Electrode assembly for an implantable medical device

Abstract

The invention relates to an electrode assembly (1) for an implantable medical device, having a tubular electrode body (2), an electrode connector (3) arranged in a proximal end portion (5) of the electrode body (2), at least three electrode poles (4, 41, 42, 43) and at least three electrode conductors (8, 9, 10, 12, 13) which run within the electrode body (2), wherein in each case one electrode conductor (8, 9, 10, 12, 13) electrically conductively connects a contact portion (31, 32, 33) of the electrode connector (3) to one of the electrode poles (4, 41, 42, 43). The electrode assembly is distinguished in that each electrode conductor (8, 9, 10, 12, 13) is surrounded by an electrically non-conductive insulator (83, 93, 103, 123, 133), wherein all electrode conductors (8, 9, 10, 12, 13) form an electrode conductor composite (7) in which the individual electrode conductors (8, 9, 10, 12, 13) are mechanically connected to one another but electrically insulated from one another.

Description

[0001] Electrode assembly for an implantable medical device

[0002] The present invention relates to an electrode assembly for an implantable medical device according to the preamble of claim 1, an implantable medical device for stimulating the human or animal heart with such an electrode assembly according to the preamble of claim 14, and a method for producing such an electrode assembly according to the preamble of claim 15.

[0003] Electrode assemblies for implantable medical devices such as pacemakers or implantable cardioverter / defibrillators known from the prior art typically have a sensitive internal mechanism, wherein individual electrode leads are routed within this internal mechanism. The problem with this design is that the electrode leads may move against each other on the one hand and against an inner wall of the electrode body on the other. This regularly results in damage to individual electrode leads during operation of such electrode assemblies, which may damage the entire electrode. This reduces the service life of implantable medical devices equipped with such an electrode assembly. In addition, the provision of an internal mechanism and the insertion of individual electrode leads into an electrode shaft makes the production of such an electrode assembly more difficult.

[0004] The present invention addresses the problem of providing an electrode assembly which has better long-term stability than the electrode assemblies known from the prior art and thus enables a longer service life of implantable medical devices which are equipped with such an electrode assembly.

[0005] This problem is solved by an electrode assembly having the features of claim 1. Such an electrode assembly is intended for use on an implantable medical device, in particular on a cardiac pacemaker, an implantable cardioverter / defibrillator (ICD) or a device for cardiac resynchronisation therapy (CRTD). The electrode assembly has a tubular electrode body. This may be made from a polymer, for example in the form of a polymer tube or a copolymer tube. A suitable polymer for producing the electrode body is, for example, a polymer from the group of thermoplastic polyamide elastomers (TPA) or thermoplastic elastomers based on polyurethane (thermoplastic polyurethanes, TPU). Other thermoplastic elastomers are also suitable for producing the electrode body. The electrode body may consist of a single polymer or various polymers or copolymers. The electrode body typically has a single-lumen design, which makes it particularly easy to produce the electrode body.

[0006] The electrode assembly also has an electrode connector, which is arranged in a proximal end portion of the electrode body. The electrode connector is used to connect the electrode assembly to an implantable medical device electrically conductively.

[0007] At least two, in particular at least three, electrode poles are arranged at the other end of the elongate electrode body, i.e. in a distal end portion of the electrode body. For example, two of these electrode poles may be used to detect physiological signals, such as cardiac signals, and the third of the electrode poles may be used to emit a stimulation pulse, such as a shock pulse for carrying out cardiac defibrillation. Embodiments in which more than three electrode poles, for example four or five electrode poles, are provided so that the electrode assembly may take on additional detection and / or stimulation tasks are also conceivable.

[0008] In addition, the electrode assembly has at least two, in particular at least three electrode conductors that run inside the electrode body. In each case, one of these electrode conductors connects a contact portion of the electrode connector to one of the electrode poles electrically conductively. The number of electrode conductors provided in the electrode assembly typically corresponds to the number of electrode poles. This means that two electrode conductors are provided for two electrode poles, three electrode conductors are provided for three electrode poles, four electrode conductors are provided for four electrode poles and five electrode conductors are provided for five electrode poles. This is because each electrode pole usually has to be electrically contacted by a separate electrode conductor in order to make it an independent electrode pole compared to the other electrode poles.

