Biostimulator delivery system with flexible tether

Abstract

A biostimulant delivery system, such as a biostimulant delivery system, is described. The biostimulator delivery system includes a flexible tether extending through a tether support to a tether loop. The tether loop passes through the attachment feature of the biological stimulator to connect the biological stimulator to the biological stimulator delivery system. The tether leg extends from the tether loop to a handle of the biostimulator delivery system. The handle includes a housing and a knob, and the tether leg is attached to the housing and the knob. The tether leg may be disconnected from the housing and the knob may be removed to pull the tether out of the attachment feature and release the biostimulator from the biostimulator delivery system. Other embodiments are also described and claimed.

Description

[0001] This application is a national phase entry of PCT / IB2023 / 056859, filed on June 30, 2023, which claims the benefit of priority to U.S. Patent Application No. 18 / 215,091, filed on June 27, 2023, which claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 358,061, entitled “Biostimulator Transport System Having Flexible Tether,” filed on July 1, 2022, and these applications are incorporated herein by reference in their entirety to provide continuity of disclosure. Technical Field

[0002] The present disclosure relates to biostimulator delivery systems and methods. More specifically, the present disclosure relates to delivery systems for delivering or retrieving leadless biostimulators. Background Art

[0003] Cardiac pacing by an artificial pacemaker provides electrical stimulation to the heart when the artificial pacemaker's own 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. This anti-bradycardia pacing provides symptom relief and even life support for hundreds of thousands of patients. Cardiac pacing can also provide electrical overdrive stimulation to inhibit or convert tachyarrhythmias, again providing symptom relief and preventing or terminating arrhythmias that could lead to sudden cardiac death.

[0004] Cardiac pacing by currently available or conventional pacemakers is typically performed by a pulse generator that is implanted subcutaneously or submuscularly in or near the pectoralis region of the patient. The generator is typically connected to the proximal end of one or more implanted leads, the distal end of which contains one or more electrodes for positioning adjacent to the inner or outer wall of the cardiac chamber. Although more than one hundred thousand conventional cardiac pacing systems are implanted each year, there are various well-known difficulties, some of which will be cited. For example, when located subcutaneously, the pulse generator presents a bulge in the skin, which the patient may find unsightly, unpleasant or irritating, and the patient may subconsciously or compulsively manipulate or "twist" the bulge. Even without persistent manipulation, subcutaneous pulse generators may also exhibit corrosion, extrusion, infection, disconnection, insulation damage, or conductor fracture at the lead wire. Although submuscular or abdominal placement can solve some problems, such placement involves more difficult surgical procedures for implantation and adjustment, which can prolong patient recovery.

[0005] Leadless cardiac pacemakers contain electronic circuits at the pacing site and eliminate leads, and thus avoid the above-mentioned disadvantages of conventional cardiac pacing systems. Leadless cardiac pacemakers can be anchored at the pacing site by an anchor. During delivery or retrieval of the leadless cardiac pacemaker, the delivery system can apply torque to the leadless cardiac pacemaker via the docking cap to screw the anchor into or out of the target tissue. Summary of the invention

[0006] Existing biostimulator delivery systems for delivering or retrieving leadless cardiac pacemakers can have a set of tethers that include end features to engage attachment features of a leadless biostimulator. The tethers can be moved relative to each other to align or misalign the end features. In an aligned state, the end features can lock the tethers to the leadless biostimulator. In a misaligned state, the end features can unlock the tethers from the leadless biostimulator. Thus, adjustment of the end features can hold or release the leadless biostimulator.

[0007] The tethers, end features, and accompanying mechanisms of existing biostimulant delivery systems can be complex and expensive. More specifically, the mechanisms and components used to implement the biostimulator retention / release features of existing biostimulator delivery systems can require precise motion and fine mechanical tolerances. Furthermore, the cyclic loading seen by biostimulator delivery systems within target anatomy can challenge the precise movement of leadless biostimulators and complicate delivery. Therefore, a biostimulant delivery system would benefit from a simple, inexpensive, and reliable retention and release mechanism.

[0008] A biostimulator delivery system is provided, such as a catheter-based system for delivering or retrieving a leadless cardiac pacemaker having a flexible tethering mechanism. In one embodiment, the biostimulator delivery system includes a handle. A torque shaft may extend longitudinally at a distal end of the handle, and a docking cap may be coupled to the torque shaft. The docking cap may have a docking cavity to receive an attachment feature of a biostimulator. In one embodiment, a tether support may extend through the torque shaft to a distal end. The tether support may have one or more support lumens to receive a tether. More specifically, the tether may extend through one or more support lumens to a tether loop at a distal end of a distal support end. The tether loop may extend through the attachment feature to hold the biostimulator. The tether may reliably hold and release the biostimulator.

[0009] The tether can have a number of tether legs extending from the tether loop. For example, the tether legs can extend proximally through a support lumen in the tether support. The tether, and therefore the tether legs, can be polymer filaments, such as ultra-high molecular weight polyethylene or polyester threads, or metal filaments. The filaments can be inexpensive and can therefore provide an economical mode of retaining and releasing the biostimulant.

[0010] In one embodiment, the handle includes a housing, and the knob can be releasably coupled to the housing. The tether can be coupled to one or more of the housing or the knob. For example, a first tether leg can be coupled to the knob, and a second tether leg can be coupled to the housing. The second tether leg can be exposed through a window in the housing so that a user can cut the second tether leg through the window. The knob can then be retracted from the housing to remove the tether from the attachment feature and release the biostimulator.

[0011] In an embodiment, the knob may be rotatably coupled to the housing. The knob may include a blade positioned such that rotation of the knob causes the blade to cut the second tether leg. The knob may then be retracted to remove the tether from the attachment feature and release the biostimulator.

[0012] Other release mechanisms for removing the tether from the attachment feature to release the biostimulator are described. For example, the rod can be releasably coupled to the second tether leg. Releasing the second tether leg from the rod can release the biostimulator. Alternatively, the biostimulator delivery system can include a snare extending through the support lumen. The snare can include a plurality of snare loops.

[0013] Embodiments include an attachment feature for a leadless biostimulator that can engage a tether. The attachment feature can include a base and a button. The button can have an insertion slot and a retention slot. The insertion slot can receive the tether, and the tether can then be secured in the retention slot. Thus, the retention slot can extend from the insertion slot, for example, in a direction transverse to the direction in which the insertion slot extends into the button. The insertion slot can be vertically oriented or horizontally oriented. The insertion slot can include a non-linear profile, such as a w-shaped profile.

[0014] The above summary does not include an exhaustive list of all aspects of the present invention. It is contemplated that the present invention includes all systems and methods that can be practiced from all suitable combinations of the various aspects summarized above and those aspects disclosed in the following detailed description and specifically pointed out in the claims filed with the present application. Such combinations have specific advantages not specifically recited in the above summary. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The novel features of the invention are particularly set forth in the claims that follow. A better understanding of the features and advantages of the invention will be obtained by referring to the following detailed description and the accompanying drawings, which set forth illustrative embodiments utilizing the principles of the invention, wherein:

[0016] Figure 1 is a schematic medial-lateral cross-section of a patient's heart illustrating an exemplary implantation of a biostimulator in the patient's heart according to an embodiment.

[0017] Figure 2is a side view of a biostimulator according to one embodiment.

[0018] Figure 3 is a perspective view of a biostimulator delivery system according to one embodiment.

[0019] Figure 4 is a side view of a distal portion of a biostimulator delivery system in a docked configuration according to an embodiment.

[0020] Figure 5 is a side view of a distal portion of a biostimulator delivery system in an undocked configuration according to an embodiment.

[0021] Figure 6 is a perspective view of a distal portion of a biostimulator delivery system in an undocked configuration according to an embodiment.

[0022] Figure 7 is a perspective view of a tether retaining an attachment feature according to an embodiment.

[0023] Figure 8 is a perspective view of a distal portion of a biostimulator delivery system in an undocked configuration according to an embodiment.

[0024] Fig. 9 is a perspective view of a distal portion of a tether support according to one embodiment.

[0025] Fig.10 is a perspective view of a handle of a biostimulator delivery system having a cutting window according to one embodiment.

[0026] Figure 11-12 is a perspective view of a handle of a biostimulator delivery system with a cutting wheel according to an embodiment.

[0027] Fig.13 is a perspective view of a handle of a biostimulator delivery system with a vise according to one embodiment.

[0028] Fig.14 is a perspective view of a handle of a biostimulator delivery system having an open shield according to one embodiment.

