Electrothermally controlled coupling system for leadless implantable medical devices

Abstract

A detachable leadless pacemaker device includes a housing containing at least one electrical component and a coupler attached to the housing. The coupler includes a first segment and a second segment. A liquid crystal elastomer (LCE) member is coupled between the first segment and the second segment. The LCE member has a first length at a first temperature and a second length at a second temperature. The second length is shorter than the first length, and the second temperature is higher than the first temperature. The device may further include an anchor configured to be attached to an organ-tissue of a patient.

Description

ELECTROTHERMALLY CONTROLLED COUPLING SYSTEM FOR LEADLESS IMPLANTABLE MEDICAL DEVICESCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is claims priority to U.S. Provisional Patent Application 63 / 610,951 filed December 15, 2023, the entire contents of which are incorporated herein by reference.BACKGROUND

[0002] Implantable medical devices, such as pacemakers, are used in various medical fields and play a vital role in saving millions of lives every year. Implantable cardiac pacemakers, cardiac defibrillators, coronary' stents, implantable insulin pumps, cochlear implants, gastric stimulators are some examples of implantable medical devices.

[0003] Pacemakers are one example of miniaturized medical devices which are small enough to be inserted into heart chambers. Many types of pacemaker devices have been developed, such as single chamber asynchronous pacemakers, dual-chamber programmable synchronous pacemakers and, leadless pacemakers (LPMs). A traditional pacemaker is a pacing system which may’ include two parts: a pulse generator and leads. The pulse generator is implanted under the skin, most commonly in the chest. The leads are implanted with the pulse generator to carry' electrical impulses from the pulse generator to the heart and then relay information about the heart's natural activity back to the pulse generator. After the implant and during checkups a healthcare professional (e.g., a doctor) may use a programmer. A programmer is a specially-designed computer made to communicate with the pulse generator. The programmer may be used for adjusting and customizing pacemakers to patient needs.

[0004] FIG. 1A shows an example embodiment of a traditional pacemaker and a schematic diagram of a pacemaker disposed next to the heart and including an electrode disposed inside the heart to pace the heart. The primary' body containing electronics and battery' is placed under the skin at the chest area, and two or more electrodes are passed through veins to the heart chambers from the primary body. Traditional pacemakers may be uncomfortable since they are large in size and contain long electrodes.

[0005] Unlike traditional pacemakers, leadless pacemakers (LP) reside entirely in the heart. That means there are no leads, no chest incisions, and no permanent pocket under the skin. A catheterthat contains the LP may be passed through a small incision in the groin and threaded into the heart using a minimally invasive procedure where the LP is then secured into the interior wall muscle of your heart. After the implant and during checkups, the doctor will use a programmer to communicate with the pulse generator of the leadless pacemaker. FIG. IB shows an example embodiment of a leadless pacemaker and a schematic diagram of a pacemaker disposed inside the heart. As shown, the leadless pacemaker is completely included inside the heart.

[0006] In contrast with the traditional pacemakers, the latest leadless pacemakers like transcatheter pacing system (TPS) (e.g., the MICRA transcatheter pacing system from Medtronic of Dublin, Ireland) and leadless cardiac pacemakers (e.g., the NANOSTIM pacemaker system of St. Jude Medical Inc. of St. Paul, MN), are very' small, around 26-42 mm in length, just 1 cm3in volume, and very' lightweight of only 2g versus 21.5 g of traditional pacemakers. These LPs are directly placed inside the heart chambers, and hence they do not require long electrodes. These LPs may have a longer battery life of 7-15 years due to the miniaturization of the electronics.

[0007] While leadless pacemakers have proven their advantages when compared to traditional pacemakers, there are still problems to be solved and challenges associated with leadless pacemakers and there is significant room for improvement.

[0008] For example, the reduced size of the LPs also imposes size restrictions for the battery as power source. Reduced battery’ size may mean that batteries do not last as long as a patient may need the LPs. A patient may need to wear a pacemaker for long time periods such as 20 years to 40 years. Since the batteries may last only for a couple of years (e.g. 10 years, 8 years, 5 years), the LPs (or part of the LPs) will need to be replaced several times during a patient’s life.

[0009] Removal of implantable device can cause severe damage to the tissue where it is attached. For example, organ tissue may attach to the implantable device and may be ripped off the organ together with the implantable device when the device is removed. For example, FIG. 2 shows a photograph of a leadless pacemaker removed from a patient's heart. Cardiac tissue and / or muscle has been removed (ripped off) together with the pacemaker. Such removal of cardiac tissue obviously damages the heart. If the cardiac pacemaker needs to be removed several times (e.g. every' 7 years, to change the battery ) from the heart, and every' time part of the cardiac tissue is ripped off, the damage to the heart can be significant.

[0010] Therefore, devices and systems that address challenges associated with leadless are needed.SUMMARY

[0011] According to one implementation, a detachable leadless pacemaker (DLP) is disclosed. The DLP includes a housing, a coupler, and an anchor. The housing contains at least one electrical component. The coupler is attached to the housing. The coupler includes a liquid crystal elastomer (LCE) member configured to move between an expanded configuration and a contracted configuration. The LCE member has a first length at a first temperature and a second length at a second temperature. The second length is shorter than the first length. The second temperature is higher than the first temperature.

[0012] In some implementations, the coupler further comprises a first segment having a first end and a second end and a second segment having a first end and a second end, wherein the LCE member is coupled to each of the first and second segments.

[0013] In some implementations, the LCE member is coupled between the second ends of the first and second segments and configured to selectively move the second ends of the first and second segments further apart from each other or closer to each other.

[0014] In some implementations, the detachable leadless pacemaker further includes an anchor configured to be attached to an organ-tissue of a patient. In some implementations, the anchor includes at least one sidewall defining a chamber with an opening on a first end. The anchor further includes at least one protrusion extending radially inward from the at least one sidewall adjacent to the first end to partially define the opening.

[0015] In some implementations, the first end of the first segment is pivotably coupled to a first portion of the coupler and the first end of the second segment is pivotably coupled to the first portion of the coupler.

[0016] In some implementations, the first length of the LCE member at the first temperature corresponds to an expanded distance between the second ends of the first and second segments of the coupler. A size of the opening of the anchor is less than the expanded distance such that the first and second segments are not insertable into the chamber of the anchor when the LCE member is at the first length and the first temperature.