[0009] According to the invention, it is provided that each electrode conductor is surrounded by an electrically non-conductive insulator. All electrode conductors together form an electrode conductor composite. In this electrode conductor composite, the individual electrode conductors are mechanically connected to each other but electrically insulated from each other. By forming such an electrode conductor composite, the mechanical forces acting on the individual electrode conductors are significantly reduced. This results in less damage to the individual electrode conductors and consequently a longer service life for the electrode conductors. A longer service life of the electrode conductors is synonymous with a longer service life of the electrode assembly and thus also a longer service life of an implantable medical device equipped with such an electrode assembly.

[0010] Improved long-term stability also improves the acceptance of medical implantable devices equipped with this type of electrode assembly among medical professionals and patients. In addition, the electrode conductor composite formed no longer requires complex internal mechanics of the electrode assembly. This simplifies the internal design of the electrode assembly, resulting in a simplified and more cost-effective manufacture compared to the manufacture of electrode assemblies known from the prior art.

[0011] By simplifying the design of the electrode body and simplifying the production of the electrode assembly by providing an electrode conductor composite, a higher degree of automation may be achieved in the production of the electrode assembly than in the production processes known from the prior art. In addition, production in a one-piece flow process (also known as labour- intensive workflow) is possible. This reduces the overall production time and allows better utilisation of production and personnel capacities.

[0012] In particular, the electrode assembly is designed in such a way that it has no internal mechanics, such as a complex screw mechanism, in its interior. In particular, only the electrode conductor composite is arranged inside the electrode body in addition to the electrode connector and the electrode poles.

[0013] To form the electrode conductor composite, the individual electrode conductors may, for example, be connected to each other in a form-fitting and / or frictionally engaged manner. In addition, an integrally bonded connection between the electrode conductors is also possible via the insulator.

[0014] In one variant, the individual electrode conductors are stranded (twisted) together. For example - depending on the number of electrode conductors present in the electrode assembly - it is possible to strand three, four or five conductors together. It is also possible to strand two conductors around a central conductor. Similarly, four conductors may be stranded around a central fifth conductor. This type of stranding creates a frictionally engaged mechanical connection via the frictional forces between the conductors, while at the same time a form-fit connection is realised by the interlocking of the individual conductors. The electrode conductors stranded together in such an electrode conductor composite have a much higher mechanical stability than individual conductors and may be drawn into the electrode body more easily. In the stranded state, they may be arranged more easily in a central region of the inner lumen of the electrode body. They may also remain in such a central region more easily if the electrode body bends due to external mechanical stress.

[0015] In one embodiment, the insulator surrounding the electrode conductors is embodied as a common insulator for several electrode conductors, in particular for all electrode conductors of the electrode assembly. The common insulator then insulates the electrode conductors from each other and at the same time holds them in the electrode conductor composite by means of an integrally bonded connection. In this embodiment, the common insulator effectively forms a stabilising framework in which the individual electrode conductors are embedded.

[0016] In one variant, the electrode conductor composite has a star-shaped structure in cross-section. The electrode conductors are only arranged in an outer cross-sectional region of the electrode conductor composite, while the common insulator is arranged both around the electrode conductors and in a central cross-sectional region of the electrode conductor composite. As a result, the electrode conductors form the points of the star, resulting in a three-pointed starshaped structure of the electrode conductor composite for three electrode conductors and a five- pointed star-shaped structure of the electrode conductor composite for five electrode conductors. In this star-shaped structure, the electrode conductors are connected to each other via the common insulator in the central cross-sectional region of the electrode conductor composite. Each electrode conductor is connected directly to the central cross-sectional region of the electrode conductor composite via the common insulator, without any other electrode conductors being arranged between the respective electrode conductor and the central cross-sectional region of the electrode conductor composite. This means that each electrode conductor (together with a corresponding region of the common insulator) protrudes directly from the portion of the common insulator that is arranged in the central cross-sectional region of the electrode conductor composite.

[0017] In one variant, the common insulator has at least one predetermined breaking point. Such a predetermined breaking point may be used to separate at least one electrode conductor (together with the region of the common insulator that surrounds this electrode conductor) from the other electrode conductors. Even after separation, the electrode conductor is electrically insulated from its external environment by the region of the common insulator that continues to surround it. The predetermined breaking point is formed in particular in a connection region between a portion of the common insulator that directly surrounds one of the electrode conductors and the portion of the common insulator that is arranged in the central cross-sectional region of the electrode conductor composite. Typically, a predetermined breaking point is provided for each electrode conductor so that each electrode conductor may be separated from the electrode conductor composite if required. This facilitates the electrical contacting of individual electrode poles of the electrode assembly. An electrode conductor is only separated from the electrode conductor composite within a short portion around the electrode pole to be contacted so that the electrode conductor composite is intact over its largest length region.

