Implantable medical device 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 section (28), a proximal section (26), at least one first fixation means (44) at a lateral surface of the distal section (28), and a first electrode (30) 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); an electrode member (32) being arranged at a distal end (54) of the housing (22) such that it protrudes from the housing (22) in distal direction and having at least one second electrode (36) exposed to the surroundings of the implantable medical device (20), wherein the second electrode (36) is electrically coupled to the electronic circuit (46); and a tine sleeve (24) having a through hole (50) extending from a proximal end of the tine sleeve (24) to a distal end of the tine sleeve (24) and having two or more tines (40) protruding from the tine sleeve (24) and being configured for attaching the implantable medical device (20) to a tissue (42) of a patient, wherein the distal section (28) of the housing (22) is arranged within the tine sleeve (24) such that the electrode member (32) at the housing (22) extends through the through hole (50) of the tine sleeve (24), the tine sleeve (24) has at least one second fixation means (52) formed within the through hole (50), the housing (22) is fixed to the tine sleeve (24) by a collaboration of the first and second fixation means (44, 52), the first and second fixation means (44, 52) are configured such that the housing (22) is arrangeable within the tine sleeve (24) at varying depths, and a length over which the electrode member (32) protrudes from the tine sleeve (24) in distal direction depends on how far the housing (22) is arranged within the tine sleeve (24).

Description

[0001] Applicant: BIOTRONIK SE & Co. KG

[0002] Our Reference: 24.100P -WO

[0003] Date: 05.12.2025

[0004] IMPLANTABLE MEDICAL DEVICE AND METHOD FOR IMPLANTING THE

[0005] IMPLANTABLE MEDICAL DEVICE

[0006] The present invention refers to an implantable medical device, 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 sticked at a tine sleeve 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 pacing (right ventricular pacing).

[0009] Implantable leadless pacemakers 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 CSP (LBB or HB 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. In addition, 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. lOOP-WO / 05.12.2025 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, 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 electrode member of the IMD at varying depth in the tissue in a controllable manner.

[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 section, a proximal section, at least one first fixation means at a lateral surface of the distal section, and a first electrode 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; an electrode member being arranged at a distal end of the housing such that it protrudes from the housing in distal direction and having at least one second electrode exposed to the surroundings of the implantable medical device, wherein the second electrode is electrically coupled to the electronic circuit; and a tine sleeve having a through hole extending from a proximal end of the tine sleeve to a distal end of the tine sleeve and having two or more tines protruding from

[0015] 24. lOOP-WO / 05.12.2025 the tine sleeve and being configured for attaching the implantable medical device to a tissue of a patient, wherein the distal section of the housing is arranged within the tine sleeve such that the electrode member at the housing at least partly extends through the through hole of the tine sleeve, the tine sleeve has at least one second fixation means formed within the through hole, the housing is fixed to the tine sleeve by a collaboration of the first and second fixation means, the first and second fixation means are configured such that the housing is arrangeable within the tine sleeve at varying depths, and a length over which the electrode member protrudes from the tine sleeve in distal direction depends on how far the housing is arranged within the tine sleeve.

[0016] Another aspect refers to a method for implanting the IMD into a body of a patient. The method comprises: providing the IMD such that the at least one first fixation means of the housing is fixed to the at least one second fixation means of the tine sleeve such that the electrode member at least partly extends through the through hole; arranging the implantable medical device at the tissue of the patient within the body by the tines of the tine sleeve; and inserting the housing further into the tine sleeve until the second electrode at the electrode member is arranged at a depth within the tissue as intended for its use.

[0017] The features, advantages and embodiments of the 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.

[0018] The IMD represents a leadless pacemaker (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. The IMD utilizes a tined fixation mechanism represented by the tine sleeve and its tines that are separate from the pacing electrode, i.e., the second electrode. Once the tines are fixated, the pacing electrode can be driven into the septum until it reaches the conduction system of any given anatomy. The pacing electrode may be a piercing the tissue, in particular the interventricular septal wall. The ability to iteratively drive the pacing electrode into the tissue allows for continual pacing and IEGM (intracardiac electrogram) readings during the deployment of the pacing electrode and electrode member into the tissue. In other words, the

[0019] 24. lOOP-WO / 05.12.2025 tine sleeve anchors the whole IMD in the tissue. The stimulation depth of the pacing electrode is defined by the depth in which the housing is arranged within the tine sleeve.

[0020] 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. 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).

