Implantable medical device, catheter, and method for implanting the implantable medical device

Abstract

An implantable medical device (20) is described. The implantable medical device (20) comprises: a housing (22) having a distal end (28) and a proximal end (26); a first electrode (30) being arranged at the housing (22) between the proximal end (26) and the distal end (28) and being exposed to surroundings of the implantable medical device (20); an energy source (48) arranged within the housing (22); an electronic circuit (46) arranged within the housing (22) and electrically coupled to the energy source (48) and the first electrode (30); and an electrode member (32) having at least one second electrode (36) exposed to the surroundings of the implantable medical device (20), with the second electrode (36) being electrically coupled to the electronic circuit (46), wherein the electrode member (32) has a proximal section (42) and a distal section (44), wherein the proximal section (42) of the electrode member (32) is arranged at the distal end (28) of the housing (22) and extends away from the housing (22) in distal direction, wherein the distal section (44) of the electrode member (32) is arranged at the proximal section (42) and extends away from the proximal section (42) in distal direction, and wherein one of the sections (42, 44) is flexible and the other one of the sections (42, 44) is rigid.

Description

[0001] Applicant: BIOTRONIK SE & Co. KG

[0002] Date: 10.12.2025

[0003] Our Reference: 24.133P-WO

[0004] IMPLANTABLE MEDICAL DEVICE, CATHETER, AND METHOD FOR

[0005] IMPLANTING THE IMPLANTABLE MEDICAL DEVICE

[0006] The present invention refers to an implantable medical device, to a catheter, and to a method for implanting the implantable medical device into a body of a human or an animal.

[0007] The Implantable Medical Device (IMD) may be an implantable intracardiac device, such as e.g. an implantable intracardiac pacemaker. Active Intracardiac Medical Devices (AIMD's) or passive intracardiac medical devices, for example implantable intracardiac pacemakers, also known as implantable leadless pacemakers (ILP's), are well known miniaturized medical devices which are entirely implanted into a heart’s chamber or atrium. Intracardiac pacemakers are used for patients who suffer from a bradycardia, that is if a heart that beats too slow to fulfil the physiological needs of the patient. Intracardiac pacemakers apply electrical stimulation in the form of pulses to the heart in order to generate a physiologically appropriate heartrate. Alternative or additional functions of intracardiac devices comprise providing other electrical or electromagnetic signals to the heart or its surrounding tissue, sensing electrical or electromagnetic signals or other physiological parameters of the heart and / or its surrounding tissue.

[0008] In order to be able to stimulate the heart by electric pulses, the IMD comprises electrodes which come in contact with the body tissue when the IMD is implanted. The electrodes allow AIMD's to treat adjacent tissue by providing an electronic stimulation site and a method of fixation to the target tissue. When developing a leadless AIMD, the fixation means must be attached to the implant and provide secure fixation without slipping or twisting, while providing a reliable contact between the stimulation electrode and the target tissue. It is known to use a tine array comprising several tines as the fixation means. The tine array may be clamped or attached to the housing of the IMD. Conduction system pacing (CSP) is emerging as a form of cardiac resynchronization for patients who are displaying signs of heart failure and reduced ejection fraction. CSP involves placing a transvenous pacing lead, referred to as electrode member in this description, into the septum of the heart of the patient either at the HIS Bundle (HB) or within the Left Bundle Branch (LBB). By targeting the conduction system directly, rather than pacing the myocardium of the ventricle, there is a reduction in activation time and improved synchrony between the right and left ventricles. This is more physiologic for the patient and shows a reduction of adverse clinical outcomes in patients with ventricular pacing requirements of more than 20% in comparison to standard RV (right ventricular) pacing.

[0009] Implantable leadless pacemakers or intracardiac pacemakers (ILP's) have also become an emerging technology that combines the lead and the implant into a single entity for implant directly into the heart. This offers a means for eliminating discomfort experienced by the presence of a large can residing within the patient’s chest while offsetting lead-based mobility restrictions. ILP's also eliminate lead-based transvenous infection pathways to the myocardium and other lead failures that can be present with transvenous pacing. Current ILP technology can only accomplish traditional right ventricle myocardium pacing due to the limitations of the electrode placement and device fixation being only in the myocardium of the right atrium or ventricle.

[0010] Transvenous pacing carries the risk of the patient developing an infection along the lead pathway that goes directly into the heart. Transvenous leads also risk mechanical failures such as fractures. The transvenous pacemaker resides in the patient’s chest which can cause physical and / or emotional discomfort and the transvenous leads can limit patient mobility. Additionally, some patients have contraindications for transvenous leads. Further, transvenous leads tend to become entangled in the tissue or damaged. Further, transvenous leads do not have a 1 : 1 torque translation between a proximal end where the user is rotating and the helix penetrating the septum. This may cause an issue with respect to torque buildup and unexpected torque breakthrough, making the electrode deployment unpredictable and risking perforations.

[0011] 24.133P-WO / 10.12.2025 As stated above, ILP's are currently limited to Right Atrial (RA) or Right Ventricular (RV) myocardial pacing and cannot reach the conduction system of the heart to perform CSP. This is due to the limitation of the depth of the pacing electrode, which is controlled by the fixation mechanism on the ILP. Some ILP's are fixed to the heart with tines that hook into the myocardium, in order to achieve contact between a tip electrode and the myocardium. Such a tip electrode does usually not pierce the myocardium. Other ILP's have a helical fixation means which can act as electrode as well. The helical fixation means has a fixed length which is not long enough to reach the conduction system. Even if the helical fixation means were extended to be long enough to reach the conduction system, it likely would not be stable enough to fix the body of the ILP securely into the septum to provide safe long-term fixation. Since conventional ILP's cannot accomplish CSP, patients who require more than 20% ventricular pacing are at risk for increased left ventricular activation time, reduced ejection fraction, and pacing induced heart failure.

[0012] Accordingly, there is a need for an IMD, in particular an ILP, a catheter, and a method for implanting the IMD which enable to securely fix the IMD to the tissue of the patient while enabling to accomplish CSP with the IMD, e.g., by enabling to arrange an Implantable Pulse Generator (IPG) of the IMD within the heart relatively independent from a position of a pacing electrode of the IMD within the tissue compared to the prior art.

[0013] The above problem is solved by the subject matter of the independent claims. Advantageous embodiments are given in the dependent claims.

[0014] An aspect refers to an IMD. The IMD comprises: a housing having a distal end and a proximal end; a first electrode being arranged on the housing between the proximal end and the distal end and being exposed to surroundings of the implantable medical device; an energy source arranged within the housing; an electronic circuit arranged within the housing and electrically coupled to the energy source and the first electrode; and an electrode member having at least one second electrode exposed to the surroundings of the implantable medical device, with the second electrode being electrically coupled to the electronic circuit, wherein the electrode member has a proximal section and a distal section, wherein the proximal section of the electrode member is arranged at the distal end of the housing and extends away

[0015] 24.133P-WO / 10.12.2025 from the housing in distal direction, wherein the distal section of the electrode member is arranged at the proximal section and extends away from the proximal section in distal direction, and wherein one of the sections is more flexible and the other one of the sections is more rigid.