[0018] In one embodiment, such a predetermined breaking point is not provided for each electrode conductor, but only for a number of electrode conductors of the electrode conductor composite reduced by one. In this case, it is not possible for any of the electrode conductors to be separated from the electrode conductor composite. This electrode conductor may be used, for example, to make contact with the electrode pole arranged furthest distally. Typically, it is no longer necessary to separate the corresponding electrode conductor from the electrode conductor composite in order to contact this most distally arranged electrode pole, as this electrode conductor is already the last electrode conductor of the electrode conductor composite that runs so far distally in the electrode body.

[0019] In another embodiment, the electrode conductor composite is not star-shaped in cross-section, but has a linear structure in cross-section. In this linear structure, the individual electrode conductors are arranged sequentially one behind the other with the regions of the common insulator surrounding them. A transition portion, which is provided by the common insulator, is formed between every two electrode conductors. This transition portion in the linear structure substantially performs a comparable function to the connection region formed by the common insulator between an electrode conductor and the portion of the common insulator arranged in the central cross-sectional region of the electrode conductor composite in the cross-sectionally star-shaped configuration of the electrode conductor composite.

[0020] In one variant, the transition portion is in the form of a web. This web connects a first region of the common insulator to a second region of the common insulator. The first region of the common insulator surrounds a first of the at least three electrode conductors. The second region of the common insulator surrounds a second of the at least three electrode conductors. Electrode conductors arranged end-to-end in the linear structure are connected to a single adjacent further electrode conductor by a single web. In this embodiment, electrode conductors arranged in a central region of the linear structure are connected to a total of two adjacent electrode conductors via two webs, wherein each of these webs establishes the connection to a single adjacent electrode conductor. Naturally, this connection is an exclusively mechanical connection, as it is realised by means of the common insulator. The individual electrode conductors are electrically insulated from each other even when mechanically connected.

[0021] The web enables limited relative movement between individual electrode conductors of the electrode conductor composite. For example, it is possible to transfer the individual electrode conductors from the linear structure to a structure arranged at an angle to each other. It is also possible to roll up the linear structure of several electrode conductors arranged sequentially to one another and form a more compact, rolled-up structure, in which an angled arrangement of two adjacent electrode conductors also results in the previously linear structure. This extends the application possibilities of the electrode conductor composite and allows the electrode conductor composite to be drawn into the inner lumen of the electrode body particularly easily.

[0022] In one variant, the transition portion has a predetermined breaking point. As already explained above with regard to the star-shaped cross-section of the electrode conductor composite, this predetermined breaking point serves to enable the electrode conductors connected by the transition portion to be separated. This means that individual electrode conductors may then be detached from the electrode conductor composite, in particular to allow simplified contacting of individual electrode poles of the electrode assembly.

[0023] In one variant, each electrode conductor has a plurality of electrode strands. For example, 2, 3, 4, 5, 6, 7, 8, 9 or 10 electrode strands may be provided to form an electrode conductor, i.e. for example 2 to 10 electrode strands, in particular 3 to 9, in particular 4 to 8, in particular 5 to 7. A particularly simple structure of an electrode conductor results from the use of 7 electrode strands, wherein 6 electrode strands may be arranged in a ring around a central electrode strand. It is provided that each electrode strand is surrounded by an electrically non-conductive strand insulator. The strand insulator may be made of the same material as the insulator for the electrode conductor or as the common insulator. However, it is also conceivable to produce the strand insulator from a different electrically non-conductive material than the material for the insulator of the electrode conductor or for the common insulator. A suitable material for the insulator, the common insulator and / or the strand insulator is an ethylene-tetrafluoroethylene copolymer (ETFE). Other common insulation materials such as perfluoroalkoxy polymers (PF A) are also suitable.

