WO2025056347A1

WO2025056347A1 - Tine array for a header assembly, header assembly for an implantable medical device, and method for mounting the header assembly

Info

Publication number: WO2025056347A1
Application number: PCT/EP2024/074415
Authority: WO
Inventors: Thomas KUSKE; Michael Stiehm; Stefan Siewert; Klaus-Peter Schmitz; Volker Lang; Marco Bosselmann; Momma CARSTEN
Original assignee: Biotronik SE and Co KG
Current assignee: Biotronik SE and Co KG
Priority date: 2023-09-13
Filing date: 2024-09-02
Publication date: 2025-03-20
Anticipated expiration: 2026-03-13

Abstract

A tine array (30) for a header assembly (22) of an implantable medical device (22) is proposed. The tine array (30) comprises a base ring (38) and at least two tines (32) extending from the base ring (38), wherein the base ring (38) has at least one element of a pin-notch- pair for preventing a rotation of the tine array (30) with respect to a header base (24) of the header assembly (22) and wherein the pin-notch-pair comprises a pin (40) and a notch (42).

Description

TINE ARRAY FOR A HEADER ASSEMBLY, HEADER ASSEMBLY FOR AN IMPLANTABLE MEDICAL DEVICE, AND METHOD FOR MOUNTING THE HEADER ASSEMBLY

DESCRIPTION

The present invention refers to a tine array for a header assembly for an implantable medical device, to the header assembly for the implantable medical device, and to a method for mounting the header assembly of the implantable medical device.

The Implantable Medical Device (IMD) may be an implantable intracardiac device, such as e.g. an implantable intracardiac pacemaker. Active or passive intracardiac medical devices, for example implantable intracardiac pacemakers (also known as leadless pacemakers), 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 and/or in the form of shocks for cardioversion or defibrillation in order to restore a more normal heart rhythm. 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.

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 of active implantable medical devices (AIMD's) can cause clinically-relevant complications. Pacemaker manufacturers face the challenge of improving the durability of the electrodes or finding solutions that eliminate the need for the electrodes altogether. 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 in a header assembly of the IMD. However, the corresponding clamping or sticking of the tine array in the IMD is very undefined. In particular, a position of the tine array with respect to the rest of the header assembly may be undefined in rotational direction. For example, the tine array may be rotated with respect to a header base and/or header cap of the header assembly.

Accordingly, there is the need for a tine array providing a low manufacturing effort and low costs, and a robust attachment mechanism which ensures an appropriate position of the tine array with respect to other components of a header assembly comprising the tine array. Further, there is the need for the header assembly comprising the tine array and for a method for mounting the header assembly.

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

An aspect refers to a tine array for a header assembly of an implantable medical device, the tine array comprising a base ring and at least two tines extending from the base ring, wherein the base ring has at least one element of a pin-notch-pair for preventing a rotation of the tine array with respect to a header base of the header assembly and wherein the pin-notch-pair comprises a pin and a notch. The header assembly may comprise a header base to which the tine array is coupled. The header base may comprise another element of the pin-notch-pair, wherein the element of the base ring and the element of the header base may be arranged such that they work together. In particular, the corresponding pin may be arranged in the corresponding notch. Another aspect refers to the header assembly for an implantable medical device, the header assembly comprising: the tine array, as described above and in the following; the header base having a tine array support, on which the tine array is arranged; and a header cap being mechanically coupled to the header base such that the tine array is sandwiched between the header base and the header cap, wherein the header base has the at least one element of the pin-notch-pair for preventing the rotation of the tine array with respect to the header base, wherein the tine array has another element of the pin-notch-pair, wherein one of the elements is the pin, wherein one of the elements is the notch, and wherein the pin is arranged in the notch. So, the header assembly may comprise one or more pin-notch-pairs, wherein one element of each pin-notch-pair is formed by the tine array and another element of the pin- notch-pair is formed by the header base.

