WO2022152586A1

WO2022152586A1 - Implantable medical device

Info

Publication number: WO2022152586A1
Application number: PCT/EP2022/050025
Authority: WO
Inventors: Andreas Becker; R. Hollis Whittington; Dirk Muessig
Original assignee: Biotronik Se & Co. Kg
Priority date: 2021-01-15
Filing date: 2022-01-03
Publication date: 2022-07-21

Abstract

The present invention refers to an implantable medical device (5) comprising a housing (4), and an anchoring device (1) coupled to the housing (4) and being configured to anchor the implantable medical device (5) in a chamber of the heart. The anchoring device (1) comprises at least in part a biodegradable material, wherein, before the biodegradable material is degraded, the anchoring device (1) provides a anchoring of the housing (4) to tissue, and wherein, after the biodegradable material is degraded, the anchoring device (1) does not provide a fixation of the housing (4) to tissue anymore.

Description

IMPLANTABLE MEDICAL DEVICE

The disclosure relates to an implantable medical device.

Medical devices are known which can be implanted into a chamber of a heart. These so called intracardiac pacing systems or leadless pacemakers are anchored to tissue inside the heart (myocardium). During implantation, it is advantageous to have a stable anchoring technique for the device that prevents dislodgement and embolization. After implantation, in some cases it may be necessary to remove the device. However, after a while the implanted device is at least partially encapsulated by bodily tissue, which is created around the device due to natural body reactions. This process leads to a more secure anchoring of the device, but may impede extraction of the device.

Two major anchoring techniques for intracardiac pacing systems are known: (i) a helical anchor, which is a sturdy wire that is threaded into the myocardium (e.g. disclosed in US 2012/0158111 Al and US 2012/0116489 Al), and (ii) tines with a backward bend, which during implantation get stretched for piercing the myocardium (e.g. disclosed in US 2014/0121719 Al).

Helical anchoring techniques can be implanted and explanted with a rotational movement to screw the device in or out the myocardium. However, screwing the device into the myocardium during initial implantation is very dangerous and can lead to a myocardial perforation. Another option is a tined device, which during initial implantation is more secure with lower risk of myocardial perforation compared to a device using a helix anchor. However, for extraction of a device with tines a longitudinal retraction force has to be applied, which can be dangerous to the patient. Accordingly, there is still a need for reliable and compliant means for anchoring a medical device, particularly an intracardiac pacing system, at the intended tissue, e.g. the myocardium.

Thus, is an objective of the present invention to provide an implantable medical device, particularly an intracardiac pacing system that avoids the above-mentioned disadvantages of the state of the art. Particularly, such implantable medical device is designed to facilitate the extraction of the implant, by which_the extraction of an implanted device shall be made safer for a patient and easier for a physician.

This objective is attained by a medical device having the features of claim 1. Appropriate embodiments thereof are stated in the dependent claims and the following description.

According to claim 1, an implantable medical device is provided.

The implantable medical device comprises a housing, and an anchoring device coupled to the housing. The anchoring device comprises at least in part a biodegradable material, wherein, before the biodegradable material is degraded, the anchoring device provides an anchoring or fixation of the housing to tissue (e.g. myocardium), and wherein, after the biodegradable material is degraded, the anchoring device does not provide an anchoring or fixation of the housing to tissue anymore. Particularly, the anchoring device is configured to anchor the implantable medical device in a chamber of the heart, e.g. in left or right atrium, or the left or right ventricle.

The term biodegradable (or biocorrodible or bioabsorbable or bioresorbable or biodissolvable) material is used in the context of present disclosure in the meaning known to the skilled person, it particularly refers to a material that is decomposed in a human or animal body, particularly in presence of bodily fluids such as blood.