[0024] In one variant, each electrode strand comprises a plurality of wires. For example, 2, 3, 4, 5, 6, 7, 8, 9 or 10 wires may be provided for the production of an electrode strand, for example 2 to 10 wires, in particular 3 to 9, in particular 4 to 8, in particular 5 to 7. A particularly simple structure of an electrode strand is possible when using 7 wires, wherein 6 of these wires may be arranged in a ring around a central wire, for example. In one variant, a 7x7 configuration of the electrode conductors is provided, i.e. the use of 7 wires to form a strand and the use of 7 strands formed in this way to provide the electrode conductor. Such an electrode conductor then has 49 individual wires. If the wires for constructing the strands are arranged in a circle and the strands for constructing the electrode conductor are arranged in a circle, this results in a particularly simple way in an electrode conductor with a circular cross-section, which may be drawn particularly easily into an inner lumen of the electrode body with a circular cross-section. The electrode wires typically consist of an electrically conductive metal or an electrically conductive metal alloy. A suitable alloy is, for example, the nickel-cobalt-based alloy marketed under the designation MP35N.

[0025] In one variant, a first of the at least three electrode poles is designed as a screw electrode. In this variant, a second of the at least three electrode poles is embodied as a ring electrode. Lastly, a third of the at least three electrode poles in this variant is embodied as a defibrillation electrode. In this embodiment, the electrode assembly is therefore particularly suitable for use as a defibrillation electrode.

[0026] The screw electrode is typically intended to be screwed into an apical region of the heart muscle tissue in the right ventricle, preferably in the septal wall of a patient. This anchors the electrode assembly in the patient's heart. The ring electrode may be used to detect cardiac signals and as a return electrode for stimulation of the human heart. The actual stimulation or defibrillation is performed using the defibrillation electrode, which may be embodied as a shock coil, for example. Typically, the ring electrode is arranged between the screw electrode and the defibrillation electrode, wherein the screw electrode is the most distally arranged electrode of the three electrodes and the defibrillation electrode is the most proximally arranged electrode of the three electrodes. Well-known connection techniques such as resistance welding and crimping are suitable for connecting the electrode conductor to the ring electrode. In one embodiment, the ring electrode has a bulge on its inner ring circumference that defines a connection option for the electrode conductor. In particular, it is provided that the electrode conductor, which is intended for contacting the ring electrode, may be inserted into this bulge and connected there to the ring electrode electrically conductively.

[0027] Even if more than three electrode poles are provided within the electrode assembly, the screw electrode typically forms the most distally arranged electrode in order to enable a particularly simple, secure and permanent fixation of the electrode assembly in the patient's heart tissue.

[0028] In one embodiment, two additional ring electrodes are provided proximal to the defibrillation electrode. In particular, the distance between the defibrillation electrode and the two additional ring electrodes is such that the two additional ring electrodes may be arranged in the atrium of a patient's heart, while the defibrillation electrode is arranged in the right ventricle of the same heart.

[0029] In an embodiment with second ring electrodes proximal to the defibrillation electrode, the defibrillation electrode may also be arranged directly behind the screw electrode. In such an arrangement, the ring electrode between the screw electrode and the defibrillation electrode may be omitted. Cardiac signals may thus be detected in a bipolar manner between the screw electrode and the defibrillation electrode. In such an arrangement, only 4 conductors would be required, which may be connected to the implant using a single IS4 / DF4 standard connector.

[0030] In one variant, the common electrode conductor composite extends from a region of the electrode body located distally of the electrode connector to the most proximally arranged electrode pole of the at least three electrode poles, for example to the defibrillation electrode. There, the electrode conductor composite is broken up to the extent that one conductor of the electrode conductor composite is separated from the electrode conductor composite and used to contact the most proximally arranged electrode pole.

[0031] In one variant, one of the at least three electrode conductors extends beyond the most proximally arranged electrode pole to the most distally arranged electrode pole of the at least three electrode poles. Furthermore, the remaining conductors of the electrode conductor composite extend to one electrode pole each, which is arranged between the most proximally arranged electrode pole and the most distally arranged electrode pole of the electrode assembly. In the case of three electrode poles, a first conductor would therefore first be separated from the electrode conductor composite in the region of the most proximal electrode pole. A second electrode conductor would then be separated from the electrode conductor composite in the region of a centrally arranged electrode, which is located between the most proximally arranged electrode pole and the most distally arranged electrode pole, and used to contact this central electrode. Consequently, only a single conductor of the conductor composite would remain in the distal direction of the electrode body and would then be used to contact the most distally arranged electrode.