A further aspect refers to a method for mounting the header assembly of the implantable medical device. The method comprises: arranging the tine array, as described above and in the following, on the tine array support of the header base, wherein the header base has the at least one element of the pin-notch-pair for preventing the rotation of the tine array with respect to the header base, wherein the tine array has another element of the pin-notch-pair, wherein one of the elements is the pin, wherein one of the elements is the notch; and mechanically coupling the header cap to the header base such that the tine array is sandwiched between the header base and the header cap and that the pin is arranged in the notch. The header assembly may be the header assembly as described above and/or in the following. The finalized header assembly may correspond to the above explained header assembly.

A further aspect refers to an Implantable Medical Device (IMD), in particular an implantable intracardiac pacemaker also referred to as leadless pacemaker, comprising the tine array or header assembly of the previously mentioned aspects.

Each of the pin-notch-pairs may provide a rotation prevention of a rotation of the tine array relative to the header assembly and thereby relative to the implantable medical device. The header cap may be coupled to the header base such that the header cap may not be rotated with respect to the header base, at least not unintentionally. In this case, the header cap may not be rotated with respect to the tine array, at least not unintentionally. So, the tine array comprising the base ring with the element of the pin-notch-pair may contribute to prevent a rotation of the tine array with respect to the Implantable Medical Device (IMD), when the IMD comprises the header assembly with the tine array. So, the header assembly comprising the tine array may contribute to prevent a rotation of the IMD with respect to the tissue in which the IMD is implanted.

The pin-notch-pairs may enable to omit any adhesive for mounting the header assembly, because the rotation prevention is provided by the pin-notch-pairs. Alternatively or additionally, a clamping mechanism that may lead to undefined plastic deformation and/or clamping creep, which may lead to a loss of contact pressure and thus to a rotation of the tine array relative to the rest of the header assembly, may be omitted. Further, when omitting the adhesive and clamping mechanism, a fabrication as well as an assembly of the header assembly may be easy and cost-efficient. In case of any component tolerances of the components of the header assembly, they may be compensated by the header assembly and the tine array having the pin-notch-pairs. Furthermore, the pin-notch-pairs may secure an appropriate seating of the tine array within the header assembly.

The pin-notch-pairs provide a form-fit-based fixation mechanism between the tine array and the header base. The form-fit connection guarantees a very good and long durability and may enable to compensate any component tolerances of the header assembly. The header assembly with the tine array having the pin-notch-pair(s) constitute a novel anti-rotation device for the IMD.

The base ring may have circular shape. The base ring may define a plane. The base ring may have a conical shape in a direction perpendicular to the plane. The tine array may comprise three, four, or more tines, which are equally distributed along the base ring. The tines may be arranged at every 90° around the base ring. The header assembly may comprise two, three or more pin-notch-pairs, e.g. four pin-notch-pairs, wherein the base ring may comprise correspondingly two, three or more, e.g. four, elements of the corresponding pin-notch-pairs. The elements may be arranged at every 90° around the base ring. The elements may be shifted around the base ring by 45° with respect to the tines. The elements of the pin-notch pairs may be equally distributed along the circumference of the header assembly and along the base ring respectively.

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.

According to an embodiment, the tines are coupled to the base ring on a first side of the base ring, and the element of the pin-notch-pair is arranged on a second side of the base ring, with the second side facing away from the first side. This may contribute to that the pin of the pin-notch-pair may not extend towards an outside of the IMD and thereby towards a tissue of the patient when the IMD is implanted.

According to an embodiment, the tines extend away from the base ring starting in a first direction, the element is the pin, and the pin extends away from the base ring in a second direction opposite to the first direction. This may contribute to that the pin of the pin-notch- pair may not extend towards an outside of the IMD and thereby towards a tissue of the patient when the IMD is implanted. The second direction may be parallel to the first direction. Each of the tines may start extending away from the base ring in the first direction. Then, the tines may be bend such that each tine may form a barb.