The anchoring device may be used for anchoring or fixing the housing of the device to tissue after implantation. After a while, the device will be at least partially encapsulated by tissue due to biological processes. Then, the encapsulation provides anchoring or fixation of the device and the anchoring device is no longer necessary. Dissolving or degrading the anchoring device in part or completely may facilitate or ease extraction of the device if this becomes necessary. After the anchoring device is partly or completely dissolved or degraded, removal of the device may be performed by applying a longitudinal force and/or a rotational force to the device.

According to one embodiment of the implantable medical device of the invention, the anchoring device comprises at least one anchoring element, wherein the anchoring comprises the biodegradable material. The anchoring element may be a tine, a hook or a barb. In one embodiment, the anchoring device may comprise four anchoring elements (e.g. tines, hooks or barbs), but other numbers are also possible.

According to one embodiment of the implantable medical device of the invention, the anchoring device is arranged at a distal end of the housing. A distal end of the housing (or another component) is an end which in the implanted state of the device is closer to tissue than a proximal end of the housing (or another component).

According to one embodiment of the implantable medical device, the anchoring device comprises a base member which is coupled to the housing, wherein the anchoring device comprises at least one anchoring element which is connected to the base member. For example, four anchoring elements (such as tines, hooks or barbs) may be connected to the base member. The base member may have a circular shape. The base member may be arranged at the distal end of the housing.

According to one embodiment of the implantable medical device of the invention, the base member comprises the biodegradable material. Alternatively or in addition, the at least one anchoring element may comprise the biodegradable material.

According to one embodiment of the implantable medical device of the invention, the at least one anchoring element comprises a base portion, wherein the base portion is adjacent to the base member, and wherein the base portion comprises the biodegradable material. According to one embodiment of the implantable medical device of the invention, the anchoring device comprises at least two anchoring elements which are connected to the base member, wherein an intermediate portion of the base member is formed between connection regions of the at least two anchoring elements with the base member, and wherein the intermediate portion comprises the biodegradable material.

According to one embodiment of the implantable medical device of the invention, the base member comprises a biodegradable or dissolvable portion, which upon dissolving, allows the anchoring device to be rotated within the device. Rotation of the anchoring device allows the device to be rotated during extraction to loosen the device from encapsulation and make extraction easier.

According to one embodiment of the implantable medical device of the invention, a proximal end of the anchoring device is arranged in a recess formed at the housing.

According to one embodiment of the implantable medical device of the invention, the recess is formed by a support member, wherein particularly the base member of the anchoring device is attached to the housing with the support member.

According to one embodiment of the medical device of the invention, the recess is at least partially filled or covered with a biodegradable material, which may be the same or a different material as the material of the anchoring device, which e.g. may differ in the degradation or dissolving rate. For example, if the anchoring device comprises one or more tines as anchoring elements, the proximal end of the tine(s) may be arranged in a recess (or several recesses), for example formed by or in the support member, wherein the recess(es) is (are) filled or covered with the biodegradable material. For example, the biodegradable material may be decomposed within a defined period of time, e.g. three to twelve months after implantation, thereby allowing access to the biodegradable tines, which are then in turn decomposed as well. Preferably, the biodegradable material covering or filling the recesses has a higher rate of degradation or dissolving than the biodegradable material comprised within the anchoring device. Alternatively, the recess may be at least partly filled or covered with a switchable material being not permeable for bodily fluids in a first state and being permeable for bodily fluids in a second state, wherein material is switchable between the first state and the second state by an external stimulus, e.g. RF energy, a magnetic field or like. For example, the switchable material may be switched after a defined period of time, e.g. two to three months after implantation, thereby again allowing access of bodily fluids to the biodegradable tines, which are then consequently decomposed. Suitable switchable materials are disclosed, e.g. in document US 2011/0276124 Al. In one embodiment, the switch time may be chosen significantly shorter in order to immediately response to the external stimulus. The switch time may be adjusted to one month or more months.