[0032] Consequently, even in this variant, the electrode conductor composite only extends over a region of the electrode body which extends from a region located distally of the electrode connector to the most proximally arranged electrode pole in the distal end region of the electrode body. However, since the electrode body is relatively long in relation to its distal end region and together proximal end region, the electrode conductor composite also extends in this variant over by far the greatest length of the electrode body, namely in particular over at least 60% of the length of the electrode body, in particular at least 70% of the length of the electrode body, in particular at least 80% of the length of the electrode body, in particular at least 90% of the length of the electrode body, in particular at least 95% of the length of the electrode body. In one variant, the electrode conductor composite extends over a proportion of 60% to 98% of the length of the electrode body, in particular over a range of 70% to 95%, in particular 80% to 90%.

[0033] One aspect of the present invention relates to an implantable medical device for stimulating the human or animal heart. Such a device comprises a stimulation unit for stimulating a cardiac region of a human or animal heart and a detection unit for detecting an electrical signal of the same heart.

[0034] The implantable medical device is distinguished in that the stimulation unit and / or the detection unit comprises at least one electrode assembly according to the previous explanations. As explained above, the at least one electrode assembly has a tubular electrode body, an electrode connector arranged in a proximal end portion of the electrode body and at least three electrode poles arranged in a distal end portion of the electrode body. In addition, at least three electrode conductors are provided which run inside the electrode body. In each case, one of these electrode conductors connects a contact portion of the electrode connector to one of the electrode poles electrically conductively. Each electrode conductor is surrounded by an electrically non- conductive insulator, wherein all electrode conductors form an electrode conductor composite. In the electrode conductor composite, the individual electrode conductors are mechanically connected to each other but electrically insulated from each other.

[0035] In one embodiment, the implantable medical device is a pacemaker, an implantable cardioverter / defibrillator or a device for cardiac resynchronisation therapy.

[0036] One aspect of the present invention relates to a method for producing an electrode assembly according to the above explanations. This method is distinguished in that the at least three electrode conductors in the form of the electrode conductor composite are drawn together into the electrode body. This joint laying of the electrode conductors in the form of the electrode conductor composite into the inner lumen of the electrode body significantly simplifies the production process compared to the production methods known from the prior art. This is because, as a result of the electrode conductor composite, only a single step is required, whereas in the solutions known from the prior art, the individual electrode conductors have to be laid separately from each other in the inner lumen of an electrode body.

[0037] All variants and embodiments of the explained electrode assembly may be combined with each other in any way and transferred individually or in any combination to the described implantable medical device and to the method for producing an electrode assembly. In the same way, variants and embodiments of the implantable medical device may be transferred individually or in any combination to the electrode assembly and to the method for producing an electrode assembly. Lastly, variants and embodiments of the method for producing an electrode assembly may be transferred individually or in any combination to the electrode assembly and to the implantable medical device.

[0038] Further details of aspects of the present invention are explained in greater detail below with reference to exemplary embodiments and accompanying figures, in which:

[0039] Fig. 1 shows a schematic view of an electrode assembly;

[0040] Fig. 2A shows a first partially sectioned schematic view of a distal end portion of the electrode assembly of Figure 1;

[0041] Fig. 2B shows a second partially sectioned schematic view of the distal end portion of the electrode assembly of Figure 1; Fig. 3 A shows a first partially sectioned schematic view of a proximal end portion of the electrode assembly of Figure 1;

[0042] Fig. 3B shows a second partially sectioned schematic view of the proximal end portion of the electrode assembly of Figure 1;

[0043] Fig. 4A shows a schematic cross-sectional view of a first electrode assembly with a first electrode conductor composite;

[0044] Fig. 4B shows a schematic side view of the first electrode conductor composite of the electrode assembly of Figure 4A;

[0045] Fig. 5A shows a schematic cross-sectional view of a second electrode assembly with a second electrode conductor composite;

[0046] Fig. 5B shows a schematic side view of the second electrode conductor composite of the electrode assembly of Figure 5 A;

[0047] Fig. 6A shows a schematic cross-sectional view of a third electrode conductor composite;

[0048] Fig. 6B shows a schematic cross-sectional view of a fourth electrode conductor composite;

[0049] Fig. 7A shows a schematic cross-sectional view of a fifth electrode conductor composite;

[0050] Fig. 7B shows a schematic cross-sectional view of a sixth electrode conductor composite;

[0051] Fig. 8A shows a perspective view of a ring electrode;

[0052] Fig. 8B shows a schematic cross-sectional view of the ring electrode of Figure 8 A;

[0053] Fig. 9 shows a perspective view of a seventh electrode conductor composite and

[0054] Fig. 10 shows a perspective view of an eighth electrode conductor composite. Figure 1 shows an electrode assembly 1 with a single-lumen electrode body 2, an electrode connector 3 and three electrode poles 4. The electrode connector 3 is arranged in a proximal end portion 5 of the electrode body 2, while the three electrode poles 4 are arranged in a distal end portion 6 of the electrode body 2.

