Medical tool employing a warning mechanism notifying that a rotational limit has been reached

A medical tool includes a rotation mechanism that further includes a warning feature. The warning feature provides an indication when the rotation mechanism has achieved a number of rotations.

FIELD OF THE INVENTION

Aspects of the present invention relate to medical apparatus and methods. More specifically, the present invention relates to a medical tool for the delivery, implantation, actuation and/or manipulation of an implantable device and/or patient tissue, such as a leadless pacemaker.

BACKGROUND OF THE INVENTION

Leadless pacemakers and their delivery systems are a new technology. Similar to implantable leads that extend from a traditional pacemaker or implantable cardioverter defibrillator (ICD), there are essentially two fixation mechanisms for anchoring the leadless pacemaker to the endocardium; tines that get pulled into tissue and a helix that is rotated to fixate to cardiac tissue (similar to a screw).

For leadless pacemakers that require rotation for fixation, there are a number of possible clinical events that can occur as a result of over or under-rotating the leadless pacemaker. If the leadless pacemaker is under-rotated, it can come loose prior to full release or migrate post-release.

If the leadless pacemaker is over-rotated, the helix portion of the leadless pacemaker can either penetrate or pinch tissue. This penetration/pinching can potentially lead to a variety of adverse clinical events.

There is a need in the art for a system for, and method of, delivering a leadless pacemaker for fixation to cardiac tissue while reducing the possibility of under/over rotation of the leadless pacemaker during fixation.

BRIEF SUMMARY OF THE INVENTION

Disclosed herein is a warning mechanism for informing the physician regarding the number of rotations associated with the fixation of the leadless pacemaker, the warning mechanism being supported on a delivery system for the delivery and fixation of the leadless pacemaker to cardiac tissue. In one embodiment, the warning system is supported on the handle of the delivery system, the handle having a torque portion, which when rotated, causes the leadless pacemaker to rotate.

The purpose of the warning mechanism is to provide the physician with information about how many rotations of the leadless pacemaker have occurred in the course of trying to anchor the leadless pacemaker to cardiac tissue via the delivery system. When the warning system provides notice to the physician that a certain number of rotations of the leadless pacemaker have occurred, the physician needs to consciously think about progressing further in the procedure.

In order to progress with rotating the leadless pacemaker past the point where the warning mechanism has notified the physician that the certain number of rotations has been reached, the physician needs to make a conscious choice to proceed, which can occur in a number of ways, depending on the embodiment of the warning mechanism. For example, the physician must actuate or disable a feature of the warning mechanism to allow further rotations. Additionally or alternatively, the physician must overcome a temporary or short term increase in resistance to bringing about further rotation of the leadless pacemaker. Additionally or alternatively, the physician may overcome a warning to bring about further rotation of the leadless pacemaker for a pre-designed number of additional implant rotations, or implant partial rotations, whereby the delivery system torque portion enters a freewheel mode of infinite rotations.

The warning mechanism is advantageous in that it allows for the leadless pacemaker to be removed and repositioned and yet provide repeated warnings to the physician when the certain number of rotations have been reached, the warning mechanism being resettable or self-resetting to allow for repeated removal/reposition/anchoring of the leadless pacemaker.

In one embodiment, the warning mechanism informs the physician of a certain level of leadless pacemaker rotations by changing the amount of effort needed to continue rotating a torque portion of a handle of the delivery system for a short period of time. As the torque portion is being rotated clockwise (CW) initially, the effort required is relatively low as a shuttle translates along the handle body. Once the shuttle contacts an O-ring, the effort required to continue rotating increases significantly. In order for the physician to continue rotating the torque portion and the leadless pacemaker operably coupled to the torque portion, the physician simply needs to increase rotational force applied to the torque portion. As the rotation force applied to the torque portion is increased, the shuttle could either expand/open slightly and/or the O-ring could be compressed slightly. A thread on a handle shaft continues to translate the shuttle until the shuttle has cleared the O-ring. Once the shuttle has cleared the O-ring, the effort required to rotate the handle returns to normal. The shuttle may cover the O-ring at this point, but does not interfere with it. This non-interference allows the feel of the torque portion to return to normal after the O-ring has been cleared. At this point, the user is free to rotate the handle in the clock-wise direction freely without a secondary warning system, although in some embodiments, additional O-ring could be employed to give additional incremental warnings.

If the physician needs to re-position the leadless pacemaker, the torque portion of the handle only needs to be turned in the opposite direction (counter-clockwise (CCW)). In order for the shuttle to properly re-engage the thread, a spring with sufficient enough force biases the shuttle up against the shaft thread segment of the torque portion of the handle. When the torque portion gets rotated CCW with the shuttle in contact with the shaft thread segment, the shuttle begins translating towards the distal end of the handle. To clear the O-ring, the shuttle again needs to expand slightly and/or compress the O-ring. Once the shuttle has cleared the O-ring, the physician can continue rotating the torque portion of the handle with normal effort until the leadless pacemaker is completely removed from cardiac tissue. Once the physician has re-positioned the leadless pacemaker to a desired location, the mechanism starts over, and will again inform the user at the set torque portion rotation level as another spring biases the shuttle back into threaded engagement with the shaft thread segment as the torque portion is rotated CW.

In one embodiment, the system employs bumps on the housing that are contacted by complementary bumps on the shuttle to provide a warning mechanism that informs the physician of a certain level of leadless pacemaker rotations by changing the amount of effort needed to continue rotating a torque portion of a handle of the delivery system for a short period of time. The bumps operate similarly to the operation of the O-ring. Specifically, a pair of plastic bumps exists along a shuttle track. The pair of plastic bumps are contacted at a certain rotation level by similar features on the shuttle. In order to move the shuttle past the shuttle track bumps and continue rotating the torque portion, the user would need to rotate the torque portion with greater/conscious effort. Once the interference/bump is cleared, the torque portion of the handle would return to normal with respect to rotational feel.

In one embodiment, the warning mechanism informs the physician of the handle rotation level by providing a hard or soft stop at a certain number of turns of the torque portion of the handle in place of, or additional to, employing the O-ring or bumps. A helical partial thread on the shaft translates a shuttle towards the proximal end. When the rotation limit is reached, the shuttle comes in contact with a mechanical or electro-mechanical obstacle, which physically prevents it from translating further, and subsequently prevents the torque portion of the handle from further rotating the shaft and, by extension, the leadless pacemaker. In order for the physician to continue rotating the torque portion and the leadless pacemaker, the physician needs to intentionally displace the switch to remove the obstacle inhibiting the shuttle. Once the switch is displaces, the shuttle is again free to translate, which allows the torque portion and leadless pacemaker to rotate freely.

After the switch is displaced, if the physician needs to unscrew the leadless pacemaker and re-position the leadless pacemaker, the physician simply rotates the handle in the other direction. By rotating the torque portion of the handle in the CCW direction, the shuttle re-engages the helical partial thread on the shaft and will translate distally until it is back at its starting point. The user would then return the switch to its starting point in order for the warning mechanism to function a second time as the shuttle is moved proximally as the torque portion of the handle is rotated CW.

Disclosed herein is a medical tool. In one embodiment, the tool includes a handle, a torque portion, a shuttle, and a warning mechanism. The torque portion is operably coupled to the housing and rotatable relative to the housing. The torque portion includes a shaft including an outer circumferential surface and a helical thread portion radially outwardly extending from the outer circumferential surface of the shaft. The shuttle is displaceable along the shaft via threaded interaction with the helical thread portion. The warning mechanism interacting with the shuttle provides a tactile indication when the torque portion has rotated a number of rotations.

The warning mechanism may include an O-ring on the shaft that is deflected by the shuttle as the shuttle passes over the O-ring, the deflection providing the tactile indication. For example, the O-ring may be deflected by a lip of the shuttle. Also, the shuttle may include a region inward of the lip that allows the O-ring to return to its non-deflected shape within the confines of the shuttle. The tactile indication may include a period of increased rotational resistance at the torque portion as the O-ring is being deflected by the shuttle.

The warning mechanism may include a structural feature on the housing that is contacted by a structural feature on the shuttle as the shuttle displaces along the shaft. For example, the structural feature on the housing may include a bump, and the structural feature on the shuttle may include a bump, at least one of the bumps deflecting as the shuttle displaces along the shaft, the deflection providing the tactile indication. The tactile indication may include a period of increased rotational resistance at the torque portion as the at least one of the bumps is being deflected.

The warning mechanism may include a hard stop contactable by the shuttle near a proximal end of the displacement of the shuttle along the shaft, the tactile indication being provided by the shuttle contacting the hard stop. The hard stop can be moved out of alignment with the shuttle such that the shuttle can be further proximally displaced along the shaft.

The shaft may include a first end and a second end opposite the first end. The shaft may be capable of infinite rotation in a first direction without causing further displacement of the shuttle along the shaft toward the first end when the shuttle is at a first location near the first end. Also, rotation of the shaft in a second direction opposite the first direction when the shuttle is at the first location causes the shuttle to displace along the shaft towards the second end.

The shaft may also be capable of infinite rotation in the second direction without causing further displacement of the shuttle along the shaft toward the second end when the shuttle is at a second location near the second end. Also, rotation of the shaft in the first direction when the shuttle is at the second location causes the shuttle to displace along the shaft towards the first end.

The tool may also include a first biasing element that biases the shuttle towards the second end when the shuttle is at the first location, and a second biasing element that biases the shuttle towards the first end when the shuttle is at the second location.

Disclosed herein is a medical tool. In one embodiment, the tool includes a rotation mechanism including a warning feature that provides a tactile indication when the rotation mechanism has achieved a number of rotations.

In one embodiment, the tactile indication is provided by interference between parts of the rotation mechanism. For example, the interference may be between an O-ring on a shaft of the rotation mechanism that is compressed by a shuttle that displaces along the shaft and is driven by the shaft. As another example, the interference may be between a shuttle of the rotation mechanism and a handle housing of the medical tool.

In one embodiment, the tactile indication includes a period of increased rotational resistance at a torque portion of a handle of the tool.

In one embodiment, the tactile indication may be provided by a shaft driven shuttle of the rotation mechanism contacting a hard stop aligned with the shuttle. The hard top can be placed out of alignment with the shuttle to allow further displacement of the shuttle.

In one embodiment, a drive shaft of the rotation mechanism includes a first end and a second end opposite the first end. The drive shaft is capable of infinite rotation in a first direction without causing further displacement of the shuttle along the drive shaft toward the first end when the shuttle is at a first location near the first end. Rotation of the drive shaft in a second direction opposite the first direction when the shuttle is at the first location causes the shuttle to displace along the drive shaft towards the second end.

The drive shaft is capable of infinite rotation in the second direction without causing further displacement of the shuttle along the drive shaft toward the second end when the shuttle is at a second location near the second end. Rotation of the drive shaft in the first direction when the shuttle is at the second location causes the shuttle to displace along the drive shaft towards the first end.

A first biasing element of the rotation mechanism biases the shuttle towards the second end when the shuttle is at the first location. A second biasing element of the rotation mechanism biases the shuttle towards the first end when the shuttle is at the second location.