[0021] The housing of the IMD may enclose everything necessary for the stimulation. The dimensions of the housing of the leadless pacemaker (intracardiac pacemaker) as IMD may be designed to fit within a chamber of the human heart.

[0022] The electrode member may extend through the through hole of the tine sleeve such that at least a tip of the electrode member facing away from the housing protrudes from the tine sleeve at a side of the tine sleeve facing away from the housing. The electrode member may have a length in a range from 3 mm to 30 mm, e.g., from 5 mm to 20 mm. When arranging the IMD in the body such that at least the part of the protruding portion of the electrode member penetrates the tissue of the patient, the electrode member may penetrate the tissue at a depth ranging from 0 mm (excluded) to 20 mm, in particular 0.1 mm to 15 mm, in particular 0.1 mm to 12 mm, in particular 0.1 mm to 10 mm, in particular 0.2 mm to 7 mm, in particular 0.3 mm to 5 mm. The farther the housing is screwed into the tine sleeve, the deeper the electrode member penetrates the tissue. So, when inserting the housing further into the tine sleeve, the electrode member may penetrate the tissue over its whole length.

[0023] The IMD may have a cylindrical shape with a longitudinal axis extending from a proximal end of the housing to a distal end of the tine sleeve. In particular, the housing and / or the tine sleeve each may have a cylindrical shape. In particular, the distal section and the proximal section of the housing each may have a cylindrical shape, wherein an outer diameter of the proximal section may correspond to an outer diameter of the tine sleeve and wherein an outer diameter of the distal section may correspond to an inner diameter of the tine sleeve.

[0024] 24.100P-WO / 05.12.2025 The IMD as described in this description represents a leadless conduction system pacemaker (LCSP) concept utilizing a tine-based fixation mechanism. It is comprised of two components. One of these components which may be referred to as Implantable Pulse Generator (IPG), comprises the housing, the energy source and the electronic circuit and fits within the inner diameter of the tine-sleeve. The housing may comprise or may be made of metal, in particular titanium. A second one of these components comprises or is the tinesleeve which comprises, holds or houses the tines. The most distal part of the IPG may be the tip of the electrode member.

[0025] The LCSP may be fixed to the tissue via delivery catheter in two instances into the ventricular septum. A first step instance involves the above mentioned arranging of the IMD in the body by deploying and fixating the tines in the tissue. This may be done with the housing and thereby the electrode member and in a retracted state. It may have an initial protrusion, e.g., the tip, to begin the process of reaching the conduction system, but it will be mostly in a retracted state. A second instance involves inserting the housing further into the tine sleeve and thereby deeper penetrating the tissue by the electrode member. This may be done iteratively and stopped whenever the conduction system is reached within each individual patient anatomy.

[0026] According to an embodiment, the first fixation means comprises an outer thread formed at a lateral surface of the distal section of the housing and the second fixation means comprises an inner thread formed at an inner surface of the tine sleeve, or the first fixation means comprises first latching means formed at a lateral surface of the distal section of the housing and the second fixation means comprises counter latching means formed at an inner surface of the tine sleeve. The threads as well as the latching means enable to arrange the housing at the tine sleeve with the distal section of the housing being arranged within the tine sleeve at varying depths in an easy and controllable manner. This enables to arrange the second electrode at varying depths within the tissue in an easy and controllable manner. In addition, the threads may enable to remove the already implanted housing (e.g. the IPG) from the tine sleeve and to explant the housing only, e.g., in order to exchange the energy source. This may be especially advantageous, if the energy source is a battery and if the battery is empty or reached its end of life. In this case, the tine sleeve can be left at the tissue. This may enable

[0027] 24. lOOP-WO / 05.12.2025 to not damage the tissue again after removing the tine sleeve and then by re-implanting the tine sleeve and by penetrating the tissue with the tines again.

[0028] The outer thread mates to the inner thread such that the outer thread may be screwed into the inner tread. Thereby, the housing may be fixed to the tine sleeve by the outer thread being screwed into the inner thread. The first latching means are configured for being latched into the counter latching means. Thereby, the housing may be fixed to the tine sleeve by the first latching means being latched into the second latching means. The first latching means may comprise barbs or hooks bended in a first direction and / or the second latching means may comprise barbs or hooks bended in a second direction opposite to the first direction.

