Implant delivery and retrieval systems and methods - Patents.com

Abstract

To provide systems and methods for delivery and retrieval of leadless pacemaker.SOLUTION: Catheter systems for delivery and retrieval of leadless pacemakers include each of a leadless pacemaker, a docking cap, and a retriever. The retriever includs a flexible grasper that interacts with the docking cap such that by disposing the flexible grasper within a chamber of the docking cap, the docking cap may be made to lock the flexible grasper onto a docking projection of the leadless pacemaker. The retriever may alternatively include a pair of lumens through which snare wires are passed forming respective loops. By translating the snare wires relative to the lumens, the snare wires may be made to tighten around the docking projection of the leadless pacemaker.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This Patent Cooperation Treaty (PCT) patent application is related to and claims priority to U.S. Patent Application No. 15 / 588,277, filed May 5, 2017, entitled "IMPLANT DELIVERY AND RETRIEVAL SYSTEMS AND METHODS," and U.S. Patent Application No. 15 / 588,307, filed May 5, 2017, entitled "IMPLANT DELIVERY AND RETRIEVAL SYSTEMS AND METHODS," the disclosures of which are incorporated herein by reference in their entireties for all purposes.

[0002] (Technical field) The present disclosure relates to leadless pacemakers and associated delivery and retrieval systems and methods, and more particularly, to systems and methods for mounting a leadless pacemaker to a catheter system for delivery to or retrieval from an implantation site. [Background technology]

[0003] Cardiac pacing with an artificial pacemaker provides electrical stimulation of the heart when a patient's heart's natural pacemaker and / or conduction system is unable to provide synchronized atrial and ventricular contractions at a rate and interval sufficient for the patient's health. Such anti-bradycardia pacing provides symptomatic relief and even life support for hundreds of thousands of patients. Cardiac pacing also inhibits or converts tachyarrhythmias by providing electrical overdrive stimulation, again providing symptomatic relief or preventing or terminating arrhythmias that may result in sudden cardiac death.

[0004] Cardiac pacing with currently available pacemakers or conventional pacemakers is typically accomplished by a pulse generator implanted subcutaneously or submuscularly in or near the patient's chest. The parameters of the pulse generator are typically interrogated and modified by an external programming device via a loosely coupled transformer with one inductance inside the body and the other outside the body, or via an electromagnetic emitter with one antenna inside the body and the other outside the body. The pulse generator is typically connected to the proximal end of one or more implanted leads, the distal end of which is provided with one or more electrodes that are positioned adjacent to the inner or outer wall of the ventricle. The leads have insulated electrical conductors for connecting the pulse generator to electrodes placed in the heart. Such electrode leads typically have a length of 50-70 cm.

[0005] Over 100,000 conventional cardiac pacing systems are implanted each year, but they present a variety of well-known problems. For example, subcutaneous placement of the pulse generator results in a protuberance on the skin that patients may find unsightly, uncomfortable, or repulsive, leading to unconscious or repeated touching. Even if not frequently touched, the subcutaneous pulse generator may erode, protrude, or become infected, or the lead wire may break, suffer insulation damage, or break. Submuscular or abdominal placement may address some of the concerns, but such placement involves more difficult surgical procedures for implantation and adjustment, and may prolong the patient's recovery.

[0006] Conventional pulse generators, whether located in the chest or abdomen, have a removable interface to the electrode leads that transmit signals to and from the heart. Typically, at least one male connector molding is used as the interface, with at least one terminal pin at the proximal end of the electrode lead. The male connector mates with a corresponding female connector molding on the pulse generator and a terminal block within the connector molding. To ensure electrical and mechanical connections, a set screw is typically threaded into at least one terminal block per electrode lead. One or more O-rings are typically used to help maintain electrical isolation between the connector moldings. A set screw cap or slotted cover is typically used to provide electrical isolation for the set screw. Due to the complex connections between the connectors and the leads, briefly described above, there are many opportunities for malfunction.

[0007] Other problems with conventional pacemakers are associated with the pulse generator and pacing leads that are implanted at a distance from one another. As another example, the pacing leads in particular can be a site of infection and disease. Many of the problems associated with conventional pacemakers are solved by the development of self-contained and autonomous pacemakers, or so-called leadless pacemakers.

[0008] Similar to implantable active fixation leads used in conventional pulse generators, leadless pacemakers are typically fixed at an implantation site within the heart by an active engagement mechanism, such as a screw or helical member that is threaded into the myocardium. Leadless pacemakers are often delivered to an implantation site within the heart using a delivery system that includes a delivery catheter. Conventional delivery catheter systems are typically long (e.g., about 42 mm or greater), making navigation of the patient's anatomy difficult and increasing the footprint of the delivery catheter system at the implantation site.

[0009] Some conventional delivery systems are tether-based systems that rely on tether alignment to attach the leadless pacemaker to the delivery catheter. Notably, if tether alignment is lost due to system tolerances or anatomical interference, the leadless pacemaker may spontaneously release from the delivery catheter. Such spontaneous release (detachment) may result in embolism, the need to retrieve the leadless pacemaker, and / or other patient risks. Retrieval of the leadless pacemaker is accomplished by removing the delivery catheter, introducing a retrieval catheter, and retrieving the leadless pacemaker through the retrieval catheter. The delivery catheter system is generally different in structure and operation than the retrieval catheter system, which increases the surgical time, complexity, and cost. If retrieval cannot be accomplished using a retrieval catheter system, the leadless pacemaker is typically retrieved by surgery, which further complicates the surgical procedure. Additionally, many conventional catheter systems are not compatible with bedside loading of the leadless pacemaker onto a previously used catheter system, so implanting a second leadless pacemaker into the patient often requires the use of a second catheter delivery system. Instead, many conventional catheter systems are pre-loaded during manufacture.It is with these observations, among others, in mind that the techniques of the present disclosure were invented and developed. Summary of the Invention [Means for solving the problem]

[0010] The embodiments described and claimed herein address the above problems by providing systems and methods for leadless pacemaker delivery and retrieval. In one embodiment, a catheter system is provided that includes a leadless pacemaker. The leadless pacemaker includes a docking end having a docking extension extending from a surface thereof. The catheter system of the present disclosure further includes a docking cap having a body portion defining a chamber and a proximal opening communicating with the chamber, the proximal opening being coaxial with a longitudinal axis of the lumen of the catheter. The catheter system of the present disclosure further includes a retriever including a flexible grasper having first and second arms disposed opposite one another. Each of the first and second arms forms a hinge portion biased radially outward from the longitudinal axis. The docking cap locks the first and second arms to the docking extension when the body portion of the docking cap covers the retriever until the flexible grasper of the retriever is located within the chamber.

[0011] In some embodiments of the catheter system of the present disclosure, the docking cap has one or more cap surfaces disposed relative to the chamber, the docking cap locking the first and second arms to the docking extension by the one or more cap surfaces displace the first and second arms radially inward and maintain the first and second arms compressed about the docking extension.

[0012] In another embodiment, the first arm includes a first flexible loop portion and the second arm includes a second flexible loop portion, in such an embodiment, the first arm and the second arm are each coupled to at least one mandrel that extends into the lumen of the catheter.

[0013] In some embodiments, the docking cap has one or more cap surfaces disposed relative to the chamber and configured to provide torque transfer by mating engagement with one or more docking surfaces of the docking extension. In such embodiments, the one or more docking surfaces may include one or more flat radial surfaces and / or may be radially symmetric. In other embodiments, at least one of the one or more cap surfaces and the one or more docking surfaces may have one or more keyed portions. At least one of the one or more cap surfaces may be flat.

[0014] In some embodiments, the docking extension includes a rounded surface that forms a dome shape. The docking extension can include a neck configured to engage with the first arm and the second arm.

[0015] In another embodiment, the first arm and the second arm extend from the base. In such an embodiment, the base includes a mandrel coupled to the base and extending through a proximal opening into the lumen of the catheter. Such an embodiment further includes a tether extending from a lumen in the mandrel through the base.

[0016] In yet another embodiment, the docking extension includes a loop portion configured to receive a tether, snare, or cable.

[0017] In another embodiment, another catheter system is provided that includes a leadless pacemaker. The leadless pacemaker includes a docking end having a docking extension extending from a surface thereof. The catheter system of the present disclosure further includes a docking cap having a body portion defining a chamber and a proximal opening communicating with the chamber, the proximal opening being coaxial with a longitudinal axis of a lumen of the catheter. The catheter system of the present disclosure further includes a retriever having a first sheath and a second sheath extending distally from the chamber, the first sheath having a first lumen and the second sheath having a second lumen. The catheter system of the present disclosure further includes a snare including a first snare wire and a second snare wire. The first snare wire extends from the first snare lumen into the second snare lumen to form a first snare loop oriented in a first direction, and the second snare wire extends from the first snare lumen into the second snare lumen to form a second snare loop oriented in a second direction different from the first direction. The first snare loop and the second snare loop form a docking space. The snare is displaceable between an engaged position and a disengaged position by displacing the first snare wire and the second snare wire within the first snare lumen and the second snare lumen. In the engaged position, the first snare wire and the second snare wire are clamped around the docking extension within the docking space.