Also disclosed herein is a delivery system. In one embodiment, the delivery system includes a handle, a torque portion, a shuttle, and a warning mechanism. The torque portion is operably coupled to the housing and rotatable relative to the housing. The torque portion includes a shaft including an outer circumferential surface and a helical thread portion radially outwardly extending from the outer circumferential surface of the shaft. The shuttle is displaceable along the shaft via threaded interaction with the helical thread portion. The electronic warning mechanism interacting with the shuttle provides an indication when the torque portion has rotated a number of rotations. The indication provided by the warning mechanism may be, among other things, a visual, audial, or tactile indication. In one embodiment, the number of rotations is determined based on a variable resistance element that interacts with the shuttle such that as the shuttle is displaced along the shaft, a resistance of the variable resistance element changes. In another embodiment, the number of rotations is determined by a switch disposed in the housing that is actuated when the shuttle reaches a predetermined position along the shaft corresponding to the number of rotations of the shaft.

DETAILED DESCRIPTION

Implementations of the present disclosure involve a medical tool including a rotation mechanism having a warning feature that provides a tactile indication when the rotation mechanism has achieved a number of rotations. The tactile indication may be provided via, for example, deflection or compression of a resilient member such as an O-ring.

Alternatively or additionally, the tactile indication may be provided by interference of structural members contacting each other, such as bumps on one element being brought into contact with bumps on another element, one or more of the bumps being caused to deflect on account of the contact.

Alternatively or additionally, the tactile indication may be provided via abutting contact between elements of the rotation mechanism, such as contact between a hard contact of a stop ring and a surface of a shuttle. The hard contact of the stop ring may be rotated out of alignment with the surface of the shuttle to facilitate resumed displacement of the shuttle.

The rotation mechanism is advantageous as it may be configured for infinite rotation in a first direction when the shuttle is at a first location on a shaft of the rotation mechanism, and infinite rotation in a second direction opposite the first direction when the shuttle is at a second location on the shaft opposite the first location. Further, the shuttle may biased such that rotation in the second direction when the shuttle is at the first location results in displacement of the shuttle towards the second location, and rotation in the first direction when the shuttle is at the second location results in displacement of the shuttle towards the first location.

Before discussing the specifics of the rotation mechanism and the warning features disclosed here, a discussion will now be provided regarding an example medical tool employing the rotation mechanism and the warning features.

A. Overview of Example Tool Embodiments Employing the Rotation Mechanism

The rotation mechanism90disclosed herein and discussed in detail below may be beneficially employed in a wide variety medical tools. For example, in one embodiment, the rotation mechanism90may be employed in the handle108of a leadless pacemaker delivery system100configured to deliver into a patient a leadless pacemaker102such as the Nanostim™ leadless pacemaker as manufactured by Abbott.

Typically, a leadless pacemaker is substantially enclosed in a hermetic housing suitable for placement on or attachment to the inside or outside of a cardiac chamber. Depending on the embodiment, the pacemaker can have two or more electrodes located within, on, or near the housing, for delivering pacing pulses to muscle of the cardiac chamber and optionally for sensing electrical activity from the muscle, and for bidirectional communication with at least one other device within or outside the body. The housing can contain a primary battery to provide power for pacing, sensing, and communication, for example bidirectional communication. The housing can optionally contain circuits for sensing cardiac activity from the electrodes. The housing contains circuits for receiving information from at least one other device via the electrodes and contains circuits for generating pacing pulses for delivery via the electrodes. The housing can optionally contain circuits for transmitting information to at least one other device via the electrodes and can optionally contain circuits for monitoring device health. The housing contains circuits for controlling these operations in a predetermined manner.

In some embodiments, a leadless pacemaker can be adapted for delivery and implantation into tissue in the human body. In a particular embodiment, a leadless pacemaker can be adapted for implantation adjacent to heart tissue on the inside or outside wall of a cardiac chamber, using two or more electrodes located on or within the housing of the pacemaker, for pacing the cardiac chamber upon receiving a triggering signal from at least one other device within the body.

Self-contained or leadless pacemakers or other biostimulators are typically fixed to an intracardial implant site by an actively engaging mechanism or primary fixation mechanism such as a screw or helical member that screws into the myocardium. Examples of such leadless biostimulators are described in the following publications, the disclosures of which are incorporated by reference herein in their entireties: (1) U.S. Pat. No. 8,457,742; (2) U.S. application Ser. No. 11/549,581 filed on Oct. 13, 2006, entitled “Leadless Cardiac Pacemaker”, and published as US2007/0088396A1 on Apr. 19, 2007; (3) U.S. application Ser. No. 11/549,591, filed on Oct. 13, 2006, entitled “Leadless Cardiac Pacemaker System with Conductive Communication” and published as US2007/0088397A1 on Apr. 19, 2007; (4) U.S. Pat. No. 8,352,025; (5) U.S. Pat. No. 7,937,148; (6) U.S. Pat. No. 7,945,333; (7) U.S. Pat. No. 8,010,209; and (8) International Application No. PCT/US2006/040564, filed on Oct. 13, 2006, entitled “Leadless Cardiac Pacemaker and System” and published as WO07047681A2 on Apr. 26, 2007.

Leadless pacemakers or biostimulators can be delivered to, and retrieved from, a patient using a delivery system100similar to that described below with respect toFIG. 1, which is an isometric view of the delivery system100. As illustrated inFIG. 1, the delivery system100can include a guide catheter sheath111including an atraumatic distal end104in the form of a pacemaker sheath104. The delivery system100can also have a pacemaker introducer sheath107and a catheter shaft106. The catheter shaft106includes at its proximal end the handle108, a deflection knob110, and a tether shuttle112. Each of the longitudinal bodies107,111,106includes a flush port114a,114b,114cextending respectively therefrom. As can be understood fromFIG. 1, the catheter shaft106extends through the guide catheter sheath111, which extends through the introducer sheath107. Each of the longitudinal bodies106,107,111are displaceable proximal-distal relative to each other.

As discussed in detail in U.S. Publication No. 20160096001, which is entitled “DELIVERY CATHETER SYSTEMS AND METHODS,” filed Oct. 7, 2014, hereby incorporated by reference in its entirety herein, in one embodiment, the atraumatic pacemaker sheath104may have a braided or woven construction that is sufficiently flexible to allow the atraumatic pacemaker sheath104to encompass the leadless pacemaker102or to have a diameter that is smaller than a diameter of the leadless pacemaker102when not encompassing the leadless pacemaker102. The deflection knob110can be used to deflect the catheter shaft106within the catheter sheath111to steer and guide the catheter during implantation and/or removal of the pacemaker. The flush ports114a,114b, and114ccan be used to flush saline or other fluids through the catheter. The atraumatic sheath104forms the distal most region of the catheter sheath111. The catheter sheath111can be advanced distally over the catheter shaft106such that the atraumatic sheath104is caused to extend over the leadless pacemaker102. Also, the distal displacement of catheter sheath111relative to the catheter shaft106can be used to provide additional steering and support for the delivery catheter during implantation and to surround the pacemaker as it is introduced through a trocar or the introducer sheath107into the patient. The catheter sheath111can be retracted proximally over the catheter shaft106such that the atraumatic sheath104is caused to retract from over the leadless pacemaker102, the braided construction of atraumatic sheath104being such that the atraumatic sheath104self-biases into a reduced diameter. The reduced diameter of the atraumatic sheath104is no greater than the diameter of the leadless pacemaker102.

As can be understood fromFIG. 1and the above-referenced patent/applications, a leadless pacemaker102is attached or connected to a distal end of the delivery system100and advanced intravenously into the heart. As discussed in greater detail below, the rotation mechanism90incorporated in the handle108of the delivery system100can be used to cause a linear member120that extends longitudinally through the catheter shaft106and is operably coupled to the rotation mechanism90to rotate relative to the catheter shaft106about the longitudinal axis of the catheter shaft106to rotate the leadless pacemaker102about its longitudinal axis such that the distal helical anchor of the leadless pacemaker102screws into the cardiac tissue if the leadless pacemaker102is being implanted or to unscrew from the cardiac tissue if the leadless pacemaker102is being explanted.

Each of the rotation mechanisms90discussed below employ a rotation limit warning mechanism by which a physician is notified that a prescribed number of rotations of the helical anchor of the leadless pacemaker has been reached. Upon having received the rotation limit warning, the physician may elect to continue to further rotate the helical anchor in the direction of tissue anchoring, to leave the anchor as is with respect to direction and number of rotations, or to rotationally withdraw the helical anchor and again attempt to rotate the helical anchor into the cardiac tissue.

B. Handle with Rotation Mechanism Employing Stop Ring Rotation Limit Warning

As shown inFIG. 2, which is an isometric view of the proximal region of the leadless pacemaker delivery system ofFIG. 1, the handle108includes a housing portion125and a torque portion130, which may be in the form of a torque knob130. The housing portion125encloses the rotation mechanism90and is coupled to the catheter shaft106. The torque portion130is operably coupled to the housing portion125such that the torque portion130can rotate relative to the housing portion125about a common longitudinal axis of the two portions125,130.

As described in detail below, rotation of the torque portion130relative to the housing portion125drives the rotation mechanism90to cause a similar rotation of the linear member120relative to the catheter shaft106, the linear member120being operably coupled to the rotation mechanism90.

As depicted inFIG. 2, in one embodiment, the torque portion125is proximal the distal housing portion125. However, in other embodiments, the arrangement may be reversed proximal-distal.

As illustrated inFIG. 3, which is the same view asFIG. 2, except with a half-shell of the housing portion125of the handle108removed to reveal the rotation mechanism90enclosed therein, the housing portion125may be a multi-piece construction that forms a shell that has various interior wall structures135. The interior wall structures reinforce the outer wall140of the housing portion125and support and longitudinally separate various components of the rotation mechanism90, the catheter shaft106, and the torque portion130. The housing portion125may be made of materials such as, for example, polymers, metals, and/or etc.

As indicated inFIG. 3, the catheter shaft106is secured to the distal region of the housing portion125. The torque portion130has structural features, such as, for example, one or more circumferential grooves145, that interface with some of the interior wall structures135to prevent the torque portion130from proximal-distal displacement relative to the housing portion125while supporting the torque portion130in rotating displacement relative to the housing portion130, the rotation being about a common longitudinal axis of the housing portion and torque portion.

As can be understood fromFIG. 3, the linear member120extends from a distal end of the rotation mechanism90, through the interior of the housing portion125, and through the catheter shaft106. The proximal end of the linear member120is coupled to the distal end of the rotation mechanism90such that rotation of the rotation mechanism90causes the linear member120to similarly rotate within the confines of the housing portion125and the catheter shaft106about a longitudinal axis of the linear member120. Thus, as can be understood fromFIGS. 1-3, rotation of the torque portion130clockwise causes the linear member120to rotate clockwise, thereby causing the leadless pacemaker102at the distal end of the delivery system100to rotate clockwise about the longitudinal axis of the leadless pacemaker102. This clockwise rotation will cause the helical anchor at the distal end of the leadless pacemaker to screw into the cardiac tissue to attach the leadless pacemaker to the cardiac tissue.

Oppositely, rotation of the torque portion130counter-clockwise causes the linear member120to rotate counter-clockwise, thereby causing the leadless pacemaker102at the distal end of the delivery system100to rotate counter-clockwise about the longitudinal axis of the leadless pacemaker102. This counter-clockwise rotation will cause the helical anchor at the distal end of the leadless pacemaker to unscrew from the cardiac tissue to detach the leadless pacemaker from the cardiac tissue.