[0017] In some implementations, the second length of the LCE member at the second temperature corresponds to a contracted distance between the second ends of the first and second segments of the coupler. A size of the opening of the anchor is greater than the contracted distance such that the first and second segments are insertable into the chamber of the anchor when the LCE member is at the second length and the second temperature.

[0018] In some implementations, the first temperature is approximately human body temperature. In some implementations, the first temperature is approximately 37 degrees Celsius and the second temperature is at least 50 degrees Celsius.

[0019] In some implementations, the first length of the LCE member is approximately 20% longer than the second length.

[0020] In some implementations, the coupler is detachably couplable to the anchor via the opening of the anchor.

[0021] In some implementations, the anchor further includes a hook extending from a second end of the anchor opposite the first end. In some implementations, the hook of the anchor includes a spiral structure with a sharp needle tip at a distal end thereof.

[0022] In some implementations, the first portion of the coupler is a hinge connector, wherein the first ends of the first and second segments are pivotably coupled to the hinge connector.

[0023] In some implementations, the first ends of the first and second segments are rotatable to increase or decrease an angle between the first and second segments.

[0024] In some implementations, the at least one protrusion of the anchor is configured to retain the first and second segments of the coupler within the chamber of the anchor when the LCE element is cooled to the first temperature and expands to the first length.

[0025] In some implementations, the detachable leadless pacemaker further includes a heater in thermal communication with the LCE element, wherein the heater is further in electrical communication with the at least one electrical component.

[0026] In some implementations, the at least one electrical component includes a controller in communication with the heater, wherein the controller is configured to deliver instructions to activate and deactivate the heater.

[0027] In some implementations, the at least one electrical component includes one or more of: a battery, an electrical signal / pulse generator, a sensor, a controller and / or programmable logic, and a signal transmission device.

[0028] In some implementations, the LCE member includes an electrothermally controlled liquid crystal elastomer.

[0029] According to another implementation, a method for implanting a detachable leadless pacemaker (DLP) is disclosed. The method includes providing an anchor attached to an organtissue. The anchor includes at least one sidewall defining a chamber with an opening on a first end and at least one protrusion extending radially inward from the at least one sidew all adjacent to the first end to partially define the opening. The anchor further includes a hook disposed on a second end of the anchor opposite the first end, the hook configured to engage with and couple to the organ-tissue. The method further includes providing a detachable leadless pacemaker (DLP) including a housing containing at least one electrical component and a coupler attached to the housing. The coupler includes a first segment having a first end pivotably coupled to a first portion of the coupler, a second segment having a first end pivotably coupled to the first portion of the coupler, and a liquid crystal elastomer (LCE) member coupled between a second end of the first segment and a second end of the second segment. The LCE member has a first length at a first temperature and a second length at a second temperature, wherein the second length is shorter than the first length, and wherein the second temperature is higher than the first temperature. The method further includes heating the LCE member to the second temperature to contract the LCE member from the first length to the second length, wherein the second ends of the first and second segments of the coupler are moved from an expanded distance to a contracted distance corresponding to the second length of the LCE member. The method further includes inserting the first and second segments of the coupler into the chamber of the anchor via the opening. The method further includes cooling the LCE member from the second temperature toward the first temperature to expand the LCE member from the second length toward the first length, wherein the second ends of the first and second segments of the coupler are moved from the contracted distance toward the expanded distance corresponding to the first length of the LCE member.

[0030] In some implementations, the detachable leadless pacemaker further includes a heater adjacent to the LCE member, the heater being in communication with the at least one electrical component, wherein activation of the heater is performed via remote communication with the at least one electrical component.

[0031] In some implementations, a method for removing a detachable leadless pacemaker is disclosed. The method includes providing an anchor attached to an organ-tissue, the anchor including at least one sidewall defining a chamber with an opening on a first end and at least one protrusion extending radially inward from the at least one sidewall adjacent to the first end to partially define the opening. The anchor further includes a hook disposed on a second end of the anchor opposite the first end, the hook configured to engage with and couple to the organ-tissue. The method further includes providing a detachable leadless pacemaker (DLP) including a housing containing at least one electrical component and a coupler attached to the housing. The coupler includes a first segment having a first end pivotably coupled to a first portion of the coupler, a second segment having a first end pivotably coupled to the first portion of the coupler, and a liquid crystal elastomer (LCE) member coupled between a second end of the first segment and a second end of the second segment. The LCE member has a first length at a first temperature and a second length at a second temperature, wherein the second length is shorter than the first length, wherein the second temperature is higher than the first temperature. The first and second segments are disposed within the chamber of the anchor so that the coupler is coupled to the anchor. The method further includes heating the LCE member to the second temperature to contract the LCE member from the first length to the second length, wherein the second ends of the first and second segments of the coupler are moved from an expanded distance to a contracted distance corresponding to the second length of the LCE member. The method further includes removing the first and second segments of the coupler from the chamber of the anchor via the opening such that the coupler is decoupled from the anchor.

[0032] In some implementations, the detachable leadless pacemaker further includes a heater adjacent to the LCE member, the heater being in communication with the at least one electrical component, wherein activation of the heater is performed via remote communication with the at least one electrical component.

[0033] This summary is illustrative only and is not intended to be in any way limiting. Other aspects, features, and advantages of the devices or processes described herein will becomeapparent in the detailed description set forth herein, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements.BRIEF DESCRIPTION OF DRAWINGS

[0034] The systems, methods, and devices are explained in even greater detail in the following drawings. The drawings are merely exemplary and certain features may be used singularly or in combination with other features. The draw ings are not necessarily draw n to scale.

[0035] FIG. 1 A shows an example embodiment of a traditional pacemaker along with a diagram show ing the pacemaker heart placement.

[0036] FIG. IB shows an example embodiment of a leadless pacemaker along with a diagram showing the leadless pacemaker heart placement.

[0037] FIG. 2 shows an image of a leadless pacemaker after extraction from a heart with damaged tissue visible, according to one implementation.

[0038] FIGS. 3A-3C show various views and positions of a detachable leadless pacemaker, according to one implementation.

[0039] FIGS. 4A and 4B show the operation and change of configurations of a detachable leadless pacemaker, according to one implementation.