[0018] In some embodiments, the first sheath and the second sheath are displaceable within the chamber and the proximal opening, respectively.

[0019] In another embodiment, the first sheath and the second sheath are disposed radially opposite one another about the longitudinal axis.

[0020] In yet another embodiment, engagement of the snare with the docking extension in the engaged position allows for displacement of the leadless pacemaker relative to the longitudinal axis.

[0021] In other embodiments, the displacement of the leadless pacemaker relative to the longitudinal axis includes at least one of displacement parallel to the longitudinal axis and displacement at an angle to the longitudinal axis.

[0022] In yet another embodiment, the docking cap includes a first tracker and a second tracker disposed within the chamber, in such an embodiment, the first sheath is displaceable within the first tracker and the second sheath is displaceable within the second tracker.

[0023] In some embodiments, the docking cap is disposed relative to the chamber and has one or more cap surfaces configured to provide torque transfer by mating engagement with one or more docking surfaces of the docking extension.

[0024] In yet another embodiment, the docking extension includes a docking button.

[0025] In another embodiment of the present disclosure, a method of engaging a leadless catheter is provided. The method of the present disclosure includes positioning a flexible gripper against a docking extension extending from a surface of a body of the leadless pacemaker. The flexible gripper has first and second arms disposed opposite each other, each of the first and second arms forming a hinge biased radially outward from a longitudinal axis. The method of the present disclosure further includes positioning the docking extension between the first and second arms and covering the flexible gripper with a body of a docking cap. The docking cap displaces the first and second arms radially inward with one or more cap surfaces disposed against the chamber and maintains the first and second arms pressed against the docking extension, thereby locking the first and second arms to the docking extension.

[0026] The disclosed methods may further include delivering the leadless pacemaker by displacing a catheter coupled to the docking cap, and retrieving the leadless pacemaker by at least one of displacing and torquing the catheter.

[0027] In yet another embodiment of the present disclosure, yet another catheter system is provided that includes a leadless pacemaker. The leadless pacemaker includes a docking end having a docking extension extending from a surface thereof. The catheter system of the present disclosure further includes a retriever having a first arm and a second arm disposed opposite each other about a central lumen. Each of the first arm and the second arm forms a hinge portion that is biased radially inward toward the central lumen. The first arm and the second arm are radially outwardly displaceable by displacing a mandrel within the central lumen toward the docking end. The radially outward displacement of the first arm and the second arm engages a surface of the docking end within the opening.

[0028] In another embodiment of the present disclosure, yet another catheter system is provided that includes a leadless pacemaker. The leadless pacemaker includes a docking end having a docking extension extending from a surface thereof. The catheter system of the present disclosure further includes a docking cap having a body portion defining a chamber and a proximal opening leading to the chamber, and a push-pull actuator extending through the proximal opening into the chamber. The catheter system of the present disclosure further includes a retriever including a flexible grasper having a first arm and a second arm. Each of the first arm and the second arm is coupled to the docking cap by one or more hinge pins. The push-pull actuator locks the first arm and the second arm to the docking extension when the push-pull actuator is displaced.

[0029] In one embodiment, the docking extension has a slot formed therein, and the first and second arms each include a gripping portion defining a notch and having a lip, the notches of the first and second arms gripping the extension by inserting the lip into the slot when the push-pull actuator is displaced.

[0030] In another embodiment, the docking extension has one or more edge docking surfaces forming a polygonal shape, and the first arm and the second arm each have a docking surface, and when the push-pull actuator is displaced, the docking surfaces of the first arm and the second arm are pressed against the edge docking surfaces.

[0031] In yet another embodiment of the present disclosure, yet another catheter system is provided that includes a docking cap having a body portion that defines a chamber. The catheter system of the present disclosure further includes a retriever having a first sheath and a second sheath extending distally from the chamber. The first sheath and the second sheath are disposed at radially opposite positions from each other about a central axis, the first sheath having a first lumen, and the second sheath having a second lumen. The catheter system of the present disclosure further includes a snare including a first snare wire and a second snare wire. The first snare wire extends from the first snare lumen into the second snare lumen to form a first snare loop having a first peak at the central axis. The second snare wire extends from the first snare lumen into the second snare lumen to form a second snare loop having a second peak at the central axis. The snare is displaceable between engaged and disengaged positions by displacing the first and second snare wires within the first and second snare lumens, such that displacing the first peak radially inward toward the second peak to an engaged position or displaces the first peak radially outward away from the second peak to a disengaged position.

[0032] In one embodiment, each of the first and second sheaths has an end coil, each of which is optionally radiopaque.

[0033] In another embodiment, the docking cap includes a first tracker and a second tracker disposed within the chamber, in such an embodiment, the first sheath is displaceable within the first tracker and the second sheath is displaceable within the second tracker.

[0034] In yet another embodiment, the first snare loop and the second snare loop form a docking space, the docking space having a smaller size in the engaged position than in the disengaged position.

[0035] In yet another embodiment, the first snare wire and the second snare wire, in the engaged position, are clamped around a docking extension of a leadless pacemaker disposed within the docking space, In such an embodiment, the docking extension can be receivable within the chamber.

[0036] In other embodiments, each of the first snare wire and the second snare wire is coupled to at least one mandrel.

[0037] In yet another embodiment of the present disclosure, a method of engaging a leadless catheter is provided. The method of the present disclosure includes positioning a docking space relative to a docking extension extending from a surface of a body of the leadless pacemaker. The docking space is defined by a first snare loop oriented in a first direction and a second snare loop oriented in a second direction different from the first direction. The first snare loop is formed from a first snare wire extending from a first snare lumen of a first sheath into a second snare lumen of a second sheath. The second snare loop is formed from a second snare wire extending from the first snare lumen of a first sheath into a second snare lumen of a second sheath. The method of the present disclosure further includes advancing the first snare loop and the second snare loop along the leadless pacemaker until the docking extension is positioned within the docking space. The method of the present disclosure further includes retracting the first and second snare wires into the first and second snare lumens until the first and second snare wires are clamped around the docking extension to reduce a size of the docking space.The method of the present disclosure further includes retracting the first and second sheaths into the lumen of the catheter until the docking extension is disposed within the chamber of the docking cap.

[0038] In one embodiment of the disclosed method, the docking cap includes a first tracker and a second tracker disposed within the chamber, and the first sheath is retractable along the first tracker and the second sheath is retractable along the second tracker.

[0039] In another embodiment, the method of the present disclosure further comprises retrieving the leadless pacemaker by displacing the catheter.

[0040] In yet another embodiment, the method of the present disclosure further comprises delivering a leadless pacemaker by displacing the catheter.

[0041] Other embodiments are also described and enumerated herein. Moreover, while multiple embodiments are disclosed, still other embodiments of the disclosed technology will become apparent to those skilled in the art from the following detailed description, which shows and describes exemplary embodiments of the disclosed technology. As will be understood, all of the disclosed technology can be modified in various aspects without departing from the spirit and scope of the disclosed technology. Thus, the drawings and detailed description should be regarded as illustrative in nature and not restrictive. [Brief description of the drawings]