FIG. 4is an exploded isometric view of the handle108and the rotation mechanism90enclosed therein. As shown inFIG. 4, the rotation mechanism90includes a ratchet assembly150, a distal spring155, a shuttle160, a proximal spring165, a stop ring170and a drive shaft175of the torque portion130. These components of the rotation mechanism90are enclosed by the housing portion125. The drive shaft175of the torque portion130distally extends from a grip180of the torque portion130.

FIG. 5is a longitudinal cross section of the handle108and rotation mechanism enclosed therein as viewed along section line5-5inFIG. 2. As can be understood fromFIGS. 2-5, the drive shaft175distally extends from the grip180of the torque portion130into the housing portion125to be supported in a rotating fashion by various interior wall structures135of the housing portion125. The drive shaft175extends through the other components of the drive mechanism90, specifically, the ratchet assembly150, the distal spring155, the shuttle160, the proximal spring165, and the stop ring170.

As depicted inFIG. 6, which is an isometric view of the torque portion130of the handle108, the drive shaft175has a generally cylindrical outer surface that is interrupted by flanges and recesses that define circumferential grooves145that interface with the interior wall structures135of the housing portion125to act as rotational bearing surfaces for the drive shaft and prevent distal-proximal displacement of the drive shaft relative to the housing125. A helical partial thread185radially projects from the cylindrical outer surface of the drive shaft175near the midpoint of the length of the drive shaft175. This helical partial tread185threadably engages threads250on the threaded cylindrical interior or axial shaft235of the shuttle160as discussed below. The torque portion130may be made of materials such as, for example, polymers, metals, and/or etc.

As indicated inFIGS. 7A and 7B, which are opposite isometric views of the ratchet assembly150of the rotation mechanism90, the ratchet assembly150includes an inner notched-rim wheel190and an outer dual pawl195that includes opposed tab arms197that engage notches or recesses200defined in the outer circumferential surface of a rim205of the inner notched-rim wheel190. A circumferentially extending key ridge210and a longitudinally extending key ridge215project radially inward from an inner circumferential surface of a cylinder portion220of the inner notched-rim wheel190.

As can be understood fromFIGS. 3-7B, the ratchet assembly150extends about the circumference of the distal end of the drive shaft175. The key ridges210,215of the inner notched-rim wheel190are received in a mating interference fit with complementary female circumferential and longitudinal slots145,225defined in the drive shaft175near its distal end. On account of this arrangement, clockwise or counter-clockwise rotation of the drive shaft175rotates the inner notched-rim wheel190in the same directions. Rotational displacement of the inner notched-rim wheel190causes the recesses200to displace against the pawl arms195, thereby creating a tactile sensation in the grip180of the torque portion130when the torque portion is rotated relative to the housing125. The inner notched-rim wheel190may be made of materials such as, for example, polymers or etc. The outer dual pawl195may be made of materials such as, without limitation, engineering polymers, and/or metals.

FIGS. 8A and 8Bare opposite isometric views of a shuttle160of the rotation mechanism90. As reflected inFIGS. 8A and 8B, the shuttle160includes a cylindrical body230with a threaded cylindrical axial shaft235extending distal-proximal through the body230, a pair of guide members240radially projecting outward from the outer circumferential surface of the body230on opposite sides of the body from each other, and pairs of longitudinally spaced apart ribs245radially projecting outward from the outer circumferential surface of the body230and extending circumferentially about the body. The shuttle160may be made of materials such as, without limitation, engineering polymers, and/or metals.

The thread250in the threaded cylindrical axial shaft235is a multi-start thread with two, three, four or more thread-start locations255intersecting the proximal rim260and the distal rim265of the threaded cylindrical axial shaft235. These thread-start locations255allow the helical partial tread185on the drive shaft175to enter the thread250at multiple locations about the circumference of the proximal and distal rims260,265and threadably engage the thread250on the threaded cylindrical interior or axial shaft235of the shuttle160, as can be understood fromFIGS. 3-5and as discussed below.

As can be understood fromFIGS. 2-5, the pair of guide members240are received in respective longitudinally extending guide slots270defined in the exterior wall140of the housing125such that the guide members240linearly displace distal-proximal along the respective guide slots270as the drive shaft175threadably drives the shuttle160distal-proximal along the length of the drive shaft160when the drive shaft is rotated clockwise or counter-clockwise. In some embodiments, the guide slots270are in the form of windows daylighting through the wall140of the housing125such that the displacement of the guide members240of the shuttle can be visually observed.

FIGS. 9A and 9Bare opposite isometric views of a stop ring170of the rotation assembly90. As indicated inFIGS. 9A and 9B, the stop ring170includes a ring275, a pair of lever arms280radially outwardly projecting from opposite sides of the ring275, and a pair of hard stop members285distally projecting from a distal edge of the ring275and at opposite locations on the ring275. The stop ring170may be made of materials such as, for example, polymers, metals, and/or etc.

As illustrated inFIGS. 2, 3 and 5, the stop ring170extends around the proximal region of the drive shaft175, the hard stop members285extending distally along the drive shaft and generally parallel to the drive shaft175. The lever arms280radially project outwardly through a respective pair of circumferentially extending window slots290defined in the exterior wall140of the housing125.

As can be understood fromFIGS. 3, 5, 7A, 7B, 8A and 8B, the distal spring155is located between the proximal face of the rim205of the inner notched-rim wheel190and the distal faces of the guide members240and the distal pair of ribs245of the shuttle160. When the shuttle160is fully distally displaced along the length of the drive shaft175, as depicted inFIGS. 3, 5, 10A and 10B, the distal spring155extends around the outer cylindrical surface of the cylinder portion220of the inner notched-rim wheel190, the outer cylindrical surface of the drive shaft175, and the outer cylindrical surface of the shuttle body230distal the guide members240.

As can be understood fromFIGS. 3, 5, 7A, 7B, 8A and 8B, the proximal spring165is located between the distal face of the ring275of the stop ring170and the proximal faces of the guide members240and the proximal pair of ribs245of the shuttle160. When the shuttle160is fully proximally displaced along the length of the drive shaft175, as depicted inFIGS. 11A and 11B, the proximal spring165extends around the outer cylindrical surface of the drive shaft175and the outer cylindrical surface of the shuttle body230proximal the guide members240. The proximal spring165will also be located radially inward of the hard stop members285.

The springs155,165may be made of materials such as, for example, metals, compressible polymers, and/or etc. While depicted as being helical springs in the various FIGS. herein, in other embodiments, the springs155,165may have other configurations such as, for example, elastomeric polymers, or may even be replaced with other biasing members such as, for example, bands that stretch and create tension on the shuttle.

As can be understood fromFIGS. 3 and 5, in some embodiments, the distal and proximal springs155,165may abut against the respective proximal and distal faces of the guide members240and ribs245. In other embodiments, as indicated inFIGS. 10A-11B, rings295extend about the outer cylindrical surfaces of the shuttle body230proximal and distal the guide members240and ribs245. These rings295may be formed of materials such as, without limitation, engineering polymers, and/or metals and will contact the respective springs155,165.

FIG. 10Ais an isometric view of the handle108with a portion of a housing125removed to reveal the rotation mechanism90enclosed therein, the shuttle160being in a most distal location along a shaft175of the torque portion130of the handle.FIG. 10Bis a longitudinal cross-section of the rotation mechanism90in the region identified inFIG. 10Aand as taken along section line10B-10B inFIG. 10A.

As illustrated inFIGS. 10A and 10B, when the shuttle160is in the most distal location along the shaft175of the torque portion130of the handle108, the distal spring155is compressed between the distal ring295of the shuttle160and an interior wall135immediately proximal the ratchet assembly150. As can be understood fromFIG. 10A, on account of the pitch direction of the helical partial thread185on the shaft175of the torque portion130, and despite the distal spring155biasing the shuttle proximally such that its distal rim265(seeFIGS. 8A and 8B) is kept in abutting contact with the thread185, the thread185of the shaft175does not engage the interior threads250of the shuttle160as long as the torque portion130is rotated counter-clockwise (CCW), the thread185simply riding along the distal rim265of the shuttle160. Thus, the torque portion130and the linear member120extending distally therefrom, as shown inFIG. 3, can infinitely rotate CCW and cause the leadless pacemaker102to rotate CCW, as can be understood fromFIG. 1, such that the helical anchor on the distal end of the leadless pacemaker will unscrew from cardiac tissue in which it may be imbedded. The CCW rotation causes the ratchet assembly150to generate an incremental/stepped tactile sensation in the grip180of the torque portion130of the handle108.

Conversely and as can be understood fromFIG. 10A, on account of the pitch direction of the helical partial thread185on the shaft175of the torque portion130, and because the distal spring155biases the shuttle proximally such that its proximal rim265is kept in abutting contact with the thread185, the thread185of the shaft175engages the interior threads250of the shuttle160once the torque portion130is rotated clockwise (CW) and the shaft thread185encounters one of the multiple thread-start locations255intersecting the proximal rim265. Once threaded engagement occurs between the shaft thread185and the shuttle threads250, further CW rotation of the torque portion130will cause the shuttle160to proximally displace along the shaft175. As can be understood fromFIGS. 1 and 3, the CW rotation of the torque portion130and the linear member120extending distally therefrom rotates the leadless pacemaker102CW such that the helical anchor on the distal end of the leadless pacemaker will screw into cardiac tissue contacting the helical anchor. The CW rotation causes the ratchet assembly150to generate an incremental/stepped tactile sensation in the grip180of the torque portion130of the handle108.

Continued CW rotation of the torque potion130further proximally displaces the shuttle160along the shaft175as the shuttle threads250move proximally along the rotating shaft thread185, which is confined to rotation about the longitudinal axis of the shaft and does not displace distal-proximal. As the shuttle moves along the shaft, the shuttle guide members240linearly displace proximally along the respective guide slots270, and this displacement can be observed through the windows created by the guide slots270in the exterior wall140of the housing125, as can be understood fromFIGS. 2, 4 and 5.

As the CW rotation of the torque portion130causes the shuttle160to displace proximally from the most distal location, as depicted inFIGS. 10A and 10B, the tactile sensation and resistance felt in the grip180of the torque portion130will remain constant as provided by the ratchet assembly150until the shuttle160is sufficiently proximally displaced such that the proximal faces of the shuttle guide members240come into abutting contact with the distal tip faces of the hard stop members285of the stop ring170, as illustrated inFIGS. 11A and 11B. In some embodiments, the rotational resistance may increase slightly as the proximal spring165is initially contacted by the shuttle proximal ring295immediately prior to the abutting contact between the shuttle guide members240and the hard stop members285, thereby placing the proximal spring165in the initial stages of compression between the shuttle proximal ring295and the distal face of the ring275of the stop ring170.

In one embodiment, the number of CW rotations needed to displace the shuttle from the most distal position depicted inFIGS. 10A and 10Bto the stopped position shown inFIGS. 11A and 11Bwill be two and one-quarter rotations of the grip180of the torque portion130of the handle108. This two and one-quarter rotations is based on what is considered to be a typical number of turns of the helical anchor of the leadless pacemaker to cause the helical anchor to fully imbed in the cardiac tissue without over-penetrating the cardiac tissue. In other embodiments, the number of rotations required to displace the shuttle between the locations depicted inFIGS. 10A-10B and 11A-11Bwill be more or less than two and one-quarter rotations.