[0016] Another aspect refers to a catheter for implanting the IMD into a body of a patient. The catheter comprises: a protector cup for accommodating the implantable medical device, wherein the protector cup has a proximal end and a distal end; a stabilizing sheath being arranged at the protector cup such that it extends away from the protector cup in distal direction, wherein the stabilizing sheath is formed and arranged such that the electrode member is held by the stabilizing sheath, when the implantable medical device is accommodated within the protector cup such that the electrode member protrudes from the protector cup in distal direction.

[0017] Another aspect refers to a method for implanting the IMD into a body of a patient. The method comprises: arranging the implantable medical device within the body of the patient such that the electrode member is engaged within the tissue; moving the housing of the implantable medical device relative to the tissue and relative to the electrode member such that the more flexible section of the electrode member is bent; and attaching the housing to the tissue of the patient after moving the housing relative to the tissue and relative to the electrode member.

[0018] Another aspect refers to a system comprising a catheter, an IMD and a stylet. The catheter comprises: a protector cup for accommodating the implantable medical device, wherein the protector cup has a proximal end and a distal end. The IMD comprises: a housing having a distal end and a proximal end; a first electrode being arranged on the housing between the proximal end and the distal end and being exposed to surroundings of the implantable medical device; an energy source arranged within the housing; an electronic circuit arranged within the housing and electrically coupled to the energy source and the first electrode; and an electrode member having at least one second electrode exposed to the surroundings of the implantable medical device, with the second electrode being electrically coupled to the electronic circuit, wherein the electrode member has a proximal section and a distal section,

[0019] 24. 133P-WO / 10.12.2025 wherein the proximal section of the electrode member is arranged at the distal end of the housing and extends away from the housing in distal direction, wherein the distal section of the electrode member is arranged at the proximal section and extends away from the proximal section in distal direction, and wherein one of the sections is more flexible and the other one of the sections is more rigid. The IMD further comprises a through hole which extends from the proximal end of the housing at least partly through the electrode member in distal direction. The stylet is configured fit within the through hole.

[0020] The features, advantages and embodiments of one of the aspects described above and in the following may easily be transferred to features, advantages and embodiments of another one of the aspects.

[0021] The IMD represents a leadless or intracardiac pacemaker capable of pacing the conduction system of the heart, e.g., HIS bundle or left bundle branch / left bundle branch area. This allows for the benefits of leadless pacing and CSP to be combined. For example, this will allow for a remote deployment of the IMD within the right ventricle of the heart of the patient. Further, this will allow patients to have physiological pacing without the discomfort or mobility restrictions of a transvenous pacemaker.

[0022] The IMD may utilize the flexibility of the flexible section of the electrode member and a fixation mechanism at the housing, e.g., a tined fixation mechanism having two or more tines which are separate from the pacing electrode, i.e., the second electrode. The second electrode may be located within the tissue by the electrode member such that a relatively high septal location and a relatively large depth within the tissue necessary to achieve conduction system pacing may be achieved, compared to the prior art. Then, because of the flexible section, the housing including the electronic circuit and the energy source, in other words the Implantable Pulse Generator (IPG), may be arranged lower than the electrode member, e.g., on the septal wall in the standard leadless pacing location. This introduced several degrees of freedom with respect to where to position the pacing electrode and where to arrange the IPG independent therefrom, what in contrast was heavily interrelated in the prior art. In particular, the pacing electrode may be located at the optimal position for pacing the heart and the IPG may be arranged at a position at which the weight and the fixation mechanism

[0023] 24. 133P-WO / 10.12.2025 of the IMD cause minimal harm to the body of the patient. In addition, the sensing vector is larger than the leadless pacing technology platforms, enabling improved far field sensing. For example, the implantable medical device may be arranged at the tissue within the body of the patient by the tines.

[0024] The patient may be a human or an animal. The tissue of the patient may be a tissue of the heart of the patient. The first electrode may act as a return electrode or anode, for example. The second electrode may be a cathode. The second electrode may be referred to as pacing electrode. The second electrode may be extended to provide a means for accessing the conduction system, e.g., HIS bundle or Left bundle branch). The second electrode may be formed at a distal tip of the electrode member and / or the tip may be formed by the second electrode. This may enable to insert the second electrode at a maximal depth within the tissue. In addition, this may allow the pacing electrode to penetrate the septum easily, in particular by a sharp and robust penetration of the tissue. Further, a large bipolar vector with fixed spacing may be provided by the second electrode being arranged at the tip of the electrode member. This may contribute to a very good atrial sensing and AV (atrial ventricular) synchrony, while the vector is maintained regardless of the pacing electrode depth.

[0025] A distal end region of the electrode member may be spear-shaped. The spear-shaped electrode member may be referred to as “electrode spear” or “electrode rod”. The spearshape of the electrode member may contribute to easily penetrate the tissue of the patient and / or to penetrate the tissue of the patient over a long range, i.e., the length of the electrode member. Alternatively, the distal end region may be helically shaped. The helically shaped distal end region of the electrode member may consist of a connection part coupled to the housing, of the tip facing away from the housing, and of a helical section or helix extending from the connection part to the tip. The helically shaped distal end region may be screwed into the tissue when rotating the electrode member relative to the housing by the stylet. Alternatively, the helically shaped distal end region may be screwed into the tissue when rotating the housing (e.g. the IMD). As such, the helically shaped electrode member may contribute to fix the IMD at the tissue of the patient. The distal end region may range from the distal end of the electrode member in proximal direction. A length of the distal end region

[0026] 24.133P-WO / 10.12.2025 may be in a range from 1% to 50% of the length of the electrode member, e.g., from 0.5% to 10%, e.g., from 1% to 5%. In either case, the electrode member may have a sharp tip at its distal end. In other words, the tip may be spiky or pointed. The sharp tip may enable to penetrate the tissue easily and with minimal impact on the tissue. In any case, the electrode member may be formed and arranged such that it may penetrate the ventricular septum when arranging the IMD at the tissue of the patient.

[0027] The second electrode may be arranged within the distal end region of the electrode member. For example, the second electrode may extend from the distal end of the electrode member in proximal direction. The electrode member may be electrically insulated against its surroundings, except for the second electrode. The electrode member may have a length in a range from 10 mm to 100 mm, e.g., from 15 mm to 70 mm. In particular, the flexible section may have a length in a range from 9 mm to 50 mm, e.g., from 10 to 50 mm, and / or the rigid section may have a length in a range from 1 mm to 50 mm, e.g., from 5 mm to 20 mm.

[0028] The IMD may have a cylindrical shape with a longitudinal axis extending from the proximal end of the housing to the distal end of the housing. In particular, the housing may have a cylindrical shape. The housing may comprise a hollow cylinder for accommodating the electronic circuit and the energy source. In addition, the IMD, in particular the housing, may be fluid-tightly sealed against its surroundings. The housing may comprise or may be made of metal.

[0029] The IMD may be sized to be implanted within the atrium or ventricle of a heart, in particular within the right ventricle of a human heart.

[0030] The IMD as described in this description represents a leadless (intracardiac) conduction system pacemaker (LCSP) concept optionally utilizing a tine-based fixation mechanism. It is comprised of two components. One of these components is the Implantable Pulse Generator (IPG) and comprises the housing, the energy source, and the electronic circuit. A second one of these components comprises or is the electrode member which comprises or

[0031] 24. 133P-WO / 10.12.2025 holds the second electrode and which has the flexible section and the rigid section. The most distal part of the IMD may be the tip of the electrode member.