[0042] [Figure 1] FIG. 1 is a schematic medial / lateral cross-sectional view of a patient's heart illustrating an exemplary cardiac pacing system having one or more leadless pacemakers. [Diagram 2] 1 illustrates an exemplary catheter system for delivering and / or retrieving a leadless pacemaker. [Diagram 3] FIG. 2 is a detailed view of the distal end of the catheter system. [Figure 4A] 4A to 4C each show a retriever positioned at a docking position with a leadless pacemaker. [Figure 4B] 1 is a side view, with the docking cap shown in phantom. [Figure 4C] 1 is a top view, with the docking cap shown in phantom. [Diagram 5] 1 illustrates an exemplary displacement of a flexible component such as a torque shaft or a catheter. [Figure 6] FIG. 1 shows a side view of a retriever releasing or capturing a leadless pacemaker. [Figure 7] FIG. 1 shows a perspective view of a retriever for releasing or capturing a leadless pacemaker. [Figure 8] 1 illustrates an example of a retriever in the form of a flexible grasper configured to radially deploy to release a leadless pacemaker. [Figure 9]13 illustrates another example of a retriever in the form of a flexible gripper configured for lateral outward pivotal displacement to release a leadless pacemaker. [Figure 10A] FIG. 1 illustrates a perspective view of an exemplary docking end of a leadless pacemaker. [Figure 10B] FIG. 1 illustrates a rear view of an exemplary docking end of a leadless pacemaker. [Figure 11] 1 illustrates an exemplary flexible gripper engaged with a docking protrusion of a leadless pacemaker. [Figure 12] 1 illustrates a perspective front view of an exemplary docking cap. [Figure 13] 1 illustrates a docking end of a leadless pacemaker having an exemplary key portion formed on the surface. [Figure 14A] 1 is a perspective view of an exemplary docking protrusion having a cross shape. [Figure 14B] FIG. 2 is a top view of an exemplary docking protrusion having a cross shape. [Figure 14C] 14C shows a flexible gripper engaged with the docking protrusion of FIG. 14A or FIG. 14B. [Figure 15A] 1 shows an example of a docking protrusion with rounded faces. [Figure 15B] 1 shows an example of a docking protrusion with rounded faces. [Figure 15C] 1 shows an example of a docking protrusion with rounded faces. [Figure 16A] 1 shows a perspective view of an exemplary set of keys formed on a surface of a docking protrusion. [Figure 16B] 1 illustrates a top view of an exemplary set of keys formed on a surface of a docking protrusion. [Figure 17A] FIG. 1 shows a top view of an exemplary leadless pacemaker including a rounded docking protrusion with a set of keys. [Figure 17B] FIG. 1 shows a perspective view of an exemplary leadless pacemaker including a rounded docking protrusion with a set of keys. [Figure 18]1 illustrates an exemplary docking cap positioned relative to an exemplary leadless pacemaker, the docking cap including one or more cap surfaces configured for mating engagement with one or more docking surfaces of a docking protrusion; [Figure 19A] 1 illustrates an exemplary docking cap engaged and disengaged from a leadless pacemaker, the docking cap having an overmolding configured to transmit torque with high friction between the docking cap and the leadless pacemaker. [Figure 19B] 1 illustrates an exemplary docking cap engaged and disengaged from a leadless pacemaker, the docking cap having an overmolding configured to transmit torque with high friction between the docking cap and the leadless pacemaker. [Figure 20] 13 shows another example of a retriever in the form of a flexible gripper that can be engaged with a docking button. [Figure 21] FIG. 13 is a cross-sectional view of the docking cap holding arm of the flexible gripper, showing the arm compressed around the docking button within the chamber. [Figure 22] FIG. 2 is a detailed view of an exemplary flexible gripper. [Diagram 23] 1 illustrates a tether extending through a lumen of an exemplary flexible grasper. [Figure 24] 1 illustrates an exemplary docking cap. [Figure 25A] Shows a hard docking button. [Figure 25B] Shows a flexible docking button. [Figure 26A] 13 shows a flexible gripper positioned against a docking button of a leadless pacemaker. [Figure 26B] 1 shows a docking button disposed between the first and second arms of the flexible grasper. [Figure 26C]1 shows a docking cap that covers the flexible gripping portion and holds the first and second arms compressed around the docking button. [Figure 27] 1 illustrates an exemplary docking protrusion having a loop configured to receive a tether, snare, or cable. [Figure 28] A cross-sectional view showing a retriever engaged with an opening in a surface of the docking end of the leadless pacemaker. [Figure 29] 1 shows a retriever with inwardly biased arms. [Figure 30A] 1 shows an example of a retriever in the form of a snare extending from a pair of sheaths. [Figure 30B] 1 shows an example of a retriever in the form of a snare extending from a pair of sheaths. [Figure 31A] 1 illustrates a detailed view of an exemplary snare. [Figure 31B] 1 illustrates a detailed view of an exemplary snare. [Diagram 32] 1 illustrates an example of a docking space positioned relative to a docking protrusion of a leadless pacemaker. [Figure 33A] 13 shows a snare advanced along a leadless pacemaker having a docking protrusion disposed within the docking space. [Figure 33B] 1 shows the snare clamped around the docking protrusion in the engaged position. [Diagram 34] FIG. 13 is a detailed view of the snare tightened around the docking protrusion in the engaged position. [Diagram 35] 13 illustrates the displacement of the leadless pacemaker relative to the longitudinal axis of the catheter in an engaged position. [Diagram 36] 1 shows a leadless pacemaker docked to a docking cap. [Figure 37] 1 illustrates an exemplary docking cap having a first tracker and a second tracker. [Figure 38] FIG. 13 is a cross-sectional view of a retriever in the form of a snare disposed within a chamber of a docking cap. [Figure 39] FIG. 13 is a cross-sectional view of the distal end of the catheter system showing the snare engaged with the docking protrusion of the leadless pacemaker. [Diagram 40] FIG. 13 is a cross-sectional view of the distal end of the catheter system showing the snare engaged with the docking protrusion of the leadless pacemaker. [Diagram 41] 1 is a front view of a retriever in the form of a hinged gripper, the hinged gripper shown engaging a slotted docking protrusion of a leadless pacemaker, the hinged gripper being displaceable by a push-pull actuator, and the docking cap shown in phantom. [Diagram 42] FIG. 42 is a side view of the hinged grip of FIG. 41. [Diagram 43] FIG. 42 is a detailed perspective view of the hinged gripper of FIG. 41, with the arms of the hinged gripper shown in phantom. [Diagram 44] FIG. 2 is a front view of a retriever in the form of another hinged grasper displaceable by a push-pull actuator, the retriever engaging a polygonal docking protrusion of a leadless pacemaker, the docking cap being shown in phantom. [Diagram 45] FIG. 45 shows a side view of the hinged gripper of FIG. [Figure 46] FIG. 45 is a detailed perspective view of the hinged gripper of FIG. 44, with the hinged gripper arms shown in phantom. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043] Aspects of the disclosure relate to systems and methods for delivery and retrieval of leadless biostimulators, such as leadless pacemakers. Typically, leadless pacemakers are delivered to or retrieved from a patient's implantation site using a catheter system. Thus, the disclosed systems and methods facilitate repeated implantation and / or retrieval of leadless pacemakers using a single catheter delivery and retrieval system, thereby reducing associated waste and costs. In addition, the systems and methods described herein enable delivery and retrieval of a variety of leadless pacemakers having different configurations with a single catheter system, thereby further reducing the workload of stocking different systems applicable to the various configurations.

[0044] In one aspect, the catheter system of the present disclosure includes a retriever in the form of a grasper, snare, or the like. The retriever is releasably engageable with the docking end of the leadless pacemaker to provide engagement and disengagement with and delivery and retrieval of the leadless pacemaker, as well as torque transfer to the leadless pacemaker during implantation of the leadless pacemaker. The retriever reduces the risk of spontaneous or other undesirable disengagement between the catheter system and the leadless pacemaker during delivery or retrieval of the leadless pacemaker. Additionally, the retriever provides positive disengagement independent of the relative position of the dual tether system. Additionally, the retriever isolates rotational forces of the leadless pacemaker from the catheter system that may cause binding and / or torque winding in the dual tether system. Tool-free bedside loading is facilitated by the disclosed technology, allowing implantation of a variety of leadless pacemakers into a patient's anatomy due to the radial deployment of the retrievers, with reduced tissue trauma to the patient's anatomy during implantation of the leadless pacemaker.

[0045] The systems and methods described herein generally relate to a loading tool having a retriever for releasably engaging a docking extension of a medical implant, and methods of delivering and retrieving a medical implant. Although the disclosure is described with respect to a leadless cardiac pacemaker and torque as loading technique, it will be apparent that the techniques disclosed are applicable to other biostimulator and / or medical implant systems and methods and loading techniques.

[0046] A detailed description of an exemplary cardiac pacing system 100 having one or more leadless pacemakers 104 begins with reference to FIGURE 1. Each of the leadless pacemakers 104 can be configured for temporary leadless pacing of a patient's heart 102. In one embodiment, each of the leadless pacemakers 104 is configured to be positioned inside or outside of or attached to a cardiac chamber, such as the right atrium and / or right ventricle, of the patient's heart 102. The leadless pacemakers 104 can be attached to cardiac tissue of the patient's heart 102 using, for example, a helical anchor 106 that penetrates the myocardium. It will be apparent that other primary fixation mechanisms, and possibly secondary fixation mechanisms, can be used to attach the leadless pacemakers 104 to tissue and / or limit displacement of the leadless pacemakers 104 during implantation.

[0047] The leadless pacemaker 104 is delivered to or retrieved from the patient's heart 102 using a catheter system 108, as shown in FIG. 2. Typically, the catheter system 108 releasably engages the leadless pacemaker 104 for intravenous advancement into the patient's heart 102. The catheter system 108 engages the leadless pacemaker 104 in a manner that facilitates fixation to cardiac tissue using, for example, a helical anchor 106. As described herein, the catheter system 108 is configured to provide torque transfer to the leadless pacemaker 104 when a fixation mechanism engages the cardiac tissue, such as by rotation, for example, by the helical anchor 106. In other words, the catheter system 108 engages components of the leadless pacemaker 104 and applies a torque to the leadless pacemaker 104, thereby screwing the helical anchor 106 into the cardiac tissue.

[0048] The catheter system 108 engages the leadless pacemaker 104 at its distal end 110 and has a handle at its proximal end 112 for steering the delivery and / or retrieval of the leadless pacemaker 104. In one embodiment, the catheter system 108 includes a torque shaft 114, a sleeve 116, and an introducer sheath 120. The catheter system 108 may also include a steerable catheter 118 for redirecting the catheter system 108 and / or one or more flush ports 128 and 130 for flushing saline or other fluids through the catheter system 108.