[0029] The second instance mentioned above involves inserting the housing further into the tine sleeve and thereby deeper penetrating the tissue by the electrode member by rotating the housing with respect to the tine sleeve what will telescope the second electrode deeper into the tissue. Another embodiment of this solution would be a friction-based translation mechanism. Instead of mating the tine sleeve to the IPG with threads, there is a press-fit interaction. During deployment, the tines are anchored to the tissue, then the tine sleeve is held in place by the catheter tip / protector cup, and the IPG is pushed into the heart tissue until the pacing electrode on the electrode extension reaches the conduction system of the heart. This can also be controlled by a locking mechanism where the IPG is mated to the tine sleeve via a keyed lock.

[0030] A 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.

[0031] According to an embodiment, the electrode member is spear-shaped; or the electrode member is helically shaped; or the electrode is cylindrically shaped. The spear-shaped

[0032] 24. lOOP-WO / 05.12.2025 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. The same applies to the cylindrically shaped electrode, whereby the cylindrically shaped electrode may comprise a tapered distal end (tip). The helically shaped 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 electrode member may be screwed into the tissue when inserting the housing into the tine sleeve. As such, the helically shaped electrode member may contribute to fix the implantable medical device at the tissue of the patient. 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.

[0033] According to an embodiment, the electrode member comprises a sharp tip at the distal end of the electrode member. In other words, the tip may be spiky or pointed. The sharp tip enables to penetrate the tissue easily and with minimal impact on the tissue.

[0034] According to an embodiment, the second electrode is arranged at the distal end of the electrode member. This enables to insert the second electrode at a maximal depth within the tissue. The distal end which has the sharp tip is the same distal tip at which the second electrode is arranged. In particular, the second electrode may be formed at the tip and / or the tip may be formed by the second electrode. In addition, this allows 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 far field atrial sensing and AV (atrioventricular) synchrony, while the vector is maintained regardless of the pacing electrode depth.

[0035] According to an embodiment, the IMD comprises: two or more further second electrodes at the electrode member, with each of the further second electrodes being exposed to the surroundings of the implantable medical device. The first and second electrodes enable to form a first electric field within the body. The arrangement of the further second electrodes

[0036] 24. lOOP-WO / 05.12.2025 enables to form two or more electric fields within the body. The further second electrodes may be arranged more proximal on the electrode member than the second electrode mentioned further above, e.g., to provide more areas of pacing capture along the septum. Optionally, additional first electrodes may be arranged at the housing to provide additional vectors of corresponding electric fields.

[0037] According to an embodiment, the first electrode is an anode, and / or the second electrode is a cathode. Alternatively, the second electrode may be an anode, and / or the first electrode may be a cathode.

[0038] According to an embodiment, the IMD comprises: a hitch for grabbing the housing and for rotating the housing relative to the tine sleeve, wherein the hitch is arranged at a proximal end of the housing. The hitch may enable to insert or to retract the housing from the tine sleeve. For example, in case of the fixation means being the threads, when rotating the housing relative to the tine sleeve, the outer thread of the housing may be screwed into or out of the inner thread of the tine sleeve depending on a direction of the rotation.

[0039] According to an embodiment, a lateral surface of the proximal section of the housing flushes with a lateral surface of the tine sleeve. This may enable to provide a large battery as the energy source, thereby enabling to provide an energy source having a very large battery capacity. In addition, this may contribute to keep an impact on the body and in particular on the tissue very small. Optionally, the lateral surface of the distal section of the housing flushes with the inner surface of the through hole of the tine sleeve. In this case, there may be a step at the transition from the proximal section to the distal section of the housing. It has to be mentioned in this context that any “lateral” surface of a body always refers to an outer lateral surface of the corresponding body in this description.

[0040] According to an embodiment, the implantable medical device is provided such that the electrode member at least partly protrudes from the tine sleeve at the side of the tine sleeve facing away from the housing, and the implantable medical device is arranged at the tissue of the patient such that at least a tip of the electrode member penetrates the tissue.

[0041] 24. lOOP-WO / 05.12.2025 According to an embodiment, the method comprises: testing whether the second electrode is arranged at the depth within the tissue as intended for its use, after the implantable medical device is arranged within the body; inserting the housing further into the tine sleeve when the electrode member is not arranged deep enough within the tissue as intended for its use; and retracting the housing from the tine sleeve when the electrode member is arranged too deep within the tissue as intended for its use. This enables to ensure that the second electrode as the pacing electrode is located at the correct position, in particular at the correct depth, within the tissue.