[0040] FIGS. 5A-5D show the operation and change of configurations of a detachable leadless pacemaker, according to another implementation.

[0041] FIG. 6A shows a graph of material properties of a liquid crystal elastomer (LCE) showing temperature vs. heat flow measured by differential scanning calorimetry, according to one implementation.

[0042] FIG. 6B shows an electrothermal response of a liquid crystal elastomer (LCE) film for a detachable leadless pacemaker (DLP), according to one implementation.

[0043] FIG. 6C shows the installation of an experimental pacemaker by a liquid crystal elastomer (LCE) assembled clamp, according to one implementation.

[0044] FIG. 6D shows the differential length of a liquid crystal elastomer (LCE) sample on a ruler, according to one implementation.

[0045] FIG. 7 shows example mechanical properties of a detachable leadless pacemaker including a graph of a tensile test of a 3D printed device along with images of example devices after a test, according to various implementations.DETAILED DESCRIPTION

[0046] Following below are more detailed descriptions of concepts related to, and implementations of, methods, apparatuses, and systems for a detachable leadless pacemaker (DLP). The figures illustrate exemplary implementations in detail and the present disclosure is not limited to the details or methodology set forth in the description or illustrated in the figures. The terminology used herein is for the purpose of description only and should not be regarded as limiting.

[0047] Implantable-devices are described hereinafter with reference to the drawings. According to some implementations, a leadless implantable-device (e.g., a leadless pacemaker) may include a first-body-portion (also referred herein as a ‘‘detachable leadless pacemaker” or DLP) and a second-body-portion (also referred herein as an “anchor”). According to some implementations, a leadless implantable-device (e.g., a leadless pacemaker) may be a detachable leadless pacemaker (DPLM) that includes, or is couplable to, a corresponding anchor.

[0048] The DLP may include an electrical-component and a coupling-system. The electricalcomponent may further include one or more of the following: a battery, an electrical signal / pulse generator, one or more sensors, a heater configured to control the temperature of the DLP and / or its components, a controller and / or programmable logic, and a signal transmission device. The heater may be an electrical heater including a heating element such as an electrical coil or a circuit. The pulse generator is configured to deliver electrical stimulation via one or more electrodes. The programmable logic may be programmed to control operation of the pulse generator, for example, to regularize the abnormal pacing of the subject's heart. Pacemaker device electronics and electrical stimulation via electrodes are well known in the art and therefore not described in furtherdetail herein. The DLP may further include a housing configured to house one or more of the components of electrical-component.

[0049] The DLP may have a size comparable with commercially available leadless pacemakers. For example, the DLP may be between 20mm and 50mm in length and between 4mm and 10mm in diameter. It should be understood that the dimensions of the DLP depend on a number of factors including, but not limited to, medical needs of the patient, materials and / or manufacturing techniques (e.g., machining, three-dimensional printing, etc ).

[0050] The coupling-system may be attached to the DLP. The coupling-system may be configured to be attached to the anchor, thereby attaching the DLP to the anchor. The couplingsystem may be configured to be decoupled from the anchor, thereby detaching the DLP from the anchor. The DLP, the anchor, and the coupling system are configured to enable the attaching of the DLP to the anchor and to enable the detaching of the DLP from the anchor. The DLP, the anchor, and the coupling system may be considered components of the same device or system.

[0051] The anchor may be configured to anchor (or couple) to a surface of the patient's heart at an attachment location (e.g., attached to tissue within a chamber of the heart). The anchor may be attached to the heart tissue at an attachment location. The anchor may include a hook or a spiralstructure with a sharp needle at its distal end. However, it should be understood and appreciated that the present disclosure is not limited only to implementations in which the anchor includes a spiral structure or spiral "hook"; rather, the anchor may include other structures or configurations of structures (not shown) for anchoring to a surface of the subject’s heart. The spiral structure may be configured to hook (e.g., by twisting the anchor-part) into the myocardium of the subject's heart chamber such that the anchor is anchored to a surface of the subject's heart.

[0052] As shown in FIGS. 3A-3C, a detachable leadless pacemaker (DLP) 100 is shown, according to one implementation. Specifically, FIGS. 3A and 3B show' a front view of the DLP 100, and FIG. 3C show s a side view of the DLP 100 without the anchor. The DLP 100 includes a housing 102. a coupler 110, and an anchor 150.

[0053] The housing 102 of the DLP 100 includes a first end 104 and a second end 106 opposite and spaced apart from the first end 104 along a central longitudinal axis 101. The housing 102 contains at least one electrical component (not shown). The at least one electrical component may include one or more of a battery, an electrical signal / pulse generator, a sensor, a controller and / orprogrammable logic, and / or a signal transmission device, for example. In general, the at least one electrical component within the housing 102 may include standard pacemaker electronics.

[0054] The coupler 110 extends from the second end 106 of the housing 102. Specifically, the coupler 110 includes a support member 112 extending longitudinally from the second end 106 of the housing 102. The coupler 110 further includes a first segment 120, a second segment 130, and a liquid crystal elastomer (LCE) member 140.

[0055] The first segment 120 includes a first end 122 and a second end 124 opposite and spaced apart from the first end 122. The first end 122 of the first segment 120 is pivotably coupled to a first portion of the coupler 110. Specifically, the first end 122 of the first segment 120 is pivotably coupled to a hinge connector 114 coupled to the support member 112. In some implementations, the hinge connector is a pin disposed within an opening defined by and extending through the first end of the first segment and the support member.

[0056] The second segment 130 includes a first end 132 and a second end 134 opposite and spaced apart from the first end 132. The first end 132 of the second segment 130 is pivotably coupled to a first portion of the coupler 110. Specifically, the first end 132 of the second segment 130 is pivotably coupled to the hinge connector 114 coupled to the support member 112.

[0057] Thus, the first end 132 of the second segment 130 and the first end 122 of the first segment 120 are both pivotably coupled to the same point on the coupler 110. The first and second segments 120, 130 are rotatable to increase or decrease an angle between the first and second segments 120, 130. In some implementations, the first and second segments are coupled to each other at the pivot point.

[0058] The LCE member 140 is coupled to and extends between the second end 124 of the first segment 120 and the second end 134 of the second segment 130. The LCE member 140 has an adjustable geometry based on its internal material properties (e.g., the polymer crystal structure) as further described herein. The LCE member 140 may be an electrothermally controlled liquid crystal elastomer.