[0049] The torque shaft 114 provides torque transfer from the steerable catheter 118 to the leadless pacemaker 104 or to displace the leadless pacemaker 104 as controlled by one or more control knobs (e.g., a first control knob 124 and a second control knob 126) disposed on a handle body 122. An introducer sheath 120 may be advanced distally along the steerable catheter 118 to provide additional control and support for the steerable catheter 118 during delivery and / or retrieval of the leadless pacemaker 104, as well as to surround the leadless pacemaker 104 as it is introduced into the patient's anatomy via a trocar or introducer. Similarly, the sleeve 116 is displaceable along the steerable catheter 118 and is displaceable distally along the leadless pacemaker 104 to cover the torque shaft 114, the leadless pacemaker 104, and the helical anchor 106 to protect the patient's tissue and anatomical structures during delivery and / or retrieval of the leadless pacemaker 104.

[0050] 3, a detailed view of the distal end 110 of the catheter system 108 is shown. In one embodiment, the steerable catheter 118 extends through a sleeve cap 134 and into a sleeve 116 where it couples with the torque shaft 114. The sleeve 116 is displaceable along the torque shaft 114 and the leadless pacemaker 104 such that the leadless pacemaker 104 is located within the sleeve 116 and proximal to the distal end 132 of the sleeve 116. The sleeve 116 may also be steerable.

[0051] In one embodiment, a docking cap 136 is coupled to the distal end of the torque shaft 114 and configured to releasably engage the leadless pacemaker 104. The torque shaft 114 and the docking cap 136 each transmit torque to the leadless pacemaker 104 during delivery and / or retrieval of the leadless pacemaker 104. FIGS. 4A-4C show the catheter system 108 in a docked or engaged position with the docking cap 136 covering the docking end of the leadless pacemaker 104. In one embodiment, the docking cap 136 includes a body portion 138 and a receiver 140 configured to couple to a distal end 146 of the torque shaft 114. During use, the distal end 146 of the torque shaft 114 remains rigidly coupled to the receiver 140.

[0052] The body portion 138 of the docking cap 136 defines a chamber 142. As can be seen in FIGS. 4B-4C , in the docked position, a docking extension 148 extending from the docking end of the leadless pacemaker 104 is located within the chamber 142. A retriever 144 is displaceable within the lumen of the torque shaft 114 and configured to releasably engage the docking extension 148. More specifically, the retriever 144 is extendable through the body portion 138 of the docking cap 136 for positioning against the docking extension 148. The docking extension 148 is then captured by the retriever 144 within the chamber 142 by covering the docking extension 148 with the body portion 138 of the docking cap 136.

[0053] In the docked position, the catheter system 108 provides torque transfer to the leadless pacemaker 104. FIG. 5 illustrates that the torque shaft 114 is torqueable and adjustable with degrees of freedom of displacement in multiple directions to reposition or otherwise steer the leadless pacemaker 104 during a test mode or during implantation of the leadless pacemaker 104. The torque shaft 114 can be flexible and / or made from a variety of materials. For example, the torque shaft 114 can be made from polymers, metals, etc. The torque shaft 114 can be made of catheter laminate structures formed as hollow helical cables and / or other structures for torque transfer and steering. In one embodiment, the torque shaft 114 and / or the steerable catheter 118 are hypotubes. In other embodiments, the torque shaft 114 and / or the steerable catheter 118 include cable tubes, laser cut tubes, extrusions, wires, wire cables, etc. for increased flexibility.

[0054] As can be seen in Figure 6, the docking cap 136 is displaceable along with the retriever 144 to displace the retriever 144 between an engaged position in which the retriever 144 and docking extension 148 are engaged within the chamber 142 to dock the catheter system 108 to the leadless pacemaker 104, and a disengaged position in which the retriever 144 and docking extension 148 are disengaged and the retriever 144 is located outside of the chamber 142 and returns to its natural state. As shown in Figures 6 and 7, in one embodiment, the docking cap 136 is retracted proximally to radially deploy the retriever 144 and return to its natural state, thereby disengaging the retriever 144 from the docking extension 148 and releasing the leadless pacemaker 104 from the catheter system 108. To recapture the leadless pacemaker, such as for retrieval or repositioning, the retriever 144 is positioned against the docking extension 148 and the docking cap 136 is placed over the retriever 144, thereby radially closing the retriever 144 within the chamber 142 and covering the docking extension 148.

[0055] In one embodiment, the retriever 144 is a flexible grasper having first and second arms disposed opposite one another, the first and second arms each configured to form a hinge biased radially outward from a longitudinal axis of the retriever 144. In other words, the retriever 144 is biased to unfold in free space and return to its natural state, as shown in Figures 6 and 7. In one embodiment, in the natural state of the retriever 144, the first and second arms define an opening having an inner diameter larger than the diameter of the docking extension 148, and in some instances the diameter of the body of the leadless pacemaker 104. The retriever 144 in the form of a flexible grasper may be made from a variety of elastic or other flexible materials, including, but not limited to, Nitinol or other shape memory wires, cables, tubes, and the like.

[0056] As can be seen in FIGS. 4A-7 , the catheter system 108 is displaced between a docked position and a released position by axial displacement of the docking cap 136 along the retriever 144. In one embodiment, the body portion 138 of the docking cap 136 includes one or more cap surfaces disposed relative to the chamber 142. The cap surfaces displace the first and second arms of the retriever 144 radially inward and maintain the first and second arms pressed against the docking extension 148. In this manner, the docking cap 136 and the docking end of the leadless pacemaker 104 are configured such that the retriever 144 is maintained locked to the docking extension 148 when the docking cap 136 covers the retriever 144. This docked position facilitates delivery of the leadless pacemaker through the patient's anatomy to a target location for implantation within the patient's heart 102. Once the leadless pacemaker is implanted, the first and second arms of the retriever 144 are allowed to deploy radially outward to their natural state by retracting the docking cap 136 proximally, thereby disengaging and releasing the docking extension 148 from the retriever 144. The catheter system 108 is then removed from the patient. The docking extension 148 can be recaptured for retrieval or repositioning by covering the retriever 144 with the docking cap 136. During release and capture, tagging or trauma to patient tissue is reduced or eliminated by the radial displacement of the first and second arms of the retriever 144 between the engaged and disengaged positions.

[0057] 8 and 9 show an example of a retriever 144 in the form of a flexible grasper having a first arm 200 and a second arm 202, each of which forms a flexible loop portion. The flexible loop portion is attached to one or more mandrels that extend through a lumen of the torque shaft 114. In one embodiment, the first arm 200 includes one or more elongated body portions (e.g., a first elongated body portion 206 and a second elongated body portion 208). The first elongated body portion 206 extends parallel to the second elongated body portion 208 in a first plane and forms a gap between the first elongated body portion 206 and the second elongated body portion 208. A first set of tapered portions connect the one or more elongated bodies to the first set of graspers. In one embodiment, the first gripping portion 214 is connected to the first elongated body portion 206 by a first tapered portion 210 in a first plane, and the second gripping portion 216 is connected to the second elongated body portion 208 by a second tapered portion 212 in the first plane. The first gripping portion 214 is generally parallel to the second gripping portion 216, the first elongated body portion 206, and the second elongated body portion 208. The distance between the first gripping portion 214 and the second gripping portion 216 is greater than the distance between the first elongated body portion 206 and the second elongated body portion 208, and the first tapered portion 210 and the second tapered portion 212 extend inwardly from the first gripping portion 214 and the second gripping portion 216 to the first elongated body portion 206 and the second elongated body portion 208. The flexible loop portion of the first arm 200 is formed by a first loop portion 218 that extends in a curved manner between a first gripping portion 214 and a second gripping portion 216 .

[0058] The second arm 202 may be symmetrical to the first arm 200. In one embodiment, the second arm 202 includes one or more elongated body portions (e.g., a third elongated body portion 220 and a fourth elongated body portion 222). The third elongated body portion 220 extends parallel to the fourth elongated body portion 222 in a second plane and forms a gap therebetween. The second plane is parallel to the first plane. The one or more elongated body portions are connected to the second set of gripping portions by a second set of tapered portions. In one embodiment, the third gripping portion 228 is connected to the third elongated body portion 220 by a third tapered portion 224 in the second plane, and the fourth gripping portion 230 is connected to the fourth elongated body portion 222 by a fourth tapered portion 226 in the second plane. The third gripping portion 228 is generally parallel to the fourth gripping portion 230, the third elongated body portion 220, and the fourth elongated body portion 222. The distance between the third gripping portion 228 and the fourth gripping portion 230 is greater than the distance between the third elongated body portion 220 and the fourth elongated body portion 222, and the third tapered portion 224 and the fourth tapered portion 226 extend inwardly from the third gripping portion 228 and the fourth gripping portion 230 to the third elongated body portion 220 and the fourth elongated body portion 222. A flexible loop portion of the second arm 202 is formed by a second loop portion 232 that extends curvilinearly between the third gripping portion 228 and the fourth gripping portion 230.