[0042] According to an embodiment, it is tested whether the second electrode is arranged at the depth within the tissue as intended for its use, by applying a voltage over the first and second electrodes by the electronic circuit and the energy source and by monitoring and analyzing a current flow through the first and second electrodes resulting from the applied voltage. This enables to simply test whether the second electrode is arranged at the depth within the tissue as intended for its use. The analyzing of the current may involve one or more impedance measurements which may be collected continually to indicate any perforations of the electrode member within the left ventricle, in particular a sudden drop in impedance may indicate a perforation of the left ventricle.

[0043] 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.

[0044] Fig. 1 shows a side view of an exemplary embodiment of an implantable medical device in a first state.

[0045] Fig. 2 shows the implantable medical device of figure 1 in a second state.

[0046] Fig. 3 shows a side view of an exemplary embodiment of an implantable medical device in a first state.

[0047] Fig. 4 shows the implantable medical device of figure 3 in a second state.

[0048] 24.100P-WO / 05.12.2025 Fig. 5 shows a detailed view of an alternative embodiment of fixation means of the implantable medical device.

[0049] Fig. 6 shows a flow-chart of an exemplary embodiment of a method for implanting the implantable medical device.

[0050] The figures are only schematic and not to scale. Same reference signs refer to same or similar features.

[0051] Fig- 1 shows a side view of an exemplary embodiment of an implantable medical device (IMD) 20 in a first state. 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 pacemaker (ILP), which may be entirely implanted into a tissue 42 of a heart’s chamber or atrium of a patient. The patient may be a human or an animal.

[0052] The IMD 20 comprises a housing 22, an electronic circuit 46 arranged within the housing 22, an energy source 48 arranged within the housing 22, an electrode member 32, and a tine sleeve 24.

[0053] The housing 22 has a proximal section 26, a distal section 28, at least one first fixation means 44 at a lateral surface of the distal section 28, and a first electrode 30 exposed to surroundings of the IMD 20. The housing 22 may comprise or may be made of metal.

[0054] 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.

[0055] The electrode member 32 is arranged at a distal end 54 (see figure 2) of the housing 22 such that it protrudes from the housing 22 in distal direction. The electrode member 32 may have

[0056] 24. lOOP-WO / 05.12.2025 a length in a range from 3 mm to 30 mm, e.g., from 5 mm to 20 mm. The electrode member 32 may comprise or may be made of an electrically conductive material. 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 the distal end 54 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).

[0057] The electrode member 32 may be spear-shaped, as shown in figure 1. Thes pear-shaped electrode member 32 may be referred to as “electrode spear” or “electrode rod”. The spearshape of the electrode member 32 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 32. The electrode member 32 may comprise a sharp tip 34 at the distal end of the electrode member 32. In other words, the tip 34 may be spiky or pointed. The distal end of the electrode member 32 which has the sharp tip 34 may be the same distal end at which the second electrode 36 is arranged. 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.

[0058] In an alternative embodiment, the electrode member 32 may be helically shaped, as it is known in the art. The helically shaped 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 (not shown) extending from the connection part to the tip 34. The helically shaped electrode member 32 may be screwed into the tissue 42 when inserting the housing 22 farther into the tine sleeve 24. As such, the helically shaped electrode member 32 may contribute to fix the IMD 20 at the tissue 42 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.

[0059] 24. lOOP-WO / 05.12.2025 The tine sleeve 24 is configured for attaching the IMD 20 to the tissue 42. The tine sleeve 24 has a through hole 50 extending from a proximal end of the tine sleeve 24 to a distal end of the tine sleeve 24. The distal section 28 of the housing 22 is arranged within the tine sleeve 24 such that the electrode member 32 at the housing 22 at least partly, e.g., completely, extends through the through hole 50 of the tine sleeve 24. The tine sleeve 24 has two or more tines 40 protruding from the tine sleeve 24, e.g., at least partly in distal direction. The tine sleeve 24 has at least one second fixation means 52 formed within the through hole 50. The housing 22 is fixed to the tine sleeve 24 by a collaboration of the first and second fixation means 44, 52.

[0060] The first and second fixation means 44, 52 are configured such that the housing 22 is arrangeable within the tine sleeve 24 at varying depths. A length over which the electrode member 32 protrudes from the tine sleeve 24 in distal direction on a side of the tine sleeve 24 facing away from the housing 22 depends on how far the housing 22 is arranged within the tine sleeve 24. The electrode member 32 may extend through the through hole 50 of the tine sleeve 24 such that at least a tip 34 of the electrode member 32 facing away from the housing 22 protrudes from the tine sleeve 24 at the side of the tine sleeve 24 facing away from the housing 22.