[0059] The LCE member 140 has a first length (e.g.. an expanded length) as shown in FIG. 3A. The first length of the LCE member 140 is provided at a first temperature of the LCE member 140. In some implementations, the first temperature is room temperature. In some implementations, thefirst temperature is human body temperature (e.g., approximately 37°C). In some implementations, the first temperature is in a range between room temperature and human body temperature. The first length of the LCE member 140 at the first temperature corresponds to an expanded distance between the second ends 124, 134 of the first and second segments 120, 130 of the coupler 110.

[0060] The LCE member 140 has a second length (e.g., a contracted length) as shown in FIG. 3B. The second length is shorter than the first length of the LCE member 140. In some implementations, the first length of the LCE member is approximately 20% longer than the second length. The second length of the LCE member 140 at the second temperature corresponds to a contracted distance between the second ends 124, 134 of the first and second segments 120 ,130 of the coupler 110.

[0061] The second length of the LCE member 140 is provided at a second temperature of the LCE member 140. The second temperature is higher than the first temperature. In some implementations, the second temperature is at 10 or more degrees above the first temperature. In some implementations, the second temperature is at least 50°C. Thus, heating of the LCE member 140 decreases the length of the LCE member 140. Correspondingly, cooling of the LCE member 140 increases the length of the LCE member 140.

[0062] The anchor 150 of the DLP 100 includes a first end 152 and a second end 154 opposite and spaced apart from the first end 152. The anchor 150 includes at least one sidewall 160 (e.g., a cylindrical sidewall). The at least one sidewall 160 defines a chamber 156 with an opening 158 on the first end 152.

[0063] The anchor 150 further includes at least one protrusion 162 extending radially inward from the at least one sidewall 160. Specifically, the at least one protrusion 162 includes two protrusions disposed adjacent to the first end 152 of the anchor 150. The at least one protrusion 162 partially defines the opening 158 of the chamber 156.

[0064] The anchor 150 further includes a hook 164 extending from the second end 154 of the anchor 150. The hook 164 is a spiral structure having a sharp needle tip at a distal end thereof. The hook 164 is configured to engage with and couple to a tissue or other structure. Thus, the anchor 150 is configured to be attached to an organ-tissue of a patient via the hook 164. For example, the anchor 150 may be coupled to a portion of cardiac tissue permanently or semi-permanently.

[0065] In general, the coupler 110 and the housing 102 attached thereto are removably couplable to the anchor 150. For example, the detachable portion of the DLP 100 - including the housing 102 and the coupler 110 - may be coupled to the anchor 150 for a period of time (e.g., a few years) before being removed and replaced with another similar detachable portion of a DLP 100.

[0066] The coupler 110 is movable between two configurations based on the length of the LCE member 140. As shown in FIG. 3A, the first length of the LCE member 140 at the first temperature corresponds to the expanded distance between the second end 124 of the first segment 120 and the second end 134 of the second segment 130. The size of the opening 158 of the chamber 156 of the anchor 150 (e.g., a diameter thereof) is less than the expanded distance between the second ends 124, 134 of the first and second segments 120, 130. Thus, the first and second segments 120, 130 are not insertable into the chamber 156 when the LCE member 140 is at the first length and the first temperature.

[0067] As shown in FIG. 3B, the second length of the LCE member 140 at the second temperature corresponds to the contracted distance between the second end 124 of the first segment 120 and the second end 134 of the second segment 130. The size of the opening 158 of the chamber 156 of the anchor 150 is greater than the contracted distance between the second ends 124, 134 of the first and second segments 120, 130. Thus, the first and second segments 120, 130 are insertable into the chamber 156 via the opening 158 when the LCE member 140 is at the second length and the second temperature.

[0068] FIGS. 4A and 4B show diagrams of the insertion and coupling process of the anchor 150 and the coupler 110 attached to the housing 102. Specifically, FIG. 4A shows the movement of the LCE member 140 from the first length at the first temperature to the second length at the second temperature. The application of heat to the LCE member 140 contracts the length of the LCE member 140.

[0069] As the LCE member 140 contracts in length, the first segment 120 and second segment 130 coupled to the LCE member 140 pivot about the hinge connector 114. The overall diameter or width of the coupler 110 measured from the first segment 120 to the second segment 130 is reduced as the LCE member 140 contracts and moves the second ends 124, 134 of the first and second segments 120, 130 toward each other. Thus, in the second panel of FIG. 4A (post-heatapplication), the first segment 120 and the second segment 130 of the coupler 110 are insertable into the chamber 156 of the anchor 150.

[0070] As the LCE member 140 cools from the heated, second temperature back toward the first temperature, the LCE member 140 expands in length. This operation is shown in FIG. 4B. The first segment 120 and second segment 130 coupled to the LCE member 140 pivot about the hinge connector 114 in an opposite direction corresponding to the expanding LCE member 140. Thus, the second ends 124. 134 of the first and second segments 120, 130 move away from each other toward the expanded distance.

[0071] Once the LCE member 140 and the second ends 124, 134 of the first and second segments 120, 130 are expanded via cooling of the LCE member 140, the at least one protrusion 162 retains the majority of the coupler 110 within the chamber 156. Specifically, the second ends 124, 134 of the first and second segments 120, 130 are spaced apart by a distance larger than that of the opening 158 partially defined by the at least one protrusion 162. Therefore, the housing 102 and coupler 110 cannot be pulled away from the anchor 150 because the second ends 124, 134 of the first and second segments 120, 130 abut the at least one protrusion 162 of the anchor 150.

[0072] In some implementations, the inner diameter or width of the chamber 156 and / or the at least one sidewall 160 is smaller than the expanded distance of the second ends 124, 134 of the first and second segments 120, 130. Therefore, in some implementations when the LCE member 140 cools to expand its length, the second ends 124, 134 of the first and second segments 120, 130 move away from each other towards, but not to, the expanded distance. In such an implementation, second ends 124, 134 of the first and second segments 120, 130 may abut the inner surfaces of the at least one sidewall 160. preventing further expansion. However, the second ends 124, 134 of the first and second segments 120, 130 are spaced apart a distance greater than the width of the opening 158 that is at least partially defined by the at least one protrusion 162. Thus, the first and second segments 120, 130 are retained within the chamber 156 of the anchor 150.