[0029] Fig.15 is a perspective view of a handle of a biostimulator delivery system having a cartridge according to an embodiment.

[0030] Figure 16-17 is a perspective view of a handle of a biostimulator delivery system with a twist release device according to one embodiment.

[0031] Figure 18-19 is a schematic diagram of a ring-rod mechanism of a biostimulator delivery system according to one embodiment.

[0032] Figure 20-21 is a schematic diagram of a loop and hook mechanism of a biostimulator delivery system according to one embodiment.

[0033] Figure 22-23 is a schematic diagram of a ring and buckle mechanism of a biostimulator delivery system according to one embodiment.

[0034] Figure 24-25 is a schematic diagram of a snare mechanism of a biostimulator delivery system according to one embodiment.

[0035] Fig.26 is a schematic diagram of a loading mechanism for a biostimulator delivery system according to one embodiment.

[0036] Figure 27-29 is a schematic diagram of a torsional loading attachment feature of a leadless biostimulator according to an embodiment.

[0037] Figure 30-32 is a schematic diagram of a w-slot attachment feature of a leadless biostimulator according to an embodiment.

[0038] Figure 33-35 is a schematic diagram of an undercut slot attachment feature of a leadless biostimulator according to an embodiment. DETAILED DESCRIPTION

[0039] The embodiments describe a biostimulator delivery system with a flexible tether, e.g., a catheter-based system for delivering or retrieving a leadless cardiac pacemaker. The biostimulator can be used to pace cardiac tissue, as described below. However, the biostimulator can be used for other applications, such as deep brain stimulation, and thus, referring to the biostimulator as a pacemaker is not limiting.

[0040] In various embodiments, description is made with reference to the accompanying drawings. However, certain embodiments may be practiced without one or more of these specific details, or in combination with other known methods and configurations. In the following description, many specific details, such as specific configurations, dimensions and processes, are set forth in order to provide a thorough understanding of the embodiments. In other cases, known processes and manufacturing techniques are not particularly described in detail to avoid unnecessarily obscuring the description. References to "one embodiment", "one embodiment" and the like throughout this specification mean that the specific features, structures, configurations or characteristics described are included in at least one embodiment. Therefore, the phrases "one embodiment", "one embodiment" and the like that appear in various places throughout this specification do not necessarily refer to the same embodiment. In addition, specific features, structures, configurations or characteristics may be combined in one or more embodiments in any suitable manner.

[0041] Relative terms are used throughout the specification to indicate relative positions or directions. For example, "distal" may indicate a first direction along the longitudinal axis of the biostimulator. Similarly, "proximal" may indicate a second direction opposite the first direction. However, such terms are provided to establish a relative frame of reference and are not intended to limit the use or orientation of the biostimulator to the specific configurations described in the various embodiments below.

[0042] In one aspect, a biostimulant delivery system is provided. The biostimulator delivery system includes a tether, such as a fiber tether, to hold a biostimulator. The tether may have a loop to connect the biostimulator to the biostimulator delivery system. The biostimulator delivery system may include a mechanism to detach the tether. For example, a handle of the biostimulator delivery system may include a cutter, a vise, or other mechanism to separate one tether leg from the handle. The other leg of the tether may be connected to a knob. The knob may be removed from the handle to remove the tether from the biostimulator. Thus, the biostimulant delivery system may provide a simple, inexpensive, and reliable mechanism to hold and release a biostimulant.

[0043] refer to Figure 1 , a schematic medial-lateral cross-section of a patient's heart is shown according to one embodiment, which shows an exemplary implantation of a biostimulator in the patient's heart. A cardiac pacing system includes one or more biostimulators 100. The biostimulators 100 can be implanted in a patient's heart 104 and can be leadless and, therefore, can be leadless cardiac pacemakers 102. Each biostimulator 100 can be placed in a cardiac chamber (e.g., the right atrium and / or right ventricle of the patient's heart 104), or attached to the inside or outside of a cardiac chamber. Attachment of the biostimulator 100 to cardiac tissue can be achieved via one or more fixation elements 106 (e.g., helical anchors). In certain embodiments, the leadless cardiac pacemaker 102 can use two or more electrodes located on or within the housing of the leadless cardiac pacemaker 102 for pacing the heart upon receiving a trigger signal from an internal circuit and / or from at least one other device within the body.

[0044] refer to Figure 2, a side view of a biostimulator according to an embodiment. The biostimulator 100 can be a leadless cardiac pacemaker 102 that can perform cardiac pacing and have many of the advantages of conventional cardiac pacemakers while extending performance, functionality, and operating characteristics. The biostimulator 100 can have two or more electrodes, such as a distal electrode 202 and a proximal electrode 204, located within, on, or near a biostimulator housing 206 of the biostimulator 100. In an embodiment, one or more fixation elements 106 form part of the distal electrode 202. The electrodes can deliver pacing pulses to the muscle of the heart and, optionally, can sense electrical activity from the muscle. The electrodes can also communicate bidirectionally with at least one other device inside or outside the body.

[0045] In one embodiment, the biostimulator housing 206 has a longitudinal axis 208, and the distal electrode 202 can be a distal pacing electrode mounted on the biostimulator housing 206 along the longitudinal axis 208. The biostimulator housing 206 can contain a main battery to provide power for pacing, sensing, and communication, which can include, for example, bidirectional communication. The biostimulator housing 206 can optionally contain an electronics compartment 210 to hold circuits suitable for different functions. For example, the electronics compartment 210 can contain circuits for sensing cardiac activity from the electrodes, circuits for receiving information from at least one other device via the electrodes, circuits for generating pacing pulses for delivery via the electrodes, or other circuits. The electronics compartment 210 can contain circuits for transmitting information to at least one other device via the electrodes, and can optionally contain circuits for monitoring device health. The circuitry of the biostimulator 100 can control these operations in a predetermined manner. In some embodiments of the cardiac pacing system, cardiac pacing is provided without a pulse generator located in the chest area or abdomen, without electrode leads separate from the pulse generator, without a communication coil or antenna, and without the additional requirement for battery power for transmitting communications.

[0046] The leadless pacemaker or other leadless biostimulator 100 can be secured to an intracardiac implantation site by one or more active engagement mechanisms or fixation mechanisms. The fixation mechanism can include a screw or helical member that is screwed into the myocardium. Alternatively, the fixation mechanism can include tines that pierce and grip the myocardium.

[0047] In one embodiment, the biostimulator 100 includes a fixation element 106 coupled to the biostimulator housing 206. The fixation element 106 can be a helical element to be screwed into the target tissue. More specifically, the fixation element 106 can helically extend from a flange 214 of the biostimulator 100 mounted on the biostimulator housing 206 to a distal tip at a helical distal end 216.

[0048] The helical distal end 216 can be located distal to the distal electrode 202 (the centrally located electrode). Thus, when the biostimulator 100 contacts the target tissue, the distal tip can penetrate the tissue and the housing 206 can be rotated to screw the external fixation element 106 into the target tissue to pull the distal electrode 202 into contact with the tissue.

[0049] The biostimulator 100 includes an attachment feature 220. The attachment feature 220 generally facilitates coupling the biostimulator to a biostimulator delivery system ( Figure 3 ). More specifically, the attachment feature may include a feature that can be engaged and retained by a tether of the biostimulator delivery system.

[0050] refer to Figure 3 , shows a perspective view of a biostimulator delivery system according to an embodiment. A leadless pacemaker or other leadless biostimulator 100 can be delivered to a patient and retrieved from the patient using a biostimulator delivery system 300, as described below. In some embodiments, the biostimulator delivery system 300 is a delivery system for delivering a leadless pacemaker to a target tissue. In some embodiments, the biostimulator delivery system 300 is a retrieval system for retrieving a leadless pacemaker from a target tissue.

[0051] The biostimulator delivery system 300 may include an elongated catheter 302 extending distally from a handle 304 to a distal catheter end 306. The elongated catheter 302 may be a deflectable catheter, and the operator may use the handle 304 to steer the distal catheter end 306 within the patient. In one embodiment, the biostimulator delivery system 300 includes a guide catheter 308 mounted on the elongated catheter 302. The guide catheter 308 may be slidably disposed on the elongated catheter 302 such that a distal portion of the guide catheter 308 may slide distally over the distal catheter end 306 of the elongated catheter 302 and / or the biostimulator 100. Similarly, the biostimulator delivery system 300 may include an introducer hub assembly 310 mounted on the guide catheter 308. The introducer hub assembly 310 can be slidably disposed on the guide catheter 308 such that the distal portion of the introducer hub assembly 310 can slide distally over the distal catheter end 306 of the elongated catheter 302 and / or the distal portion of the guide catheter 308. More specifically, the introducer hub assembly 310 can be inserted into an access sheath to access the patient's vasculature, and after establishing access, the distal portion of the guide catheter 308 and / or the distal catheter end 306 of the elongated catheter 302 can be advanced through the access sheath into the patient's body.