Once the proximal faces of the shuttle guide members240come into abutting contact with the distal tip faces of the hard stop members285of the stop ring170, as illustrated inFIGS. 11A and 11B, this contact will notify the physician that the prescribed number of rotations of the helical anchor of the leadless pacemaker has been reached. At this point, should the physician decide additional CW rotations of the helical anchor of the leadless pacemaker are necessary to achieve a desired level of fixation to the cardiac tissue, as illustrated inFIGS. 12A and 12B, the lever arms280of the stop ring170may be rotated about the longitudinal axis of the shaft175to cause the hard stop members285to move out of the way of the shuttle guide members240such that continued CW rotations of the grip180of the torque portion130of the handle108will continue to proximally displace the shuttle160.

As indicated inFIGS. 12A and 12B, sufficient CW rotations of the grip180of the torque portion130of the handle108will cause the shuttle160to fully compress the proximal spring165and the shuttle160to move proximally past the shaft thread185such that the shaft thread185no longer is in threaded engagement with the shuttle threads250but is distal the shuttle threads250. At this point, the grip180of the torque portion130of the handle108can be rotated infinitely CW as the shaft thread185simply rides along the proximal edge260of the shuttle160on account of the pitch direction of the shaft helical partial thread185. Thus, the torque portion130and the linear member120extending distally therefrom, as shown inFIG. 3, can infinitely rotate CW and cause the leadless pacemaker102to rotate CW, as can be understood fromFIG. 1, such that the helical anchor on the distal end of the leadless pacemaker will screw into cardiac tissue for fixation thereto.

Conversely and as can be understood fromFIG. 12B, on account of the pitch direction of the helical partial thread185on the shaft175of the torque portion130, and because the proximal spring165biases the shuttle distally such that its distal proximal rim260is kept in abutting contact with the thread185, the thread185of the shaft175engages the interior threads250of the shuttle160once the torque portion130is rotated counter-clockwise (CCW) and the shaft thread185encounters one of the multiple thread-start locations255intersecting the distal rim260. Once threaded engagement occurs between the shaft thread185and the shuttle threads250, further CCW rotation of the torque portion130will cause the shuttle160to distally displace along the shaft175. This distal displacement of the shuttle will continue until it reaches the most distal location on the shaft, as indicated inFIGS. 10A and 10B, or the grip180of the torque portion130is again rotated CW. In either case, the CCW rotation of the grip180will bring about CCW rotation of the helical anchor for unscrewing from cardiac tissue, and CW rotation of the grip180will bring about CW rotation of the helical anchor for screwing into cardiac tissue.

In the event the grip180is again rotated CW to bring about screwing of the helical anchor into the cardiac tissue, to again allow for the advantages of the rotation limit warning afforded by the stop ring170, the stop ring170can be reset (rotated) such that its hard stop members285are again aligned with the shuttle guide members240to come into abutting contact with the distal tip faces of the of the stop ring170, as can be understood fromFIGS. 10A-11B.

The warning aspect of the rotation mechanism90ofFIGS. 2-12Bcould be adapted to provide multiple warnings to the physician when a certain number of rotations of the leadless pacemaker has occurred. For instance, as illustrated inFIG. 9C, which is a side plan view of a modification to the stop ring170ofFIGS. 9A and 9B, a warning could be provided every full rotation of the torque portion130of the handle108to alert the physician of another complete rotation of the leadless pacemaker. This could be achieved, for example, by providing hard stop members285that have a stepped configuration with a series of steps287A-D that are radially offset from each other and increasingly proximally located. Each step287A-D provides an increasingly proximal point of contact with the shuttle guide members240. Thus, once the shuttle guide members240have contacted a first pair of steps287A of the hard stop members285and the physician desires to make an additional rotation of the leadless pacemaker, the stop ring170can be incrementally rotated to align the shuttle guide members240with the next radially adjacent pair of steps287B, this next radially adjacent pair of steps287B being located more proximally than the initially contacted pair of steps287A. The physician can then rotate the leadless pacemaker a full turn before contacting the second pair of steps287B. The process can then be repeated for successive contacts with the rest of the steps287C and287D for two more purposeful and incremental rotations of the leadless pacemaker.

The warning mechanism afforded by the embodiment ofFIGS. 2-12Bprovides a hard stop at a certain rotation level in the torque portion of the handle. It eliminates any chance of the physician by-passing a more passive indicator by requiring an extra motion to continue rotating, guaranteeing that the physician will notice the warning by completely preventing further rotations until actively addressing the hard stop. Specifically, it requires another user action in order to continue rotating the torque portion of the handle and, by extension, the leadless pacemaker. A visual indicator on the outside of the handle presents that the warning system has been contacted.

C. Handle with Rotation Mechanism Employing O-Ring Rotation Limit Warning

To begin a discussion of another embodiment of the rotation mechanism90of the handle108of the leadless pacemaker delivery system ofFIG. 1, reference is now made toFIGS. 13 and 14.FIG. 13is an isometric view of the handle108with a portion of a housing125of the handle108removed to reveal the alternative rotation mechanism90enclosed therein, andFIG. 14is a longitudinal cross section of the handle108and alternative rotation mechanism90enclosed therein as viewed along section line13-13inFIG. 13.

As can be understood from a comparison ofFIGS. 13 and 14toFIGS. 3-5, the alternative version of the rotation mechanism90and the surrounding elements of the handle108and leadless pacemaker delivery system of the version ofFIGS. 13 and 14share the majority of elements and operation as discussed above with respect toFIGS. 1-12B, except an O-ring300has replaced the stop ring170and the shuttle160employs features that interact with the O-ring300. Accordingly, the preceding discussion ofFIGS. 1-12Bis equally applicable to the version of the rotation mechanism90and surrounding elements of the handle108shown inFIGS. 13 and 14, except as will now be specifically discussed with respect toFIGS. 13-18B.

As indicated inFIGS. 13 and 14, the O-ring300extends circumferentially around, and is coaxial with, the shaft175of the torque portion130. Also, the O-ring300is sandwiched between parallel and spaced-apart flange rings305of the shaft175and extend radially outwardly from the outer circumference of the shaft175. The O-ring300and flange rings305are located near the proximal end of the shaft175of the torque portion130. The O-ring300may be made of materials such as, for example, elastomeric polymer and have a durometer of between approximately 10 and approximately 100 Shore A. The O-ring300, which is compressible, may have a circular transverse cross-section as shown inFIG. 15B. Alternatively, the O-ring300may have a transverse cross-section that is oval, square, rectangular, or etc.

As shown inFIG. 14, the shuttle160includes a proximal inner circumferential chamber310at the proximal end of the shuttle and a distal inner circumferential chamber315at the distal end of the shuttle. Each chamber310,315includes a pair of spaced-apart radially inwardly extending lips, these lips being an outer lip and an inner lip. Specifically, for the proximal chamber310, the outer lip is a proximal outer lip320at the proximal edge of the shuttle160, and the inner lip is a distal inner lip325distal the proximal outer lip320. The lips320,325are spaced-apart from each other and radially inwardly project from an inner cylindrical surface327of the proximal chamber310. For the distal chamber315, the outer lip is a distal outer lip330at the distal edge of the shuttle160, and the inner lip is a proximal inner lip335proximal the distal outer lip330. The lips330,335are spaced-apart from each other and radially inwardly project from an inner cylindrical surface337of the distal chamber315.

FIG. 15Ais an isometric view of the handle108with a portion of a housing125removed to reveal the rotation mechanism90enclosed therein, the shuttle160being in a most distal location along a shaft175of the torque portion130of the handle and the springs155,165being hidden for clarity purposes.FIG. 15Bis a longitudinal cross-section of the rotation mechanism90in the region identified inFIG. 15Aand as taken along section line15B-15B inFIG. 15A.

As illustrated inFIGS. 15A and 15B, when the shuttle160is in the most distal location along the shaft175of the torque portion130of the handle108, the distal spring155(shown inFIGS. 13 and 14) is compressed between the distal ring295of the shuttle160and an interior wall135immediately proximal the ratchet assembly150. As can be understood fromFIG. 15A, on account of the pitch direction of the helical partial thread185on the shaft175of the torque portion130, and despite the distal spring155biasing the shuttle proximally such that its distal rim265is kept in abutting contact with the thread185, the thread185of the shaft175does not engage the interior threads250of the shuttle160as long as the torque portion130is rotated counter-clockwise (CCW), the thread185simply riding along the distal rim265of the shuttle160. Thus, the torque portion130and the linear member120extending distally therefrom, as shown inFIG. 13, can infinitely rotate CCW and cause the leadless pacemaker102to rotate CCW, as can be understood fromFIG. 1, such that the helical anchor on the distal end of the leadless pacemaker will unscrew from cardiac tissue in which it may be imbedded. The CCW rotation causes the ratchet assembly150to generate an incremental/stepped tactile sensation in the grip180of the torque portion130of the handle108.

Conversely and as can be understood fromFIG. 15A, on account of the pitch direction of the helical partial thread185on the shaft175of the torque portion130, and because the distal spring155(shown inFIGS. 13 and 14) biases the shuttle proximally such that its proximal rim265is kept in abutting contact with the thread185, the thread185of the shaft175engages the interior threads250of the shuttle160once the torque portion130is rotated clockwise (CW) and the shaft thread185encounters one of the multiple thread-start locations255intersecting the proximal rim265. Once threaded engagement occurs between the shaft thread185and the shuttle threads250, further CW rotation of the torque portion130will cause the shuttle160to proximally displace along the shaft175. As can be understood fromFIGS. 1 and 13, the CW rotation of the torque portion130and the linear member120extending distally therefrom rotates the leadless pacemaker102CW such that the helical anchor on the distal end of the leadless pacemaker will screw into cardiac tissue contacting the helical anchor. The CW rotation causes the ratchet assembly150to generate an incremental/stepped tactile sensation in the grip180of the torque portion130of the handle108.

Continued CW rotation of the torque potion130further proximally displaces the shuttle160along the shaft175as the shuttle threads250move proximally along the rotating shaft thread185, which is confined to rotation about the longitudinal axis of the shaft and does not displace distal-proximal. As the shuttle moves along the shaft, the shuttle guide members240linearly displace proximally along the respective guide slots270. In some embodiments where the guide slots270daylight through the exterior wall140of the housing125, the displacement of the shuttle guide members240can be observed through the windows created by the guide slots270in the exterior wall140of the housing125, similar to that discussed above with respect toFIGS. 2, 4 and 5.

As the CW rotation of the torque portion130causes the shuttle160to displace proximally from the most distal location, as depicted inFIGS. 15A and 15B, the tactile sensation and resistance felt in the grip180of the torque portion130will remain constant as provided by the ratchet assembly150until the shuttle160is sufficiently proximally displaced such that the proximal boundary of the proximal outer lip320, which is at the shuttle proximal edge260, encounters the distal boundary of the O-ring300, as illustrated inFIGS. 16A and 16B. At this time, the resistance felt in the grip180of the torque portion130will begin to gradually increase as the radially inwardly projecting lip320begins to compress the O-ring300as the lip320is caused to increasingly move proximally over the O-ring300. In some embodiments, the rotational resistance may also increase slightly as the proximal spring165(shown inFIGS. 13 and 14) is initially contacted by the shuttle proximal ring295immediately prior to the radially inwardly projecting lip320begins to encounter and radially inwardly compress the O-ring300, thereby placing the proximal spring165in the initial stages of compression between the shuttle proximal ring295and an interior wall135of the housing125.