According to an embodiment, the element of the pin-notch-pair of the tine array, in particular of the base ring, is the pin, and the tine array, in particular the base ring, has a notch of another pin-notch-pair for preventing the rotation of the tine array with respect to the header base of the header assembly. So, the tine array may comprise two or more elements of correspondingly two or more pin-notch-pairs, wherein the tine array may comprise the pin of one of the pin-notch-pairs and the notch of another one of the pin-notch-pairs.

According to an embodiment, the header cap is coupled to the header base such that the header cap is pressed against the base ring such that the pin is pressed into the notch. This contributes to that the pin is securely arranged in the notch and thereby that the tine array may not rotate with respect to the header base and the header cap. The header cap may be coupled to the header base by a press- or force-fit while pressing the pin into the notch. In this context, it may be regarded as equivalent whether the pin is pressed into the notch, or whether the pin is arranged in the notch and the notch is pressed against the pin.

According to an embodiment, the element of the pin-notch-pair of the tine array, in particular of the base ring, is the pin, and the element of the pin-notch-pair of the header base is the notch. Optionally, the tine array comprises two or more pins of correspondingly two or more pin-notch-pairs and the header base comprises the corresponding notches of the pin-notch- pairs.

According to an embodiment, the element of the pin-notch-pair of the tine array, in particular of the base ring, is the notch, and the element of the pin-notch-pair of the header base is the pin. Optionally, the tine array comprises two or more notches of correspondingly two or more pin-notch-pairs and the header base comprises the corresponding pins of the pin-notch- pairs.

According to an embodiment, the element of the pin-notch-pair of the tine array, in particular of the base ring, is the pin, the element of the pin-notch-pair of the header base is the notch, the tine array, in particular the base ring, has the notch of another pin-notch-pair for preventing the rotation of the tine array with respect to the header base of the header assembly, the header base has the pin of the other pin-notch-pair, and the pin of the other pin-notch-pair is arranged in the notch of the other pin-notch-pair.

According to an embodiment, the header cap comprises a cylindrical portion, the header base comprises a circular recess, the header cap is coupled to the header base such that the cylindrical portion extends through the base ring and is arranged at least in part in the circular recess of the header base. This may contribute to an easy assembling of the header cap to the header base and/or to an accurate fixation of the tine array between the header cap and the header base. According to an embodiment, the header cap is coupled to the header base by a press-fit. This may contribute to an easy assembly of the header assembly. The press-fit may be so strong that the header cap may not be easily rotated with respect to the header base. In this way, the unintentional rotation of the header cap with respect to the header base may be prevented.

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.

DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a side view of an exemplary embodiment of a header assembly of an implantable medical device.

Fig. 2 shows an exploded side view of the header assembly of figure 1.

Fig. 3 shows a perspective view of an exemplary embodiment of a tine array and of a header base of the header assembly of figures 1 and 2.

Fig. 4 shows a cross-section of the tine array and the header base of figure 3.

Fig. 5 shows another cross-section of the tine array and the header base of figure 3.

Fig. 6 shows a perspective view of another exemplary embodiment of a tine array and of a header base of the header assembly of figures 1 and 2.

Fig. 7 shows a cross-section of the tine array and the header base of figure 6.

Fig. 8 shows another cross-section of the tine array and the header base of figure 6. Fig. 9 shows a flow-chart of an exemplary embodiment of a method for mounting the header assembly of figures 1 and 2.

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

DETAILED DESCRIPTION

Fig- 1 shows a side view of an exemplary embodiment of a header assembly 22 of an Implantable Medical Device (IMD) 20. In particular, figure 1 shows a distal end of the IMD 20 which is formed by the header assembly 22. The IMD 20 may be an implantable intracardiac device, e.g. a leadless pacemaker. The header assembly 22 is mechanically coupled to a housing 28 of the IMD 20. The housing 28 may have a cylindrical shape. The IMD 20, in particular the housing 28, may be rotationally symmetric with respect to an axis 36. An electrode 34, e.g. a pin-shaped electrode, of the IMD may extend from the housing 28 in distal direction.