[0059] As can be seen from Figures 8 and 9, which respectively show the docked and natural states of the retriever 144, in one embodiment, the first arm 200 and the second arm 202 each form a hinge biased radially outward from the longitudinal axis of the retriever 144. When the retriever 144 is in the docked state, the first set of grippers 214 and 216 are adjacent to the second set of grippers 228 and 230 in the first and second planes. In the docked state, the first loop portion 218 and the second loop portion 232 extend in opposite directions relative to each other, forming a ring between the first loop portion 218 and the second loop portion 232 that defines the docking space 234. The docking space 234 is sized and shaped to match the size and shape of the docking extension 148. As described herein, the first arm 200 and the second arm 202 are configured to matingly engage with components of the docking extension 148.

[0060] When the retriever 144 changes to the neutral state, the first arm 200 and the second arm 202 pivotally displace radially outward from the longitudinal axis such that the first set of grippers 214 and 216 are at an angle relative to the second set of grippers 228 and 230, or such that the first set of grippers 214 and 216 are at an angle relative to a first plane and the second set of grippers 228 and 230 are at an angle relative to a second plane. In one embodiment, retracting the docking cap 136 proximally causes the ring formed by the first loop portion 218 and the second loop portion 232 to expand radially outward to a larger ring diameter, thereby disengaging and releasing the docking extension 148 from the retriever 144.

[0061] 10A-10B, the docking extension 148 has components configured to matingly engage the first and second arms 200, 202, and the docking cap 136 to facilitate capture by the retriever 144 and provide torque transfer. In one embodiment, the leadless pacemaker 104 includes a docking extension 148 extending from a surface 302 of a docking end of the body portion 300. The docking extension 148 is positioned against the chamber 142 of the docking cap 136 and has one or more docking surfaces, including an edge docking surface 306 configured to matingly engage a corresponding cap surface, and an end surface 308, to provide torque transfer for the leadless pacemaker 104. In one embodiment, the edge docking surface 306 includes one or more flat radial surfaces that may be radially symmetric about the docking extension 148. The edge docking surface 306 may be positioned relative to the end surface 308 to form a ledge that extends perpendicular to the end surface 308. In one embodiment, the end surface 308 is flat and the surface 302 of the body portion 300 is flat, with the end surface 308 and the surface 302 of the body portion 300 providing additional surfaces for torque transfer.

[0062] The docking surface may have one or more keys configured to matingly engage with corresponding components of the docking cap 136 and / or retriever 144. The docking extension 148 and / or surface 302 of the docking end of the body 300 may have one or more keys. In one embodiment, the docking extension 148 has a side key 310 that extends through the docking extension 148 from the surface 302 to the end surface 308 of the body 300. The side keys 310 may be oriented radially opposite one another such that they are radially symmetrical to one another. As shown in FIG. 11, in one embodiment, the side keys 310 are configured to engage with portions of the first arm 200 and the second arm 202 of the retriever 144 in the engaged position. For example, when docking cap 136 covers docking extension 148, gripping portion 214, gripping portion 216, gripping portion 228, and gripping portion 230 are displaced into side key 310 and held in an engaged position by docking cap 136. Side key 310 may include one or more key faces 312 for transmitting torque through first arm 200 and second arm 202 of retriever 144.

[0063] Similarly, the docking extension 148 may include a neck portion 304 recessed from the edge docking surface 306 and configured to matingly engage at least a portion of the first and second arms 200 and 202 of the retriever 144. For example, the docking cap 136 may pivotally displace the first and second loop portions 218 and 232 radially inwardly into mating engagement with the neck portion 304. In addition, the docking cap 136 maintains the first and second loop portions 218 and 232 pressed against the docking extension 148 in the engaged position. The recessed neck portion 304 prevents the first and second arms 200 and 202 from disengaging longitudinally from the docking extension 148. The geometric shape of the docking extension 148 facilitates smooth capture and release by the retriever 144 when the docking cap 136 is displaced distally to cover the docking extension 148 or when the docking cap 136 is retracted proximally from the docking extension 148.

[0064] 12 , the body portion 138 of the docking cap 136 includes one or more cap surfaces disposed relative to the chamber 142, the one or more cap surfaces configured for mating engagement with a docking surface of a docking end of the leadless pacemaker 104 and / or a component of a retriever 144. In one embodiment, the one or more cap surfaces include a distal end surface 400, a proximal chamber surface 402, one or more ledge surfaces 406 disposed proximal to the distal end surface 400 within the chamber 142, and one or more side surfaces 404 extending between the proximal chamber surface 402 and the ledge surface 406. The distal end surface 400 defines an opening into the chamber 142, and the proximal chamber surface 402 defines a proximal opening 408 through the receiver 140 and into the chamber 142. The proximal opening 408 is coaxial with the lumen of the torque shaft 114 and the longitudinal axis of the retriever 144 .

[0065] The ledge surface 406 may mirror the size and shape of the surface 302 of the docking end of the body portion 300 of the leadless pacemaker 104. For example, both the ledge surface 406 and the surface 302 may be flat. Similarly, the proximal chamber surface 402 may be sized and shaped to matingly engage the end surface 308 of the docking extension 148 and for the side surface 404 to engage the edge docking surface 306. The mating engagement of each of the various cap surfaces with its corresponding docking surface provides torque transfer. When in the docked state, the engagement of the docking extension 148 with the docking cap 136 generates a torque of approximately 1.5 inch-ounces at a mating normal force of approximately 500 g. The generated torque is therefore an order of magnitude higher than the 0.125 inch-ounce or less torque typically required to implant a leadless pacemaker in human tissue.

[0066] Examples of various geometries for the docking end of the leadless pacemaker 104 are shown in Figures 13-18. The geometries include one or more keying features in the form of torque transfer keys, dimples, and / or geometric features that matingly engage with corresponding features of the docking cap 136. Referring first to Figure 13, in one embodiment, the surface 302 of the body portion 300 has one or more undercut keys 314 formed therein. Alternatively or additionally, the docking extension 148 may have a cross shape with side keys 310 forming angled cutouts, as shown in Figures 14A-14C.

[0067] In another embodiment, as shown in Figures 15A-18, the end surface 308 of the docking extension 148 is formed with a rounded shape. The contour of the end surface 308 can vary from a low contour curve to a high dome-shaped contour, in either case the end surface 308 is an atraumatic smooth rounded surface. The docking cap 136 includes a corresponding cap surface that mirrors the size and shape of the end surface 308 to maintain the retriever 144 pressed against the docking extension 148 in the engaged position. Frictional contact between the cap surface and the end surface 308 provides torque transfer. To further facilitate torque transfer, the end surface 308 can have a side key 310 configured for mating engagement with a cap key 410, as can be seen in Figures 16A-18. As shown in Figures 19A-19B, an overmolding 412 made from silicone or a similar material may be applied to the cap surface and / or docking extension 148 within the chamber 142 to increase friction of the mating surfaces.

[0068] 17A-18, the helical anchor 106 is provided at a fixed end of the leadless pacemaker 104 opposite the docking end. In one embodiment, the fixed end is at a distal end of the leadless pacemaker 104 and the docking end is at a proximal end of the leadless pacemaker 104. It will be apparent that some or all of these components may be reversed (protruding from their surface) depending on size limitations of the leadless pacemaker 104.

[0069] 20-26C, another example of a retriever 144 in the form of a flexible grasper and a corresponding example of a docking extension 148 will be described in detail. Referring first to FIG. 20, in one embodiment, the docking extension 148 includes a docking button 320 attached to the end surface 308 by one or more posts (e.g., a first post 316 and a second post 318). As can be seen in FIG. 21, the docking button 320 can be integral with the posts 316 and 318. Additionally, the docking button 320 can be a rounded surface extending between a first end 322 and a second end 324.

[0070] 21 and 22, the retriever 144 includes a mandrel 500 coupled to a base portion 504. The mandrel 500 may be coupled to the base portion 504 directly or indirectly via a retriever shaft 502. The mandrel 500 extends into the lumen of the torque shaft 114 through a proximal opening 408. The retriever 144 may be made from a variety of elastic or other flexible materials, such as, but not limited to, polymers (e.g., polyetheretherketone (PEEK)), Nitinol or other shape memory wires, cables, tubes, and the like.

[0071] The retriever 144 includes a first arm 506 and a second arm 508 extending from the base portion 504, the first arm 506 and the second arm 508 defining a docking space 514 therebetween. In one embodiment, the first arm 506 and the second arm 508 form a jaw having a hinged portion configured to grip at least a portion of the docking extension 148, such as the docking button 320, within the docking space 514 when the docking cap 136 covers the retriever 144 and changes the retriever 144 to a docked state. In another embodiment, one or more hinged portions are provided at the connection points of the first arm 506 and the second arm 508 to the base portion 504. The first arm 506 has a first lip portion 510 and the second arm 508 has a second lip portion 512. First lip 510 and second lip 512 each extend inwardly toward a longitudinal axis of a lumen 516 of retriever 144 .