[0032] The LCSP may be fixed to the tissue via the delivery catheter in two steps into the ventricular septum. A first step involves penetrating the tissue by the electrode member and fixing the electrode member within the tissue. A second step involves arranging the IPG within the body apart from the second electrode by bending the flexible section and fixing the IPG to the tissue, e.g., by the tines.

[0033] The catheter for implanting the IMD will allow for close to a 1 : 1 torque translation to control the deployment of the second electrode into the tissue to avoid risk of perforating into the left ventricle. This avoids an issue of the prior art IMDs with respect to torque buildup and unexpected torque breakthrough which make the electrode deployment unpredictable and risking perforations. In contrast, the torque translation being closer to a 1 : 1 ratio may contribute to provide a controlled rotational deployment of the electrode member and thereby the pacing electrode, i.e., the second electrode.

[0034] According to an embodiment, the proximal section is more flexible. Thus, the distal section is more rigid. This enables to penetrate the tissue by the rigid distal section and to move the housing relative to the distal section by bending the flexible proximal section.

[0035] Generally, the flexible section has a higher mechanical flexibility than the rigid section.. I.e. the flexible section may be deformed with lower forces than the rigid section. Therein, any deformation may be mainly elastic. A flexibility in one of the sections may be homogeneous or may vary only slightly along each one of the sections, whereas a difference in flexibility between both sections may be significantly higher than any flexibility variation within a single one of the sections.

[0036] According to an embodiment, the rigid one of the sections has a stiffness which may be between 1.5 and 10 times of the stiffness of the flexible one of the sections. This contributes to that the rigid section is rigid enough to penetrate the tissue and that the flexible section is

[0037] 24. 133P-WO / 10.12.2025 flexible enough to be bended by moving the housing without transferring to much force to the rigid section thereby protecting the tissue.

[0038] According to an embodiment, the proximal section is lumenless, and / or the distal section is lumenless. In case of both sections being lumenless, the whole electrode member may be lumenless. That a section or the electrode member is lumenless may mean in this context that the section or the electrode member, respectively, are solid and do not surround any free volume, e.g., a through hole, extending through the corresponding section or the electrode member, respectively. Alternatively, an electrically conductive lead may extend through the electrode member up to the second electrode for coupling the second electrode to the electronic circuit. The lead may be helically-shaped, in particular in the flexible section, in order to allow the flexibility of the flexible section while ensuring a proper electric coupling of the second electrode to the electronic circuit. As another alternative, a through hole may extend from the proximal end of the housing at least partly through the electrode member in distal direction. The through hole may be configured for accommodating a distal part of a stylet for moving the electrode member, in particular, the distal and / or rigid section of the electrode member, as explained further below.

[0039] According to an embodiment, a third electrode is arranged at the rigid section, the third electrode is exposed to the surroundings of the implantable medical device, and the third electrode is electrically coupled to the electronic circuit. Preferably, the third electrode may be arranged at the distal section of the IMD. So, the third electrode may be located within a reinforced region of the electrode member, which may be referred to as “micro-lead”. The third electrode may enable electrical sensing, in particular voltage change sensing, during implantation, to confirm Conduction System (CS) capture. Optionally, one or more further electrodes may be arranged at the housing to provide additional electromagnetic vectors. One or more of the further electrodes may be arranged along the length of the electrode member to provide more areas of pacing capture along the septum.

[0040] According to an embodiment, the housing has a through hole extending from the proximal end to the distal end and to the electrode member, and the through hole is configured for accommodating a stylet for moving the electrode member. The through hole may be

[0041] 24.133P-WO / 10.12.2025 surrounded by a tube of the housing. The tube may extend from the proximal end of the housing to the distal end of the housing. The stylet may be a part of a catheter for implanting the IMD. Alternatively, the stylet may be a component of the IMD and may be grabbed and / or rotated by the catheter. Alternatively, the stylet may be a separate component configured to fit in the through hole and optionally into a specific lumen of the catheter. During deployment, the electrode member may be moved and / or pushed into the heart tissue by the stylet until the pacing electrode on the electrode member reaches the conduction system of the heart. The stylet may be used for bending the flexible section of the electrode member. The stylet may be used for rotating the electrode member. This may be especially advantageous when a tip of the electrode member is helically shaped. In this case and when the tip is fixedly arranged at the distal section, the stylet may rotate the electrode member and thereby the tip with respect to the housing such that the helically shaped tip may be screwed into the tissue. Alternatively in this case, when the tip may be rotated with respect to the distal section, the stylet may rotate the tip with respect to the housing such that the helically shaped tip may be screwed into the tissue.

[0042] According to an embodiment, the energy source and the electronic circuit are arranged one after the other in distal direction and the through hole extends through the energy source and the electronic circuit. In this case, the energy source and the electronic circuit are arranged on top of each other, in case of the IMD being arranged such that its axis is vertically oriented. Alternatively, the energy source and the electronic circuit are arranged perpendicularly to the distal direction next to each other and the through hole extends between the energy source and the electronic circuit. In this case, the energy source and the electronic circuit are arranged horizontally next to each other, in case of the IMD being arranged such that its axis is vertically oriented. This may contribute to easily form the through hole through the housing and / or to easily arrange the tube surrounding the through hole.

[0043] According to an embodiment, the electrode member has a locking part of a locking mechanism at its proximal end, the locking part is configured for being mechanically coupled to a counter locking part of the locking mechanism, the counter locking part is formed at a distal end of the stylet, the counter locking part is configured for mating the

[0044] 24.133P-WO / 10.12.2025 locking part, and the locking mechanism is configured such that the electrode member can be moved by the stylet when the counter locking part of the stylet is engaged with the locking part of the electrode member. The locking part and the counter-locking part may be formed such that the electrode member and / or the tip of the electrode member are pushable, pullable, and / or rotatable by the stylet when the locking part is mechanically coupled to the counterlocking part. The locking mechanism enables to fixedly arrange the stylet at the electrode member. The locking mechanism may principally work by a form-fit, e.g., corresponding to a bayonet attachment. For example, the counter-locking part of the stylet may be inserted into the locking part of the electrode member. Then, counter-locking part may be rotated within the locking part, e.g., at about 90 degrees, such that the counter-locking part engages in the locking part. For example, the locking part may comprise a protrusion under which the counter-locking part may be rotated such that the counter-locking part is engaged in the locking part after the rotation. Then, the stylet cannot be separated from the electrode member by pushing or pulling it parallel to the distal direction. Then, a translational pushingforce in distal direction or a retraction pulling-force in proximal direction may be transferred to the electrode member by the stylet. In addition, the locking mechanism may be configured such that when the counter locking part is rotated such that it engages with the locking part and when the counter locking part is rotated further in the same direction of rotation, the rotation may be transferred to the electrode member such that the electrode member is rotated. To remove the stylet it may be rotated back 90 degrees and may be withdrawn from the electrode member in proximal direction.

[0045] According to an embodiment, the IMD comprises two or more tines being arranged at the distal end of the housing, protruding from the housing at least partly in distal direction, and being configured for attaching the implantable medical device to a tissue of a patient. The tines enable to fix the IMD to the tissue securely. In particular, the tines may enable to secure the IMD to the myocardium. The tines may have a higher profile than conventional tines known in the art. The tines may have a curved section followed by a straight section. The curved section may have a radius between 1.5 mm and 6 mm. The overall dimension of the tines in the distal direction may be between 0.7 mm and 8 mm. The length of the straight section may be between 0.5 mm and 3 mm. This may enable to secure the IMD by the tines within the right ventricle while enabling a small gap between the IMD and the tissue. The

[0046] 24.133P-WO / 10.12.2025 tines may be selectively coated on their respective tips with a material to improve radiopacity, such as gold, for example. The tines may be made of a super-elastic material, such as Nitinol, for example. The tines may be attached to the leadless pacemaker housing in a header assembly that enables rotation but not detachment from the device.