[0073] In some implementations, the temperature of the LCE member 140 in the coupled configuration (e.g., in the second panel of FIG. 4B) is higher than the temperature of the LCE member 140 in the initial, un-implanted configuration (e.g., in the first panel of FIG. 4A). For example, in the initial configuration before implantation, the LCE member 140 may be at room temperature. Then, when the LCE member 140 is heated to a second, higher temperature tocontract its length, the coupler 110 is coupled to the anchor 150 that is implanted within a patient (e.g., in a portion of cardiac tissue). Thus, when the LCE member 140 cools from the heated, second temperature toward the first temperature, the LCE member 140 may only cool to human body temperature - not back to room temperature. However, the LCE member 140 is configured such that human body temperature is a sufficiently cool temperature to ensure expansion of the LCE member 140 at or near the expanded, first length.

[0074] In some implementations, the housing 102 and the at least one electrical component therein includes a heater that is in thermal communication with the LCE member 140. In some implementations, the DLP 100 includes a heater that is adjacent to the LCE member 140. In some implementations, heating the heater and / or the LCE member is accomplished via remote communication with the heater or an electrical component coupled thereto. For example, a healthcare professional may operate a controller or programmable device to (i) communicate with the DLP 100 and (ii) activate and / or deactivate the heater.

[0075] In some implementations, the LCE member is attached to a portion of the coupler and configured to expand and contract to couple with the anchor. In other words, some implementations of the detachable leadless pacemaker do not include the first and second segments, but the LCE member itself contracts to fit within the opening of the anchor and expands to lock the coupler onto the anchor. In some implementations, the first and second segments are movable via the LCE member but are not pivotably movable with respect to the coupler (e.g., linearly movable).

[0076] FIGS. 5A-5D show another implementation of a detachable leadless pacemaker (DPLM) that is substantially similar to the DLP 100 of FIGS. 3A-4B. Thus, like reference numbers denote like elements between the figures.

[0077] FIG. 5 A shows an initial, uncoupled state wherein the LCE member 140 is in the expanded state. FIG. 5B shows the contracted state wherein the LCE member 140 has been heated to contract its length and pivot the first and second segments 120, 130 radially inward.

[0078] FIG. 5C shows the contracted state of the coupler 110 and associated elements inserted into the chamber 156 of the anchor 150. FIG. 5D shows the LCE member 140 cooled to an expanded length, wherein the at least one protrusion 162 retains the first and second segments 120, 130 within the chamber 156 of the anchor 150.Examples and Experimental Results

[0079] As one approach in medical areas, solid components connection is widely utilized to assemble conventional life supporting and monitoring devices such as pacemakers, dialyzers and blood sugar monitoring systems. However, due to the high power consumption and operational complexities, the traditional medical devices are shifting towards miniaturized implantable medical devices (IMDs) which can make patients' daily lives more comfortable. One striking example of IMDs is leadless the pacemaker, which is installed directly inside a heart chamber and is powered by a battery. When the battery completely drains out, either the whole equipment is replaced, or it is charged wirelessly. However, both strategies bring their own disadvantages. For example, the replacement process usually damages the human tissue, while the wirelessly chargeable device is not compatible with magnetic resonance imaging (MRI) measurements. Thus, one of the major challenges associated with leadless pacemakers is management of the device in case of battery depletion or components failure during long-term usage.

[0080] Currently, tw o popular methods are used to resolve this challenge. This first one involves turning the device off remotely and leaving it inside the heart permanently. However, this can result in multiple devices remaining within a single chamber of the heart, which cannot be medically favorable. The second method is the extraction of the device from the heart, which is not a safe and simple procedure, and the extraction may cause severe damage to cardiac tissues (see, e.g.. FIG. 2).

[0081] To address these concerns, the disclosed implantable medical device includes two separate parts: A main portion (e.g., a housing with a coupler) and another portion (e.g., an anchor) with a fixation hook attached to organ tissue. These two parts can be coupled and decoupled by the use of liquid crystal elastomer enabled parts. Electrothermally controllable liquid crystal elastomer provides powerful actuation within a narrow space for this purpose.

[0082] Liquid crystal elastomer (LCE) is a kind of organic compound elastomer. The LCE has a special feature in that it shrinks when it is heated and elongates when cooled. In the devices of the present disclosure, heat is provided, in some implementations, with electric heating methods. In other implementations, other heating methods may be provided (e.g., resistive, conductive, convective, or chemical heating methods). To avoid the heat effect to the tissue, heating elements may be buried inside the elastomer and local heating is done without effecting the tissues.

[0083] A study was conducted, and two smart structures were developed. A first device was developed by modifying a substrate with a shape memory polymer (e.g., an LCE member), as shown in the top-right panel of FIG. 7. A second device was developed having a mechanical leg structure, as shown in the bottom-right panel of FIG. 7. Both of the developed example devices include a reversible shape deformation component that enables easy attachment and detachment of solid components interlock. The devices are specifically designed for use in the next generation leadless pacemakers for the safe installation of the pacemaker and safe replacement of the main body. The shape deformation performance of the component was thoroughly tested to ensure its reliability and effectiveness.

[0084] To develop the next generation pacemaker with an easy-extraction system, an anchor portion of the leadless pacemaker was developed consisting of one hook that is permanently hooked to the myocardium of the heart. The main part of the leadless pacemaker that contains electronics and a battery was also developed such that the main part is removably couplable to the anchor. This detachable functionality has been achieved with two approaches, one with a mechanical claw structure that couples two parts with negligible force and another with the application of electrothermally controlled novel liquid crystal elastomer (LCE) material enabled locking mechanism. This functionality enables extraction of the dead pacemaker and replacement of it with the new one with the help of self-developed specialized controlling catheters easily, similar to a plug-and-play system. In addition, it is also compatible with MRI, which is not possible with other actuators like magnets and coils. The system developed herein has many advantages not only to solving afterlife management challenges of implantable devices, but also in providing extraordinary MRI compatibility, simple operational procedure, and low voltage power consumption.LCE FILM PREPARATION