[0061] For example, the first fixation means 44 comprises an outer thread formed at a lateral surface of the distal section 28 of the housing 22 and the second fixation means 52 comprises an inner thread formed at an inner surface of the tine sleeve 24. The outer thread mates to the inner thread such that the outer thread may be screwed into the inner thread. Thereby, the housing 22 may be fixed to the tine sleeve 24 by the outer thread being screwed into the inner thread.

[0062] The IMD 20 may comprise a hitch 38 for grabbing the housing 22 and optionally for rotating the housing 22 relative to the tine sleeve 24, in particular when the fixation means 44, 52 are embodied as the outer and, respectively, inner threads. The hitch 38 may be fixedly arranged at the housing 22 at a proximal end 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

[0063] 24. lOOP-WO / 05.12.2025 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 tine sleeve 24, e.g., by a catheter. For example, in case of the fixation means 44, 52 being the threads, when rotating the housing 22 relative to the tine sleeve 24, the outer thread of the housing 22 may be screwed into or out of the inner thread of the tine sleeve 24 depending on a direction of the rotation.

[0064] When arranging the IMD 20 in the body such that at least the part of the electrode member 32 penetrates the tissue 42, the electrode member 32 may penetrate the tissue 42 at a first depth DI, e.g., ranging from 0 mm (excluded) to 10 mm, e.g., from 1 mm to 8 mm, corresponding to the first state of the IMD 20 shown in figure 1. The farther the housing 22 is inserted into the tine sleeve 24, in particular by screwing the housing 22 farther into the tine sleeve 24, the deeper the electrode member 32 penetrates the tissue 42. So, when inserting the housing 22 further into the tine sleeve 24, the electrode member 32 may penetrate the tissue 42 over its whole length (see figure 2).

[0065] The IMD 20 may have a cylindrical shape with a longitudinal axis extending from a proximal end of the housing 22 to a distal end of the tine sleeve 24. In particular, the housing 22 and / or the tine sleeve 24 each may have a cylindrical shape. In particular, the distal section 28 and the proximal section 26 of the housing 22 each may have a cylindrical shape. An outer diameter of the proximal section 26 may correspond to an outer diameter of the tine sleeve 24. In particular, a lateral surface of the proximal section 26 of the housing 22 may flush with a lateral surface of the tine sleeve 24. It has to be mentioned in this context that any “lateral” surface of a body always refers to an outer lateral surface of the corresponding body in this description. Optionally, an outer diameter of the distal section 28 may correspond to an inner diameter of the tine sleeve 24. In particular, the lateral surface of the distal section 28 of the housing 22 may flush with the inner surface of the through hole 50 of the tine sleeve 24. In this case, there may be a step at the transition from the proximal section 26 to the distal section 28 of the housing 22.

[0066] The IMD 20 represents a leadless conduction system pacemaker (LCSP) concept utilizing a tine-based fixation mechanism, i.e., the tine sleeve 24 having the tines 40. It is comprised of

[0067] 24. lOOP-WO / 05.12.2025 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 and the electronic circuit 46 and may fit within the inner diameter of the tine-sleeve 24. The most distal part of the IPG may be the tip 34 of the electrode member 32. A second one of these components comprises or is the tine-sleeve 24 which comprises, holds or houses the tines 40.

[0068] Optionally, the IMD 20 may comprise two or more further second electrodes 36 at the electrode member 32, with each of the further second electrodes 36 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 the further second electrodes 36 correspondingly form two or more further electric fields within the body. The further second electrodes 36 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.

[0069] Fig. 2 shows the IMD 20 of figure 1 in a second state. In the second state, the housing 22 is inserted into the tine sleeve 24 so far that the electrode member 32 completely penetrates the tissue 42. In this state, the tip 34 and optionally a distal end of the second electrode 36 are arranged at a second depth D2 within the tissue 42. Optionally, in the second state, the electrode member 32 may be arranged at the depth, i.e., the second depth D2, within the tissue 42 as intended for its use. In the embodiment shown in figures 1 and 2, the IMD 20 may be brought from the first to the second state by rotating the housing 22 into the tine sleeve 24, e.g., via the hitch 38.

[0070] Fig. 3 shows a side view of an exemplary embodiment of an IMD 20 in the first state. The IMD 20 and the first state shown in figure 3 may widely correspond to the IMD 20 and the first state of the IMD 20 described with respect to figure 1. Therefore and in order to provide a concise description and to avoid unnecessary repetitions, only that feature of the IMD 20 shown in figure 3 is explained in the following, in which the IMD 20 shown in figure 3 differs from the IMD 20 shown in figure 1.