The housing 28 may contain a battery and an electronic module (not shown) comprising a processor and ensure hermetically sealing of these components. These components may be electrically connected to the electrode 34 and may provide an electrical stimulation of the heart or a processing of electrical signals determined from the heart. Further, the housing 28 may contain components for communication such as an antenna (not shown). The housing 28 may be coated, e.g. with Parylene, to electrically isolate the housing 28 from the electrode 34.

Fig- 2 shows an exploded side view of the header assembly 22 of figure 1. The header assembly 22 comprises a tine array 30, a header base 24, and a header cap 26. The header cap 26 is mechanically coupled to the header base 24 such that the tine array 30 is sandwiched between the header base 24 and the header cap 26. The header base 24 may be circular and/or ring-shaped and/or rotationally symmetric. The header cap 26 may be basically cylindrical-shaped and/or rotationally symmetric. The header cap 26 may comprise an inclined side surface formed at an outer side surface of the header cap, a lateral surface running perpendicular to the axis 36 and a ring-shaped protrusion located at a lateral surface forming a ridge at its top. The ring-shaped protrusion is further located adjacent the opening.

The tine array 30 comprises a base ring 38 and at least two, e.g. four, tines 32 extending away from the base ring 38. The base ring 38 may have circular shape. The base ring 38 may define a plane. In other words, the base ring 38 may completely lie in the plane. The base ring 38 may have a conical shape in a direction perpendicular to the plane. In particular, the base ring 38 may be conically formed in such way that a distal end of the base ring 38 has a greater diameter compared with its proximal end.

The tine array 30 may comprise three, four, or more tines 32. In case of four tines 32, the tines may be arranged at every 90° around the base ring 38. The tines 32 may be formed integrally with the base ring 38. In other words, the tines 32 and the base ring 38 may be formed of one piece. Each of the tines 32 may start extending away from the base ring 38 in a first direction. Then, the tines 32 may be bend such that each of the tines 32 may form a barb. In particular, each tine 32 may have an abutting section (flex zone) starting at the base ring 38, a curved middle section and a straight end section (furthest away from the base ring 38) kinked outwardly. The tines 32 may provide the mechanical fixing of the IMD 20 within a heart of a patient after deployment and penetration of the heart's tissue such that the electrode 34 is in mechanical and electrical contact with an inner tissue of the heart, e.g. within one chamber or atrium.

The header base 24, the header cap 26, and the base ring 38 each may comprise a central through-going opening for accommodating the electrode 34. The opening is formed and arranged such that the electrode 34 may be located within this opening.

Fig- 3 shows a perspective view of an exemplary embodiment of a tine array 30 and of a header base 24 of the header assembly 22 of figures 1 and 2.

The base ring 38 of the tine array 30 has at least one element of a pin-notch-pair for preventing a rotation of the tine array 30 with respect to the header base 24 of the header assembly 22. The pin-notch-pair comprises a pin 40 and a notch 42. The header base 24 may comprise another element of the pin-notch-pair. The element of the base ring 38 and the element of the header base 24 may be arranged such that they work together. In particular, the corresponding pin 40 may be arranged in the corresponding notch 42. So, the header base 24 has the at least one element of the pin-notch-pair for preventing the rotation of the tine array 30 with respect to the header base 24, and the tine array 30 has another element of the pin-notch-pair, wherein one of the elements is the pin 40, wherein one of the elements is the notch 42, and wherein the pin 40 is arranged in the notch 42. The header assembly 22 may comprise one or more of such pin-notch-pairs, wherein one element of each pin-notch-pair is formed by the tine array 30 and another element of the corresponding pin-notch-pair is formed by the header base 24.