In some embodiments, the shuttle may be able to expand to clear the O-ring or a similar structural impediment to the proximal displacement of the shuttle along the shaft. This expansion capability of the shuttle may be in place of the O-ring compressing or in addition to the O-ring compressing.

In one embodiment, the number of CW rotations needed to displace the shuttle from the most distal position depicted inFIGS. 15A and 15Bto the stopped position shown inFIGS. 16A and 16Bwill be two and one-quarter rotations of the grip180of the torque portion130of the handle108. This two and one-quarter rotations is based on what is considered to be a typical number of turns of the helical anchor of the leadless pacemaker to cause the helical anchor to fully imbed in the cardiac tissue without over-penetrating the cardiac tissue. In other embodiments, the number of rotations required to displace the shuttle between the locations depicted inFIGS. 15A-15B and 16A-16Bwill be more or less than two and one-quarter rotations.

Once the proximal boundary of the proximal outer lip320, which is at the shuttle proximal edge260, encounters the distal boundary of the O-ring300, as illustrated inFIGS. 16A and 16B, this contact will notify the physician that the prescribed number of rotations of the helical anchor of the leadless pacemaker has been reached. At this point, should the physician decide additional CW rotations of the helical anchor of the leadless pacemaker are necessary to achieve a desired level of fixation to the cardiac tissue, as can be understood fromFIGS. 16A-17B, continued CW rotations of the grip180of the torque portion130of the handle108will continue to proximally displace the shuttle160and drive the radially inwardly projecting lip320at the shuttle proximal edge260completely over and proximally past the O-ring300such that the O-ring300is received in the proximal inner circumferential chamber310as indicated inFIGS. 17A and 17B.

Since the O-ring300is confined distally and proximally by flange rings305of the shaft175, when the lip320is caused to pass over the O-ring300, the O-ring is compressed such that it is deflected into an elliptical cross-section from its self-biasing, or non-deflected, circular cross-section. This change in cross-section of the O-ring300increases resistance to the rotation of the torque portion130of the handle108, thereby notifying the physician that the prescribed number of rotations of the helical anchor of the leadless pacemaker has been reached.

As indicated inFIGS. 18A and 18B, sufficient CW rotations of the grip180of the torque portion130of the handle108will cause the shuttle160to fully compress the proximal spring165(shown inFIGS. 13 and 14) and the shuttle160to move proximally past the shaft thread185such that the shaft thread185no longer is in threaded engagement with the shuttle threads250but is distal the shuttle threads250. At this point, the grip180of the torque portion130of the handle108can be rotated infinitely CW as the shaft thread185simply rides along the proximal edge260of the shuttle160on account of the pitch direction of the shaft helical partial thread185. Thus, the torque portion130and the linear member120extending distally therefrom, as shown inFIG. 13, can infinitely rotate CW and cause the leadless pacemaker102to rotate CW, as can be understood fromFIG. 1, such that the helical anchor on the distal end of the leadless pacemaker will screw into cardiac tissue for fixation thereto.

Conversely and as can be understood fromFIG. 18B, on account of the pitch direction of the helical partial thread185on the shaft175of the torque portion130, and because the proximal spring165biases the shuttle distally such that its distal proximal rim260is kept in abutting contact with the thread185, the thread185of the shaft175engages the interior threads250of the shuttle160once the torque portion130is rotated counter-clockwise (CCW) and the shaft thread185encounters one of the multiple thread-start locations255intersecting the distal rim260. Once threaded engagement occurs between the shaft thread185and the shuttle threads250, further CCW rotation of the torque portion130will cause the shuttle160to distally displace along the shaft175. This distal displacement of the shuttle will cause the lip320to displace distally over the O-ring300such that the lip320is once again distal the O-ring300and outside the proximal chamber310, as shown inFIGS. 16A and 16B. Further CCW rotation of the torque portion130further drives the shuttle160distally until it reaches the most distal location on the shaft, as indicated inFIGS. 15A and 15B, or the grip180of the torque portion130is again rotated CW. In either case, the CCW rotation of the grip180will bring about CCW rotation of the helical anchor for unscrewing from cardiac tissue, and CW rotation of the grip180will bring about CW rotation of the helical anchor for screwing into cardiac tissue.

As can be understood fromFIGS. 17A-18B, the proximal-distal width of the inner cylindrical surface327of the proximal chamber310provides proximal-distal space for the O-ring300reside to allow the distal spring165(seeFIGS. 13 and 14) to reengage the shaft helical partial thread185with the shuttle inner thread250via one of the thread-start locations255inward of the distal rim265of the shuttle160.

In the event the grip180is again rotated CW to bring about screwing of the helical anchor into the cardiac tissue, the embodiment ofFIGS. 13-18Bis advantageous in that there is nothing to “reset” to again allow for the advantages of the rotation limit warning afforded by the O-ring300. Specifically, the resilience of the O-ring300and the lip320being positioned distal the O-ring300is sufficient to again avail the rotation mechanism90of the operational benefits of the rotation limit warning of the O-ring300.

The warning aspect of the rotation mechanism90ofFIGS. 13-18Bcould be adapted to provide multiple warnings to the physician when a certain number of rotations of the leadless pacemaker has occurred. For instance, additional O-rings300could be incrementally located along the shaft175proximal from a first O-ring300such that a purposeful increase in effort must be undertaken by the physician each time the physician desires to proceed with another rotation of the leadless pacemaker.

This O-ring embodiment ofFIGS. 13-18Bhas a number of advantages. For example, the O-ring embodiment provides tactile feedback at a certain rotation level in the handle. The O-ring embodiment may be adjustable for different levels of physician effort to over-come the warning mechanism; for example, by modifying the O-ring size and durometer or changing the interference level on the shuttle.

The O-ring embodiment allows a physician to maintain focus on any fluoroscopy or information screens in the operating room. Also, no extra motion is required by the physician to over-come warning system. The O-ring embodiment informs the physician during initial implant as well as during a re-positioning of the leadless pacemaker. The warning mechanism of the O-ring embodiment may be completely hidden within the confines of the handle. Finally, the handle is omni-directional in that it does not need to be oriented in a specific fashion to go past the warning mechanism.

D. Handle with Rotation Mechanism Employing Handle Bump Limit Warning

To begin a discussion of yet another version of the rotation mechanism90of the handle108of the leadless pacemaker delivery system ofFIG. 1, reference is now made toFIG. 19, which is an isometric view of half of the shuttle160employed in this third version of the rotation mechanism. As shown inFIG. 19and similar to the shuttle160discussed above with respect toFIGS. 8A and 8B, the shuttle160includes a cylindrical body230with a threaded cylindrical axial shaft235extending distal-proximal through the body230, a pair of guide members240radially projecting outward from the outer circumferential surface of the body230on opposite sides of the body from each other, and pairs of longitudinally spaced apart ribs245radially projecting outward from the outer circumferential surface of the body230and extending circumferentially about the body. A rounded bump or ridge400is located on the lateral sides of each guide member240. All other aspects of the shuttle160are as discussed above with respect toFIGS. 8A and 8B.

FIG. 20is an isometric view of a half of a proximal end of the housing125that is immediately adjacent the torque portion130of the handle108, as can be understood by comparison toFIG. 4.FIG. 21is a plan view of the half of the housing125. As can be understood fromFIGS. 20 and 21and similar to the discussion above with respect toFIGS. 3-5, the housing125includes the interior and exterior walls135,140and the longitudinally extending guide slot270, which is defined by parallel longitudinally extending rails405. Just proximal of the midpoint of the slot270are opposed rounded bumps410projecting inwardly from its associated rail405.

At this point, it should be noted that other aspects of the handle108and rotation mechanism90of this version of the device are substantially similar, if not identical, to those aspects and features described herein with respect to other implementations of the present disclosure, except that this version does not employ the hard stop170or the O-ring300and its interacting lips320,325, chamber310and inner circumferential surface327. Also, the displacement of the shuttle160along the shaft175, its incremental tactile sensation via the ratchet assembly150, and its directional biasing via the springs155,165all occur as discussed above with respect toFIGS. 1-18B, the difference of this version versus the previous versions being that the rotation limit warning of this third version is facilitate via the interaction of the rail bumps410and the shuttle bumps400, as will now be discussed with respect toFIG. 22.

As can be understood fromFIG. 22, which is a bottom plan view of the rotation mechanism90and housing125, a guide member240is located in a slot270between the rails405, the bumps400of the guide member240projecting towards the rails405, and the bumps410of the rails405projecting towards the guide member240. As the shuttle160displaces proximally along the shaft175via CW rotation of the torque portion130, the bumps400,410contact, and deflect against, each other to provide a tactile increase in rotational effort at the grip180of the torque portion130, thereby indicating to the physician that prescribed number of rotations of the helical anchor of the leadless pacemaker has been reached. At this point, should the physician decide additional CW rotations of the helical anchor of the leadless pacemaker are necessary to achieve a desired level of fixation to the cardiac tissue, additional CW rotations may take place. Thus, the operation of the limit warning of this third version of the rotation mechanism may be said to operate similar to that of the O-ring version discussed above with respect toFIGS. 13-18B, the exception being that the interaction of the O-ring and lips is replace by the interaction of the bumps400,410.

The warning aspect of the rotation mechanism90ofFIGS. 19-22could be adapted to provide multiple warnings to the physician when a certain number of rotations of the leadless pacemaker has occurred. For instance, additional pairs of rail bumps410could be incrementally located along the slot270proximal from a first pair of rail bumps410such that a purposeful increase in effort must be undertaken by the physician each time the physician desires to proceed with another rotation of the leadless pacemaker.

The warning mechanism afforded by the bumps can be adjusted for different levels of physician effort to overcome the warning mechanism; for example, by modifying the level of interference by changing bump height and modifying flexural stiffness of shuttle ribs on which the housing bumps are located. All the bump features can be molded into place. The warning mechanism allows the physician to maintain focus on any fluoroscopic or information screens in the operating room, and no extra motion is required by the user to over-come warning system. The warning mechanism may inform the physician during initial implant as well as during a re-positioning. The warning mechanism may be completely encapsulated inside handle, and the handle may be omni-directional in that it does not need to be oriented in a specific fashion to go past the warning mechanism.