[0071] 24. lOOP-WO / 05.12.2025 In the embodiment shown in figure 3, the housing 22 of the IMD 20 has the same circumference in the distal section 28 as in the proximal section 26.

[0072] Fig. 4 shows the IMD of figure 3 in a second state. The second state illustrated in figure 4 corresponds to the second state explained with respect to figure 2. Therefore, and in order to provide a concise description and to avoid unnecessary repetitions, it is referred to the description of figure 2 for further details of the second state.

[0073] Fig. 5 shows a detailed view of an alternative embodiment of fixation means 44, 52 of the IMD 20. As an alternative to the threads described above, the first fixation means 44 may comprise first latching means 58 formed at a lateral surface of a side wall 56 of the distal section 28 of the housing 22 and the second fixation means 52 may comprise counter latching means 60 formed at an inner surface of the tine sleeve 24. The latching means 44, 52 embody a form-fit between the housing 22 and the tine sleeve 24.

[0074] The first latching means 58 may be configured for being latched into the counter latching means 60. Thereby, the housing 22 may be fixed to the tine sleeve 24 by the first latching means 58 being latched into the second latching means 60. The first latching means 58 may comprise barbs or hooks bended in a first direction, e.g., in proximal direction, and / or the second latching means 60 may comprise barbs or hooks bended in a second direction, e.g., in distal direction, opposite to the first direction. The distal direction may correspond or may be parallel to an inserting direction 62 along which the housing 22 may be inserted into the tine sleeve 24.

[0075] The latching means 58, 60 enable to insert the housing 22 into the tine sleeve 24 along the inserting direction 26. In addition, the latching means 58, 60 prevent a retraction of the housing 22 from the tine sleeve 24 in a direction opposite to the inserting direction 26. Thereby, the latching means 58, 60 enable to fix the housing 22 to the tine sleeve 24 at variable depth, e.g., the first and / or second depth DI, D2.

[0076] In another alternative embodiment not shown in the figures a friction-based translation mechanism may be used for inserting the housing 22 into the tine sleeve 24 and for fixing

[0077] 24. lOOP-WO / 05.12.2025 the housing 22 to the tine sleeve at a desired depth. For example, instead of mating the tine sleeve 24 to the IPG with the threads 44, 52 or using the latching means 58, 60, there may be a press-fit interaction between the housing 22 and the tine sleeve 24. For example, neither the housing 22 nor the tine sleeve 24 comprise threads 44, 52 or latching means 58, 60, but the outer diameter of at least a part of the distal section 28 of the housing 22 may be formed with an interference fit with respect to the inner diameter of the tine sleeve 24, in particular of the through hole 50. The corresponding press-fit connection may be configured such that the housing 22 is insertable into the tine sleeve 24 until a predetermined depth is reached, e.g., the second depth D2, and that the housing 22 is then held in place relative to the tine sleeve 24,

[0078] Fig. 6 shows a flow-chart of an exemplary embodiment of a method for implanting the IMD 20.

[0079] In an optional step S2, which may be carried out when the housing 22 is decoupled from the tine sleeve 24, the housing 22 and the tine sleeve 24 may be provided separately first.

[0080] In a step S4, the IMD 20 may be mechanically coupled to the tine sleeve 24. In particular, the IMD 20 may be provided such that the at least one first fixation means 44 of the housing 22 is fixed to the at least one second fixation means 52 of the tine sleeve 24 such that the electrode member 32 at least partly extends through the through hole 50. For example, the IMD 20 may be provided such that the electrode member 32 at least partly protrudes from the tine sleeve 24 at the side of the tine sleeve 24 facing away from the housing 22.

[0081] In a step S6, the IMD 20 may be arranged at the tissue 42 of the patient within the body by the tines 50 of the tine sleeve 24, as it is known in the art. For example, the IMD 20 may be arranged at the tissue 42 of the patient such that at least the tip 34 of the electrode member 32 penetrates the tissue 42. The IMD 20 may be implanted within the body via a delivery catheter. The IMD 20 may be implanted into the ventricular septum. Optionally, prior to deployment, a pace mapping may be carried out via the second electrode 36 at the tip 34 or via electrodes embedded in a protector cup of the delivery catheter (not shown) to establish a target location.