[0047] According to an embodiment, the IMD comprises a hitch for grabbing the housing, wherein the hitch is arranged at the proximal end of the housing. The hitch may enable to insert or to retract the housing from the body. In addition, the hitch may enable to rotate the housing. In case of the through hole for the stylet extending through the housing, the through hole may extend through the hitch.

[0048] According to an embodiment, a distal end of the stabilizing sheath of the catheter is formed and arranged such that it touches the electrode member and centers the electrode member with respect to a longitudinal axis of the implantable medical device, when the implantable medical device is accommodated within the protector cup such that the electrode member protrudes from the protector cup in distal direction. The stabilizing sheath may enable to guide the at least partly flexible electrode member when implanting the IMD. The stabilizing sheath may be formed by one piece or may comprise two or more pieces.

[0049] According to an embodiment, an outer diameter of the stabilizing sheath decreases from the distal end of the protector cup in distal direction such that an inner diameter of the stabilizing sheath at its distal end at least approximately corresponds to an outer diameter of the electrode member. The stabilizing sheath may be tube shaped having a tapered portion extending from a distal end of the protector cup to the electrode member, wherein the inner diameter of the stabilizing sheath may decrease in distal direction, e.g., when the stabilizing sheath is formed by one piece only. Alternatively, the stabilizing sheath may comprise two separate sub-sheets each extending from a side of the protector cup to the electrode member, wherein the sub-sheets are arranged at opposing sides of the protector cup. In this case, the “inner diameter” refers to a clear width between the sub-sheets.

[0050] According to an embodiment, the catheter comprises an alignment torquer at least in part extending through the protector cup in distal direction and comprising a recess for

[0051] 24.133P-WO / 10.12.2025 accommodating the hitch of the IMD, wherein the recess is formed at a distal end of the alignment torquer and wherein the alignment torquer is configured for rotating the implantable medical device via the hitch being arranged in the recess. The recess may have a negative form with respect to the hitch such that the hitch may be inserted into the recess tightly.

[0052] The catheter may comprise a first shaft comprising the protector cup as distal section. The catheter may further comprise at least one inner shaft arranged within the first shaft and comprising the alignment torquer as distal section. The at least one inner shaft and the outer shaft may be movable with respect to each other axially, torsionally, or both. The catheter may further comprise an outer shaft comprising the stabilizing sheath as distal section. The outer shaft may be movable with respect to the first shaft and / or the inner shaft. The outer shaft may also be removable to expose the more flexible region of the electrode member.

[0053] According to an embodiment the catheter may comprise a lumen for accommodating a stylet. The stylet may be a part of the catheter or a separate part. The stylet may be used for bending the flexible section of the electrode member. The stylet may be used for rotating the electrode member. The stylet may enable to guide the at least partly flexible electrode member when implanting the IMD. If a stylet is used, there may be no need for the stabilizing sheath.

[0054] In the following, advantageous embodiments of the invention will be described with reference to the enclosed drawings. However, neither the drawings nor the description shall be interpreted as limiting the invention.

[0055] Fig. 1 shows a side view of an exemplary embodiment of an implantable medical device.

[0056] Fig. 2 shows the implantable medical device of figure 1 arranged in a protector cup of an exemplary embodiment of a catheter.

[0057] Fig. 3 shows the implantable medical device of figure 1 arranged in a protector cup of another exemplary embodiment of the catheter.

[0058] 24.133P-WO / 10.12.2025 Fig. 4 shows a perspective view of an exemplary embodiment of an alignment torquer of the catheter.

[0059] Fig. 5 shows a side view of the alignment torquer of figure 4 and an exemplary embodiment of a stylet.

[0060] Fig. 6 shows a cross-sectional side view of an exemplary embodiment of an implantable medical device and two different cross-sectional top views of the implantable medical device.

[0061] Fig. 7 shows a cross-sectional side view of an exemplary embodiment of an implantable medical device and a cross-sectional top view of the implantable medical device.

[0062] Fig. 8 shows a flow-chart of an exemplary embodiment of a method for implanting the implantable medical device.

[0063] The figures are only schematic and not to scale. Same reference signs refer to same or similar features.

[0064] Fig. 1 shows a side view of an exemplary embodiment of an implantable medical device (IMD) 20. The IMD 20 may be an implantable intracardiac device, such as e.g. an implantable intracardiac pacemaker, in particular an Active Intracardiac Medical Device (AIMD), also known as implantable leadless (intracardiac) pacemaker (ILP), which may be entirely implanted into a tissue of a heart’s chamber or atrium of a patient. The patient may be a human or an animal.

[0065] The IMD 20 comprises a housing 22, a first electrode 30 exposed to surroundings of the IMD 20, an electronic circuit 46 (see figs. 6 and 7) arranged within the housing 22, an energy source 48 arranged within the housing 22, and an electrode member 32. The housing 22 has a proximal end 26 and a distal end 28. The IMD 20 may have a cylindrical shape with a longitudinal axis extending from the proximal end 26 of the housing 22 to the distal end 28 of the housing 22. In particular, the housing 22 may have a cylindrical shape.

[0066] 24. 133P-WO / 10.12.2025 The first electrode 30 may be arranged at the housing 22 between the proximal end 26 and the distal end 28. The first electrode 30 may be exposed to surroundings of the IMD 20.

[0067] The electrode member 32 has at least one second electrode 36 exposed to the surroundings of the IMD 20. The second electrode 36 is electrically coupled to the electronic circuit 46. The electrode member 32 has a proximal section 42 and a distal section 44. The proximal section 42 of the electrode member 32 is arranged at the distal end 28 of the housing 22 and extends away from the housing 22 in distal direction. The distal section 44 of the electrode member 32 is arranged at the proximal section 42 and extends away from the proximal section 42 in distal direction. One of the sections 42, 44 is flexible and the other one of the sections 42, 44 is rigid. For example, the proximal section 42 is flexible. In this case, the distal section 44 is rigid. In an alternative embodiment (not shown), the distal section 44 may be flexible and the proximal section 42 may be rigid. The electrode member 32 may have a length in a range from 10 mm to 100 mm, e.g., from 15 mm to 70 mm. In particular, the flexible section may have a length in a range from 9 mm to 50 mm, e.g., from 10 to 50 mm, and / or the rigid section may have a length in a range from 1 mm to 50 mm, e.g., from 5 mm to 20 mm. The electrode member 32 may comprise or may be made of an electrically conductive material, e.g., platinum iridium or nitinol. The electrode member 32 may be electrically insulated against its surroundings, except for the second electrode 36.