[0052] The distal catheter end 306 of the elongated catheter 302 can be selectively connected to the biostimulator 100. More specifically, the biostimulator 100 can be mounted on the distal catheter end 306 of the elongated catheter 302. The biostimulator 100 can be protected by a protective sheath ( Figure 4-5 ) protection. Thus, the biostimulator 100 can be advanced into the patient's body together with the catheter distal end 306.

[0053] The leadless pacemaker system can be used to implant one or more biostimulators 100 into the atria and / or ventricles of a patient's heart 104. Implantation of each biostimulator 100 can be achieved in part by endocardial insertion of the biostimulator 100. For example, the elongated catheter 302 of the leadless pacemaker system can include a torque shaft ( Figure 6 The docking cap 320 may have a docking cavity ( Figure 4 ) to receive the attachment feature 220 of the biostimulator 100. The torque shaft can be twistable, and rotation of the torque shaft can cause the docking cap 320 to rotate, which can impart rotation to the attachment feature 220. Thus, torque can be transmitted through the torque shaft to rotate the biostimulator 100 in a first direction (e.g., clockwise). Rotating the biostimulator 100 when the fixation element 106 is in contact with the cardiac tissue can cause the fixation element 106 to screw into the cardiac tissue and secure the biostimulator 100 to the cardiac tissue. Similarly, removal and retrieval of the biostimulator 100 can be accomplished on the endocardium. For example, the torque shaft of the elongated catheter 302 can be rotated in a second direction (e.g., counterclockwise) to transmit torque to the attachment feature 220 through the docking cap 320, thereby detaching the biostimulator 100 from the cardiac tissue. Thus, having a configuration similar to Figure 3 The delivery and retrieval system of the illustrated configuration may be used to deliver and / or retrieve the biostimulator 100 from the target anatomy.

[0054] refer to Figure 4 , shows a side view of a distal portion of a biostimulator delivery system in a docked configuration according to an embodiment. The distal portion of the guide catheter 308 may include a protective sheath 402 that flares radially outward in the distal direction. The guide catheter 308 is movable in a longitudinal direction relative to the elongated catheter 302, and thus, the protective sheath 402 may be retracted to expose the docking cap 320 at the distal end of the elongated catheter 302.

[0055] In one embodiment, the docking cap 320 has a docking cavity 404 to receive a portion of the biostimulator 100. More specifically, when the biostimulator is in a docked state relative to the biostimulator delivery system 300, the docking cavity 404 can receive the attachment feature 220 of the biostimulator 100. In the docked state, the rotation of the docking cap 320 can be translated into the rotation of the biostimulator 100 via engagement with the attachment feature 220.

[0056] refer to Figure 5 , shows a side view of a distal portion of a biostimulator delivery system in an undocked configuration according to an embodiment. The biostimulator 100 can be moved to an undocked state relative to the biostimulator delivery system 300. More specifically, the elongated conduit 302 can be moved proximally relative to the biostimulator 100 to retract the docking cap 320 and move the attachment feature 220 out of the docking cavity 404.

[0057] In one embodiment, when the biostimulator 100 is in an undocked state, the biostimulator 100 remains connected to the biostimulator delivery system 300 via a tether subsystem. The tether subsystem can include a tether support 502 extending longitudinally from the elongated conduit 302 toward the attachment feature 220 of the biostimulator 100. The tether subsystem can also include a tether 504 extending through the tether support 502 to the attachment feature 220. More specifically, the tether 504 can engage the attachment feature 220, and the tether support 502 can extend around the tether 504 to provide column strength to the tether 504 when the biostimulator 100 is detached from the docking cap 320. In the undocked state, the biostimulator 100 can be rotatably separated from the docking cap 320 while remaining tethered to the biostimulator delivery system 300.

[0058] refer to Figure 6 , shows a perspective view of a distal portion of a biostimulator delivery system in an undocked configuration according to one embodiment. In the perspective view, the elongated catheter 302 is hidden to expose and show a torque shaft 602 having a distal shaft end 603. The distal shaft end 603 can be coupled to the docking cap 320. Thus, the torque shaft 602 can rotate to transmit torque to the docking cap 320 (and the biostimulator 100 in a docked state).

[0059] The torque shaft 602 may include a shaft lumen, and the tether support 502 may extend through the shaft lumen to a distal support end 604. Similarly, the tether 504 may extend through the lumen of the tether support 502. The tether 504 may engage the attachment feature 220 of the biostimulator 100. The tether support 502 may be axially movable relative to the tether 504. Thus, the distal support end 604 may be advanced closer to the attachment feature 220 to reduce the exposed length of the tether 504. In contrast, the distal support end 604 may be retracted further away from the attachment feature 220 to increase the exposed length of the tether 504. The tether 504 may be less rigid than the tether support 502, and therefore, when more of the tether 504 is exposed, the biostimulator motion is more decoupled from the action of the biostimulator delivery system 300.

[0060] refer to Figure 7 , shows a perspective view of a tether retaining an attachment feature according to an embodiment. The close-up view of the attachment feature 220 indicates that the attachment feature 220 can include a recess in the proximal end of a button 702 of the attachment feature 220. The button 702 can be a proximal portion of the attachment feature 220 that engages a corresponding feature within the docking cap 320. More specifically, the button 702 can engage a key of the docking cap 320 such that rotation of the docking cap 320 can cause the key to engage the button 702 and transmit torque to the biostimulator 100 through the button 702.

[0061] A beam 704, a post, or the like may extend above the recess. Thus, a gap may be formed between the beam 704 and the inner surface of the recess. In one embodiment, the tether 504 includes a tether loop 706 looped around the beam 704. More specifically, the tether 504 may extend through the gap and around the beam 704 to form the tether loop 706. The tether loop 706 can be disposed within the gap distal to the distal support end 604 of the tether support 502.

[0062] refer to Figure 8, shows a perspective view of a distal portion of a biostimulator delivery system in an undocked configuration according to an embodiment. The biostimulator delivery system 300 can be transformed into a tethered mode. For example, after the biostimulator 100 has been secured to a target pacing site, the tether support 502 can be retracted to expose more of the tether 504. When the system is in tethered mode, the biostimulator 100 can simulate the movement it would experience if it were freely secured to the target tissue. More specifically, the biostimulator 100 can behave as if it is disconnected from the biostimulator delivery system 300. This behavior is possible because the tether 504 can be formed of a flexible material, as described below, which does not hinder the movement of the biostimulator 100. In tethered mode, the integrity of the fixation of the biostimulator 100 to the target tissue can be evaluated. Additionally, the electrical performance of the biostimulator 100 may be evaluated, for example, the threshold voltage (the minimum voltage required to deliver a pacing pulse to the target tissue), impedance, and injury current may be evaluated while the biostimulator 100 is in tethered mode prior to release of the biostimulator 100 from the biostimulator delivery system 300.

[0063] In the tethered mode, the biostimulator 100 can be connected to the biostimulator delivery system 300 by several lengths of the flexible tether 504. More specifically, the tether 504 can include a first tether leg 802 extending proximally from the tether loop 706 and a second tether leg 804 extending proximally from the tether loop 706. The tether legs can extend longitudinally adjacent to each other between the attachment feature 220 and the docking cap 320. The tether legs can be flexible, and thus the biostimulator 100 is not rigidly attached to the biostimulator delivery system 300. That is, the biostimulator 100 can move freely in the tethered mode without being hindered by the attached tether. However, the ends of the tether legs can extend through the elongated catheter 302 and attach to the handle 304. Thus, the tether legs can physically connect the biostimulator 100 to the biostimulator delivery system 300 while decoupling the movement of the biostimulator 100 from the biostimulator delivery system 300.