[0072] 23, in one embodiment, a tether 518 may be introduced during tether mode or test mode to, among other things, check the threshold. The tether 518 may be, but is not limited to, a snare, a flexible shaft, or the like. For example, the tether 518 may include a distal loop 522 and an elongated body portion 520 that extends distally through the lumen 516 of the retriever 144 to the distal loop 522.

[0073] 24, another example of a docking cap 136 is shown. As described herein, the body portion 138 of the docking cap 136 has one or more cap surfaces configured to provide torque to the leadless pacemaker 104 via a docking surface at the docking end of the leadless pacemaker 104 and to displace the first arm 506 and the second arm 508 into an engaged position about the docking extension 148. In one embodiment, the one or more cap surfaces are disposed relative to the chamber 142 and configured to engage with a docking surface and / or components of the retriever 144. The one or more cap surfaces may include a distal end surface 400, a proximal chamber surface 402, a ledge surface 406 located proximal to the distal end surface 400 within the chamber 142, and a side surface 404 extending between the proximal chamber surface 402 and the ledge surface 406. The distal end face 400 defines an opening to the chamber 142, and the proximal chamber face 402 defines a proximal opening 408 that passes through the receiver 140 and into the chamber 142. The proximal opening 408 is coaxial with the longitudinal axis of the lumen of the torque shaft 114 and / or steerable catheter 118, as well as the lumen 516 of the retriever 144.

[0074] The ledge surface 406 may mirror the size and shape of the surface 302 of the docking end of the body portion 300 of the leadless pacemaker 104. For example, both the ledge surface 406 and the surface 302 may be flat. Mating engagement of each of the various cap surfaces with its corresponding docking surface provides torque transfer. To further facilitate torque transfer, one or more of the cap surfaces may have cap keys 410. In one embodiment, the cap keys 410 are multiple and are disposed circumferentially along a distal side surface 414 extending from the ledge surface 406 toward the distal end surface 400. The cap keys 410 may be configured to matingly engage corresponding side keys 310 defined in the docking extension 148 for torque transfer.

[0075] Further examples of docking extensions 148 are shown in Figures 25A-25B. In one embodiment, side keys 310 are formed on edge docking surfaces 306 of docking extensions 148, which extend from surface 302 of body portion 300 to end surface 308. The side keys 310 may be oriented radially opposite one another so as to be radially symmetrical with respect to one another. In one embodiment, docking cap 136 is configured to matingly engage docking extension 148 by disposing edge docking surface 306 along distal side 414 and disposing cap keys 410 within side keys 310.

[0076] The ledge surface 406 is configured to displace the first and second arms 506, 508 radially inward from their natural state in which they are biased radially outward. In one embodiment, the ledge surface 406 displaces the first and second arms 506, 508 until they close around the docking button 320 in the engaged position shown in FIG. 21. The side surface 404 retains the first and second arms 506, 508 around the docking button 320 with the first and second lips 510, 512 extending inward beyond the outer edge of the docking button 320, thereby preventing the docking button 320 from displacing distally from the docking space 514 and releasing (detaching) from the retriever 144.

[0077] The docking button 320 may be attached to the end surface 308 by a first post 316 and a second post 318. As can be seen in FIGS. 25A-25B, the docking button 320 may be integral, rigidly coupled, and / or flexibly connected to the posts 316 and 318. In one embodiment, the docking button 320 is a rounded surface extending between a first end 322 and a second end 324, which are separated from one another by a gap opening leading to a button lumen 326. The docking button 320 has a first slot 328 and a second slot 330 configured to receive and engage the first post 316 and the second post 318, respectively.

[0078] Engagement and disengagement of the leadless pacemaker 104 for delivery and / or retrieval will now be described in more detail with reference to FIGS. 26A-26C. In one embodiment, the retriever 144 is positioned relative to the docking extension 148. FIG. 26A shows the retriever 144 approaching the docking extension 148 for engagement. The docking extension 148 is positioned within the docking space 514 between the first arm 506 and the second arm 508. For example, as shown in FIG. 26B, the docking button 320 of the docking extension 148 may be positioned within the docking space 514. The docking end of the leadless pacemaker 104, including the docking extension 148, is then positioned within the chamber 142 by covering the retriever 144 with the body portion 138 of the docking cap 136. The docking cap 136 holds the retriever 144 pressed around the docking button 320 to lock the leadless pacemaker 104 in the docked state shown in FIGURE 26C. The leadless pacemaker 104 is then docked with the catheter system 108 and ready for delivery through the patient's anatomy to an implantation site, for example, within the patient's heart 102. The engagement between the docking cap 136 and the docking end of the leadless pacemaker 104 may be strong enough to maintain the leadless pacemaker 104 in the docked state against the force of gravity.

[0079] Once at the implantation site, the catheter system 108 is rotated using the handle body 122. The torque of this rotation is transferred to the leadless pacemaker 104 by mating engagement of one or more cap surfaces with one or more docking surfaces, thereby anchoring the leadless pacemaker 104 to tissue at the implantation site using the helical anchor 106. In some implementations, the tether 518 is used to check the threshold. Once the leadless pacemaker 104 is anchored at the implantation site, the catheter system 108 releases the leadless pacemaker 104. In one embodiment, the body 138 of the docking cap 136 is retracted proximally until the retriever 144 is outside the chamber 142, causing the first arm 506 and the second arm 508 to spring radially outward and deploy, thereby disengaging the retriever 144 from the docking button 320. The catheter system 108 is then removed from the patient's body by retracting it along the patient's anatomy.

[0080] During retrieval of the leadless pacemaker 104, the catheter system 108 is introduced into the patient and advanced through the patient's anatomy toward the implantation site until the retriever 144 is positioned against the docking extension 148. The retriever 144 is then advanced until the docking button 320 is positioned within the docking space 514 between the first arm 506 and the second arm 508. The leadless pacemaker 104 is then locked to the catheter system 108 in a docked state by covering the retriever 144 with the body portion 138 of the docking cap 136 as described herein. The catheter system 108 is then rotated through mating engagement between the docking extension 148 and the docking cap 136 to transfer torque to the leadless pacemaker 104, thereby disengaging the helical anchor 106 from the tissue at the implantation site. The retriever 144, or other components of the catheter system 108, such as a cutting edge, can be used to remove tissue overgrowth on the leadless pacemaker 104. The leadless pacemaker 104 is maintained in a docked state and the leadless pacemaker 104 is retrieved by retracting the catheter system 108 through the patient's anatomy.

[0081] Another example of a docking cap configured to lock the retriever 144 in an engaged position about the docking extension 148 is described with reference to FIG. 27. In one embodiment, the docking cap includes an elongated body 524. The elongated body 524 has a lumen 526 defined therein. A tether 528, which may be a snare, cable, or other tether, extends through the lumen 526 of the elongated body 524 and through the lumen 516 of the retriever 144. The tether 528 is looped by threading it through the docking extension 148 and back into the handle body 122 of the catheter system 108.

[0082] In one embodiment, the docking extension 148 of the leadless pacemaker 104 includes a docking button 320 attached by a post 316 to the surface 302 of the body 300 of the leadless pacemaker 104. The docking button 320 includes a flat distal surface and a hook 332 extending from the distal surface. The tether 528 is looped through the hook 332.

[0083] As described herein, when the docked retriever 144 is engaged with the docking extension 148, the elongated body 524 is displaced distally along the first and second arms 506, 508 to lock the docking button 320 in an engaged position in the docking space 514. When the leadless pacemaker 104 is released from the retriever 144, the elongated body 524 is displaced proximally until the first and second arms 506, 508 spring radially outward to their natural positions to disengage the retriever 144 from the docking button 320.

[0084] 28 and 29, another example of a retriever 144 is shown. In one embodiment, the retriever 144 includes a retriever base 600 having a set of arms 602 extending therefrom, including a first arm and a second arm disposed opposite one another about a central lumen 604. In one embodiment, the set of arms 602 are provided on and / or integral with a retriever shaft 606 that extends through the retriever base 600. The central lumen 604 extends through the retriever shaft 606, the retriever base 600, and the set of arms 602.

[0085] In a natural or disengaged state, the set of arms 602 are biased radially inward toward the central lumen 604. In one embodiment, displacement of a mandrel 608 within the central lumen 604 displaces the set of arms 602 between an engaged position and a disengaged position relative to the docking extension 148. More specifically, the docking extension 148 can have a docking face opening 334 defined in a docking face 306 extending from a surface 302 or portion thereof of the docking end of the body portion 300 of the leadless pacemaker 104. The set of arms 602 have a first tab 610 and a second tab 612 extending radially outward from the central lumen 604. In a natural or disengaged state, the set of arms 602 are biased radially inward, which allows the set of arms 602 to advance through the docking face opening 334. The mandrel 608 can be advanced distally through the central lumen 604 to resiliently space the pair of arms 602 relative to one another, causing the first tab 610 and the second tab 612 to displace radially outwardly into engagement with edges defining the docking face opening 334, thereby locking the retriever 144 to the docking extension 148.