Each pin-notch-pair provides a rotation prevention of rotation of the tine array 30 relative to the rest of the header assembly 22 and thereby to the IMD 20. The header cap 26 may be coupled to the header base 24 such that the header cap 26 may not be rotated with respect to the header base 24, at least not unintentionally. In this case, the header cap 26 may not be rotated with respect to the tine array 30 also, at least not unintentionally. So, the tine array 30 comprising the base ring 38 with the element of the pin-notch-pair may contribute to prevent a rotation of the tine array 30 with respect to the IMD 20. So, the header assembly 22 comprising the tine array 30 may contribute to prevent a rotation of the IMD 20 with respect to the tissue in which the IMD 20 is implanted.

The pin-notch-pairs provide a form-fit-based fixation mechanism. The form-fit connection guarantees a very good and long durability and may enable to compensate any component tolerances of the header assembly 22.

The header assembly 22 may comprise two, three or more pin-notch-pairs, e.g. four pin- notch-pairs, wherein the base ring 38 may comprise correspondingly two, three or more, e.g. four, elements of the corresponding pin-notch-pairs. The elements may be arranged at every 90° around the base ring 38. The elements may be shifted around the base ring 38 by 45° with respect to the tines 32. The tines 32 may be coupled to the base ring 38 on a first side of the base ring 38. The base ring's 38 element of the pin-notch-pair may be arranged on a second side of the base ring 38, with the second side facing away from the first side. In the embodiment shown in figures 3, 4, and 5, the base ring's 38 element of the pin-notch-pair may be the notch 42 and the header base's 24 element of the pin-notch-pair may be the pin 40. In particular, the base ring 38 may comprise four notches 42. Optionally, the tine array 30 may comprise two or more notches 42 of correspondingly two or more pin-notch-pairs and the header base 24 may comprise the corresponding pins 40 of the pin-notch-pairs. The notches 42 may be material relief notches, in other words slots. The notches 42 may extending from a proximal side of the base ring 38 into a body of the base ring 38 to allow for accompanying a corresponding pin 40 of the header base 24. The notches 42 may disposed over a circumference of the base ring 38, as explained above.

Fig- 4 shows a cross-section of the tine array 30 and the header base 24 of figure 3. The header base 24 may have a tine array support 31, on which the tine array 30 is arranged.

Fig- 5 shows another cross-section of the tine array 30 and the header base 24 of figure 3, and of the header cap 26. The header cap 26 may comprise a cylindrical portion. The header base 24 may comprise a circular recess. The header cap 26 may be coupled to the header base 24 such that the cylindrical portion of the header cap 26 may extend through the base ring 38 and may be arranged at least in part in the circular recess of the header base 24. The header cap 26 may be coupled to the header base 24 by a press-fit. The press-fit may be so strong that the header cap 26 may not be easily rotated with respect to the header base 24. In this way, the unintentional rotation of the header cap 26 with respect to the header base 24 may be prevented. The press-fit may be provided by an interference-fit between the cylindrical portion of the header cap 26 and the circular recess of the header base 24.

Fig- 6 shows a perspective view of another exemplary embodiment of the tine array 30 and of the header base 24 of the header assembly 22 of figures 1 and 2. The tine array 30 and header base 24 of figure 6 may widely correspond to the tine array 30 and header base 24 of figure 3, in particular except for the position of the elements of the pin-notch pairs. Therefore, only those features of the tine array 30 and header base 24 are described in the following, in which the tine array 30 and header base 24 of figure 6 differ from the tine array 30 and header base 24 of figure 3.

In the embodiment shown in figures 6, 7, and 8, the base ring's 38 element of the pin-notch- pair may be the pin 40 and the element of the pin-notch-pair of the header base 24 may be the notch 42. The pin 40 may extend away from the base ring 38 in the second direction opposite to the first direction. Optionally, the tine array 30 may comprise two or more pins 40 of correspondingly two or more pin-notch-pairs and the header base 24 may comprise the corresponding notches 42 of the pin-notch-pairs. The header cap 26 may be coupled to the header base 24 such that the header cap 26 is pressed against the base ring 24 such that the pins 40 are pressed into the corresponding notches 42.