[0064] refer to Fig. 9, showing a perspective view of a distal portion of a tether support according to an embodiment. The flexibility of the tether 504 may be advantageous during the tether mode, however, in other situations, it may be necessary to support the tether 504. For example, it may be necessary to apply forward pressure to the biostimulator 100 in an undocked state, and given that the tether 504 is flexible and cannot be pushed on the biostimulator 100, the tether support 502 may be advanced on the tether 504 to apply forward pressure to the button 702. Therefore, the tether support 502 may have a structure that imparts column strength to the tether 504 and does not buckle when forward pressure is applied to the biostimulator 100. The tether support 502 may be formed, for example, from a solid tube. The tubular structure may be formed from a polymer and may have sufficient stiffness to avoid buckling during use. Alternatively, the tether support 502 may be formed from a coil. The coil may include a metal wire. The coil may provide good flexibility, however, the turns of the coil may be stacked on top of each other to also impart good column strength to the overall structure. Thus, the tether support 502 may be flexible enough to track through the anatomy, and rigid enough to apply forward pressure on the biostimulator 100 when desired.

[0065] The flexibility of the tether legs may cause the tether 504 to become tangled in certain circumstances. For example, when the torque shaft 602 and / or the docking cap 320 rotate, a torsion may be applied to the tether 504, causing the tether to become twisted and tangled. In addition, when the tether is exposed distally from the docking cap 320, the cyclic movement of the tether 504 may cause torsion and / or tangling on the attachment feature 220. The tangling of the tether 504 may hinder the release of the biostimulator 100 because the tangled tether 504 may not be able to move freely and retract from the attachment feature 220. Therefore, the support tube may have a structure that maintains the relative position between the tether legs to prevent tangling.

[0066] In one embodiment, the tether support 502 has one or more support lumens extending longitudinally within the outer support wall. For example, the one or more support lumens can be a single tubular lumen extending through the length of a flexible metal coil or polymer extrusion. Alternatively, the one or more support lumens 902 can include a first support lumen 904 separated from a second support lumen 906 by a support septum 908. For example, the tether support 502 can include a dual-lumen polymer extrusion. The support septum 908 can extend longitudinally along the length of the tether support 502 to form a first support lumen 904 radially separated from the second support lumen 906. The tether support 502 and the (one or more) lumens can terminate at the distal support end 604. Therefore, the support lumen can be open to the surrounding environment at the distal support end 604.

[0067] As described above, the tether 504 can extend through the support lumen 902. For example, the tether leg can extend proximally from the tether loop 706 and enter the opening at the distal support end 604 to pass through one or more support lumens. More specifically, the tether 504 can extend through the support lumen(s) to the tether loop 706. In the case of a single support lumen 902, both tether legs can pass from the handle 304 through the support lumen 902 to the tether loop 706. However, when the tether support 502 has a multi-lumen structure, the first tether leg 802 can extend proximally from the tether loop 706 through the first support lumen 904, and the second tether leg 804 can extend proximally from the tether loop 706 through the second support lumen 906. In either case, the tether support 502 can provide column strength to the tether 504. Additionally, support lumen 902 can reduce the likelihood that tether 504 will become tangled on and / or entangled with button 702. For example, support membrane 908 can maintain the tether legs in a radially separated configuration to reduce the likelihood that the legs will twist around themselves and / or button 702.

[0068] The tether 504 can have a variety of flexible configurations. For example, the tether 504 can be formed of a flexible non-metallic material. The non-metallic material can include a polymer. For example, the tether 504 can be formed of a suture material, such as one or more of ultra-high molecular weight polyethylene (UHMWPE) or polyester (PE). Alternatively, the tether 504 can include a suturing material such as Vectran TM And other materials.

[0069] Tether 504 can be formed by fibers or filaments of non-metallic materials. For example, tether 504 can have a monofilament configuration. Alternatively, several fibers or filaments can be combined to form a continuous tether length. For example, tether 504 can include polymer filaments, such as UHMWPE or PE lines, which are braided, twisted or otherwise combined to form tether 504, and the length of tether 504 is enough to pass through the elongated catheter 302 and tether support 502 from the first end at the handle 304, and pass through the ring to return to the second end at the handle 304. Fiber polymer tether 504 can have high tensile strength and almost unlimited fatigue life, while also showing compliance and flexibility at low cost. In one embodiment, tether 504 has a test strength of at least 5 pounds of force.

[0070] In one embodiment, the tether 504 is formed of a metal material. More specifically, the tether 504 may include a metal filament. The tether 504 may have a monofilament (e.g., line) structure or a multifilament (e.g., cable) structure. The metal material may be selected from a biocompatible metal, such as stainless steel or nickel titanium. The metal tether 504 may be flexible and have a high tensile strength to perform as described herein.

[0071] The above describes the use of a flexible tether 504 to connect the biostimulator 100 to the biostimulator delivery system 300. In one embodiment, to release the biostimulator 100 at the target tissue site, one of the tether legs is retracted to pull the tether 504 through the gap until the other tether leg is retracted away from the attachment feature 220, thereby detaching the biostimulator 100 from the tether 504 and the biostimulator delivery system 300. During delivery, the tether leg can be connected to a portion of the biostimulator delivery system 300, such as the handle 304, to secure the biostimulator 100. Therefore, to release the biostimulator 100, the biostimulator delivery system 300 can include a mechanism that allows the tether leg to be released and / or removed from the handle 304. An embodiment of such a mechanism is described below.

[0072] refer to Fig.10 , shows a perspective view of a handle of a biostimulator delivery system with a cutting window according to an embodiment. The handle 304 of the biostimulator delivery system 300 may include a housing 1002. The housing 1002 may provide a shell that surrounds the internal components of the handle 304 and allows a user to grasp and manipulate the handle 304. The handle 304 may also include a knob 1004 that is releasably coupled to the housing 1002. For example, the knob 1004 may be locked to the housing 1002 in a first configuration, and the user may rotate the knob 1004 to unlock the knob from the housing 1002. When unlocked, the user may pull the knob 1004 to retract the knob from the housing 1002 and separate the knob from the handle 304. The knob 1004 may be locked to the housing 1002 by various mechanisms, including threads, keys, detents, etc. Therefore, the mechanisms described herein for securing the knob 1004 to the handle 304 are provided as examples and not limitations.

[0073] In one embodiment, a first tether leg 802 (not shown) extends proximally from the tether loop 706 and is coupled to the knob 1004. For example, an end of the first tether leg 802 may be adhered to or tied to the knob 1004. The first tether leg 802 may be attached so that when the knob 1004 is retracted from the housing 1002, the first tether leg 802 is pulled together with the knob 1004. However, the second tether leg 804 of the tether 504 may extend proximally from the tether loop 706 to attach to the housing 1002. Therefore, when the second tether leg 804 is secured to the housing 1002, the knob 1004 may not be retracted because the tether 504 will hold the knob 1004 and prevent it from being removed from the housing 1002.

[0074] The handle 304 may include a mechanism that cuts, breaks, or otherwise releases the second tether leg 804 from the housing 1002 to allow the knob 1004 to be released and removed from the housing 1002. In an embodiment, the housing 1002 includes a window 1006, and the second tether leg 804 may be exposed through the window 1006 in the housing 1002. The window 1006 may be a cutaway portion of a housing wall, and the portion may be positioned laterally from and above the second tether leg 804 such that the window 1006 provides a line of sight from the surrounding environment to the second tether leg 804 within the housing 1002.

[0075] 1006. The second tether leg 804 may be accessed through the window 1006. More specifically, the user may insert a scalpel or another cutting device through the window 1006 toward the second tether leg 804. The user may cut the second tether leg 804 through the window 1006 to release the second tether leg 804 from the housing 1002. After severing the tether 504, the knob 1004 may be unlocked and pulled out of the housing 1002. The knob 1004 may be retracted until the severed end of the second tether leg 804 is pulled through the gap in the attachment feature 220, thereby releasing the biostimulator 100 from the tether 504. Thus, the process of releasing the biostimulator 100 may include disconnecting one end of the tether 504 from the housing 1002, and pulling the other end of the tether 504 until the tether is disconnected from the attachment feature 220.

[0076] refer to Fig.11 , shows a perspective view of a handle of a biostimulator delivery system with a cutting wheel according to one embodiment. Various mechanisms for achieving the above-described release process are contemplated. In one embodiment, the knob 1004 is rotatably coupled to the housing 1002. For example, the knob 1004 can be threadedly engaged to the housing 1002. The knob 1004 can be operably connected to a blade 1102 within the housing 1002. The blade 1102 can be part of a cutting wheel 1103 that is rotatably coupled to the housing 1002. More specifically, the cutting wheel 1103 can be longitudinally constrained and freely rotate within the housing 1002. The cutting wheel 1103 can have a keyway that is engaged by the distal end of the knob 1004. Thus, the blade 1102 can be mounted on the knob 1004 via the cutting wheel 1103, such that rotation of the knob 1004 causes the blade 1102 to move or rotate within the housing 1002.