[0082] 24. lOOP-WO / 05.12.2025 In an optional step S8, it may be tested whether the second electrode 36 is arranged at the depth within the tissue 42 as intended for its use. For example, it may be tested whether the second electrode 36 is arranged at the depth within the tissue 42 as intended for its use, by applying a voltage over the first and second electrodes 30, 36 by the electronic circuit 46 and the energy source 48 and by monitoring and analyzing a current flow through the first and second electrodes 30, 36 resulting from the applied voltage. The analyzing of the current may involve one or more impedance measurements which may be collected continually to indicate any perforations of the electrode member within the left ventricle.

[0083] In a step S10, the housing 22 may be inserted further into the tine sleeve 24 until the second electrode 36 at the electrode member 32 is arranged at a depth within the tissue 42 as intended for its use, e.g., at the second depth D2. For example, when the step S8 has been carried out, the housing 22 may be inserted further into the tine sleeve 24 when the test result is that the electrode member 32 is not arranged deep enough within the tissue 42 as intended for its use. Alternatively, the housing 22 may be retracted from the tine sleeve 24 when the electrode member 32 is arranged too deep within the tissue 42 as intended for its use.

[0084] Vividly spoken, the IMD 20 may be fixed to the tissue 42 in two instances. A first instance involves the above mentioned arranging of the IMD 20 in the body by deploying and fixating the tines 40 in the tissue 42. This may be done with the housing 22 and thereby the electrode member 32 and in a retracted state, at least mostly in a retracted state e.g., in the first state described above, wherein the distal end of the electrode member 32, e.g., the tip 34 and / or the second electrode 36, may be arranged within the tissue 42 to begin the process of reaching the conduction system. The second instance involves inserting the housing 22 further into the tine sleeve 24 and thereby deeper penetrating the tissue 42 by the electrode member 32 including the second electrode 36, e.g., by rotating the housing 22 with respect to the tine sleeve 24 what will telescope the second electrode 36 deeper into the tissue 42, in case of the fixation means 44, 52 comprising the threads. This may be done iteratively, e.g., under one or more test sequences as described in optional step S8, and may be stopped whenever the conduction system is reached within each individual patient anatomy. The

[0085] 24. lOOP-WO / 05.12.2025 delivery catheter will allow for close to a 1 : 1 torque translation to control the deployment of the second electrode 36 into the tissue 42 to avoid risk of perforating into the left ventricle.

[0086] In case of the fixation means 44, 52 being embodied as the latching means 58, 60 the tines 40 may be anchored to the tissue 42 during the deployment. Then, the tine sleeve 24 may be held in place by a catheter tip or protector cup, as they are known in the art, and the IPG may be pushed into the tissue 42 of the heart until the pacing electrode, i.e., the second electrode 36, on the electrode member 32 reaches the conduction system of the heart. This may also be controlled by the latching, in other words locking, mechanism where the IPG is mated to the tine sleeve 24 via a keyed lock, as depicted in figure 5.

[0087] 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.