Fig. 7 shows a cross-section of the tine array 30 and the header base 24 of figure 6, in which the tine array support 31 of the header base 24 may be seen.

Fig- 8 shows another cross-section of the tine array 30 and the header base 24 of figure 6, in which the cylindrical portion of the header cap 26 arranged in the circular recess of the header base 24 may be seen. The header cap 26 may be coupled to the header base 24 by a press- or force-fit while pressing the pins 40 into the corresponding notches 42, as explained above. In this context and all over the present description, it may be regarded as equivalent whether the pin 40 is pressed into the notch 42, or whether the pin 40 is arranged in the notch 42 and the notch 42 is pressed against the pin 42.

Fig- 9 shows a flow-chart of an exemplary embodiment of a method for mounting the header assembly 22 of figures 1 and 2.

Before starting the method, the tine array 30 as explained above may be formed. For example, the tine array 30 may comprise or may be made of a super-elastic material, e.g. such as nitinol. In this case, the tine array 30 may be laser cut from a nitinol tube and formed into the desired shape afterwards. The tine array 30 then may be finished by abrasive blasting, etching, and/or electropolishing, e.g. to remove sharp edges and/or to reduce a susceptibility of the tine array 30 to corrosion. In a step S2, the tine array 30 as described above may be arranged on the tine array support 31 of the header base 24. The header base 24 has at least one element of one of the pin- notch-pairs for preventing the rotation of the tine array 30 with respect to the header base 24. The tine array 30 has another element of one of the pin-notch-pairs. One of these elements is one of the pins 40 and one of these elements is one of the notches 42. The tine array 30 may be arranged on the tine array support 31 of the header base 24 such that the two elements of one of the pin-notch-pairs work together with the corresponding pin 40 being arranged in the corresponding notch 42.

In a step S4, the header cap 26 may be mechanically coupled to the header base 24 such that the tine array 30 is sandwiched between the header base 24 and the header cap 26 and that the pin 40 is arranged in the notch 42. The finalized header assembly 22 may correspond to the above explained header assembly 22 shown in figures 1 and 2.

The invention is not restricted to the above explained embodiments. In particular, the embodiments may be combined to form one or more further embodiments. For example, the tine array 30 has the pin 40 of one pin-notch-pair and the notch 42 of another pin-notch-pair, wherein the header base 24 has the notch 40 of the one pin-notch-pair and the pin 40 of the other pin-notch pair. Further, the tines 32 and/or elements of the pin-notch-pairs may be arranged at different angels around the circumference of the base ring 38. Furthermore, there may be more or less tines 32 and/or elements of the pin-notch-pairs.

It will be apparent to those skilled in the art that numerous modifications and variations of the described examples and embodiments are possible in light of the above teaching. The disclosed examples and embodiments are presented for purposes of illustration only. Other alternate embodiments may include some or all of the features disclosed herein. Therefore, it is the intent to cover all such modifications and alternate embodiments as may come within the true scope of this invention.

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.

List of Reference Numerals

20 IMD

22 header assembly 24 header base

26 header cap

28 housing

30 tine array

31 tine array support 32 tine

34 electrode

36 axis

38 base ring

40 pin 42 notch

44 cylindrical portion

46 circular recess,

Claims

1. Tine array (30) for a header assembly (22) of an implantable medical device (22), the tine array (30) comprising:

- a base ring (38); and

- at least two tines (32) extending from the base ring (38), wherein the base ring (38) has at least one element of a pin-notch-pair for preventing a rotation of the tine array (30) with respect to a header base (24) of the header assembly (22) and wherein the pin-notch-pair comprises a pin (40) and a notch (42).

2. Tine array (30) according to claim 1, wherein

- the tines (32) are coupled to the base ring (38) on a first side of the base ring (38),

- the element of the pin-notch-pair is arranged on a second side of the base ring (38), with the second side facing away from the first side.