[0077] As described above, the first tether leg 802 can be connected to the knob 1004. In contrast, the second tether leg 804 can be connected to the housing 1002. For example, the second tether leg 804 can be fixed to an attachment point on the housing 1002, for example, by a screw 1104 (such as a socket head screw). The second tether leg 804 can extend distally from the attachment point and wrap around the post 1106. When the tether 504 (e.g., the second tether leg 804) is wrapped around the post 1106, the clamping force required to secure the tether 504 at the attachment point can be reduced. The length of the tether 504 between the attachment point and the post 1106 can be aligned with the blade 1102. More specifically, the rotation of the cutting wheel 1103 can move the blade 1102 around the central axis to contact the tether 504.

[0078] refer to Fig.12 , shows a perspective view of a handle of a biostimulator delivery system with a cutting wheel according to an embodiment. Rotation of the knob 1004 can drive rotation of the cutting wheel 1103. The distal end of the knob 1004 can have a knob key 1202 that engages a keyway of the cutting wheel 1103. Thus, when the cutting wheel 1103 rotates, for example, due to rotation of the knob 1004, the blade 1102 can cut the tether 504, such as the second tether leg 804, to release the tether 504 from the housing 1002. When the tether 504 is severed, the knob 1004 can be further rotated until the threads on the knob 1004 disengage from the housing 1002. The knob 1004 can then be retracted to pull the tether 504 out of the attachment feature 220 and away from other components of the biostimulator delivery system 300. Thus, the biostimulator 100 can be released at the target tissue site.

[0079] refer to Fig.13 , shows a perspective view of a handle of a biostimulator delivery system with a vise according to an embodiment. As described above, one end of a tether 504 (e.g., a second tether leg 804) can be attached to a handle 304 (e.g., a housing 1002) via a clamping mechanism, and the other end of the tether 504 (e.g., a first tether leg 802) can be attached to a knob 1004. The tether leg attached to the handle 304 can be released, and the knob 1004 can be removed to retract the tether 504 from the biostimulator 100. In an embodiment, the release of the tether 504 can be by releasing the grip on the tether rather than by cutting the tether. The handle 304 can include a vise to grasp the tether. The vise can have a vise block 1302 extending from the housing wall into the interior space of the housing 1002, and a clamping mechanism, such as a screw 1304, such as a socket head screw or a set screw, that moves relative to the vise block 1302. The clamping mechanism may clamp the second tether leg 804 onto the vise block 1302 to secure the second tether leg 804 to the housing 1002 .

[0080] One end of the tether 504 can be wrapped around the post 1106 to reduce the required clamping force, as described above. The user can rotate the screw 1304 to loosen the tether 504. The knob 1004 can be keyed so that rotating the knob 1004 by a predetermined angle (e.g., 90 degrees) can allow the knob 1004 to be removed proximally from the housing 1002. Thus, when the knob 1004 is unlocked from the housing 1002, the knob can be retracted to pull the tether 504 out of the attachment feature 220, thereby releasing the biostimulator 100 at the target tissue site.

[0081] refer to Fig.14 , shows a perspective view of a handle of a biostimulator delivery system with an open shield according to an embodiment. The handle 304 (e.g., housing 1002) can have an open shield design. Similar to the above-described vise embodiment, the tether 504 (e.g., the second tether end 804) can be connected to a clamping mechanism including a knob 1402, and the other end of the tether 504 (e.g., the first tether end 802) can be connected to another clamping mechanism, such as a set screw 1404. More specifically, one end of the tether 504 can be wrapped around and held by the knob 1402, the knob 1402 can be screwed into the housing 1002, and the other end of the tether 504 can be wrapped around and held by the screw 1404. The second tether leg 804 can be released by disengaging the screw 1402 or by cutting the tether between the screws 1402 and 1404. After releasing the second tether leg 804, the tether 504 can be grasped at the distal end of the screw 1404. A tether leg, such as second tether leg 804 , may be pulled proximally to remove tether 504 and release biostimulator 100 .

[0082] refer to Fig.15 , shows a perspective view of a handle of a biostimulator delivery system with a chuck according to an embodiment. The handle 304 (e.g., housing 1002) can include a chuck 1502 mounted therein. The chuck 1502 can include a tapered block that is squeezed by the shuttle 1504. More specifically, the shuttle can move longitudinally within the housing 1002 and can have a tapered recess that conforms to the jaws of the chuck 1502. The shuttle can be advanced distally by rotating the knob 1004 in a first direction. In contrast, rotation of the knob 1004 in an opposite direction can move the shuttle proximally. When the shuttle moves proximally and the tapered surface of the recess is pulled against the jaws, the chuck 1502 can clamp radially inward. In an embodiment, the second tether leg 804 passes through the jaws. Therefore, when the shuttle squeezes the jaws inward, the jaws can clamp the tether 504, such as the second tether leg 804. As described above, first tether leg 802 may pass through housing 1002 and connect to knob 1004 .

[0083] Rotation of the knob 1004 in a first direction (e.g., clockwise) may drive the shuttle forward, causing the jaws of the chuck to open. Although the tether 504 (e.g., the second tether leg 804) is coupled to the housing 1002 via the chuck 1502, the tether may be released when the jaws open. Rotation of the knob 1004 in a second direction (e.g., counterclockwise) may unscrew the knob 1004 from the housing 1002. Thus, the knob 1004 may be released from the housing 1002, and the user may pull the knob 1004 to release the tether 504 from the biostimulator 100.

[0084] refer to Fig.16 , shows a perspective view of a handle of a biostimulator delivery system with a twist release according to an embodiment. The knob 1004 can have several components that operate together to provide a twist release mechanism. In an embodiment, the knob 1004 includes an inner knob 1602 that can be threadably coupled to an outer knob 1604. For example, a distal portion of the inner knob 1602 can have threads that engage corresponding threads of the outer knob 1604. When the inner knob 1602 is screwed into the outer knob 1604, the distal end of the inner knob 1602 can be flush with or protrude from the distal knob end 1606 of the outer knob 1604.

[0085] The spring-loaded shaft 1608 may be mounted within the housing 1002 at a distal end of the distal knob end 1606. The spring-loaded shaft 1608 may have a proximal end opposite the distal end of the distal knob end 1606 or the inner knob 1602. Thus, a leg of the tether 504, such as the second tether leg 804, may be clamped between the spring-loaded shaft 1608 and the inner knob 1602 or the outer knob 1604. Alternatively, the second tether leg 804 may be looped around the inner knob 1602 at the distal end of the knob, with the distal end of the knob protruding beyond the distal knob end 1606. The first tether leg 802 may extend through the central lumen of the spring-loaded shaft 1608 to connect to the inner knob 1602 or the outer knob 1604.

[0086] refer to Fig.17 , shows a perspective view of a handle of a biostimulator delivery system with twist release according to one embodiment. External knob 1604 can be releasably coupled to housing 1002. For example, one or more keys can extend laterally outward from an outer surface of external knob 1604. When external knob 1604 is in a first configuration, the keys can engage opposing faces of housing 1002. However, when external knob 1604 is rotated, for example, 90 degrees, the keys can align with keyways extending through the housing wall to the surrounding environment. Thus, when external knob 1604 is rotated to a second configuration, external knob 1604 can freely exit housing 1002 through the slotted keyway.

[0087] Even when the outer knob 1604 is in the second configuration, the movement of the outer knob 1604 may be limited by the tether 504. More specifically, when the second tether leg 804 is fixed to the outer knob 1604 or the inner knob 1602, the tension in the tether 504 may prevent the knob from being retracted from the housing 1002. In an embodiment, the inner knob 1602 may be twisted to release the tether 504. More specifically, the tether 504, such as the second tether leg 804, which may be looped around the inner knob 1602, may be released by rotating the inner knob 1602 so that the distal end of the inner knob 1602 is retracted into the body of the outer knob 1604. When the tether 504 is released, the outer knob 1604 may be pushed forward and then rotated from the first configuration to the second configuration. In the second configuration, the key of the outer knob 1604 may be aligned with the keyway of the slotted slot, and thus, the outer knob 1604 may be pulled out of the housing 1002. When the external knob 1604 is retracted, the release end of the second tether leg 804 will pass through the attachment feature 220 to release the biostimulator 100 .