The biodegradable material may be a biodegradable metal, a biodegradable metal alloy, a biodegradable polymer, a biodegradable ceramic or the like. The biodegradable metal alloy may include magnesium, iron and/or zinc as a main alloy component or an alloy component. The main alloy component is the component, whose amount by weight in the alloy is the greatest. The main alloy component may amount to more than 90 % by weight, more than 70 % by weight, and in particular more than 50 % by weight. In one embodiment, the main alloy component is Magnesium. Suitable alloys are Magnesium Zinc Calcium alloys, which are disclosed in documents WO 2014/001321 Al and WO 2014/001241 Al, Magnesium Aluminum alloys as disclosed in document WO 2014/001240 Al, or Magnesium Aluminum Zinc alloys as disclosed in document WO 2014/001191 Al. Suitable biodegradable polymers are polylactic acid (PLA), poly-L-lactide (PLLA), and poly-D-lactide (PDLA), etc.

The biodegradable material may be completely degraded after 3 to 12 months after degradation is initiated. In case the biodegradation is initiated with implanting the device and getting in contact with bodily media, the biodegradable material is completely degraded 3 to 12 months after implantation of the device. By this time, the anchoring device, or at least the part of the anchoring device which comprises the biodegradable material, loses its mechanical integrity. In this time, it is expected that the implantable medical device is encapsulated in tissue to an extent, which is considered to hold the device fixedly attached to the tissue without the possibility of dislodgement. The degradation time may be adjusted to less than 12 months, less than 8 months, or to 3 to 6 months.

According to one embodiment of the implantable medical device of the invention, the recess is aligned to the portion of the at least one anchoring element or to the intermediate portion of the base member such that bodily fluids or tissue are able to contact the portion of the at least one anchoring element or to the intermediate portion of the base member.

According to one embodiment of the implantable medical device of the invention, switching of the switchable material is triggerable by an external stimulus, e.g. RF energy or a magnetic field.

Using an anchoring device (e.g. comprising one or more a tines) may allow longitudinal insertion of the device for secure implantation and placement. The anchoring device then at least partially dissolves in the body after implantation, ideally once encapsulation is sufficient to anchor the device. If explantation is needed, the device can be captured, twisted to break attachment to fibrous encapsulation without damaging the heart, and then extracted with longitudinal force.

In another aspect of the invention, an implantable medical device is provided which comprises a housing, and an anchoring device coupled to the housing. The anchoring device is configured to provide a temporary anchoring of the housing to tissue (e.g. myocardium). The housing comprises a motion-converting structure which is configured to convert a rotation of the housing in a linear motion of the housing.

The temporary anchoring of the housing may be provided by the anchoring device comprising at least in part a biodegradable material as disclosed herein.

In one embodiment, the housing comprises a motion-converting structure which is configured to convert a rotation of the housing in a linear motion of the housing. In one embodiment, the motion-converting structure is arranged on a surface of the housing. In one embodiment, the housing is designed in form of a cylinder, wherein the motionconverting structure is arranged on the lateral area of the cylinder.

In one embodiment, the motion converting structure extends form a distal end of the housing to a proximal end of the housing.

In one embodiment, the motion-converting structure is formed by a single motion-converting element.

In one embodiment, the motion-converting structure is formed by a plurality of motionconverting elements which are separated from each other.

In one embodiment of the implantable medical device of the invention, the motionconverting structure protrudes from the surface of the housing.

In another embodiment of the implantable medical device of the invention, the motionconverting structure is recessed in the surface of the housing.

In one embodiment of the implantable medical device of the invention, the motionconverting structure is formed by a thread or a threaded groove.

In one embodiment, the motion-converting structure is designed as a thread or a thread structure on the housing. Such thread or thread structure may be formed by a helical protrusion running around the housing.

The motion-converting structure may be formed by material deposition, e.g. physical vapor deposition (PVC), chemical vapor deposition (CVC), welding, or soldering.