E. Handle with Rotation Mechanism Employing Malleable Thread

To begin a discussion of yet another version of the rotation mechanism90of the handle108of the leadless pacemaker delivery system ofFIG. 1, reference is now made toFIG. 23, which is a longitudinal cross-section of a rotation mechanism90in accordance with this disclosure. As shown inFIG. 23and similar to the shuttle160discussed above with respect toFIGS. 8A and 8B, the shuttle160includes a cylindrical body230with a threaded cylindrical axial shaft235extending distal-proximal through the body230and including one or more threads250, a pair of guide members240radially projecting outward from the outer circumferential surface of the body230on opposite sides of the body230from each other, and pairs of longitudinally spaced apart ribs245radially projecting outward from the outer circumferential surface of the body230and extending circumferentially about the body. The shuttle160ofFIG. 23is sized such that when the shuttle160is in a proximal position, at least a portion of the threads250engage a helical partial thread180of a torque portion130of a handle108. Generally, the proximal position of the shuttle160is a position in which further proximal translation of the shuttle160is prevented by another structure or component of the rotation mechanism90. For example, in certain implementations, the proximal position may correspond to a maximum proximal position at which the shuttle160abuts a proximal interior wall of the handle108(such as the interior wall135shown inFIG. 18B) or is prevented from additional proximal translation by a compressed spring, bumper, or similar resilient structure disposed between the shuttle160and a proximal interior wall of the handle108. As illustrated inFIG. 23, the proximal position may also correspond to one or more positions of the shuttle160at which the shuttle160is prevented from additional proximal translation by a stop ring170having one or more distinct stops (as previously discussed in the context ofFIGS. 2-12B). At this point, it should be noted that other aspects of the handle108and rotation mechanism90of this version of the device are substantially similar, if not identical, to those aspects and features described herein with respect to the other versions of the present disclosure, except in this version the shuttle160is sized such that at least a portion of the threads250of the shuttle160engage the partial helical partial thread185of the handle108when the shuttle160is in a proximal position.

In rotation mechanisms according to this version of the rotation mechanism, tactile feedback is provided by threads adapted to deform or fail when sufficient torque is applied to the torque portion130of the handle108after the shuttle160has reached a proximal position. More specifically, when the shuttle160reaches the proximal position by rotation of the torque portion130, additional translation of the shuttle160is prevented by features of the rotation mechanism90, such as the stop ring170, or, in other implementations a spring (such as the spring165shown inFIG. 14), an interior wall of the handle108(such as the interior wall135shown inFIG. 18B), a bumper (such as the elastomeric bumpers490,495shown inFIG. 25), or any similar structure disposed between the handle108that prevents proximal translation of the shuttle160.

When the shuttle160is in the proximal position (as shown inFIG. 23), additional torque applied to the torque portion130results in stress applied to a portion of the threads250of the shuttle160and the partial helical partial thread185of the handle108. If the torque applied is sufficiently high, one or both of the threads250and the partial helical partial thread185may deform and/or fail. When such deformation or failure occurs, the threads250and the partial helical thread285may disengage and, as a result, the torque portion130may freely rotate within the housing180.

In light of the foregoing, the rotation mechanism90illustrated inFIG. 23provides tactile feedback and warning by resisting rotation of the torque portion130when the shuttle160reaches the proximal position. More specifically, as the shuttle160translates towards the proximal position, rotation of the torque portion130is opposed by a rotational resistance which may be attributable to friction of components of the rotation mechanism90or other features, such as springs, that may be disposed proximal the shuttle160. When the shuttle160reaches the proximal position, the shuttle160is generally prevented from further translation in the proximal direction and, as a result, a warning in the form of substantially increased rotational resistance occurs. In certain implementations, the rotation mechanism90may be configured to translate the shuttle160from a distal position to the proximal position in a predetermined number of rotations of the torque portion130, such as two and one quarter rotations.

When the shuttle160reaches the proximal position, a user may continue to rotate the torque portion130to cause further rotation of the leadless pacemaker coupled to the handle108. However, because the shuttle160is substantially prevented from further advancement, such additional rotation causes stress on the threads250of the shuttle160and the partial helical thread portion185of the torque portion130and, as a result, increases resistance to rotation of the torque portion130. In certain implementations, further rotation of the torque portion130may result in reversible elastic deformation of one or both of the threads250and the helical thread portion185. If the number of additional rotations results in sufficient stress, one or both of the threads250and the helical thread portion185may plastically deform or otherwise fail. In cases of brittle failure of one or both of the threads250and the helical partial thread185, a substantial reduction in resistance to rotation of the torque portion130may occur. In cases of ductile failure, the tactile feedback may be felt by a user as a gradual decrease in resistance to rotation of the torque portion130. In either case, when sufficient failure has occurred, resistance to rotation of the torque portion130may be reduced to a nominal level as the threads250and the partial helical partial thread185(to the extent either remains after the failure) will be substantially disengaged.

The warning aspect of the rotation mechanism90ofFIG. 23may be adapted to provide controlled failure of either the threads250or the partial helical partial thread185in response to a particular torque applied using the torque portion130. By varying the structure, material, shape, or other aspects of the portion of the threads250or the partial helical partial thread185, failure and, as a result, feedback provided in conjunction with such failure may be controlled. For example, one or both of the materials of the thread250and the partial helical partial thread185may be selected to have a specific hardness, elastic modulus, or other material property related to failure. Alternatively or in addition to specific material selection, the thread250or the partial helical partial thread185may have a predetermined cross-section, thickness, or shape corresponding to a particular point of failure. Notably, the parameters used to modify the failure point of the thread250or the partial helical partial thread185may be applied to the thread250or the partial helical partial thread185in their entirety or may only correspond to a portion thereof. For example, as shown inFIG. 23, a known portion of the thread250may engage the partial helical partial thread185when the shuttle160is in the proximal position based on the geometry of components of the handle108. Accordingly, in certain implementations, only the known portion of the thread250may be formed of a particular material or have a particular geometry corresponding to achieve the desired failure point and rotational resistance profile.

F. Handle with Rotation Mechanism Employing a Bump and Compliant Shuttle

To begin a discussion of another embodiment of the rotation mechanism90of the handle108of the leadless pacemaker delivery system ofFIG. 1, reference is now made toFIGS. 24A-26.FIG. 24Ais an isometric view of the handle108with a portion of a housing125of the handle108removed to reveal the alternative rotation mechanism90enclosed therein.FIG. 24Bis a longitudinal cross-section of the rotation mechanism90in the region identified inFIG. 24Aand as taken along section line24B-24B inFIG. 24A.FIGS. 25 and 26are additional longitudinal cross-sections of the rotation mechanism90in the region identified inFIG. 24A.

As can be understood from a comparison ofFIG. 24A-26toFIGS. 1-18B, the alternative version of the rotation mechanism90and the surrounding elements of the handle108and leadless pacemaker delivery system ofFIGS. 24A-26share the majority of elements and operation as discussed above with respect toFIGS. 1-18B. With reference toFIGS. 13-18B, in particular, however, the O-ring300ofFIGS. 13-18Band relate retention structure has replaced by a bump500disposed on the shaft175and the rings295coupled to the shuttle160have been replaced by a pair of garter springs502,504extending around the shuttle160. Further, the shuttle160is a multi-part shuttle that includes at least two separate shuttle segments161,163. The springs155,165have also been omitted for clarity. Accordingly, the preceding discussion ofFIGS. 1-18Bis equally applicable to the version of the rotation mechanism90and surrounding elements of the handle108shown inFIGS. 24B-26, except as will now be specifically discussed with respect toFIGS. 24B-26.

As indicated inFIGS. 24A and 24B, the garter springs502,504extend circumferentially around a distal and proximal end of the shuttle160and are coaxial with, the shaft175of the torque portion130. The garter springs502,504exert an inward force on the shuttle160such that the shuttle segments161,163are made to abut each other and retain the overall shape of the shuttle160in a resting configuration. In certain implementations, the garter springs502,504may be retained within structures of the shuttle160such as between parallel circumferential flanges of the shuttle160or within grooves defined in the outer surface of the shuttle160. The garter springs502,504may be made of materials, such as, for example, metals or elastomeric polymers. In certain implementations one or both of the garter springs502,504may be replaced by an elastic band or similar compliant member shaped to extend around the shuttle160. Also, while illustrated inFIGS. 24A-25as including two garter springs502,504additional garter springs (or similar compliant) may be included.

As shown inFIG. 24B, the proximal end of the shaft175of the torque portion130includes a bump500or similar structure extending from the shaft175. The bump500may be integrally formed with the shaft175and may extend around all or part of the circumference of the shaft175. The bump500may have various shapes and sizes, however, as further discussed with respect toFIGS. 24B-26, below, the bump500generally extends from the shaft175such that as the shuttle160translates proximally along the shaft175, the bump500contacts a feature, such as a proximal edge260, a bump, a lip, or similar protrusion of the shuttle160. Further translation of the shuttle160causes the bump500to force the shuttle segments161,163apart, providing tactile feedback in the form of increased resistance to the user of the rotation mechanism90. In certain implementations, the bump500may be substituted with an O-ring or similar structure retained on the shaft175, such as illustrated inFIGS. 13-18B. In such implementations, the O-ring may function similarly to the bump500ofFIGS. 24-26Bby, among other things, resisting proximal translation of the shuttle160such that proximal translation of the shuttle160requires separation of the161,163. Deformation of the O-ring may also occur such that the increased rotational resistance provided to a user results from a combined effect of the O-ring deformation and the behavior of the garter springs502,504.

As shown inFIG. 24A, the shuttle160may include a proximal inner circumferential chamber310at the proximal end of the shuttle and a distal inner circumferential chamber315at the distal end of the shuttle. Each chamber310,315may include a pair of spaced-apart radially inwardly extending lips, bumps, or similar features. In the example ofFIG. 24A, these lips include an outer lip and an inner lip. Specifically, for the proximal chamber310, the outer lip is a proximal outer lip320at the proximal edge of the shuttle160, and the inner lip is a distal inner lip325distal the proximal outer lip320. The lips320,325are spaced-apart from each other and radially inwardly project from an inner cylindrical surface327of the proximal chamber310. For the distal chamber315, the outer lip is a distal outer lip330at the distal edge of the shuttle160, and the inner lip is a proximal inner lip335proximal the distal outer lip330. The lips330,335are spaced-apart from each other and radially inwardly project from an inner cylindrical surface337of the distal chamber315.

When the shuttle160is in the most distal location along the shaft175of the torque portion130of the handle108, the distal spring155(shown inFIGS. 13 and 14) is compressed between the distal ring295of the shuttle160and an interior wall135immediately proximal the ratchet assembly150. On account of the pitch direction of the helical partial thread185on the shaft175of the torque portion130, and despite the distal spring155biasing the shuttle proximally such that its distal rim265is kept in abutting contact with the thread185, the thread185of the shaft175does not engage the interior threads250of the shuttle160as long as the torque portion130is rotated counter-clockwise (CCW), the thread185simply riding along the distal rim265of the shuttle160. Thus, the torque portion130and the linear member120extending distally therefrom (as shown and discussed in the context ofFIG. 13), can infinitely rotate CCW and cause the leadless pacemaker102to rotate CCW, as can be understood fromFIG. 1, such that the helical anchor on the distal end of the leadless pacemaker will unscrew from cardiac tissue in which it may be imbedded. The CCW rotation causes the ratchet assembly150to generate an incremental/stepped tactile sensation in the grip180of the torque portion130of the handle108.