[0088] The above embodiments describe a tether release mechanism located within the handle 304. As described below, the tether release mechanism may alternatively be located at the distal end of the biostimulator delivery system 300. In each embodiment, the biostimulator delivery system 300 may include the above components, such as the handle 304, the docking cap, and the torque shaft 602. As described below, additional mechanisms may be integrated into the delivery system to releasably tether the biostimulator 100 to the biostimulator delivery system 300.

[0089] refer to Fig.18 , a schematic diagram of a loop-rod mechanism of a biostimulator delivery system according to an embodiment is shown. The biostimulator delivery system 300 may include a tubular member 1802. The tubular member 1802 may, for example, be a component of the tether support 502. Thus, the tubular member 1802 may have a support lumen 902. In an embodiment, a rod 1804 extends through the support lumen 902. In several embodiments described below, a first tether leg 802 may be coupled to the tubular member 1802, and a second tether leg 804 may be releasably coupled to the rod 1804. More specifically, the rod 1804 may have a first state and a second state. In the first state, the rod 1804 may hold the second tether leg 804 and thus connect the biostimulator 100 to the delivery system. In the second state, the second tether leg 804 is released, and thus, the biostimulator 100 may be released from the delivery system.

[0090] The first end of the first tether leg 802 can be anchored at a suitable location on the tubular member 1802. The first end can be anchored by an adhesive or a mechanical connection. The second end of the tether 504 (e.g., the end of the second tether leg 804) can include a loop 1806. More specifically, the tether 504 can extend from the first end at the tubular member 1802 through the gap in the attachment feature 220 to the second end at the loop 1806.

[0091] The ring 1806 can be held in place within the tubular member 1802 by the rod 1804. In one embodiment, the tubular member 1802 includes a side port 1801 through a side wall of the tubular member 1802. The ring 1806 can extend radially through the side port 1801, and the rod 1804 can extend longitudinally through the ring 1806. The rod 1804 can thus lock the ring 1806 in place within the tubular member 1802 because lateral movement of the ring 1806 is resisted by the rod 1804.

[0092] refer to Fig.19 , a schematic diagram of a ring-rod mechanism of a biostimulator delivery system according to one embodiment is shown. Rod 1804 can move within tubular member 1802. More specifically, rod 1804 can extend from rod 1804 through ring 1806 ( Fig.18 ) to a second state where the ring 1806 is at the distal end of the rod 1804. For example, the rod 1804 can be retracted to slide through the ring 1806 until the distal end of the rod 1804 is at the proximal end of the ring 1806.

[0093] When the rod 1804 is removed from the ring 1806, the ring may no longer be locked within the tubular member 1802. More specifically, the ring 1806 may be moved laterally through the side port 1801 to release the tether 504 and allow it to be removed through the gap in the attachment feature 220. Thus, the biostimulator 100 may be released.

[0094] refer to Fig. 20, a schematic diagram of a loop and hook mechanism of a biostimulator delivery system according to an embodiment is shown. The loop 1806 can be held in place within the tubular member 1802 by the hook 1902. The hook 1902 can be a feature of the rod 1804. More specifically, the hook 1902 can be integrated into the rod 1804. The rod 1804 can move within the tubular member 1802, and in a first state, the rod 1804 can be retracted so that the hook 1902 is located within the tubular member 1802. The outer diameter of the rod 1804 can closely match the inner diameter of the tubular member 1802. Therefore, in the first state, the loop 1806 can be on the hook 1902, captured between the concave surface of the rod 1804 and the inner surface of the tubular member 1802 in a strategic location of the hook 1902. In the first state, the loop 1806 is held on the hook 1902, and thus the attachment feature 220 is tied to the biostimulator delivery system 300.

[0095] refer to Fig.21 , shows a schematic diagram of the loop and hook mechanism of a biostimulator delivery system according to one embodiment. To release the biostimulator 100, the rod 1804 can be moved from the first state (loop 1806 is on the hook 1902) Fig. 20 ) to a second state in which the loop 1806 is disengaged from the hook 1902. The rod 1804 can be advanced so that the hook 1902 is exposed distally from the tubular member 1802. When the hook 1902 is at the distal end of the tubular member 1802, the loop 1806 can no longer be captured by the inner surface of the tubular member 1802, and the loop 1806 can therefore fall off from the key part of the hook 1902. When the loop 1806 is disengaged from the hook 1902, the tubular member 1802 can be retracted to allow the tether 504 and the loop 1806 to pass through the gap in the attachment feature 220. As a result, the biostimulator 100 can be released from the biostimulator delivery system 300.

[0096] refer to Fig. 22 , shows a schematic diagram of a ring and buckle mechanism of a biostimulator delivery system according to one embodiment. Ring 1806 can be held in place within tubular member 1802 by a deflectable element. For example, rod 1804 can include a deflectable tip 2202. More specifically, rod 1804 can be formed of an elastic wire that can move from a bent configuration to a straightened configuration.

[0097] In one embodiment, the rod 1804 can move within the tubular member 1802, and in the first state, the rod 1804 bends and retracts so that the deflectable tip 2202 of the rod 1804 forms a clasp located within the tubular member 1802. The clasp can pass through the loop 1806 of the tether 504. Therefore, the deflectable tip 2202 can maintain the loop 1806 in the first state, and thus the attachment feature 220 is tethered to the biostimulator delivery system 300.

[0098] refer to Fig.23 , shows a schematic diagram of a ring and buckle mechanism of a biostimulator delivery system according to one embodiment. To release the biostimulator 100, the rod 1804 can be moved from a first state ( Fig. 22 ) to a second state, in which the ring 1806 is located on the clasp formed by the deflectable tip 2202 of the rod 1804, and in which the rod 1804 is straightened and the ring 1806 can slide off the deflectable tip 2202. The rod 1804 can be advanced (or the tubular member 1802 can be retracted) so that the deflectable tip 2202 is exposed distally from the tubular member 1802. When the deflectable tip 2202 is at the distal end of the tubular member 1802, the deflectable tip 2202 can elastically return to its formed straightened configuration. The ring 1806 may no longer be captured by the clasp, and the ring 1806 may therefore fall off from a key portion of the clasp. When the ring 1806 is disengaged from the clasp, the tubular member 1802 can be retracted to allow the tether 504 and the ring 1806 to pass through the gap in the attachment feature 220. Thus, the biostimulator 100 can be released from the biostimulator delivery system 300.

[0099] refer to Fig.24 , a schematic diagram of a snare mechanism of a biostimulator delivery system according to an embodiment is shown. The tether release mechanism may include a snare 2402. The snare 2402 can extend through a support lumen 902 formed in a tether support 502. In an embodiment, the snare 2402 includes a plurality of snare loops. For example, a first snare loop 2404A and a second snare loop 2404B can extend toward a distal end of the tether support 502. The snare loops can be disposed on a button 702 of an attachment feature 220. More specifically, the button 702 can have a shape including a laterally directed knob, and each snare loop can surround a corresponding knob.

[0100] In the first state, if Fig.24 As shown, the snare loop 1806 can be tightened to the attachment feature 220 by positioning the tether support 502 adjacent to the attachment feature 220. More specifically, as the tether support 502 slides distally over the snare 2402, the snare loop can decrease in size to tighten onto the button 702. The tether 504 can thus maintain the attachment feature 220 and connect the biostimulator 100 to the biostimulator delivery system 300.

[0101] refer to Fig.25, shows a schematic diagram of a snare mechanism of a biostimulator delivery system according to one embodiment. In a second state, the tether support 502 can be retracted to release the snare 2402. As the tether support 502 moves proximally, the size of the snare loop can increase. The larger loop may no longer tightly hold the button 702 and can move laterally outward to release from the attachment feature 220. When the increased slack in the system allows the snare loop to slide off the attachment feature 220, the biostimulator 100 is released from the biostimulator delivery system 300.

[0102] refer to Fig.26 , shows a schematic diagram of a loading mechanism for a biostimulator delivery system, according to one embodiment. A biostimulator 100 that can be packaged separately from a biostimulator delivery system 300 may be advantageous. Different types of biostimulators, such as types intended for operation at different treatment sites, may be used with the same delivery system. However, requiring the biostimulator 100 to be packaged with the delivery system may take up more shelf space in a catheterization laboratory. Thus, the loading mechanism allows the biostimulant to be packaged and stored separately and loaded into the delivery system at the point of care.