In one embodiment, the housing comprises a surface being configured to prevent or decrease in-growth of the housing, wherein particularly the surface is characterized by a predefined roughness. If an implanted device could be rotated, the extraction procedure would be even less risky to the patient. After a while, at earliest after at least partial encapsulation of the device or after a trigger event, the anchoring device may at least partially bio-degrade so that the initially intended anchoring may be terminated and the device is held in place by the encapsulation only. Extraction of the device is for example possible by applying a rotational movement. A physician does not need to apply a pulling force to explant the device.

Particularly, the implantable medical device may be an active implant, e.g. an intracardiac pacing system or a monitoring system. The device may comprise at least one electrode, e.g. a pacing electrode and/or a sensing electrode. The housing may enclose an electronic circuit and a battery.

The aspect of the biodegradable anchoring device can be combined with the aspect of the motion-converting structure of the housing in any manner. All embodiments of the biodegradable anchoring device can be combined with all embodiments of the motionconverting structure.

Following, embodiments are described with reference to figures.

Fig. 1 A - 1C show a first embodiment of an implantable medical device with a temporary anchoring device.

Fig. 2A - 2C show a second embodiment of an implantable medical device with a temporary anchoring device.

Fig. 3 A - 3C show a third embodiment of an implantable medical device with a temporary anchoring device.

Fig. 4A - 4C show a fourth embodiment of an implantable medical device with a temporary anchoring device. Fig. 5 shows an embodiment of an implantable medical device with a temporary anchoring device and a motion-converting structure.

Same reference numerals are used for same components.

Figs. 1A to 1C show an implantable medical device 5 that comprises a housing 4, an anchoring device 1, and a support member 3. For example, the implantable medical device 5 is an implantable cardiac pacemaker, particularly an intracardiac pacing system (IPS). Such an IPS is configured to be implanted into a ventricle and/or an atrium of the patient’s heart, particularly into the right ventricle, left ventricle, right atrium or left atrium, particularly via a catheter. Alternatively, such a device may be anchored to the epicardial surface of the heart.

The implantable medical device 5 particularly comprises a hermetically sealed housing 4. The housing 4 particularly encloses a pulse generator for generating pacing pulses that are to be applied to the patient’s heart via at least one pacing electrode, sensing circuits for sensing physiological signals from the body of the patient, and a battery for supplying energy to the pulse generator and/or to the sensing circuits. These components are not shown in the figures for the sake of brevity. Also, other in the pacemaker industry well-known components may be enclosed in the housing.

The anchoring device 1 comprises at least one tine 20. Here, four tines 20 are shown, but other numbers of tines are possible. The anchoring device 1 is used to anchor the housing 4 of the implantable medical device 5 to bodily tissue, e.g. myocardium. With the support member 3, the anchoring device 1 is at least temporary mounted to the housing 4 of the implantable medical device 5. The anchoring device 1 is mounted in or at the implantable medical device 5 such that the tines 20 protrude out of or away from the housing 4 for anchoring the implantable medical device 5 to tissue of a bodily cavity.

At least a part of the anchoring device 1 is preferably made of a biodegradable metal, a biodegradable metal alloy or a biodegradable polymer. Thus, the anchoring device 1 is partially or completely biodegradable in vivo. At a specific time, the complete anchoring device 1, or at least the parts of the anchoring device 1, which comprises the biodegradable material, loses its mechanical integrity. The specific time depends on the material composition of the material used for forming the anchoring device 1 or its components. The degradation products are mainly resorbed by the body, although small residues are in general tolerable. Alternatively, the anchoring device 1 may be designed in form of a screw or wire helix, which may be made of a biodegradable material or a biostable, biocompatible material, such as, e.g. nitinol.

The at least one tine 20 may be a single tine or may alternatively be implemented as a tine array comprising an annular ring 10 (see Figs. 2 - 4) and a plurality of elongated tines 20 connected to the annular ring 10 and protruding from the annular ring 10. An example, which is incorporated by reference, is shown in US provisional patent application No. 62/516,869.