[0086] To release the leadless pacemaker 104 by disengaging the retriever 144 from the docking extension 148, the mandrel 608 is retracted proximally within the central lumen 604, causing the set of arms 602 to spring radially inward to their natural position, thereby disengaging the first and second tabs 610, 612 from the edges defining the docking surface opening 334 and allowing the catheter system 108 to be retracted.

[0087] 30A-40, an example of a retriever 144 in the form of a snare loop will be described in detail. Referring first to FIGURES 30A-30B, in one embodiment, a body portion 138 of a docking cap 136 is secured to a component of the catheter system 108, such as the torque shaft 114. A chamber 142 of the docking cap 136 is coaxial with a lumen of the catheter system 108, such as the lumen of the torque shaft 114.

[0088] In one embodiment, the retriever 144 includes a first sheath 702 and a second sheath 704 extending distally from the chamber 142. The first sheath 702 and the second sheath 704 extend proximally through the chamber 142 and into a lumen of the catheter system 108. The first sheath 702 and the second sheath 704 are longitudinally displaceable through the lumen of the chamber 142 and the torque shaft 114, respectively.

[0089] A snare 700 extends distally from the first sheath 702 and the second sheath 704. The snare 700 is displaceable within the first sheath 702 and the second sheath 704. The snare 700 is configured to be displaceable between an engaged position and a disengaged position for releasably engaging the docking extension 148. The first sheath 702 and the second sheath 704 may be made from a variety of materials, including, but not limited to, steel, elastic cable tubing, braided or coiled polytetrafluoroethylene (PTFE) impregnated polyimide tubing, and the like. The snare 700 may be made from a variety of flexible materials, such as Nitinol or other elastic materials.

[0090] 31A and 31B, in one embodiment, a snare 700 extends from a first snare lumen 710 of a first sheath 702 and a second snare lumen 712 of a second sheath 704 and is displaceable within the first snare lumen 710 and the second snare lumen 712. The snare 700 is displaceable between an engaged position and a disengaged position within the first snare lumen 710 and the second snare lumen 712 to capture or release the docking extension 148 of the leadless pacemaker 104. In one embodiment, the first sheath 702 has a first end coil 706 and the second sheath 704 has a second end coil 708. Radiopacity can be achieved by making the first end coil 706 and the second end coil 708 radiopaque. Alternatively or additionally, NiTi DFT composite wires combining Nitinol with titanium or platinum in various sheath / core ratios, tungsten or tantalum strands in NiTi cables, etc. may be used for radiopacity. Additionally, radiopaque coils and / or marker bands may be crimped or otherwise attached to the snare 700. Radiopaque coils may also be wound around a NiTi core, etc.

[0091] In one embodiment, the snare 700 includes a first snare wire 714 and a second snare wire 716. The first snare wire 714 extends from the first snare lumen 710 into the second snare lumen 712 to form a first snare loop oriented in a first direction, and the second snare wire 716 extends from the first snare lumen 710 into the second snare lumen 712 to form a second snare loop oriented in a second direction. In one embodiment, the first direction is different from the second direction, such that a docking space is formed between the first and second snare loops. The first direction may be oriented relative to the second direction such that the snare 700 forms a duckbill shape.

[0092] As can be seen from FIGS. 32-36 , to engage the docking extension 148 with the catheter system 108 and lock the leadless pacemaker 104 in a docked position with the catheter system 108, the docking space formed by the snare 700 is positioned against at least a portion of the docking extension 148, such as the docking button 320, as shown in FIG. 32. The snare 700 is then advanced distally along the leadless pacemaker 104 until the docking extension 148 is positioned within the docking space. For example, as shown in FIG. 33A , the first snare loop and the second snare loop are advanced distally until the docking button 320 is positioned within the docking space of the snare 700. Advancement of the snare 700 can be accomplished by advancing the catheter system 108, the snare 700, and / or the first sheath 702 and the second sheath 704. The first sheath 702 and the second sheath 704 are displaceable through the docking cap 136, and the first snare wire 714 and the second snare wire 716 are displaceable within the first snare lumen 710 and the second snare lumen 712, respectively.

[0093] The snare 700 is displaceable from a disengaged position to an engaged position (see FIGS. 33B and 34) by proximally displacing the first and second snare wires 714, 716 within the first and second snare lumens 710, 712. In other words, the first and second snare wires 714, 716 are retracted within the first and second snare lumens 710, 712, respectively. The proximal displacement of the first and second snare wires 714, 716 tightens the snare 700, narrowing the first and second snare loops into smaller loops. In other words, the tip (peak) of each snare loop formed by the first snare wire 714 and the second snare wire 716 is displaced proximally toward the distal end of the first sheath 702 and the second sheath 704, thereby reducing the size of each snare loop. In addition, the peaks of the snare loop formed by the first snare wire 714 and the second snare wire 716 are simultaneously displaced toward each other and toward the central axis of the docking space during the proximal displacement of the first snare wire 714 and the second snare wire 716. The displacement of the peaks radially inward toward each other and toward the central axis reduces the size of the docking space, causing the first snare wire 714 and the second snare wire 716 to tighten around at least a portion of the docking extension 148, thereby locking the docking extension 148 in the engaged position. For example, as shown in Figures 33B and 34, the size of the docking space can be reduced until the first snare wire 714 and the second snare wire 716 surround the first post 316 and the second post 318 and / or until the size of the docking space is smaller than the size of the docking button 320.

[0094] The snare 700 captures the docking extension 148 and locks it in an engaged position with the leadless pacemaker 104 having freedom of displacement. More specifically, as shown in FIGURE 35, the engagement of the snare 700 with the docking extension 148 provides a junction that allows displacement of the leadless pacemaker 104 relative to a longitudinal axis extending through the chamber 142 and / or one or more lumens of the catheter system 108. Such displacement can be parallel to the longitudinal axis or at an angle to the longitudinal axis without releasing the leadless pacemaker 104 from the catheter system 108. For example, as shown in FIGURE 35, such a junction acts like a hinge, allowing the leadless pacemaker 104 to be repositioned without releasing the leadless pacemaker 104.

[0095] 36 , when the snare 700 is in the engaged position with the docking extension 148, the first sheath 702 and the second sheath 704 are retracted proximally until the docking extension 148 is disposed within the chamber 142 of the docking cap 136 to displace the leadless pacemaker 104 into a docked position with the catheter system 108. In the docked position, the leadless pacemaker 104 can be displaced through the patient's anatomy to and / or from the implantation site. During retrieval of the leadless pacemaker 104, the snare 700 and / or other components of the retriever 144 can use cutting edges or similar components to remove tissue overgrowth on the leadless pacemaker 104. Additionally, the retriever 144 may be used in a tethered mode and / or a test mode to test the threshold, for example, by advancing the first sheath 702 and the second sheath 704 together with the first snare wire 714 and the second snare wire 716 such that engagement between the docking extension 148 and the snare 700 is maintained.

[0096] 37-40, the interaction of the retriever 144 and the docking cap 136 will be described in detail. In one embodiment, the body portion 138 of the docking cap 136 has one or more cap surfaces configured to provide torque to the leadless pacemaker 104 via a docking surface at the docking end of the leadless pacemaker 104 as described herein. In one embodiment, the one or more cap surfaces are disposed relative to the chamber 142 and configured for mating engagement with the docking surface and / or components of the retriever 144. The one or more cap surfaces may include a distal end surface 400, a proximal chamber surface 402, and a side surface 404 extending between the proximal chamber surface 402 and the distal end surface 400. The distal end surface 400 defines an opening into the chamber 142, and the proximal chamber surface 402 defines a proximal opening 408 into the chamber 142 that extends through the receiver 140. The proximal opening 408 may be coaxial with the longitudinal axis of the lumen of the torque shaft 114 and / or the steerable catheter 118 and with the central axis of the snare 700.

[0097] Torque transfer is provided by mating engagement of each of the various cap surfaces with its corresponding docking surface. To further facilitate torque transfer, one or more of the cap surfaces may have cap keys 410. In one embodiment, the cap keys 410 are provided in multiple locations along the circumference of the side surface 404, e.g., radially opposite one another about the longitudinal axis. The cap keys 410 may be configured to matingly engage with corresponding side keys 310 defined in the docking extension 148 for torque transfer, as described herein.

[0098] In one embodiment, the docking cap 136 further includes one or more trackers corresponding to one or more sheaths of the retriever 144. For example, the docking cap 136 may include a first tracker 416 corresponding to the first sheath 702 and a second tracker 418 corresponding to the second sheath 704. In one embodiment, the first tracker 416 and the second tracker 418 maintain the orientation of the first sheath 702 and the second sheath 704 relative to each other and to a central axis coaxial with the longitudinal axis extending through the proximal opening 408. The orientation may include, for example, maintaining the first sheath 702 and the second sheath 704 in radially opposite positions relative to each other about the central axis. In other words, the first sheath 702 and the second sheath 704 may be disposed at an angle of about 180 degrees relative to each other about the central axis.