[0103] In one embodiment, the biostimulator assembly 2602 includes the biostimulator 100, the tether support 502, and the tether 504, which are integrated into a single unit and separate from the biostimulator delivery system 300. The biostimulator 100 has an attachment feature 220, and the tether 504 is looped through the attachment feature 220 to form a loop within the gap of the attachment feature 220. The tether leg extends proximally from the loop through the support lumen 902 of the tether support 502.

[0104] Cross section AA of tether support 502 shows the tether legs within support lumen 902 of tether support 502. Tether support 502 may be formed, for example, from a coil. Tether support 502 may thus be a flexible support that provides column strength to tethers 802, 804.

[0105] To load the biostimulator 100 onto the biostimulator delivery system 300, the proximal end of the tether support 502 can be inserted through the central lumen of the delivery system (e.g., through the docking cap 320 and the torque shaft 602) toward the handle 304. The handle 304 can be adapted to attach to the proximal end of the tether support 502 and the tether legs. For example, the handle 304 can have a mechanism to secure the proximal ends of the tether legs to hold the biostimulator 100 as described above.

[0106] The biostimulator assembly 2602 may be loaded into an annular packaging assembly, such as a so-called "racetrack" assembly, and distributed separately from the biostimulator delivery system 300. The biostimulator assembly 2602 may then be unpacked and loaded into the delivery system as needed to treat a particular target site.

[0107] The biostimulator delivery system 300 can incorporate a tether 504 that loops around the attachment feature 220 to retain the biostimulator 100 on the biostimulator delivery system 300. For example, the tether 504 can loop around the gap formed by the post or beam 704 of the button 702, as described above. In alternative embodiments, the attachment feature 220 can have a geometry that receives and retains the tether 504, and that also allows the tether loop 706 to be loaded into the attachment feature 220 without having to pass the entire length (or a portion of the length) through the gap. Several such embodiments are described below.

[0108] refer to Fig. 27 , shows a schematic diagram of a torsion loading attachment feature of a leadless biostimulator according to an embodiment. Attachment feature 220 can have a base 2702 attached to the body of the biostimulator. Base 2702 can have an annular wall connected to the body, and a tapered wall can extend proximally from base 2702 to stem 2704. Stem 2704 can extend proximally from base 2702 to button 702. Thus, button 702 can extend proximally from stem 2704 and / or base 2702.

[0109] As described above, the button 702 can engage with the docking cap 320 and provide a mechanism for connecting to the tether 504. In an embodiment, the button 702 includes an insertion slot 2708 extending from an outer surface 2710 of the button 702 into the button in a first direction. The first direction can be, for example, along the central axis 2712. The central axis 2712 can be an axis of symmetry of the base 2702. More specifically, the annular wall of the base 2702 can be centered on the central axis 2712 and extend around the central axis 2712.

[0110] Insertion slot 2708 may be sized to receive tether 504. For example, a portion of tether 504, such as tether loop 706, may be passed through insertion slot 2708 by tensioning tether 504 and then guiding the tether downward through insertion slot 2708. The width of insertion slot 2708 may be 1-5 times the width of tether 504, such that tether 504 may pass downward through insertion slot 2708 when tensioned, but is less likely to pass upward through insertion slot 2708 when slack.

[0111] The insertion slot 2708 can extend along a vertical plane. For example, the insertion slot 2708 can extend vertically through the button 702 along the central axis 2712. The vertical plane can be tilted relative to the axis of symmetry of the button 702. More specifically, when viewed from above, the button 702 can have an elliptical shape that is symmetrical about two vertical axes. The insertion slot 2708 can extend along a plane that is tilted relative to these axes.

[0112] In one embodiment, the retaining slot 2714 can extend from the insertion slot 2708 in a second direction (e.g., along a horizontal plane) transverse to the first direction (e.g., along the direction of the central axis 2712). The retaining slot 2714 extends horizontally through the button 702 transverse to the central axis 2712. For example, the retaining slot 2714 can be formed along a horizontal plane, and the central axis 2712 can be orthogonal to the horizontal plane. Therefore, when the tether 504 is inserted through the insertion slot 2708, it can contact the bottom surface 2720 defining the retaining slot 2714. The tether 504 or the button 702 can then rotate around the central axis 2712, such as pivoting, to slide above the bottom surface 2720 and below the teeth 2716 of the button 702. The teeth 2716 can be a portion of the button 702 that extends on the bottom surface 2720. Therefore, the retaining slot 2714 can be defined between the teeth 2716 and the bottom surface 2720.

[0113] In one embodiment, the button 702 includes a gripping slot 2718 extending upward from the retaining slot 2714. The gripping slot 2718 can be a vertically extending slot offset from the insertion slot 2708. After rotating through the retaining slot 2714, the tether 504 can be lifted upward into the gripping slot 2718. When in the gripping slot 2718, the tether 504 can be separated from the insertion slot 2708 by the teeth 2716. Therefore, the tether 504 can be retained in the gripping slot 2718 and may be less likely to fall out of the insertion slot 2708. More specifically, the tether loop 706 inserted into the button 702 along the central axis 2712 can be retained in the button 702 until the force is removed to slide it through the gap in the button 702, as described above.

[0114] refer to Fig.28, a schematic diagram of a torsional loading attachment feature of a leadless biostimulator according to an embodiment is shown. The symmetry of the button 702 is visible when viewed from above. In addition, the oblique orientation of the insertion slot 2708 relative to the axis of symmetry of the button 702 is shown. Similarly, the gripping slot 2718 is shown, which extends along an axis oblique or perpendicular to the axis of the insertion slot 2708. It should be understood that the tether 504 can be inserted through the insertion slot 2708 from above along the central axis 2712. Such insertion will be in the direction of entering the page. The tether 504 can then be rotated along the retaining slot 2714. For example, the rotation can be performed by rotating the tether 504 clockwise. When the tether 504 is aligned with the gripping slot 2718, the tether 504 can be pulled upward. The upward force can pull the tether 504 into the gripping slot 2718 to capture and secure the tether loop 706 within the button 702.

[0115] refer to Fig.29 , shows a schematic diagram of a torsional loading attachment feature of a leadless biostimulator according to an embodiment. In the side view, the lateral separation between the gripping slot 2718 and the insertion slot 2708 is visible. In this view, the lateral separation is in the horizontal direction and corresponds to Fig.28 In addition, the horizontal extension of the retaining slot 2714 between the insertion slot 2708 and the gripping slot 2718 is shown. More specifically, the Fig.28 The retaining slot 2714 is hidden in the insertion slot 2708 and provides a horizontal path between the insertion position at the base of the insertion slot 2708 and the capture position at the base of the gripping slot 2718. Therefore, it should be understood that the tether 504 can be inserted through the insertion slot 2708 and then corresponding to the Fig.28 The rotation in moves horizontally from the insertion slot 2708 to the grasping slot 2718 to retain the tether 504 within the button 702.

[0116] refer to Fig.30 , a schematic diagram of a w-slot attachment feature of a leadless biostimulator according to an embodiment is shown. The w-slot attachment feature may include a base 2702 and a stem 2704 having similar geometries to those described above. In an embodiment, the insertion slot 2708 may extend horizontally through the button 702, rather than vertically through the button 702. For example, the insertion slot 2708 may extend transversely (e.g., perpendicularly) relative to the vertical center axis 2712.

[0117] Insertion slot 2708 can have a profile that can resemble a W when viewed from the side. For example, the profile of insertion slot 2708 can be wavy, undulating, etc. In order to load tether loop 706 into button 702, tether 504 can be manipulated to assume the shape of insertion slot 2708. When properly shaped, tether 504 can then be moved or manipulated toward central axis 2712 by button 702 and / or stem 2704. Tether 504 may be less likely to spontaneously disengage from insertion slot 2708 because the shape of insertion slot 2708 may be a shape that tether 504 does not naturally assume.

[0118] In one embodiment, the retaining slot 2714 extends vertically upward from the insertion slot 2708. More specifically, the retaining slot 2714 can extend vertically through the button 702 along the central axis 2712. The button 702 can include a crossbar 3002 at the proximal end of the button 702. The crossbar 3002 can extend horizontally, and the central axis 2712 can extend orthogonal to the crossbar 3002. In one embodiment, the gripping slot 2718 can be on either side of the crossbar 3002. Therefore, after the tether 504 is inserted through the insertion slot 2708, the tether 504 can be moved upward through the retaining slot 2714, and then the tether legs can be tensioned to tighten the tether 504 on the crossbar 3002 within the corresponding gripping slot 2718. Thus, it should be understood that the tether 504 can be inserted through the insertion slot 2708 and then moved vertically from the insertion slot 2708 to the gripping slot 2718 to retain the tether 504 within the button 702.