Conversely, on account of the pitch direction of the helical partial thread185on the shaft175of the torque portion130, and because the distal spring155(shown inFIGS. 13 and 14) biases the shuttle proximally such that its proximal rim265is kept in abutting contact with the thread185, the thread185of the shaft175engages the interior threads250of the shuttle160once the torque portion130is rotated clockwise (CW) and the shaft thread185encounters one of the multiple thread-start locations255intersecting the proximal rim265. Once threaded engagement occurs between the shaft thread185and the shuttle threads250, further CW rotation of the torque portion130will cause the shuttle160to proximally displace along the shaft175. As can be understood fromFIGS. 1 and 13, the CW rotation of the torque portion130and the linear member120extending distally therefrom rotates the leadless pacemaker102CW such that the helical anchor on the distal end of the leadless pacemaker will screw into cardiac tissue contacting the helical anchor. The CW rotation causes the ratchet assembly150to generate an incremental/stepped tactile sensation in the grip180of the torque portion130of the handle108.

Continued CW rotation of the torque potion130further proximally displaces the shuttle160along the shaft175as the shuttle threads250move proximally along the rotating shaft thread185, which is confined to rotation about the longitudinal axis of the shaft and does not displace distal-proximal. As the shuttle moves along the shaft, the shuttle guide members240linearly displace proximally along the respective guide slots270. In some embodiments where the guide slots270daylight through the exterior wall140of the housing125, the displacement of the shuttle guide members240can be observed through the windows created by the guide slots270in the exterior wall140of the housing125, similar to that discussed above with respect toFIGS. 2, 4 and 5.

As the CW rotation of the torque portion130causes the shuttle160to displace proximally from the most distal location, the tactile sensation and resistance felt in the grip180of the torque portion130will remain constant as provided by the ratchet assembly150until the shuttle160is sufficiently proximally displaced such that the proximal boundary of the proximal outer lip320, which is at the shuttle proximal edge260, encounters the bump500, as illustrated inFIGS. 24A and 24B. At this time, the resistance felt in the grip180of the torque portion130will begin to gradually increase as the radially inwardly projecting lip320travels across the bump500. More specifically, the bump500causes separation of the shuttle segments161,163, which is increasingly resisted by the proximal garter spring504as the separation increases.

In one embodiment, the number of CW rotations needed to displace the shuttle from a most distal position to the stopped position shown inFIGS. 24A and 24Bwill be two and one-quarter rotations of the grip180of the torque portion130of the handle108. This two and one-quarter rotations is based on what is considered to be a typical number of turns of the helical anchor of the leadless pacemaker to cause the helical anchor to fully imbed in the cardiac tissue without over-penetrating the cardiac tissue. In other embodiments, the number of rotations required to displace the shuttle between the most distal location and the location depicted inFIGS. 24A-24Bwill be more or less than two and one-quarter rotations.

Once the proximal boundary of the proximal outer lip320, which is at the shuttle proximal edge260, encounters the bump500, as illustrated inFIGS. 24A and 24B, this contact will notify the physician that the prescribed number of rotations of the helical anchor of the leadless pacemaker has been reached. At this point, should the physician decide additional CW rotations of the helical anchor of the leadless pacemaker are necessary to achieve a desired level of fixation to the cardiac tissue, as can be understood fromFIGS. 25-26, continued CW rotations of the grip180of the torque portion130of the handle108will continue to proximally displace the shuttle160and drive the radially inwardly projecting lip320at the shuttle proximal edge260completely over and proximally past the bump500such that the bump500is received in the proximal inner circumferential chamber310as indicated inFIG. 26.

In certain implementations, such as that illustrated inFIGS. 24A-26, the bump500may permit reversal of the shuttle160. For example, after the radially inwardly projecting lip320passes a peak of the bump500, the grip180may be rotated CCW to cause the shuttle160to translate in the distal direction. As the shuttle160distally translates, the bump500will again the shuttle160and, as the shuttle further translates, separation of the shuttle segments161,163, resulting in tactile feedback as previously described.

The warning aspect of the rotation mechanism90ofFIGS. 24A-26may be adapted to provide multiple and varying warnings to a physician in response to rotation of the leadless pacemaker. For instance, additional bumps500could be incrementally located along the shaft175proximal from a first bump such that each bump causes a change in the rotational resistance of the grip180. Such a sequence of bumps may be distributed along the shaft175such that each bump corresponds to a specific number of rotations of the leadless pacemaker. The shuttle160may also include multiple lips or similar features that contact and must pass over one or more bumps disposed along the shaft175. The shape of the bump500or lip of the shuttle160may also be altered to change the resistance encountered during rotation of the grip180. For example, the overall height of the bump500or lip may be increased or decreased to modify the peak rotational force required to overcome the bump500. Similarly, the length and slope of the bump500or lip may be altered to change the rate at which the rotational resistance of the grip180increases. Resistance to rotation of the grip180may also be modified by changing the inward force provided by the compliant members502,504to the shuttle segments161,163. For example, one or more of the material, thickness, quantity, and placement of the compliant members502,504may be modified to vary the resistance to rotation of the grip180provided by the compliant members502,504.

G. Handle with Rotation Mechanism Employing Elastomeric Bumper

To begin a discussion of yet another version of the rotation mechanism90of the handle108of the leadless pacemaker delivery system ofFIG. 1, reference is now made toFIG. 27, which is an isometric view of the handle108with a portion of a housing125of the handle108removed to reveal the alternative rotation mechanism90enclosed therein.

As can be understood from a comparison ofFIG. 27toFIGS. 13-14, the alternative version of the rotation mechanism90and the surrounding elements of the handle108and leadless pacemaker delivery system of the version ofFIG. 25share the majority of elements and operation as discussed above with respect toFIGS. 13-14, except that the springs155,165disposed between the shuttle160and the interior walls135have been removed and replaced with elastomeric bumpers490,495. Accordingly, the preceding discussion ofFIGS. 13-14is equally applicable to the version of the rotation mechanism90and surrounding elements of the handle108shown inFIG. 27, except as will now be specifically discussed with respect toFIG. 27.

As indicated inFIG. 27, a distal bumper490and a proximal bumper495are retained against distal and proximal interior walls135of the housing180. As shown inFIG. 25, each of the distal bumper490and the proximal bumper495extend circumferentially around, and are coaxial with, the shaft175of the torque portion130. The bumpers490,495are disposed between the shuttle160and corresponding distal and proximal internal walls135of the handle108such that as the shuttle160approaches its distal and proximal extents within the handle108, the distal and proximate bumpers490,495are compressed between the shuttle160and the distal and proximal internal walls135, respectively. In an alternative implementation, one or both of the distal bumper490and the proximal bumper495may instead be retained on distal and proximal ends of the shuttle160, respectively, and perform similar functions as described below. In still other implementations, the distal bumper490may be omitted.

When the shuttle160is in the most distal location along the shaft175of the torque portion130, the distal bumper490is compressed between the shuttle160and an interior wall135immediately proximal the ratchet assembly150. On account of the pitch direction of the helical partial thread185on the shaft175of the torque portion130, and despite the distal compliant member390biasing the shuttle160proximally such that its distal rim265(see, e.g.,FIGS. 8A and 8B) is kept in abutting contact with the thread185, the thread185of the shaft175does not engage the interior threads250of the shuttle160as long as the torque portion130is rotated counter-clockwise (CCW), the thread185simply rides along the distal rim265of the shuttle160. Thus, the torque portion130and the linear member120extending distally therefrom, as shown inFIG. 3, can infinitely rotate CCW and cause the leadless pacemaker102to rotate CCW, as can be understood fromFIG. 1, such that the helical anchor on the distal end of the leadless pacemaker will unscrew from cardiac tissue in which it may be imbedded.

Conversely, on account of the pitch direction of the helical partial thread185on the shaft175of the torque portion130, and because the distal compliant member390biases the shuttle160proximally such that its proximal rim265is kept in abutting contact with the thread185, the thread185of the shaft175engages the interior threads250of the shuttle160once the torque portion130is rotated clockwise (CW) and the shaft thread185encounters one of the multiple thread-start locations255intersecting the proximal rim265. Once threaded engagement occurs between the shaft thread185and the shuttle threads250, further CW rotation of the torque portion130will cause the shuttle160to proximally displace along the shaft175. As can be understood fromFIGS. 1 and 3, the CW rotation of the torque portion130and the linear member120extending distally therefrom rotates the leadless pacemaker102CW such that the helical anchor on the distal end of the leadless pacemaker will screw into cardiac tissue contacting the helical anchor. In certain implementations, the CW rotation causes the ratchet assembly150to generate an incremental/stepped tactile soft-stop sensation in the grip180of the torque portion130of the handle108.

As the CW rotation of the torque portion130causes the shuttle160to displace proximally from the most distal location, the tactile sensation and resistance felt in the grip180of the torque portion130will remain constant as provided by the ratchet assembly150until the shuttle160is sufficiently proximally displaced such that the proximal face of the shuttle160contacts the proximal bumper495, which is disposed adjacent a proximal interior wall135. Further CW rotation of the torque portion130causes compression of the proximal bumper495and, as a result, increased resistance to continued movement of the shuttle160in the proximal direction. Accordingly, a user of the rotation mechanism90receives an initial warning in the form of increased resistance to rotation of the torque portion130. After initial contact between the proximal compliant member195and the proximal internal wall135, a user of the rotation mechanism90may decide whether additional CW rotations of the helical anchor of the leadless pacemaker are necessary to achieve a desired level of fixation to the cardiac tissue. If additional CW rotations are applied, the rotational resistance provided by the proximal bumper495may increase accordingly.

Each of the bumpers490,495may be made of materials such as, for example, metals, compressible polymers, and/or etc. While depicted as being solid tubules in the implementation ofFIG. 27, the bumpers490,495are not limited to such a shape. For example, in certain implementations, the compliant member490,495may be helical springs or may include internal or external grooves, cutouts, or combinations thereof. In certain instances, the bumpers490,495may include multiple sections, each of which may be composed of a different material or have a different geometry. In light of the foregoing, the warning aspect of the rotation mechanism90ofFIG. 27may be adapted by modifying the material and structure of the bumpers490,495. For example, a high rotational resistance and a high rate of rotational resistance increase may be achieved by using bumpers composed of relatively stiff materials. Rotational resistance may also be modified by forming grooves or cutouts (including, without limitation, longitudinal, circumferential, and helical grooves or cutouts) on the bumper, with the relative spacing, depth, and width of the grooves or cutouts modifying the overall stiffness of the bumper.

H. Handle with Electronic Warning Mechanism

Reference is now made toFIGS. 28A-28Bwhich are cross-sectional side views of another version of a handle108with a portion of a housing125of the handle108removed to reveal a rotation mechanism90according to the present disclosure.

As can be understood from a comparison ofFIG. 27toFIGS. 1-27, the alternative version of the rotation mechanism90and the surrounding elements of the handle108and leadless pacemaker delivery system of the version ofFIGS. 28A-28Bshare the majority of elements and operation as discussed above with respect toFIGS. 1-27, except that the springs155,165disposed between the shuttle160and the interior walls135have been replaced with a distal bellows1005, and a proximal bellows1010, respectively. The version of the handle108shown inFIGS. 28A-28Bfurther incorporate electrical circuitry adapted to provide feedback to a user in response to the position of the shuttle160within the housing108. Accordingly, the preceding discussion ofFIGS. 1-27is equally applicable to the version of the rotation mechanism90and surrounding elements of the handle108shown inFIGS. 28A-28B, except as will now be specifically discussed with respect toFIGS. 28A-28B.