The support member 3 can be a polymer ring or a ceramic ring, which is cast-molded around the anchoring device 1 and a part of the housing 4 or glued or otherwise adhered to anchoring device 1 and housing 4. In a further alternative or cumulative variant, the support member 3 can be part of the housing 4, for example in form of a groove, notches, indentations and the like.

In the embodiment shown in Figs. 1A to 1C, the tines 20 or the tine array is/are preferably made of a biodegradable material, for example a biodegradable metal or metal alloy as specified above. Immediately after implantation, the tines 20 or the tine array start(s) to degrade and to lose their mechanical integrity by a graduate biodegradation. This progressive degradation is exemplary shown in Fig. IB. After for example 12 months, the tines 20 or tine array is/are completely disappeared (Fig. 1C) and the device 5 is anchored by tissue only (the tissue is not shown).

Figs. 2A - 2C and 3A - 3C show two exemplary alternatives of the anchoring device 1 for temporarily anchoring the device 5 to tissue of a patient. The anchoring device 1’, 1”, which is also denoted as tine array, comprises an annular ring 10’, 10” and a plurality of elongated tines 20’, 20” connected to the annular ring 10’, 10” and protruding from the annular ring 10’, 10”. The annular ring 10’, 10” and the tines 20’, 20” are formed out of a super-elastic alloy comprising nickel and titanium, particularly Nitinol. The annual ring 10’, 10” is attached to an end of the housing 4 and secured by the support member 3 (see Fig. 1 A).

According to Fig. 2A, each of the tines 20’ has a portion 100’ consisting of a biodegradable material as mentioned before, preferably a biodegradable metal or a biodegradable metal alloy. Each portion 100’ is situated at the base of each tine 20’, where each tine 20’ is connected to the annular ring 10’. Other positions are possible. After the earlier mentioned adjusted degradation time, the portion 100’ is completely degraded and parts of the tines 20’, preferably the tips protruding from the housing 4, are separated from the annular ring 10’ (see Fig. 2B). At this time the device 5 is anchored by the ingrowth only. In this situation, if the device 5 has to be explanted, tines 20’ remain in the tissue, which is not problematic due to complete ingrowth.

According to the embodiment shown in Fig. 3 A, the annular ring 10” has portions 100” consisting of the biodegradable material. The portions 100” are situated between the tines 20” and may extend such that only a base portion 200 is integrally connected to each tine 20”. After the earlier mentioned adjusted degradation time, the portion 100” is completely degraded and parts of the tines 20”, preferably the tips protruding from the housing 4, are separated from the annular ring 10” (see Fig. 3B). At this time, the device 5 is anchored by the ingrowth of the housing 4 only. In the case the device 5 has to be explanted, the tines 20” remain in the tissue, which due to complete ingrowth is not problematic.

Alternatively, the base portion 200 may consist of biodegradable material, and the portions 100” may consist of a material which is not biodegradable. In another alternative, the annular ring 10” completely consists of the biodegradable material. In all embodiments, the tines 20” are separated from the device 5 after the biodegradable material is degraded.

Also, the support member 3 may comprise recesses 30’ 30”, which are aligned to either portion 100’ or 100” in order to enable bodily tissue to get in contact with the portions 100’, 100” (see Figs. 2C, 3C). The support member 3 comprises a material, which is bio stabile and not biodegradable. The recesses 30’, 30” however are filled with a biodegradable material, for example a biodegradable polymer, which may degrade faster than the biodegradable material of portions 100’, 100”. In a special variant the recesses may be filled with a material, which is not permeable for bodily fluids under normal conditions, but may be converted by an external trigger into a form, in which it is permeable for bodily fluids in order to start degradation of the portions 100’, 100”. For example, technology disclosed in document US 2011/0276124 Al can be used. Advantageously, the degradation process of portions 100’, 100” can be started at the right time.