[0119] refer to Fig.31 , shows a schematic diagram of a w-shaped slot attachment feature 220 of a leadless biostimulator 100, according to an embodiment. When viewed from above, it can be seen that the gripping slots 2718 on each side of the crossbar 3002 extend along a plane extending parallel to and through the central axis 2712. After being inserted through the insertion slot 2708, the tether 504 can extend substantially through this plane and can be pulled upward so that the tether legs extend out of the page.

[0120] refer to Fig.32 , shows a schematic diagram of a w-shaped slot attachment feature of a leadless biostimulator according to an embodiment. When viewed from the side, it can be seen that the profile of the insertion slot 2708 has a w-shape or a partial w-shape. More specifically, the profile can undulate and arc above the crest. The slot can have a curved shape into which the tether 504 must be manipulated in order to load the tether 504 into the insertion slot 2708.

[0121] refer to Fig.33, a schematic diagram of an undercut slot attachment feature of a leadless biostimulator according to an embodiment is shown. As described above, the insertion slot 2708 can extend horizontally through the stem 2704 and / or the button 702. As with any insertion slot 2708 described herein, the slot width can be similar to the width of the tether 504. In an embodiment, the insertion slot 2708 can form an interference fit with the tether 504. More specifically, the slot width can be less than the tether width. Thus, a user can press (e.g., with dental floss) the tether 504 through the insertion slot 2708 into the retention slot 2714. The retention slot 2714 can be wider than the tether 504, and thus, the tether 504 can fit within the retention slot 2714 with a sliding fit. Thus, the tether 504 can be more likely to remain within the retention slot 2714, rather than spontaneously exiting through the insertion slot 2708 having an interference fit.

[0122] In one embodiment, the button 702 includes teeth 2716. The teeth 2716 can extend along a plane parallel to the insertion slot 2708. In addition, the teeth 2716 can act as a shelf below the retention slot 2714. Therefore, the tether 504 can enter the retention slot 2714 by inserting the slot 2708 and around the teeth 2716. Once the tether 504 is located in the retention slot 2714, it may be less likely to bypass the teeth 2716 and return to the insertion slot 2708. The attachment feature 220 may include a gripping slot 2718 and a crossbar 3002, as described above with reference to Figure 30 to Figure 32 Thus, it should be understood that the tether 504 can be inserted through the insertion slot 2708 and then moved vertically from the insertion slot 2708 to the gripping slot 2718 to retain the tether 504 within the button 702 .

[0123] refer to Fig.34 , shows a schematic diagram of an undercut slot attachment feature of a leadless biostimulator according to an embodiment. When viewed from above, it can be seen that the gripping slots 2718 on each side of the crossbar 3002 extend along a plane extending parallel to and through the central axis 2712. After insertion through the insertion slot 2708, the tether 504 can extend substantially through this plane and can be pulled upward so that the tether legs extend out of the page.

[0124] refer to Fig.35, shows a schematic diagram of an undercut slot attachment feature of a leadless biostimulator, according to an embodiment. When viewed from the side, it can be seen that the profiles of the insertion slot 2708 and teeth 2716 form a lateral u-shape, such that the tether 504 must pass along and around the teeth 2716 in order to access their attention slots. Thus, the slots can have a unique shape into which the tether 504 must be manipulated, for example via flossing, in order to load the tether 504 into the retention slot 2714 and / or the gripping slot 2718.

[0125] In the foregoing description, the present invention has been described with reference to specific exemplary embodiments of the present invention. It will be apparent that various modifications may be made thereto without departing from the broader spirit and scope of the present invention as set forth in the appended claims. Therefore, the description and drawings are to be regarded as illustrative rather than restrictive.

Claims

1. A biostimulator delivery system, comprising: handle; a docking cap having a docking cavity to receive an attachment feature of a biostimulator; a torque shaft connected to the docking cap; a tether support extending through the torque shaft to a distal support end, wherein the tether support has one or more support lumens; and A tether extends through one or more support lumens to a tether loop distal to the distal support end.

2. The biostimulator delivery system of claim 1 , wherein the one or more support lumens include a first support lumen separated from a second support lumen by a support diaphragm, and wherein the tether includes a first tether leg extending proximally from the tether loop through the first support lumen and a second tether leg extending proximally from the tether loop through the second support lumen.

3. The biostimulator delivery system of claim 1, wherein the tether comprises a polymer filament.

4. The biostimulator delivery system of claim 3, wherein the polymer filaments comprise one or more of ultra-high molecular weight polyethylene threads or polyester threads.

5. The biostimulator delivery system of claim 1, wherein the tether comprises a metal filament.

6. The biostimulator delivery system of claim 1 , wherein the handle comprises a housing and a knob releasably coupled to the housing, wherein the tether comprises a first tether leg extending proximally from the tether loop and coupled to the knob, and wherein the tether comprises a second tether leg extending proximally from the tether loop and coupled to the housing.

7. The biostimulator delivery system of claim 6, wherein the second tether leg is exposed through a window in the housing.

8. The biostimulator delivery system of claim 6, wherein the knob is rotatably coupled to the housing, and wherein a blade is mounted on the knob such that rotation of the knob causes the blade to sever the second tether leg.

9. The biostimulator delivery system of claim 6, wherein the handle comprises a vise, and wherein the second tether leg is coupled to the housing via the vise.

10. The biostimulator delivery system of claim 6, wherein the handle comprises a clamp, and wherein the second tether leg is coupled to the housing via the clamp.

11. The biostimulator delivery system of claim 6, wherein the knob comprises an inner knob threadably coupled to an outer knob, wherein the outer knob is releasably coupled to the housing, and wherein a second tether leg is tightened between the inner knob and a spring-loaded shaft.

12. A biostimulator delivery system comprising: handle; a docking cap having a docking cavity to receive an attachment feature of a biostimulator; a torque shaft having a distal shaft end coupled to the docking cap; a tether support extending through the torque shaft to a distal support end, wherein the tether support includes a tubular member having a support lumen and a rod extending through the support lumen; and A tether having a tether loop between a first tether leg and a second tether leg, wherein the first tether leg is coupled to the tubular member and the second tether leg is releasably coupled to the pole.

13. The biostimulator delivery system of claim 12, wherein the second tether leg comprises a loop, and wherein the rod is movable from a first state in which the rod extends through the loop to a second state in which the loop is at a distal end of the rod.

14. The biostimulator delivery system of claim 12, wherein the second tether leg comprises a loop, wherein the rod comprises a hook, and wherein the rod is movable from a first condition wherein the loop is on the hook to a second condition wherein the loop is detached from the hook.

15. The biostimulator delivery system of claim 12, wherein the second tether leg comprises a loop, wherein the rod comprises a deflectable tip, and wherein the rod is movable from a first condition in which the loop is positioned over the deflectable tip to a second condition in which the loop is disengaged from the deflectable tip.

16. A biostimulator delivery system comprising: handle; a docking cap having a docking cavity to receive an attachment feature of a biostimulator; a torque shaft coupled to the handle and a distal shaft end coupled to the docking cap; a tether support extending through the torque shaft to a distal support end, wherein the tether support has a support lumen; and A snare extends through the support lumen, wherein the snare includes a plurality of snare loops.

17. A biostimulator assembly comprising: A biostimulator having an attachment feature; a tether support having a support lumen; and A tether includes a loop coupled to the biostimulator, wherein the tether includes a first tether leg extending proximally from the loop through the support lumen and a second tether leg extending proximally from the loop through the support lumen.

18. The biostimulator assembly of claim 17, wherein the tether support comprises a coil.

19. An attachment feature for a leadless biostimulator, comprising: base; and A button extends proximally from the base, wherein the button includes an insertion slot extending from an outer surface into the button in a first direction, and a retention slot extending from the insertion slot in a second direction transverse to the first direction.

20. The attachment feature of claim 19, wherein the insertion slot extends vertically through the button along a central axis, and wherein the retention slot extends horizontally through the button transverse to the central axis.

21. The attachment feature of claim 19, wherein the insertion slot extends horizontally through the button transverse to the central axis, and wherein the retention slot extends vertically through the button along the central axis.

22. The attachment feature of claim 21 wherein the insertion slot is w-shaped.

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