3. Tine array (30) according to claim 2, wherein

- the tines (32) extend away from the base ring (38) starting in a first direction,

- the element is the pin (40), and

- the pin (40) extends away from the base ring (38) in a second direction opposite to the first direction.

4. Tine array (30) according to one of the preceding claims, wherein the element of the pin-notch-pair of the tine array (30) is the pin (40), and the tine array (30) has a notch (42) of another pin-notch-pair for preventing the rotation of the tine array (30) with respect to the header base (24) of the header assembly (22).

5. Header assembly (22) for an implantable medical device (22), the header assembly (22) comprising:

- a tine array (30) in accordance with one of the preceding claims;

- a header base (24) having a tine array support (31), on which the tine array (30) is arranged; and - a header cap (26) being mechanically coupled to the header base (24) such that the tine array (30) is sandwiched between the header base (24) and the header cap (26), wherein the header base (24) has at least one element of a pin-notch-pair for preventing a rotation of the tine array (30) with respect to the header base (24), the tine array (30) has another element of the pin-notch-pair, one of the elements is a pin (40), one of the elements is a notch (42), and the pin (40) is arranged in the notch (42).

6. Header assembly (22) according to claim 5, wherein

- the header cap (26) is coupled to the header base (24) such that the header cap (26) is pressed against the base ring (38) such that the pin (40) is pressed into the notch (42).

7. Header assembly (22) according to one of claims 5 or 6, wherein the element of the pin-notch-pair of the base ring (38) is the pin (40), and the element of the pin-notch-pair of the header base (24) is the notch (42).

8. Header assembly (22) according to one of claims 5 or 6, wherein the element of the pin-notch-pair of the base ring (38) is the notch (42), and the element of the pin-notch-pair of the header base (24) is the pin (40).

9. Header assembly (22) according to one of claims 5 or 6, wherein the element of the pin-notch-pair of the base ring (38) is the pin (40), the element of the pin-notch-pair of the header base (24) is the notch (42), the base ring (38) has a notch (42) of another pin-notch-pair for preventing the rotation of the tine array (30) with respect to the header base (24) of the header assembly (22), the header base (24) has a pin (40) of the other pin-notch-pair, and the pin (40) of the other pin-notch-pair is arranged in the notch (42) of the other pin- notch-pair.

10. Header assembly (22) according to one of claims 5 to 9, wherein the header cap (26) comprises a cylindrical portion (44), the header base (24) comprises a circular recess (46), the header cap (26) is coupled to the header base (24) such that the cylindrical portion (44) extends through the base ring (38) and is arranged at least in part in the circular recess (46) of the header base (24).

11. Header assembly (22) according to one of claims 5 to 10, wherein the header cap (26) is coupled to the header base (24) by a press-fit.

12. Method for mounting a header assembly (22) of an implantable medical device, the method comprising:

- arranging a tine array (30) in accordance with one of claims 1 to 4 on a tine array support (31) of a header base (24), wherein the header base (24) has at least one element of a pin-notch-pair for preventing a rotation of the tine array (30) with respect to the header base (24), wherein the tine array (30) has another element of the pin- notch-pair, wherein one of the elements is a pin (40), wherein one of the elements is a notch (42); and

- mechanically coupling a header cap (26) to the header base (24) such that the tine array (30) is sandwiched between the header base (24) and the header cap (26) and that the pin (40) is arranged in the notch (42).

13. Method in accordance with claim 12, wherein the header cap (26) comprises a cylindrical portion (44), the header base (24) comprises a circular recess (46), the header cap (26) is coupled to the header base (24) such that the cylindrical portion (44) extends through the base ring (38) and is arranged at least in part in the circular recess (46) of the header base (24).

14. Method in accordance with one of claims 12 or 13, wherein the header cap (26) is coupled to the header base (24) by a press-fit.