According to the exemplary embodiments of Fig. 4A - 4C, the support member 3’, which establishes secure attachment of anchoring device 1 to the housing 4 of the device 5, is made of a biodegradable material, for example a biodegradable polymer or a biodegradable ceramic. The whole support member 3’ dissolves in an adjusted time, which leads to a detachment of the anchoring device 1 from the housing 4 (Fig. 4B). In this situation, the housing 4 may be easily detached and be explanted, while particularly the tines 20 or the tine array remain in the body, as exemplarily shown in Fig. 4C, wherein the tines 20 are may be made of a biostable, biocompatible material, such as, e.g. ninitol.

The design of the tines 20, 20’, 20” of the embodiments shown in Figs. 1 to 4 is exemplary only and not limited to the exactly shown shape. Other shapes and amount of tines are possible.

Use of a biodegradable material for the anchoring device allows sufficient encapsulation to anchor the device during the acute implant and chronic encapsulation or ingrowth phase. After an encapsulation period, the anchoring device is partly or completely dissolved and the device is anchored by the encapsulation around the device.

Fig. 5 shows the implantable medical device 5 that comprises the anchoring device 1 with at least one tine 20 in an initial state before implantation or shortly after. The anchoring device 1 is used to anchor the housing 4 of the implantable medical device 5 to bodily tissue.

The anchoring device 1 is formed for a temporary anchoring of the device 5 to tissue. For example, the anchoring device 1 may comprise at least in part (or completely) the biodegradable material disclosed herein. The anchoring device 1 can be formed particularly according to one of the embodiments shown in Figs. 1 to 4. With other words, the “active” anchoring with means of the anchoring device terminates and the implantable medical device 5 is anchored “passively” by the at least partial encapsulation of the (e.g. cylindrical) housing 5. In order to enable easy extraction of the implantable medical device 5 in the “passive” anchor situation without the need of applying pulling forces along the longitudinal axis of the housing 4, the surface of the housing 4 comprises a motion-converting structure 50, which upon twisting the implantable medical device (for example by attaching the proximal end of the housing 4 to an explantation device known from the art, which comprises means suitable to transfer rotational movements to the housing) creates a movement of the device 5 along the longitudinal axis in proximal direction.

The motion-converting structure 50 may be formed along the whole surface, e.g. extending helically from the distal end of the housing 5 to the proximal end of the housing 5. It may also extend only partially on the outer surface, for example on the most distal half of the housing, a middle part or a distal part.

The motion-converting structure 50 may protrude from the surface of housing 4. It may be formed on the housing 4 by gluing, welding or soldering material on the housing 4, or by embossing the sheath-like metal of the housing 4. The motion-converting structure 50 may also be in form of a groove in the surface of housing 4. . Therein, the housing or the housing parts facing to the tissue are preferably made of titanium or a titanium alloy, particularly since titanium causes rather the formation of a bodily mucus or gel than becoming ingrown by tissue, which in turn significantly improves the explantability of the device.

In one embodiment, the motion-converting structure 50 is in the form of a thread, which is wound helically around the surface of the housing 4.

The embodiments disclosed herein may have the advantage that they combine the safety of the tined implant approach and the explantability of the helix approach. Helices are known to be sensitive to heart wall contact forces, number of turns during deployment, and the nature of the tissue in contact with the helix. Excessive turning can lead to damage of the tissue. Tines do not have this problem. However, tines are difficult to remove once the device is encapsulated due to the adhesion forces of the capsule. These forces can be overcome with lower risk by twisting the device. Thus this device can avoid helix problems during implant and avoid tines problems during explant, since the tines would not obstruct rotation after dissolving. In particular, the embodiment shown in Fig. 5 allows the extraction of an implantable medical device without applying pulling forces on the anchoring, which may lead to damage of the anchoring tissue or the encapsulation.