[0085] The LCE film is prepared by a dual crosslink process. l,4-bis-[4-{3- acryloyloxy propyl oxy) benzoyloxy] -2-methylbenzene (RM257) was first mixed with chloroform until it was fully dissolved. Then, a mixture of 2,2-(ethylenedioxy) diethanethiol (EDDET) and pentaerythritol tetrakis 3 -mercaptopropionate (PETMP) with a mole ratio of di-thiol to tetra-thiol functional group of 85: 15 was added to the RM 257 solution, with the total mole of thiol functional group exceeding the acry late group by 15%. Pentaerythritol allyl ether (PAE) was utilized as the second crosslinker to react with the extra thiol functional group. Catalyst dipropyl amine (DPA)and photo initiator (2-hydroxyethoxy)-2-methylpropiophenone (HHMP) were added, and the liquid was stirred vigorously to ensure complete mixing. The liquid was then degassed to prevent air bubble formation during the crosslinking process and transferred to a module. After an overnight reaction between thiol-acrylate groups, the single-crosslinking LCE film was obtained, which was later stretched by hang weights on the edge side. The elongated film was exposed to ultraviolet (UV) light to trigger the second crosslink for 5 mins. The monodomain LCE film was obtained and installed into DPLM device. The shape deformation temperature of the LCE film was tested by differential scanning calorimetry (DSC, TA instrument, DSC QI 00).PACEMAKER CHARACTERIZATION

[0086] In this study, in order to mimic the real circumstance when the pacemaker is placed into a heart and functionalized, a lab-made heart comparable in size to a human heart was 3D printed by stereolithography technology. An opening was manufactured in the front part of the heart to access an overwhelming view of the pacemaker detachability mechanism. Moreover, a soft muscle-like part with silicon mold was prepared on the bottom part of the right ventricle to simulate the myocardium of the heart where the leadless pacemakers are implanted.

[0087] The pacemaker was assembled into the heart by the following process. The 3D printed heart was placed in a stand vertically. The main pacemaker with the hook locked was grabbed by the catheter controller and was introduced from the superior vena cava of the heart and inserted through the right atrium and tricuspid valve to reach the right ventricle of the heart. After adjusting the position to the proper place of implantation, the spiral sharp at the end of the hook was twisted into the myocardium by controller. After successfully implanting the pacemaker into the heart, the controller was detached from the pacemaker with push-release action in mechanical legs derived or by cutting off the electrothermal power supply in the LCE-enabled DLP. After making sure that the controller arm had released the pacemaker, the controller was retracted back and pulled out of the heart. Then, the connection force of the DLP to the heart was tested to ensure the tight linkage of each component by shaking the heart and by pulling the pacemaker gently. A microtester tensile test (522 system, LLC.) was carried out for both mechanical and LCE enabled locking mechanisms to study the maximum force of breaking of the devices.

[0088] The replacement of the detachable DLP system, that is to extract the old pacemaker from the heart and replace a new pacemaker on the same old hook, was also studied. For this, the studyintroduced the controller in the same fashion in the implantation process but without the DLP. The controller was guided into the heart chamber and the arms were released to make it ready for grabbing the DLP. The old DLP was detached from the hook with grab-pull action with mechanical DLP and by supplying electrothermal energy in LCE enabled DLP, and it was extracted out of the heart successfully. The new DLP was guided inside the heart chamber in same regular path and launched onto the hook. The controller was retracted and pulled out of the heart. Proper attachment of the new DLP on the same old hook was tested by shaking the heart and pulling the DLP for a second time.RESULTS AND DISCUSSION

[0089] The detachability of the DLP derived by two novel structures was evaluated by testing the force between the hook and main body component. To ensure safe usage, the force produced during installation should be lower than the force that would cause the device to break.LCE MATERIAL PROPERTIES

[0090] In order to test if the LCE is a suitable material for DLP application, the material properties of the LCE were first tested. DSC was performed to test the phase transition temperature of the dual-crosslinked LCE materials with a range from -25 °C to 100 °C. As shown in FIG. 6A, the glass transition temperature (Tg) of -5.37 °C illustrates the flexible elastomer property of this crosslinked polymer at room temperature. The peak at approximately 61.89 °C (TNI) indicates the nematic- isotropic phase transition, during which the liquid crystal functional group switches between poly domain and monodomain, resulting in the shape extension or shrinkage of the LCE film.

[0091] The reversible shape deformation performance w as further tested by placing an LCE film on the ruler (See FIG. 6D). At room temperature, the approximately 10 mm LCE film was prepared. After being placed into an oven at 60 °C, the length shrinks to around 8 mm. The 20% shape deformation is recovered when the temperature cools down below the phase transition temperature. According to FIG. 6B, when a power supply is applied to the electrode that is wTapped around the LCE film, the color of the LCE changed from opaque white to transparent, indicating a phase transition. Meanwhile, the length of the LCE film noticeably decreases (See FIG. 6B) during the electrothermal on state. When the power supply is cut off. the length of the LCE extends again. Thus, for the electrothermal method that was applied in the novel pacemaker, the heatgenerated is sufficient to trigger the phase transfer of the LCE and further lead to reversible shape deformation, ensuring the detachability of the device. As a result, due to the clear shape deformation observed, the LCE can be applied to the clamp of the novel DLP.PACEMAKER REPLACEMENT

[0092] The DLP components, including a clamp structure and a cylinder, are prepared by 3D printing to test the installation of the LCE-derived DLP. In order to have an instant view of the shape deformation behavior, the LCE assembled clamp was first installed in a reversed direction as shown in FIG. 6C (i.e., the widened side facing the hook cylinder). At room temperature, the distance between the two clamp arms is larger than the diameter of the cylinder, while the shrinkage of the LCE at high temperature shortens the distance. Thus, the clamp can easily separate from the cylinder after a heating process.

[0093] Additionally, to simulate the real situation, the clamp with widened side facing out of the cylinder is fabricated. After a vigorous shaking of the device, the clamp will not fall apart due to the extension of the LCE preventing the movement of the component. However, after the heating process, the clamp easily falls off from the cylinder. Thus, the reversible shape deformation of the clamp ensures the easy detachability of the DLP.