[0068] The electrode member 32 may comprise a sharp tip 34 at a distal end 54 of the electrode member 32. In other words, the tip 34 may be spiky or pointed. A distal end region of the electrode member 32 may be helically shaped, as it is known in the art. The distal end region may range from the distal end 54 of the electrode member 32 in proximal direction. The helically shaped distal end region of the electrode member 32 may consist of a connection part coupled to the housing 22, of the tip 34 facing away from the housing 22, and of a helical section or helix extending from the connection part to the tip 34. A length of the distal end region may be in a range from 0.1% to 20% of the length of the electrode member, e.g., from 0.5% to 10%, e.g., from 1% to 5%. A diameter of the electrode member 32 may be reduced compared to conventional electrode members 32. For example, an outer diameter of the

[0069] 24.133P-WO / 10.12.2025 electrode member 32 within the distal and / or proximal sections 44, 42 may be in a range from 0.5 mm to 2 mm.

[0070] The helically shaped distal end region may be screwed into the tissue when inserting the electrode member 32 farther into the tube 24. As such, the helically shaped distal end region of the electrode member 32 may contribute to fix the IMD 20 at the tissue of the patient. In any case, the electrode member 32 may be formed and arranged such that it may penetrate the ventricular septum of the patient.

[0071] Alternatively, the electrode member 32 may be spear-shaped. In particular, the distal end region of the electrode member 32 may be spear-shaped. The spear-shaped electrode member 32 may be referred to as “electrode spear” or “electrode rod”.

[0072] The electrode member 32 has at least one second electrode 36 exposed to the surroundings of the IMD 20. The second electrode 36 may be arranged at a distal end of the electrode member 32. In particular, the second electrode 36 may be formed at the tip 34 or the tip 34 may be formed by the second electrode 36. The second electrode 36 may be arranged within the distal end region of the electrode member 32. For example, the second electrode 36 may extend from the distal end 54 of the electrode member 32 in proximal direction. For example, the range over which the second electrode 36 ranges starting from the tip 34 may correspond to the distal end region of the electrode member 32. The second electrode 36 is electrically coupled to the electronic circuit 46. The second electrode 36 may be directly connected to the energy source 48 or may be coupled to the energy source 48 via the electronic circuit 46. The second electrode 36 may be a cathode. The second electrode 36 may comprise or may be made of platinum and / or iridium. The first electrode 30 may act as a return electrode or anode. Alternatively, the second electrode 36 may be an anode and the first electrode 30 may be a cathode. The second electrode 36 may be referred to as pacing electrode. The second electrode 36 may be extended to provide a means for accessing the conduction system, e.g., HIS bundle or Left bundle branch).

[0073] Optionally, the proximal section 42 is lumenless, and / or the distal section 44 is lumenless, in other words solid. In case of both sections 42, 44 being lumenless, the whole electrode

[0074] 24.133P-WO / 10.12.2025 member 32 may be lumenless. Alternatively, an electrically conductive lead (not shown) may extend through the electrode member 32 up to the second electrode 36 for coupling the second electrode 36 to the electronic circuit 46. The lead may be helically-shaped and / or coiled, e.g., at distinct pitches, in particular in the flexible section, for strain relief and / or in order to allow the flexibility of the flexible section while ensuring a proper electric coupling of the second electrode 36 to the electronic circuit 46.

[0075] Optionally, a third electrode 50 may be arranged at the rigid and / or distal section 44. The third electrode 50 may be exposed to the surroundings of the IMD 20. The third electrode 50 may be electrically coupled to the electronic circuit 46. Optionally, one or more further electrodes (not shown) may be arranged at the housing 22 to provide additional electromagnetic vectors. One or more of the further electrodes may be arranged along the length of the electrode member 32 to provide more areas of pacing capture along the septum.

[0076] The IMD 20 may comprise two or more tines 40 for fixing the IMD 20 to the tissue, as it is known in the art. The tines 40 may be arranged at the distal end 28 of the housing 22. The tines 40 may at least partly extend in distal direction. The tines 40 may be configured for attaching the IMD to the tissue of the patient. The tines 40 may have a higher profile than conventional tines known in the art. The tines 40 may be selectively coated on their respective tips with a material to improve radiopacity, such as gold, for example. The tines 40 each may be made of a super-elastic material, such as Nitinol, for example. The tines 40 may be attached to the housing 22 by a header assembly (not shown in detail) that enables rotation but not detachment from the housing 22. The tines 40 may be optimized to be implanted into the trabeculated septal wall but to keep the housing 22 slightly distant from the wall to allow passage of the electrode member 32.

[0077] The IMD 20 may comprise a hitch 38 for grabbing the housing 22. The hitch 38 may be fixedly arranged at the housing 22 at the proximal end 26 of the housing 22. The hitch 38 may be arranged at the housing 22 such that the hitch 38 cannot be rotated relative to the housing 22. For example, the hitch 38 and at least a part of the housing 22 may be made of one piece. The hitch 38 may enable to insert or to retract the housing 22 from the body of

[0078] 24.133P-WO / 10.12.2025 the patient, e.g., by a catheter. In addition, the hitch 38 may enable to rotate the housing 22 relative to the body.

[0079] The electronic circuit 46 is arranged within the housing 22 and is electrically coupled to the energy source 48 and the first electrode 30. The energy source 48 may be a battery. The first electrode 30 may be directly connected to the energy source 48 or may be coupled to the energy source 48 via the electronic circuit 46.

[0080] The IMD 20 represents a leadless conduction system pacemaker (LCSP) concept utilizing a tine-based fixation mechanism, i.e., the tines 40. It is comprised of two components. One of these components may be referred to as Implantable Pulse Generator (IPG). The IPG comprises the housing 22, the energy source 48, the electronic circuit 46, and the tines 40. The most distal part of the IPG may be the distal end 28 of the housing 22 or the tines 40. A second one of these components comprises or is the electrode member 32 which has the flexible and rigid sections.

[0081] Optionally, the IMD 20 may comprise one or more third electrodes 50 at the electrode member 32, with each of the third electrodes 50 being exposed to the surroundings of the IMD 20. The first and second electrodes 30, 36 enable to form a first electric field within the body. The first electrode 30 and in case the third electrodes 50 may correspondingly form two or more further electric fields within the body. The third second electrodes 50 may be arranged more proximal on the electrode member 32 than the second electrode 36 mentioned further above, e.g., to provide more areas of pacing capture along the septum. Optionally, additional first electrodes 30 may be arranged at the housing 22 to provide additional vectors of corresponding electric fields.

[0082] Fig. 2 shows the IMD 20 of figure 1 arranged in a protector cup 56 of an exemplary embodiment of a catheter. The catheter may be used for implanting the IMD 20 into the body of the patient. The catheter comprises the protector cup 56 as distal section of a first shaft and a stabilizing sheath 60 as distal section of an outer shaft. The protector cup 56 is configured for accommodating the IMD 20. The protector cup 56 has a proximal end and a distal end. The stabilizing sheath 60 is arranged at the protector cup 56 such that it extends

[0083] 24.133P-WO / 10.12.2025 away from the protector cup 56 in distal direction. The IMD 20 is accommodated within the protector cup 56 such that the electrode member 32 protrudes from the protector cup 56 in distal direction. The stabilizing sheath 60 is formed and arranged such that the electrode member 32 is held by the stabilizing sheath 60. In particular, a distal end of the stabilizing sheath 60 may be formed and arranged such that it touches the electrode member 32, e.g., at the distal section 44, and centerers the electrode member 32 with respect to a longitudinal axis of the IMD 20. The stabilizing sheath 60 may enable to guide the at least partly flexible electrode member 32 when implanting the IMD 20.