The features disclosed in the specification, the claims and the figures may be relevant for realizing embodiments either alone or in any combination with each other.

List of reference numerals:

1 anchoring device

3, 3’ support member 4 housing

5 implantable medical device

10’, 10” annular ring

20, 20’, 20” tines

30’, 30” recess 50 motion-converting structure

100’, 100” portion

200 base portion

Claims

1. An implantable medical device (5) comprising:

- a housing (4), and

- an anchoring device (1) coupled to the housing (4) and configured to anchor the implantable medical device (5) in a chamber of the heart, wherein the anchoring device (1) comprises at least in part a biodegradable material, wherein, before the biodegradable material is degraded, the anchoring device (1) provides an anchoring of the housing (4) to tissue, and wherein, after the biodegradable material is degraded, the anchoring device (1) does not provide an anchoring of the housing (4) to tissue anymore.

2. The implantable medical device (5) of claim 1, wherein the anchoring device (1) comprises at least one anchoring element (20, 20’, 20”), and wherein the anchoring element (20, 20’, 20”) comprises the biodegradable material.

3. The implantable medical device (5) of claim 1, wherein the anchoring device (1) comprises a base member (10, 10’, 10”) which is coupled to the housing (4), and wherein the anchoring device (1) comprises at least one anchoring element (20, 20’, 20”) which is connected to the base member (10, 10’, 10”).

4. The implantable medical device (5) of claim 3, wherein the base member (10, 10’, 10”) comprises the biodegradable material.

5. The implantable medical device (5) of claim 3, wherein the at least one anchoring element (20, 20’, 20”) comprises the biodegradable material.

6. The implantable medical device (5) of claim 5, wherein the at least one anchoring element (20, 20’, 20”) comprises a portion (100’) adjacent to the base member (10, 10’, 10”), and wherein the portion (100*) comprises the biodegradable material. The implantable medical device (5) of claim 3, wherein the anchoring device (1) comprises at least two anchoring elements (20, 20’, 20”) which are connected to the base member (10, 10’, 10”), wherein an intermediate portion ( 100”) of the base member is formed between connection regions of the at least two anchoring elements (20, 20’, 20”) with the base member (10, 10’, 10”), and wherein the intermediate portion (100”) comprises the biodegradable material. The implantable medical device (5) of any one of the preceding claims, wherein a proximal end of the anchoring device (1) is arranged in a recess (30’, 30”) formed at the housing (4). The implantable medical device (5) according to claim 3 and 8, wherein the recess (30’, 30”) is formed by a support member (3, 3’), wherein particularly the base member (10, 10’ 10”) is attached to the housing (4) with the support member (3,3’). The implantable medical device (5) according to claim 8 or 9, wherein

- the recess (30’, 30”) is at least partially filled or covered with the biodegradable material or a switchable material being not permeably for bodily fluids in a first state and being permeable for bodily fluids in a second state, or

- the support member (3, 3’) comprises the biodegradable material. The implantable medical device (5) of claim 6 or 7 and claim 10, wherein the recess is aligned to the portion (100’) of the at least one anchoring element (20, 20’, 20”) or to the intermediate portion ( 100”) of the base member such that bodily fluids are able to contact the portion (100’) of the at least one anchoring element (20, 20’, 20”) or to the intermediate portion ( 100”) of the base member. The implantable medical device (5) of claim 10 or 11, wherein switching of the switchable material is triggerable by an external stimulus, e.g. RF energy or a magnetic field. - 18 -

13. The implantable medical device (5) of any one of the preceding claims, wherein the biodegradable material is a biodegradable metal, a biodegradable metal alloy or a biodegradable polymer. 14. The implantable medical device (5) of any one of the preceding claims, wherein the biodegradable material is completely degraded after 3 to 12 months after degradation is initiated.

15. The implantable medical device (5) of any one of the preceding claims, wherein the implantable medical device is an intracardiac pacing system or a monitoring system.