blocking position to the clearing position; positioning, with the lock member in the clearing position, the actuation member in the actuation position; exerting, using the actuation member in the actuation position, a driving force on a tether head assembly, wherein the actuation member is configured to cause a distal body portion of an elongate body to exert the driving force on the tetherhead assembly when the actuation member is in an actuation position and configured to cause the distal body portion to cease exerting the driving force on the tether head assembly when the actuation member is in a rest position, wherein a proximal body portion opposite the distal body portion is coupled to a handle assembly supporting the locking member and the actuation member, wherein the proximal body portion extends through an inner volume defined by the handle assembly, and wherein the tether head assembly is configured to transition between an engagement configuration to engage an implantable medical device and a disengagement configuration to disengage from the implantable medical device in response to the driving force exerted on the tether head assembly; and positioning, with the actuation member in the actuation position, the lock member in a locking position, wherein the lock member is configured to prevent the actuation member from transitioning from the actuation position to the rest position in the locking position.

[0191] Example 29. The method of Example 28, further comprising: causing, using the actuation member in the actuation position, the elongate body to define a first path from the proximal body portion to the distal body portion, wherein the elongate body is configured to exert the driving force on the tether head assembly when the elongate body defines the first path; and causing, using the actuation member in the rest position, the elongate body to define a second path from the proximal body portion to the distal body portion, wherein the elongate body is configured to cease exerting the driving force on the tether head assembly when the elongate body defines the second path.

[0192] Example 30. The method of Example 28 or Example 29, further comprising permitting, using the lock member in the clearing position, an actuation elastic member to drive the actuation member from the actuation position to the rest position.

[0193] Example 31. The method of any of Examples 28-30, further comprising preventing, using the lock member in the locking position, the actuation elastic member from driving the actuation member from the actuation position to the rest position.

[0194] Example 32. The method of any of Examples 28 - 31, further comprising preventing, using the actuation member in the actuation position, a lock member spring from driving the locking member from at least one of the locking position or the clearing position to the blocking position.

[0195] Example 33. The method of any of Examples 28 - 32, further comprisingpermitting, using the actuation member in the rest position, the lock member spring to drive the locking member from at least one of the locking position or the clearing position to the blocking position.

[0196] Example 34. The method of any of Examples 28-33, further comprising engaging the lock member and the actuation member within the inner volume.

[0197] Example 35. The method of any of Examples 28-34, further comprising causing, using an actuation operator accessible from outside the inner volume of the handle assembly, the actuation member to transition from the rest position to the actuation position.

[0198] Example 36. The method of Example 35, further comprising, overcoming, using the actuation operator, a an actuating spring force on the actuation member from the actuation elastic member.

[0199] Example 37. The method of any of Examples 28-36, further comprising causing, using a lock operator accessible from outside the inner volume of the handle assembly, the lock member to transition from the blocking position to at least one of the clearing position or the locking position.

[1100] Example 38. The method of Example 37, further comprising, overcoming, using the lock operator, a locking spring force on the lock member from the lock member spring.

[1101] Example 39. The method of any of Examples 28-38, further comprising exerting, using an elastic member of the tether head assembly, a member force on the distal body portion, wherein the member force is opposite the driving force on the tether head assembly exerted by the distal body portion.

[1102] Example 40. The method of any of Examples 28-39, further comprising transitioning, using at least one of the driving force on the tether head assembly or a cessation of the driving force on the tether head assembly, the tether head assembly between the engagement configuration and the disengagement configuration.