[0084] The stabilizing sheath 60 may be formed by one piece or may comprise two or more pieces. The stabilizing sheath 60 may be tube shaped having a tapered portion 64 extending from a distal end of the protector cup 56 to the electrode member 32. An inner diameter of the stabilizing sheath 60 may decrease within the tapered portion 64 in distal direction. In this case, the stabilizing sheath 60 may be formed by one piece only. For example, an outer diameter of the stabilizing sheath 60 may decrease from the distal end of the protector cup 56 in distal direction such that an inner diameter of the stabilizing sheath 60 at its distal end at least approximately corresponds to an outer diameter of the electrode member 32. Alternatively, the stabilizing sheath 60 may comprise two separate sub-sheets each extending from a side of the protector cup 56 to the electrode member 32, wherein the subsheets are arranged at opposing sides of the protector cup 56. In this case, the “inner diameter” refers to a clear width between the sub-sheets. For example, the stabilizing sheath 60 may be splitable and may be removed from the electrode member 32 after its implantation. The stabilizing sheath 60 may be braided with a material, e.g., such as Nitinol, in particular in its distal end region, to provide sufficient strength during deployment of the electrode member 32.

[0085] The first shaft (not shown) comprising the protector cup 56 as distal section may be arranged within the outer shaft (not shown) comprising the stabilizing sheath 60 as distal section. The first shaft may be movable with respect to the outer shaft.

[0086] In this embodiment, the electrode member 32 may be lumenless and may extend beyond a transition from the proximal section 42 to the distal section 44, in particular when the

[0087] 24.133P-WO / 10.12.2025 proximal section 42 is the flexible section. The delivery catheter may be pre-shaped and may be steerable in at least one direction, wherein the pre-shape of the catheter may result in a corresponding bending and thereby pre-shaping of the electrode member 32, in particular of the flexible section of the electrode member 32. During implant, the delivery catheter may be navigated to the mid-septal wall of the heart. The first to third electrodes 30, 36, 50 may be used to identify the correct location for cathode placement. Once the target location is confirmed, the catheter having the protector cup and thereby the IMD 20 may rotated with respect to the body of the patient to advance the helically shaped second electrode 32 into the septal wall. Testing may be performed to confirm pacing capture of the conduction system. Next, stiffened nubs (not shown) on the protector cup 56 may enable the splitable stabilizing sheath 60 to be removed. Thereby, the flexible proximal section 42 of the electrode member 32 is exposed. The protector cup 56 may then navigated to the mid to lower septal wall region. Then, the IPG may be advanced, enabling the tines 40 to secure the IMD 20 to the myocardium. A notch (not shown) in the protector cup 56 may allow the electrode member 32 to exit the protector cup 56 while tips of the tines 40 may be pressed flush against the myocardium to engage with the tissue for IMD 30 deployment.

[0088] Fig. 3 shows the IMD 20 of figure 1 arranged in the protector cup 56 of another exemplary embodiment of the catheter. The catheter may correspond to the catheter explained with respect to figure 2, except for the stabilizing sheath 60. In particular, the catheter according to figure 3 may not comprise any stabilizing sheath 60. Instead, the electrode member 32, in particular the proximal section 42 and optionally the distal section 44, may have a through hole 76 axially extending in distal direction (see figures 6 and 7) and a stylet 58 for moving, in particular bending, the flexible proximal section 42 may be arranged within the through hole 76, as explained in more detail with respect to figure 5 below.

[0089] During implant the steerable, optionally pre-shaped delivery catheter may be navigated to the mid-septal wall with the stylet 58 being straight and arranged within the through hole. That the catheter may be pre-shaped may mean that the flexible section may be bended before implanting the IMD 20. The first and second electrodes 30, 36 may be used to identify the correct location for cathode placement. Once the target location is confirmed, the IMD 20 may be rotated by the catheter to advance the helically shaped second electrode 36 into

[0090] 24.133P-WO / 10.12.2025 the septal wall. Testing may be performed to confirm conduction system pacing capture. The stylet 58 then may be removed from the IMD 20 to expose the flexible proximal section 32 of the electrode member 32. Then, the protector cup 56 may be navigated to the mid to lower septal wall region. The IPG may be advanced, enabling the tines 40 to secure the housing 22 to the myocardium.

[0091] Fig. 4 shows a perspective view of an exemplary embodiment of an alignment torquer 70 as distal section of an inner catheter (not shown) of the catheter. The alignment torquer 70 may at least in part extend through the protector cup 56 in distal direction. The alignment torquer 70 may comprise a recess 72 for accommodating the hitch 38 of the IMD 20. The recess 72 may be formed at a distal end of the alignment torquer 70. The alignment torquer 70 may be configured for rotating the IMD 20 via the hitch 38 being arranged in the recess 72. The recess 72 may have a negative form with respect to the hitch 38 such that the hitch 38 may be inserted into the recess 72 tightly. In other words, there may a form-fit between the hitch 38 and the recess 72 as, for example, between a plug and the corresponding socket.

[0092] Fig. 5 shows a side view of the alignment torquer 70 of figure 4 and an exemplary embodiment of the stylet 58. The alignment torquer 70 may have a hole (not shown) which extends through the alignment torquer 70 in axial direction and which opens out into the recess 72. The hole may be configured for accommodating at least a part of the stylet 58. In other words, the stylet 58 may extend in axial direction through the hole of the alignment torquer 70. So, the alignment torquer 70 may be configured and used for grabbing, moving, and / or rotating the hitch 38 and thereby the whole IMD 20, whereas the stylet 58 may be configured and used for grabbing, moving, and / or rotating the electrode member 32 and thereby the pacing electrode, i.e., the second electrode 36.

[0093] The electrode member 32 may have a locking part (not shown) of a locking mechanism at its proximal end 52. The locking part may be configured for being mechanically coupled to a counter locking part 74 of the locking mechanism. The counter locking part 74 may be formed at a distal end of the stylet 58. The counter locking part 74 may be configured for mating the locking part. The locking mechanism may be configured such that the electrode member 32 can be moved by the stylet 58 when the counter locking part 74 of the stylet 58

[0094] 24.133P-WO / 10.12.2025 is engaged with the locking part of the electrode member 32. The locking part and the counter-locking part 74 may be formed such that the electrode member 32 and / or the tip 34 of the electrode member 32 are pushable, pullable, and / or rotatable by the stylet 58 when the locking part is mechanically coupled to the counter-locking part 74. The locking mechanism may enable to fixedly arrange the stylet 58 at the electrode member 32.

[0095] The locking mechanism may principally work by a form-fit, e.g., corresponding to a bayonet attachment. For example, the counter-locking part 74 of the stylet 58 may be inserted into the locking part of the electrode member 32. Then, counter-locking part 74 may be rotated within the locking part, e.g., at about 90 degrees, such that the counter-locking part 74 engages in the locking part. For example, the locking part may comprise a protrusion under which the counter-locking part 74 may be rotated such that the counter-locking part 74 is engaged in the locking part after the rotation. Then, the stylet 58 cannot be separated from the electrode member 32 by pushing or pulling it parallel to the distal direction. Then, a translational pushing-force in distal direction or a retraction pulling-force in proximal direction may be transferred to the electrode member 32 by the stylet 58. In addition, the locking mechanism may be configured such that when the counter locking part 74 is rotated such that it engages with the locking part and when the counter locking part 74 is rotated further in the same direction of rotation, the rotation may be transferred to the electrode member 32 such that the electrode member 32 is rotated. This may be used to screw the helically shaped distal end region of the electrode member 32 into the tissue. To remove the stylet 58 it may be rotated back 90 degrees and may be withdrawn from the electrode member 32 in proximal direction.