As indicated inFIGS. 28A-28B, a distal bellows1005and a proximal bellows1010are coupled to distal and proximate ends of a shuttle160, respectively. The handle108includes a torque portion130that, when rotated, causes rotation of a leadless pacemaker coupled to the handle108as well as translation of the shuttle160within the handle108. For example, in certain implementations, clockwise (CW) rotation of the torque portion130causes the shuttle160to move proximally while counterclockwise (CCW) rotation of the torque portion130causes the shuttle160to move distally. In certain implementations, the handle108may include a ratchet assembly (such as the ratchet assembly ofFIGS. 7A and 7Band previously discussed in this disclosure) that provides tactile feedback to a user of the handle108as the torque portion130is rotated. As previously described in this disclosure, other tactile feedback features may also be incorporated in the handle108to provide varying resistance to rotation of the torque portion130and tactile warnings to a user as the shuttle160translates within the housing108. In other implementations, the shuttle160may be substituted with an alternative body translatable within the housing108in response to rotation of the torque portion130.

As illustrated by the difference betweenFIGS. 28A and 28B, the proximal bellows1010is constructed into the handle108such that the proximal bellows1010compresses as the shuttle160approaches a proximal end of the handle108. Such translation also causes expansion of the distal bellows1005. Similarly, as the shuttle160is made to translate distally, the distal bellows1005is compressed and the proximal bellows1010expands. In certain implementations, the proximal bellows1010may be spring bellows such that as the proximal bellows1010is compressed, the amount of resistance to additional compression and, as a result, additional rotation of the torque portion130may be increased, thereby providing tactile feedback relative to the position of the shuttle160.

The handle108ofFIGS. 28A-28Bincludes electrical components adapted to determine the position of the shuttle160within the housing108and provide feedback to a user of the handle108. More specifically, the electrical components measure or otherwise determine the position of the shuttle160within the housing108relative to one or more predetermined shuttle positions corresponding to a number of rotations of the torque portion130. Feedback and warnings are then provided to a user based on the position of the shuttle160, such as through illumination of one or more LEDs1020visible to the user.

In the implementation illustrated inFIGS. 28A-28B, the handle108is communicatively coupled to a computing device (CPU)1015configured to send and receive signals to and from the handle108. In certain implementations, the computing device1015may be incorporated into the handle108. The computing device1015may include at least one processor and memory that includes instructions executable by the processor to receive signals from the handle108and to determine a position of the shuttle160based on the received signals. The computing device1015may then transmit signals to the handle108that cause appropriate feedback to be provided to the user. For example, such signals from the computing device1015may cause one or more LEDs1020to illuminate. In other implementations, the computing device1015may instead be replaced by other circuitry configured to activate one or more feedback devices based on the position of the shuttle160within the housing108. For example, in one implementation, such a circuit may include a switch coupled to a power source that, when closed by action of the shuttle160, causes an LED to illuminate.

In the implementation illustrated inFIGS. 28A-28B, each of the distal bellows1005and the proximal bellows1010are constructed of an electrically conductive material such that the resistance of the distal bellows1005ad the proximal bellows1010vary as the bellows1005,1010are compressed and expanded. The distal bellows1005and the proximal bellows1010are coupled to the computing device1015by a first lead1035and a second lead1040such that the computing device1015may monitor the resistances of the bellows1005,1010and determine a corresponding position of the shuttle160within the housing108. The computing device1015may also be coupled to the LEDs1020such that the computing device1015may illuminate one or more of the LEDs in response to the position of the shuttle160. For example, in one implementation, the LEDs may be color coded (e.g., green, yellow, red) to indicate the relative proximity of the shuttle160to a predetermined location within the housing108and the computing device1015may selectively illuminate the LEDs based on the position of the shuttle160.

In other implementations, switches, variable resistors, and other components may be used to determine the location of the shuttle160within the housing108. For example, one or more limit switches may be disposed along the housing108such that as the shuttle160translates within the housing108, the shuttle160closes the switches, indicating its position within the housing108. Switch elements may also be integrated into the distal or proximal bellows1005,1010such that the switches close in responses to the distal or proximal bellows1005,1010being compressed or expanded. Movement of the shuttle160within the housing108resulting from rotation of the torque portion130may also causes changes to a variable resistance element (e.g. a potentiometer) such that the position of the shuttle160may be determined in response to measuring the resistance of the variable resistance element.

The use of one or more LEDs as a warning mechanism is intended only as an example and other warning mechanisms may be used to alert a user when the shuttle106reaches a position within the handle108corresponding to a specific number of rotations. For example, the handle108may include other components adapted to produce other types of feedback, such as vibrations or audible signals, in response to the shuttle160reaching certain positions within the handle108that correspond to predetermined numbers of rotations of a leadless pacemaker. Such feedback may be progressive such that the character or intensity of the feedback may vary based on the proximity of the shuttle160to one or more of the predetermined positions. For example, the volume or tone of an audible feedback signal or the intensity of a vibration may increase as the shuttle160approaches a predetermined position. In still other implementations, the handle108may include a screen or display, such as a liquid crystal display (LCD), on which information may be provided to the user of the handle108. Such information may include, for example, a visual indicator or other visual indicator (including an actual number) corresponding to the number of rotations of the torque portion130of the handle108.

To facilitate use of the handle108illustrated inFIGS. 28A-28B, an internal or external power source may be included in or otherwise coupled to the handle108. For example, in certain implementations, the handle108may include a battery or similar internal power source which may be rechargeable and/or replaceable. Alternatively, the handle108may include a cord to electrically couple the handle108to an external power source, such as, without limitation, an external battery, a power pack, and a wall socket.

I. Example Feedback Profiles

FIGS. 27A-Iillustrate different feedback profiles that may be implemented in leadless pacemaker delivery systems according to the present disclosure. In general, each feedback profile shows the resistance to rotation of a component of the leadless pacemaker delivery systems, such as the torque portion130of the handle108, relative to the rotational position of the component. The example feedback profiles are intended as examples only and are not intended to limit the types of feedback profiles that may result from implementations of the present disclosure.

For purposes of this discussion, rotation is assumed to be applied by a user to a torque portion, such as torque portion130, of a leadless pacemaker delivery system in accordance with this disclosure.

FIG. 29Ais a first feedback profile illustrating one full rotation of a torque portion of a first leadless pacemaker delivery system. As shown inFIG. 29A, a base rotational resistance is provided over the majority of the rotation, however, as a full rotation nears completion, the rotational resistance rises exponentially and continues to increases the more a full rotation is exceeded.

FIG. 29Bis a second feedback profile illustrating two full rotations of a torque portion of a second leadless pacemaker delivery system. As shown inFIG. 29B, a based rotational resistance is provided for the majority of each rotation, however, the rotational resistance is periodically increased to indicate every half rotation (i.e., every 180 degrees).

FIG. 29Cis a third feedback profile illustrating one full rotation of a torque portion of a third leadless pacemaker delivery system. Similar to the feedback profile illustrated inFIG. 29A, a base rotational resistance is provided over the majority of the rotation, however, as a full rotation nears completion, the resistance rises to provide an indication of the rotation to a user. In contrast to the feedback profile ofFIG. 29A, additional rotation of the rotational resistance causes the rotational resistance to fall back to the base rotational resistance.

FIG. 29Dis a fourth feedback profile illustrating one full rotation of a torque portion of a fourth leadless pacemaker delivery system. Similar to the feedback profile illustrated inFIG. 29C, a base rotational resistance is provided over the majority of the rotation, however, as a full rotation nears completion, the resistance rises to provide an indication of the rotation to a user. In contrast to the feedback profile ofFIG. 29D, the increased rotational resistance is maintained for approximately one quarter rotation before returning to the base rotational resistance.

FIG. 29Eis a fifth feedback profile illustrating two full rotations of a torque portion of a fifth leadless pacemaker delivery system. Similar to the feedback profile illustrated inFIG. 29D, a base rotational resistance is increased and maintained as a first rotation is completed. The increased rotational resistance is maintained for approximately one half turn before returning to the base rotational resistance. A second increase in the rotational resistance then occurs in response to the completion of a second rotation.

FIG. 29Fis a sixth feedback profile illustrating one full rotation of a torque portion of a sixth leadless pacemaker delivery system. The feedback profile illustrated inFIG. 29Fcombines aspects of the feedback profiles ofFIG. 29Aand that ofFIG. 29D. More specifically, a base rotational resistance is increased in response to completion of a first rotation. The increased rotational resistance is then maintained for approximately one quarter rotation before the rotational resistance continues to increase exponentially.

FIG. 29Gis a seventh feedback profile illustrating one full rotation of a torque portion of a seventh leadless pacemaker delivery system. Similar to the feedback profile illustrated inFIG. 29D, a base rotational resistance is increased and maintained as a first rotation is completed. The increased rotational resistance is maintained for approximately one half turn before returning to the base rotational resistance. However, the feedback profile ofFIG. 29Gfurther includes a brief increase in rotational resistance at approximately three quarter rotations. Accordingly, the brief increase may server as a preliminary indication that a full rotation is near completion.

FIG. 29His an eighth feedback profile illustrating one full rotation of a torque portion of an eighth leadless pacemaker delivery system. In contrast to the previous feedback profiles ofFIGS. 29A-29G, the eighth feedback profile includes a decrease in rotational resistance from a base rotational resistance to a reduced rotational resistance in response to completing a full rotation.

The foregoing example feedback profiles were described in the context of one or two full rotations for clarity only. Accordingly, the illustrated feedback profiles or variations thereof may be modified such that they occur over a quantity of rotations other than one or two full rotations. For example and as previously disclosed in the context ofFIGS. 10A-11B, fixation of a leadless pacemaker into cardiac tissue may generally require two and one quarter rotations. As a result, the foregoing feedback profiles may be offset or modified to include a change in rotational resistance corresponding to two and one quarter rotations or otherwise be based around a two and one quarter rotation target.

While the above-described rotation mechanism and its various warning mechanisms are discussed in the context of a leadless pacemaker delivery device, those skilled in the art will readily understand that the rotation mechanism and its various warning mechanisms may be employed with other medical devices such as, for example, minimally invasive surgery (MIS) tools, including for example, endoscopic devices, laparoscopic devices, and similar devices. The rotation mechanism and its various warning mechanisms may be employed with tools for the delivery and fixation of a standard implantable lead, for the delivery, fixation and/or actuation of other implantable devices. Example of actuating an implanted devices include turning on an implantable device, opening a valve, causing a device to change states, etc., wherein any of these actuations or operational settings may be achieved via rotation of an element of the implanted device via the above-described rotation mechanism, and the rotation should be measured to prevent damage to the device and/or body tissue, the measured rotation being made possible via the warning mechanisms described herein.

The foregoing merely illustrates the principles of the invention. Various modifications and alterations to the described embodiments will be apparent to those skilled in the art in view of the teachings herein. It will thus be appreciated that those skilled in the art will be able to devise numerous systems, arrangements and methods which, although not explicitly shown or described herein, embody the principles of the invention and are thus within the spirit and scope of the present invention. From the above description and drawings, it will be understood by those of ordinary skill in the art that the particular embodiments shown and described are for purposes of illustrations only and are not intended to limit the scope of the present invention. References to details of particular embodiments are not intended to limit the scope of the invention.