[0094] In addition to the easy extraction of the hook and main body, the tight connection of these two components is also helpful for the safe usage of the device. Thus, the tensile test was applied in 3D-printed hook and main body of DLP being locked at room temperature (see FIG. 7). For the mechanical legs-derived DLP, with the stretch of the device, the claws start to take off from the main body, causing the vibration of the load. When all claws separate, the load decreases dramatically. For LCE-derived DLP, it is surprising to observe that the 3D-printed clamp broke first (See FIG. 7), resulting in a drop of the force. This indicates the strong connection of the LCE to lock the hook and main body, which ensures safety usage. As shown in the graph of FIG. 7, it was discovered that the load of failure of the mechanical-legs connection was lower than for the LCE enabled connection. Owing to this force of breaking, there is no chance for accidental detachment of the main DLP part from the hook during any daily activities.

[0095] In summary, solid-solid interlock is a crucial aspect in designing complex structures, especially in achieving an easy extraction system. In this research, a modified solid surface by a shape memory polymer was prepared and applied to pacemaker application, which could exhibita smart reversible shape deformation triggered by thermal. Due to the shrinkage of the LCE at high temperature and the extension at low temperature, the modified clamp structure was able to achieve the easy implantation, detachment and replacement process to the tw o components of solid pacemaker. The shape deformation temperature of the LCE is well controlled to approximately 60 °C to ensure its safe usage in the human heart. These designs applied to leadless pacemakers effectively reduce the risk of failure extraction and simplify the implantation process. Additionally, the advanced LCE reversible shape performance properties, combined with the modified surface structure have the potential to be applied to various biomedical devices in the future. For example, the structure and function of the movable segments coupled to the LCE member in the novel device may be applicable to other medical implants not herein described.

[0096] The interlock between the hook and main body of the pacemaker guarantees its safety while the easy-detachable is also significant during the replacement. This study has developed a prototype of an innovative DLP having the functionality of detach ability with mechanical -legs and LCE techniques. This study has successfully demonstrated the implantation, detachment, and replacement of the DLP in an artificial heart chamber utilizing the solid-solid interconnection approach. The LCE derived DLP device has a shape deformation temperature of approximately 60 °C, which can be triggered by electrothermal transfer, ensuring safe usage. Both designs feature an easy detachable mechanical performance, largely reducing the risk of failure during the extraction of the DLP and simplifying the process of implantations. The advanced approach has the potential to be developed into other solid-solid interlocking medical devices.Conclusion

[0097] For purposes of this description, certain advantages and novel features of the aspects and configurations of this disclosure are described herein. The described methods, systems, and apparatus should not be construed as limiting in any way. Instead, the present disclosure is directed toward all novel and nonobvious features and aspects of the various disclosed aspects, alone and in various combinations and sub-combinations with one another. The disclosed methods, systems, and apparatus are not limited to any specific aspect, feature, or combination thereof, nor do the disclosed methods, systems, and apparatus require that any one or more specific advantages be present or problems be solved.

[0098] Although the figures and description may illustrate a specific order of method steps, the order of such steps may differ from what is depicted and described, unless specified differently above. Also, two or more steps may be performed concurrently or with partial concurrence, unless specified differently above. Such variation may depend, for example, on the software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations of the described methods could be accomplished with standard programming techniques with rule-based logic and other logic to accomplish the various connection steps, processing steps, comparison steps, and decision steps.

[0099] Features disclosed in this specification (including any accompanying claims, abstract, and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The claimed features extend to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract, and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0100] As used in the specification and the appended claims, the singular forms “a”, "an", and ■‘the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about”, it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. The terms “about” and “approximately” are defined as being “close to” as understood by one of ordinary skill in the art. In one non-limiting aspect the terms are defined to be within 10%. In another non-limiting aspect, the terms are defined to be within 5%. In still another non-limiting aspect, the terms are defined to be within 1%.

[0101] The terms "coupled", "connected", and the like as used herein mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g.. permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additionalintermediate members being attached to one another. If “coupled” or variations thereof are modified by an additional term (e.g., directly coupled), the generic definition of “coupled” provided above is modified by the plain language meaning of the additional term (e g., “directly coupled” means the joining of two members without any separate intervening member), resulting in a narrower definition than the genenc definition of “coupled” provided above. Such coupling may be mechanical, electrical, or fluidic.

[0102] Certain terminology is used in the following description for convenience only and is not limiting. The words “right”, “left”, “lower”, and “upper” designate direction in the drawings to which reference is made. The words “inner” and “outer” refer to directions toward and away from, respectively, the geometric center of the described feature or device. The words “distal” and “proximal” refer to directions taken in context of the item described and. with regard to the instruments herein described, are typically based on the perspective of the practitioner using such instrument, with “proximal” indicating a position closer to the practitioner and “distal” indicating a position further from the practitioner. The terminology7includes the above-listed words, derivatives thereof, and words of similar import.

[0103] Throughout the description and claims of this specification, the word “comprise” and variations of the word, such as “comprising” and “comprises”, means “including but not limited to”, and is not intended to exclude, for example, other additives, components, integers or steps. “Exemplary” means “an example of’ and is not intended to convey an indication of a preferred or ideal aspect. “Such as” is not used in a restrictive sense, but for explanatory purposes.

[0104] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present disclosure has been presented for purposes of illustration and description but is not intended to be exhaustive or limited to the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the present disclosure.

Claims

What is claimed is:

1. A detachable leadless pacemaker (DLP) comprising: a housing containing at least one electrical component; and a coupler attached to the housing, the coupler comprising a liquid crystal elastomer (LCE) member configured to move between an expanded configuration and a contracted configuration, wherein the LCE member has a first length at a first temperature and a second length at a second temperature, wherein the second length is shorter than the first length, wherein the second temperature is higher than the first temperature.

2. The detachable leadless pacemaker of claim 1, wherein the coupler further comprises a first segment having a first end and a second end and a second segment having a first end and a second end, wherein the LCE member is coupled to each of the first and second segments.

3. The detachable leadless pacemaker of claim 2, wherein the LCE member is coupled between the second ends of the first and second segments and configured to selectively move the second ends of the first and second segments further apart from each other or closer to each other.

4. The detachable leadless pacemaker of any of claims 1-3, further comprising: an anchor configured to be attached to an organ-tissue of a patient.

5. The detachable leadless pacemaker of claim 4, wherein the anchor comprises: at least one sidewall defining a chamber with an opening on a first end; and at least one protrusion extending radially inward from the at least one sidewall adjacent to the first end to partially define the opening.