[0096] Fig. 6 shows a cross-sectional side view of an exemplary embodiment of the IMD 20 and two different cross-sectional top views of the IMD 20. The IMD 20 shown in figure 6 may widely correspond to the IMD 20 explained with respect to figure 1. Therefore, only those features of the IMD 20 shown in figure 6 are described in the following in which the IMD 20 of figure 6 differs from the IMD 20 shown in figure 1 or which are not visible in figure 1.

[0097] 24.133P-WO / 10.12.2025 The housing 22 may have a through hole 76 extending from the proximal end 26 to the distal end 28 and to the electrode member 32. The through hole 76 may be configured for accommodating the stylet 58 for moving the electrode member 32. The through hole 76 may be surrounded by a tube 78 of the housing 22. The tube 78 may extend from the proximal end 26 of the housing 22 to the distal end 28 of the housing 22. The stylet 58 may be a part of the catheter for implanting the IMD 20. Alternatively, the stylet 58 may be a component of the IMD 20 and may be grabbed and / or rotated by the catheter.

[0098] During deployment of the IMD 20, the electrode member 32 may be moved and / or pushed into the heart tissue by the stylet 58 until the second electrode 36 on the electrode member 32 reaches the conduction system of the heart. The stylet 58 may be used for bending the flexible section of the electrode member 32. The stylet 58 may be used for rotating the electrode member 32. This may be especially advantageous when the distal end region of the electrode member 32 is helically shaped. In this case, the stylet 58 may rotate the electrode member 32 and thereby the tip 34 with respect to the housing 22 such that the helically shaped end region including the tip 34 may be screwed into the tissue.

[0099] In case of the through hole 76 extending through the IPG, the energy source 48 and the electronic circuit 46 may be arranged one after the other in distal direction and the through hole 76 extends through the energy source 48 and the electronic circuit 46. In this case, the energy source 48 and the electronic circuit 46 may be arranged on top of each other, in case of the IMD 20 being arranged such that its axis is vertically oriented. This configuration of the energy source 48 and the electronic circuit 46 may be referred to as donut-configuration.

[0100] In case of the through hole 76 for the stylet 58 extending through the housing 22, the through hole 76 may extend through the hitch 38.

[0101] The tube 24 surrounds a through hole 50 extending through the housing 22, in particular the tube 24, from the proximal end 26 of the housing 22 to the distal end 28 of the housing 22. In other words, the through hole 50 of the housing 22 may be formed by the hollow tube 42 of the housing 22. So, the housing 22 may comprise the tube 24 and a hollow cylinder for accommodating the electronic circuit 46, the energy source 48, and the tube 24. The housing

[0102] 24. 133P-WO / 10.12.2025 22 and / or in particular the tube 24 may comprise or may be made of metal. The housing 22 may be fluid-tightly sealed against its environment. The housing 22 may comprise or may be made of metal.

[0103] Fig. 7 shows a cross-sectional side view of an exemplary embodiment of an IMD 20 and a cross-sectional top view of the IMD 20. The IMD 20 shown in figure 7 may widely correspond to the IMD 20 explained with respect to figure 1. Therefore, only those features of the IMD 20 shown in figure 7 are described in the following in which the IMD 20 of figure 7 differs from the IMD 20 shown in figure 1 or which are not visible in figure 1.

[0104] In this embodiment, the energy source 48 and the electronic circuit 46 are arranged perpendicularly to the distal direction next to each other and the tube 24, in particular the through hole 50, extends between the energy source 48 and the electronic circuit 46. In this case, the energy source 48 and the electronic circuit 46 are arranged horizontally next to each other, in case of the IMD 20 being arranged such that its axis is vertically oriented. This configuration of the energy source 48 and the electronic circuit 46 may be referred to as clamshell-configuration.

[0105] Fig. 8 shows a flow-chart of an exemplary embodiment of a method for implanting the IMD 20. The IMD 20 may be implanted by using the stabilizing sheath 60 or the stylet 58.

[0106] In a step S2, the IMD 20 may be implanted within the body of the patient such that the electrode member 32 is at least partly arranged within the tissue of the patient. For example, in case of the proximal section 42 being the flexible section of the electrode member 32, the distal section 44 may at least partly, e.g., completely arranged within the tissue of the patient. For example, the electrode member 32 may be fixed within the tissue by screwing the distal end region of the electrode member 32 into the tissue, e.g., by the stylet 58. In particular, the helically shaped pacing electrode may be deployed into the RV septum to access the conduction system (e.g., His Bundle or Left Bundle Branch / Left Bundle Branch Area). The distal section 44 may be arranged to access and pace the conduction system of the patient.

[0107] 24.133P-WO / 10.12.2025 The IMD 20 may be implanted at different angles for a jugular access and femoral access. With the jugular approach, the electrode member 32 may be steered to enter the right ventricle through the superior vena cava and right atrium, e.g., while the housing 22 is held at a higher location than the electrode member 32 with respect to the body, and may only require one curve at the flexible section to reach the right ventricular septum. In contrast, with a femoral approach, the electrode member 32 may be steered to enter the right ventricle through the inferior vena cava and right atrium, e.g., while the housing 22 is held at a lower location than the electrode member 32 with respect to the body, and may require two curves at the flexible portion to reach the right ventricular septum. Due to the length of the electrode member 32 having the sections 42, 44 and the need to implant the electrode member 32 prior to the IPG body, i.e., the housing, the jugular approach with only one curve may be preferred. The curves may be the result of steering the electrode member 32 and thereby bending the flexible section, e.g., by the catheter and / or the stylet 58. Alternatively, the curves within the flexible section may be the result of a corresponding pre-shape in the catheter, or stylet 58.

[0108] Optionally, when implanting the IMD 20 just before penetrating the tissue by the electrode member 32, the first and second electrodes 30, 36 may be used to identify the correct location for cathode placement. Once the target location is confirmed, the electrode member 32 may be rotated to advance the helically shaped second electrode 36 into the septal wall. Then, in case of using the stabilizing sheath 60 for implanting the IMD 20, stiffened nubs (not shown) on the protector cup 56 may enable the stabilizing sheath 60 to be removed such that the flexible region of the electrode member 32 is exposed to the surroundings of the IMD 20.

[0109] In an optional step S4, during the implantation a sensing procedure may be carried out to confirm the Conduction System (CS) capture. The sensing procedure may be carried out by using the second and / or third electrodes 36, 50. In case of the CS not being captured, the electrode member 32, in particular the distal section 44, may be moved again and / or may be rearranged at the tissue, e.g., by at least partly carrying out step S2 again. In case of the CS being captured, the method may proceed in step S6. In addition, one or more impedance measurements may be carried out, e.g., continually, to indicate any perforations of the second electrode 36 into the left ventricle.