Claims

WHAT IS CLAIMED:

1. A medical system comprising: a tether head assembly configured to establish an engagement configuration to engage an implantable medical device and establish a disengagement configuration to disengage from the implantable medical device, the tether head assembly configured to transition between the engagement configuration and the disengagement configuration in response to a driving force exerted on the tether head assembly; a handle assembly including a housing defining an inner volume, the handle assembly including an actuation member having an actuation position and a rest position, and the handle assembly including a lock member having a blocking position, a clearing position, and a locking position; and an elongate body including a proximal body portion coupled to the handle assembly and extending into the inner volume, the elongate body including a distal body portion opposite the proximal body portion, wherein the distal body portion is configured to exert the driving force on the tether head assembly, wherein the actuation member is configured to cause the distal body portion to exert the driving force on the tether head assembly when the actuation member is in the actuation position and cease exerting the driving force on the tether head assembly when the actuation member is in the rest position, wherein the lock member in the blocking position is configured to prevent the actuation member from positioning in the actuation position, wherein the lock member in the clearing position is configured to permit the actuation member to position in the actuation position, and wherein the lock member in the locking position is configured to prevent the actuation member from transitioning from the actuation position to the rest position.

2. The medical system of claim 1, wherein: the elongate body is configured to define an actuation path from the proximal body portion to the distal body portion when the distal body portion exerts the driving force on the tether head assembly, the elongate body is configured to define a rest path from the proximal body portion to the distal body portion when the distal body portion ceases to exert the drivingforce on the tether head assembly, and the actuation member is configured to cause the proximal body portion to define the actuation path in the actuation position and configured to cause the proximal body portion to define the rest path in the rest position.

3. The medical system of claim 2, wherein the elongate body is configured to define the actuation path within the inner volume and configured to define the rest path within the inner volume, and wherein the actuation member is configured to deflect the elongate body from the rest path to the actuation path when the actuation member transitions from the rest position to the actuation position.

4. The medical system of any of claims 1-3, further comprising an actuation elastic member configured to drive the actuation member from the actuation position to the rest position.

5. The medical system of claim 4 wherein: the lock member, in the locking position, is configured to engage the actuation member to prevent the actuation elastic member from driving the actuation member from the actuation position to the rest position, and the lock member, in the clearing position, is configured to disengage from the actuation member to permit the actuation elastic member to drive the actuation member from the actuation position to the rest position.

6. The medical system of any of claims 1-5, further comprising a lock elastic member configured to drive the lock member from the locking position to the blocking position.

7. The medical system of claim 6, wherein the lock elastic member is configured to drive the lock member from the clearing position to the locking position.

8. The medical system of claim 6 or claim 7, wherein the lock elastic member is configured to drive the lock member from the clearing position to the blocking position.

9. The medical system of any of claims 6-8, wherein: the actuation member, in the actuation position, is configured to engage the lock member to prevent the lock elastic member from driving the lock member from the locking position to the blocking position, and the actuation member, in the rest position, is configured to disengage from the lock member to permit the lock elastic member to drive the lock member from the locking position to the blocking position.

10. The medical system of any of claims 1-9, wherein the actuation member defines an actuation operator accessible from outside the inner volume of the handle assembly, wherein the actuation operator is configured to cause the actuation member to transition from the rest position to the actuation position.

11. The medical system of any of claims 1-10, wherein the lock member defines a lock operator accessible from outside the inner volume of the handle assembly, wherein the lock operator is configured to cause the lock member to transition from the blocking position to the clearing position.

12. The medical system of any of claims 1-11, wherein the tether head assembly includes an elastic member configured to exert a member force on the distal body portion, wherein the member force is opposite the driving force on the tether head assembly exerted by the distal body portion.

13. The medical system of any of claims 1-12, wherein the tether head assembly defines an aperture, wherein the aperture is configured to receive an attachment member of the implantable medical device in the engagement configuration, and wherein the aperture is configured to trap the attachment member in the disengagement configuration.

14. The medical system of claim 13, wherein the tether head assembly is configured to transition from the disengagement configuration to the engagement configuration when the elongate body exerts the driving force on the tether head assembly.

15. The medical system of any of claims 1-14, wherein the medical system defines a distal direction from the handle assembly to the tether head assembly and a proximal direction opposite the distal direction, and further comprising a tether, wherein the tether head assembly is coupled to a distal portion of the tether, and wherein the handle assembly is coupled to a proximal portion of the tether.

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