[0088] 24.100P-WO / 05.12.2025 List of Reference Numerals

[0089] 20 IMD

[0090] 22 housing

[0091] 24 tine sleeve

[0092] 26 proximal section

[0093] 28 distal section

[0094] 30 first electrode

[0095] 32 electrode member

[0096] 34 tip

[0097] 36 second electrode

[0098] 38 hitch

[0099] 40 tine

[0100] 42 tissue

[0101] 44 first fixation means

[0102] 46 electronic circuit

[0103] 48 energy source

[0104] 50 through hole

[0105] 52 second fixation means

[0106] 54 distal end of housing

[0107] 56 side wall

[0108] 58 latching means

[0109] 60 counter latching means

[0110] 62 inserting direction

[0111] DI first depth

[0112] D2 second depth

[0113] 24.100P-WO / 05.12.2025

Claims

Claims1. Implantable medical device (20), comprising: a housing (22) having a distal section (28), a proximal section (26), at least one first fixation means (44) at a lateral surface of the distal section (28), and a first electrode (30) 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); an electrode member (32) being arranged at a distal end (54) of the housing (22) such that it protrudes from the housing (22) in distal direction and having at least one second electrode (36) exposed to the surroundings of the implantable medical device (20), wherein the second electrode (36) is electrically coupled to the electronic circuit (46); and a tine sleeve (24) having a through hole (50) extending from a proximal end of the tine sleeve (24) to a distal end of the tine sleeve (24) and having two or more tines (40) protruding from the tine sleeve (24) and being configured for attaching the implantable medical device (20) to a tissue (42) of a patient, wherein the distal section (28) of the housing (22) is arranged within the tine sleeve (24) such that the electrode member (32) at the housing (22) at least partly extends through the through hole (50) of the tine sleeve (24), the tine sleeve (24) has at least one second fixation means (52) formed within the through hole (50), the housing (22) is fixed to the tine sleeve (24) by a collaboration of the first and second fixation means (44, 52), the first and second fixation means (44, 52) are configured such that the housing (22) is arrangeable within the tine sleeve (24) at varying depths, and a length over which the electrode member (32) protrudes from the tine sleeve (24) in distal direction depends on how far the housing (22) is arranged within the tine sleeve (24).

24. lOOP-WO / 05.12.20252. Implantable medical device (20) in accordance with claim 1, wherein the first fixation means (44) comprises an outer thread formed at a lateral surface of the distal section (28) of the housing (22) and the second fixation means (52) comprises an inner thread formed at an inner surface of the tine sleeve (24), or the first fixation means (44) comprises first latching means formed at a lateral surface of the distal section (28) of the housing (22) and the second fixation means (52) comprises counter latching means formed at an inner surface of the tine sleeve (24).

3. Implantable medical device (20) in accordance with one of the preceding claims, wherein the electrode member (32) is spear-shaped; or the electrode member is cylindrically shaped; or the electrode member (32) is helically shaped.

4. Implantable medical device (20) in accordance with one of the preceding claims, wherein the electrode member (32) comprises a sharp tip (34) at the distal end (54) of the electrode member (32).

5. Implantable medical device (20) in accordance with one of the preceding claims, wherein the second electrode (36) is arranged at the distal end (54) of the electrode member (32).

6. Implantable medical device (20) in accordance with one of the preceding claims, comprising: two or more further second electrodes (36) at the electrode member (32), with each of the further second electrodes (36) being exposed to the surroundings of the implantable medical device (20).

24. lOOP-WO / 05.12.20257. Implantable medical device (20) in accordance with one of the preceding claims, wherein the first electrode (30) is an anode, and / or the second electrode (36) is a cathode.

8. Implantable medical device (20) in accordance with one of the preceding claims, comprising: a hitch (38) for grabbing the housing (22) and for rotating the housing (22) relative to the tine sleeve (24), wherein the hitch (38) is arranged at a proximal end of the housing (22).

9. Implantable medical device (20) in accordance with one of the preceding claims, wherein a lateral surface of the proximal section (26) of the housing (22) flushes with a lateral surface of the tine sleeve (24).

10. Method for implanting an implantable medical device (20) in accordance with one of the preceding claims into a body of a patient, the method comprising: providing the implantable medical device (20) such that the at least one first fixation means (44) of the housing (22) is fixed to the at least one second fixation means (52) of the tine sleeve (24) such that the electrode member (32) at least partly extends through the through hole (50); arranging the implantable medical device (20) at the tissue (42) within the body of the patient by the tines (40) of the tine sleeve (24); and inserting the housing (22) further into the tine sleeve (24) until the second electrode (36) at the electrode member (32) is arranged at a depth (D2) within the tissue (42) as intended for its use.

11. Method in accordance with claim 10, wherein the implantable medical device (20) is provided such that the electrode member (32) at least partly protrudes from the tine sleeve (24) at the side of the tine sleeve (24) facing away from the housing (22), and24. lOOP-WO / 05.12.2025the implantable medical device (20) is arranged at the tissue (42) of the patient such that at least a tip (34) of the electrode member (32) penetrates the tissue (42).

12. Method in accordance with one of claims 10 or 11, comprising: testing whether the second electrode (36) is arranged at the depth (D2) within the tissue (42) as intended for its use, after the implantable medical device (20) is arranged within the body; inserting the housing (22) further into the tine sleeve (24) when the electrode member (32) is not arranged deep enough within the tissue (42) as intended for its use; and retracting the housing (22) from the tine sleeve (24) when the electrode member (32) is arranged too deep within the tissue (42) as intended for its use.

13. Method in accordance with claim 12, wherein it is tested whether the second electrode (36) is arranged at the depth (D2) within the tissue (42) as intended for its use, by applying a voltage over the first and second electrodes (30, 36) by the electronic circuit (46) and the energy source (48) and by monitoring and analyzing a current flow through the first and second electrodes (36) resulting from the applied voltage.

24. lOOP-WO / 05.12.2025

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