[0110] 24.133P-WO / 10.12.2025 In step S6, the housing 22 of the IMD 20 may be moved relative to the tissue and relative to the electrode member 32, in particular to the fixed distal section 44 of the electrode member 32, such that the flexible section of the electrode member 32 is bend. In this step, the IPG may be arranged at location within the body at which the housing 22 and thereby a mass of the IPG may lie on a part of the tissue. For example, the housing 22 may be arranged on the septal wall of the heart, e.g., in a standard leadless pacing location. In this situation, a very large sensing vector may be achieved because of the very large distance from the second electrode 32 at the tip 32 of the electrode member 32 to the first electrode 30 at the housing 22. In particular, the sensing vector may be larger than in other, known leadless pacing technology platforms, enabling an improved far field sensing.

[0111] In a step S8, the housing 22 may be attached to the tissue of the patient, e.g., by the tines 40. For example, the tines 40 may be used to secure the housing 22 to the myocardium of the patient. A notch (not shown) in the protector cup 56 may allow the electrode member 32 to exit the protector cup 56 while tips of the tines 40 are pressed flush against the myocardium to engage with the tissue for device deployment.

[0112] Finally, it should be noted that the term “comprising” does not exclude other elements or steps and the “a” or “an” does not exclude a plurality. Also elements described in association with different embodiments may be combined. It should also be noted that reference signs in the claims should not be construed as limiting the scope of the claims.

[0113] 24.133P-WO / 10.12.2025 List of Reference Numerals

[0114] 20 IMD

[0115] 22 housing

[0116] 26 proximal end of housing

[0117] 28 distal end of housing

[0118] 30 first electrode

[0119] 32 electrode member

[0120] 34 tip

[0121] 36 second electrode

[0122] 38 hitch

[0123] 40 tine

[0124] 42 proximal section

[0125] 44 distal section

[0126] 46 electronic circuit

[0127] 48 energy source

[0128] 50 third electrode

[0129] 52 proximal end of electrode member

[0130] 54 distal end of electrode member

[0131] 56 protector cup

[0132] 58 stylet

[0133] 60 stabilizing sheath

[0134] 62 distal end of stabilizing sheath

[0135] 64 tapered portion

[0136] 66 locking mechanism

[0137] 70 alignment torquer

[0138] 72 recess

[0139] 74 counter locking part

[0140] 76 through hole

[0141] 78 tube

[0142] 24.133P-WO / 10.12.2025

Claims

Claims1. Implantable medical device (20), comprising: a housing (22) having a distal end (28) and a proximal end (26); a first electrode (30) being arranged at the housing (22) between the proximal end (26) and the distal end (28) and being exposed to surroundings of the implantable medical device (20); an energy source (48) arranged within the housing (22); an electronic circuit (46) arranged within the housing (22) and electrically coupled to the energy source (48) and the first electrode (30); and an electrode member (32) having at least one second electrode (36) exposed to the surroundings of the implantable medical device (20), with the second electrode (36) being electrically coupled to the electronic circuit (46), wherein the electrode member (32) has a proximal section (42) and a distal section (44), wherein the proximal section (42) of the electrode member (32) is arranged at the distal end (28) of the housing (22) and extends away from the housing (22) in distal direction, wherein the distal section (44) of the electrode member (32) is arranged at the proximal section (42) and extends away from the proximal section (42) in distal direction, and wherein one of the sections (42, 44) is more flexible and the other one of the sections (42, 44) is more rigid.

2. Implantable medical device (20) in accordance with claim 1, wherein the proximal section (42) is more flexible.

3. Implantable medical device (20) in accordance with one of the preceding claims, wherein the proximal section (42) is lumenless, and / or the distal section (44) is lumenless.

4. Implantable medical device (20) in accordance with one of the preceding claims, wherein a third electrode (50) is arranged at the rigid section,24.133P-WO / 10.12.2025the third electrode (50) is exposed to the surroundings of the implantable medical device (20), and the third electrode (50) is electrically coupled to the electronic circuit (46).

5. Implantable medical device (20) in accordance with one of the preceding claims, wherein the housing (22) has a through hole (50) extending from the proximal end (26) to the distal end (28) and to the electrode member (32), and the through hole (50) is configured for accommodating a stylet (58) for moving the electrode member (32).

6. Implantable medical device (20) in accordance with claim 5, wherein the energy source (48) and the electronic circuit (46) are arranged one after the other in distal direction and the through hole (50) extends through the energy source (48) and the electronic circuit (46), or the energy source (48) and the electronic circuit (46) are arranged perpendicularly to the distal direction next to each other and the through hole (50) extends between the energy source (48) and the electronic circuit (46).

7. Implantable medical device (20) in accordance with one of the preceding claims, wherein the electrode member (32) has a locking part of a locking mechanism (66) at its proximal end (52), the locking part is configured for being mechanically coupled to a counter locking part (74) of the locking mechanism (66), the counter locking part (74) is formed at a distal end of the stylet (58), the counter locking (74) part is configured for mating the locking part, and the locking mechanism (66) is configured such that the electrode member (32) can be moved by the stylet (58) when the counter locking part (74) of the stylet (58) is engaged with the locking part of the electrode member (32).24.133P-WO / 10.12.20258. Implantable medical device (20) in accordance with one of the preceding claims, comprising: two or more tines (40) being arranged at the distal end (28) of the housing (22), protruding from the housing (22) at least partly in distal direction, and being configured for attaching the implantable medical device (20) to a tissue of a patient.

9. Implantable medical device (20) in accordance with one of the preceding claims, comprising: a hitch (38) for grabbing the housing (22), wherein the hitch (38) is arranged at a proximal end (26) of the housing (22).

10. Catheter for implanting an implantable medical device (20) in accordance with one of the preceding claims into a body of a patient, the catheter comprising: a protector cup (56) for accommodating the implantable medical device (20), wherein the protector cup (56) has a proximal end and a distal end; a stabilizing sheath (60) being arranged at the protector cup (56) such that it extends away from the protector cup (56) in distal direction, wherein the stabilizing sheath (60) is formed and arranged such that the electrode member (32) is held by the stabilizing sheath (60), when the implantable medical device (20) is accommodated within the protector cup (56) such that the electrode member (32) protrudes from the protector cup (56) in distal direction.

11. Catheter in accordance with claim 10, wherein a distal end of the stabilizing sheath (60) is formed and arranged such that it touches the electrode member (32) and centers the electrode member (32) with respect to a longitudinal axis of the implantable medical device (20), when the implantable medical device (20) is accommodated within the protector cup (56) such that the electrode member (32) protrudes from the protector cup (56) in distal direction.

12. Catheter in accordance with claim 11, wherein an outer diameter of the stabilizing sheath (60) decreases from the distal end of the protector cup (56) in distal direction such that an inner diameter of the stabilizing24.133P-WO / 10.12.2025sheath (60) at its distal end at least approximately corresponds to an outer diameter of the electrode member (32).

13. Catheter in accordance with one of claims 10 to 12, comprising: an alignment torquer (70) at least in part extending through the protector cup (56) in distal direction and comprising a recess (72) for accommodating a hitch (38) of the implantable medical device (20), wherein the recess (72) is formed at a distal end of the alignment torquer (70) and wherein the alignment torquer (70) is configured for rotating the implantable medical device (20) via the hitch (38) being arranged in the recess (72).

14. System comprising a catheter, an implantable medical device according to claim 5 to 9 and a stylet, whereby the catheter comprises: a protector cup for accommodating the implantable medical device, wherein the protector cup has a proximal end and a distal end, and whereby the stylet is configured fit within the through hole.

15. The system according to claim 14, whereby the catheter comprises a lumen configured to accommodate the stylet.24.133P-WO / 10.12.2025

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