6. The detachable leadless pacemaker of any of claims 1-5, wherein the first end of the first segment is pivotably coupled to a first portion of the coupler and the first end of the second segment is pivotably coupled to the first portion of the coupler.

7. The detachable leadless pacemaker of any of claims 1-6, wherein the first length of the LCE member at the first temperature corresponds to an expanded distance between the second ends of the first and second segments of the coupler, wherein a size of the opening of the anchor is less than the expanded distance such that the first and second segments are not insertable into the chamber of the anchor when the LCE member is at the first length and the first temperature.

8. The detachable leadless pacemaker of any of claims 1-7, wherein the second length of the LCE member at the second temperature corresponds to a contracted distance between the second ends of the first and second segments of the coupler, wherein a size of the opening of the anchor is greater than the contracted distance such that the first and second segments are insertable into the chamber of the anchor when the LCE member is at the second length and the second temperature.

9. The detachable leadless pacemaker of any of claims 1-8, wherein the first temperature is approximately human body temperature.

10. The detachable leadless pacemaker of any of claims 1-9, wherein the first temperature is approximately 37 degrees Celsius and the second temperature is at least 50 degrees Celsius.

11. The detachable leadless pacemaker of any of claims 1-10, wherein the first length of the LCE member is approximately 20% longer than the second length.

12. The detachable leadless pacemaker of any of claims 1-11, wherein the coupler is detachably couplable to the anchor via the opening of the anchor.

13. The detachable leadless pacemaker of any of claims 1-12, wherein the anchor further comprises a hook extending from a second end of the anchor opposite the first end.

14. The detachable leadless pacemaker of any of claims 1-13, wherein the hook of the anchor comprises a spiral structure with a sharp needle tip at a distal end thereof.

15. The detachable leadless pacemaker of any of claims 1-14, wherein the first portion of the coupler is a hinge connector, wherein the first ends of the first and second segments are pivotably coupled to the hinge connector.

16. The detachable leadless pacemaker of any of claims 1-15, wherein the first ends of the first and second segments are rotatable to increase or decrease an angle between the first and second segments.

17. The detachable leadless pacemaker of any of claims 1-16. wherein the at least one protrusion of the anchor is configured to retain the first and second segments of the coupler within the chamber of the anchor when the LCE element is cooled to the first temperature and expands to the first length.

18. The detachable leadless pacemaker of any of claims 1-17, further comprising a heater in thermal communication with the LCE element, wherein the heater is further in electrical communication with the at least one electrical component.

19. The detachable leadless pacemaker of any of claims 1-18. wherein the at least one electrical component comprises a controller in communication with the heater, wherein the controller is configured to deliver instructions to activate and deactivate the heater.

20. The detachable leadless pacemaker of any of claims 1-19. wherein the at least one electrical component comprises one or more of a battery, an electrical signal / pulse generator, a sensor, a controller and / or programmable logic, and a signal transmission device.

21. The detachable leadless pacemaker of any of claims 1-20, wherein the LCE member comprises an electrothermally controlled liquid crystal elastomer.

22. A method for implanting a detachable leadless pacemaker, the method comprising:(i) providing an anchor attached to an organ-tissue, the anchor comprising: at least one sidewall defining a chamber with an opening on a first end;at least one protrusion extending radially inward from the at least one sidewall adjacent to the first end to partially define the opening; and a hook disposed on a second end of the anchor opposite the first end, the hook configured to engage with and couple to the organ-tissue;(ii) providing a detachable leadless pacemaker comprising: a housing containing at least one electrical component, and a coupler attached to the housing, the coupler comprising: a first segment having a first end pivotably coupled to a first portion of the coupler; a second segment having a first end pivotably coupled to the first portion of the coupler; and a liquid crystal elastomer (LCE) member coupled between a second end of the first segment and a second end of the second segment, wherein the LCE member has a first length at a first temperature and a second length at a second temperature, wherein the second length is shorter than the first length, wherein the second temperature is higher than the first temperature;(iii) heating the LCE member to the second temperature to contract the LCE member from the first length to the second length, wherein the second ends of the first and second segments of the coupler are moved from an expanded distance to a contracted distance corresponding to the second length of the LCE member;(iv) inserting the first and second segments of the coupler into the chamber of the anchor via the opening; and(v) cooling the LCE member from the second temperature toward the first temperature to expand the LCE member from the second length toward the first length, wherein the second ends of the first and second segments of the coupler are moved from the contracted distance toward the expanded distance corresponding to the first length of the LCE member.

23. The method of claim 22, wherein the detachable leadless pacemaker further comprises a heater adjacent to the LCE member, the heater being in communication with the at least one electrical component, wherein activation of the heater is performed via remote communication with the at least one electrical component.

24. A method for removing a detachable leadless pacemaker, the method comprising:(i) providing an anchor attached to an organ-tissue, the anchor comprising: at least one sidewall defining a chamber with an opening on a first end; at least one protrusion extending radially inward from the at least one sidewall adjacent to the first end to partially define the opening; and a hook disposed on a second end of the anchor opposite the first end, the hook configured to engage with and couple to the organ-tissue;(ii) providing a detachable leadless pacemaker comprising: a housing containing at least one electrical component, and a coupler attached to the housing, the coupler comprising: a first segment having a first end pivotably coupled to a first portion of the coupler; a second segment having a first end pivotably coupled to the first portion of the coupler; and a liquid crystal elastomer (LCE) member coupled between a second end of the first segment and a second end of the second segment, wherein the LCE member has a first length at a first temperature and a second length at a second temperature, wherein the second length is shorter than the first length, wherein the second temperature is higher than the first temperature, wherein the first and second segments are disposed within the chamber of the anchor so that the coupler is coupled to the anchor;(iii) heating the LCE member to the second temperature to contract the LCE member from the first length to the second length, wherein the second ends of the first and second segments of the coupler are moved from an expanded distance to a contracted distance corresponding to the second length of the LCE member; and(iv) removing the first and second segments of the coupler from the chamber of the anchor via the opening such that the coupler is decoupled from the anchor.

25. The method of claim 24, wherein the detachable leadless pacemaker further comprises a heater adjacent to the LCE member, the heater being in communication with the at least one electrical component, wherein activation of the heater is performed via remote communication with the at least one electrical component.

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