[0099] The first sheath 702 and the second sheath 704 are displaceable within the first tracker 416 and the second tracker 418, respectively. In one embodiment, as shown in FIGS. 38-40, the first tracker 416 has a first tracker lumen 420 through which the first sheath 702 is displaceable, and the second tracker 418 has a second tracker lumen 422 through which the second sheath 704 is displaceable. In this way, the first tracker 416 and the second tracker 418 maintain the first sheath 702 and the second sheath 704 in an orientation suitable for positioning the snare 700 to capture the docking extension 148. As a result, the snare 700 can be displaced to a docking position within the chamber 142 by retracting the first sheath 702 and the second sheath 704 into the lumen of the torque shaft 114.

[0100] In one embodiment, as shown in FIGS. 39-40 , the docking button 320 is attached to the docking extension 148 by a pair of docking balls secured to a first post 316 and a second post 318. The first post 316 may extend between a first proximal ball 336 and a first distal ball 340. The first proximal ball 336 is disposed within the first slot 328 and the first distal ball 340 extends through an opening in the end face 308 such that the docking button 320 is attached to the docking extension 148 by the first post 316. Similarly, the second post 318 may extend between a second proximal ball 338 and a second distal ball 342. A second proximal ball 338 is disposed in the second slot 330 and a second distal ball 342 extends through another opening in the end face 308 such that the docking button 320 is attached to the docking extension 148 by the second post 318. In one embodiment, the first post 316 is attached to the docking extension 148 and the docking button 320 such that it is radially symmetrical with the second post 318.

[0101] It will be apparent that, as described herein, the docking cap 136 may be used to displace the retriever 144 into engagement with the docking extension 148. Additionally or alternatively, a push-pull actuator 826 may be used to engage and disengage the retriever 144 from the docking extension 148. For example, with reference to Figures 41-46, in one embodiment, the retriever 144 is in the form of a hinged grasper and is displaceable between engaged and disengaged positions by the push-pull actuator 826.

[0102] 41-43, in one embodiment, the leadless pacemaker 104 includes a docking extension 148 extending from a surface 302 of a docking end of a body portion 300. The docking extension 148 includes an extension 800 that defines a slot 802. In one embodiment, the extension 800 has a length extending in a first direction across the surface 302, the length being approximately the same as a diameter of the surface 302. The extension 800 also has a narrow width extending in a second direction across the surface 302, the width being less than the diameter of the surface 302.

[0103] The extension 800 defines a slot 802 and includes one or more docking surfaces configured for mating engagement with corresponding components of the retriever 144 to provide torque transfer to the leadless pacemaker 104. In one embodiment, the retriever 144 in the form of a hinged gripper is configured with a first arm 804 and a second arm 806. A first gripper 808 is disposed at a distal end of the first arm 804. The first gripper 808 also includes a first notch 812. Similarly, a second gripper 810 is disposed at a distal end of the second arm 806. The second gripper 810 also includes a second notch 814.

[0104] The first and second notches 812, 814 cooperatively define a docking space 816 configured to engage the extension 800. More specifically, to engage the leadless pacemaker 104 in the engaged position, the docking extension 148 is grasped by the retriever 144 by inserting the lips of the first and second gripping portions 808, 810 into the slot 802 with a proximal portion of the extension 800 disposed within the docking space 816. When the first and second arms 804, 806 are displaced radially outward to a disengaged position, the first and second gripping portions 808, 810 expand the docking space 816 to release the extension 800. In one embodiment, first arm 804 and second arm 806 each taper in width proximally from first gripping portion 808 and second gripping portion 810 to base portion 818 .

[0105] When the first arm 804 and the second arm 806 are displaced between the engaged and disengaged positions, the push-pull actuator 826 is displaced within the chamber 142 relative to the docking cap 136. The push-pull actuator 826 extends through the lumen of the torque shaft 114 and is displaceable within the lumen of the torque shaft 114. In one embodiment, the push-pull actuator 826 includes a neck 824 extending distally from a body of the push-pull actuator 826. The neck 824 has one or more knobs 822 extending radially outward from a longitudinal axis of the push-pull actuator 826. The neck 824 is disposed within a gap 830 formed in each of the first arm 804 and the second arm 806, and each of the knobs 822 engages a corresponding track 820 on each of the first arm 804 and the second arm 806. One or more hinge pins 828 extend through holes formed in the docking cap 136 and the arms 804, 806, thereby rotatably mounting the retriever 144 to the docking cap 136. Engagement of the knob 822 with the first and second arms 804, 806 in the track 820 allows the first and second arms 804, 806 to be displaced radially inward or outward about the axis of rotation of the hinge pin 828 when the body of the push-pull actuator 826 is displaced distally or proximally.

[0106] 44-46, the first arm 804 and the second arm 806 are displaceable between an engaged position and a disengaged position with the push-pull actuator 826. In one embodiment, the docking extension 148 includes one or more docking surfaces, such as edge docking surface 306, configured to engage corresponding components of the first arm 804 and the second arm 806 to provide torque transfer to the leadless pacemaker 104. The docking surface 306 can define a hexagonal or other polygonal shape of the docking extension 148. The first arm 804 can have a first docking surface 832, and the second arm 806 can have a second docking surface 834. Each of the first docking surface 832 and the second docking surface 834 can be a planar or other shape corresponding to the shape of the edge docking surface 306.

[0107] The first docking surface 832 and the second docking surface 834 are configured to engage one or more edge docking surfaces 306 of the docking extension 148. More specifically, to engage the leadless pacemaker 104 in the engaged position, the first docking surface 832 and the second docking surface 834 are pressed against the edge docking surfaces 306 such that the docking extension 148 is gripped by the retriever 144. When the first arm 804 and the second arm 806 are displaced radially outward to a disengaged position, the first gripping portion 808 and the second gripping portion 810 release the docking extension 148.

[0108] The above description merely illustrates the principles of the technology of the present disclosure. Various modifications and alterations to the described embodiments will be apparent to those skilled in the art in light of the teachings herein. Thus, it will be apparent to those skilled in the art that various systems, configurations and methods may be devised that embody the principles of the technology of the present disclosure, although not explicitly shown or described herein, and are within the spirit and scope of the technology of the present disclosure. From the above description and drawings, those skilled in the art will appreciate that the specific embodiments shown and described are for illustrative purposes only and are not intended to limit the scope of the technology of the present disclosure. Reference to details of specific embodiments is not intended to limit the scope of the technology of the present disclosure.

Claims

1. 1. A leadless pacemaker catheter system, comprising: an outer catheter having a cap attached to a shaft defining a lumen, the lumen having a longitudinal axis, the cap configured to receive a docking extension of a leadless pacemaker, the docking extension including a docking button attached to a body of the leadless pacemaker by a post, the cap having a side portion including a distal side portion and a proximal side portion, the distal side portion of the side portion including one or more keys disposed at respective circumferential positions, the proximal side portion being located proximally of the one or more keys; an inner catheter having a flexible mandrel extending along the longitudinal axis within the lumen of the shaft, a base, and a number of arms extending from the base, wherein a central lumen extends through the flexible mandrel and the base, and the side portion of the cap is configured such that when the docking extension is received within the cap, the one or more keys of the distal side portion surround the proximal post of the body of the leadless pacemaker and the proximal side portion surrounds the docking button and holds the arms laterally against an outer periphery of the docking button; a tether having an elongated body extending through the central lumen to a distal loop, the distal loop having a first portion extending radially outward from the elongated body and a second portion having a shape that wraps around a central axis of the elongated body from a radial end of the first portion; A leadless pacemaker catheter system, characterized in that the tether is usable by engaging with the docking extension.

2. 2. The leadless pacemaker catheter system of claim 1, The cap includes a side portion extending between a proximal chamber surface and a ledge surface, the side portion defining the chamber.

3. 2. The leadless pacemaker catheter system of claim 1, the inner catheter includes a docking space configured to receive the docking extension; At least a portion of the docking extension extends distally beyond the base and the docking space.

4. 2. The leadless pacemaker catheter system of claim 1, At least a portion of the inner catheter may extend around an outer edge of the docking extension.

5. 5. The leadless pacemaker catheter system of claim 4, the inner catheter includes a docking space configured to receive the docking extension and a lip portion extending beyond the outer edge of the docking extension when the docking extension is received within the docking space.

6. The leadless pacemaker catheter system according to any one of claims 1 to 5, A leadless pacemaker catheter system further comprising a leadless pacemaker.

7. 7. The leadless pacemaker catheter system of claim 6, The docking button has an opening on the docking surface.

8. 7. The leadless pacemaker catheter system of claim 6, The docking surface comprises a rounded surface.

9. The leadless pacemaker catheter system according to any one of claims 1 to 5, a handle coupled to the outer catheter and the inner catheter at a proximal end of the leadless pacemaker catheter system; The leadless pacemaker, the docking button is attached to the body portion of the leadless pacemaker by the post and a second post; the docking button has a button lumen opening through the docking button between the post and the second post and a radial gap opening into the button lumen; the tether extends distally from the handle through the central lumen; when the tether is engaged to a distal end of the leadless pacemaker catheter system, the elongated body of the tether extends through the button lumen and the distal loop extends around the post and the second post of the docking extension.

Images