[0055] Figure 2A shows an enlarged, partially sectioned representation of the distal end portion 6 of the electrode body 2 of Figure 1. In this and all subsequent figures, comparable elements are always provided with the same reference signs.

[0056] Figure 2A shows a shock coil 41, a ring electrode 42 and a screw electrode 43. The shock coil 41 serves as the first electrode pole, the ring electrode 42 as the second electrode pole and the screw electrode 43 as the third electrode pole. The shock coil 41 is arranged furthest proximal from the three electrode poles, while the screw electrode 43 is arranged furthest distal from the three electrode poles. The ring electrode 42 may also be referred to as the central electrode.

[0057] In a central region of the electrode body and therefore also in a central region of the shock coil 41, there is an electrode conductor composite 7, which comprises a first electrode conductor 8, a second electrode conductor 9 and a third electrode conductor 10. The first electrode conductor 8 is used to make contact with the shock coil 41. The second electrode conductor 9 is used to make contact with the ring electrode 42. Lastly, the third electrode conductor 10 is used to make contact with the screw electrode 43.

[0058] In the region of the shock coil 41, the electrode conductor composite 7 is partially broken up by separating the first electrode conductor 8 from the electrode conductor composite 7. It then continues to exist in the more distally oriented portion of the electrode assembly 1 only in the form of a reduced electrode conductor composite, which is formed by the second electrode conductor 9 and the third electrode conductor 10.

[0059] The second electrode conductor 9 is separated from the remaining reduced electrode conductor composite in the region of the ring electrode 42 and used to contact the ring electrode 42. This leaves, distal to the ring electrode 42, only the third electrode conductor 10, which is used to contact the screw electrode 43.

[0060] As is visible from Figure 1, the distal end portion 6 only makes up a small length region of the electrode assembly 1. Consequently, the electrode conductor composite 7 extends over by far the largest length portion of the electrode body 2. Only in the outermost distal end region 6, in which the three electrode poles 4 are arranged, is the electrode conductor composite broken up by separating individual electrode conductors from the electrode conductor composite 7.

[0061] Figure 2B shows a perspective view of the shock coil 41, ring electrode 42 and screw electrode 43 already known from Figure 2A. In this view, the contacting of the individual electrodes 41, 42, 43 by the electrode conductors 8, 9, 10 assigned to them is visible even more precisely. For example, the first electrode conductor 8 is electrically conductively connected to a cylindrical (ring-shaped) contact element 11. The cylindrical contact element 11 is in turn electrically conductively connected to the shock coil 41.

[0062] The second electrode conductor 9 is inserted into a bulge 420 on the inner circumference 421 of the ring electrode 42 and is firmly and electrically conductively connected to the ring electrode 42 by means of a crimp.

[0063] Lastly, the screw electrode 43 is also firmly and electrically conductively connected to the third electrode conductor 10 by means of a crimp.

[0064] Figures 3A and 3B each show a partially sectioned first view of the proximal end portion 5 of the electrode assembly 1 of Figure 1. In this proximal end portion 5, the electrode connector 3 is formed according to the IS4 / DF4 standard, which has three electrically separate ring-shaped contact portions 31, 32, 33 and a central contact portion (connector pin) 34. The contact portions 31, 32 are electrically conductively connected to the two electrode conductors 9, 10, while the central contact portion 34 is connected to electrode conductor 8. In a configuration with three electrode conductors, the contact portion 34 is not occupied and would be available for an additional conductor. The electrode conductors 8, 9, 10 are then led away from the three contact portions 31, 32, 34 in a distal direction and brought together somewhat distally of the three contact portions 31, 32, 33 to form the electrode conductor composite 7. The electrode conductor composite 7 is then led through an inner lumen of the electrode body 2 in the direction of the electrode poles.

[0065] Figure 4A shows a cross-sectional view of a first electrode assembly 1 with a first electrode conductor composite 7, which comprises a first electrode conductor 8, a second electrode conductor 9 and a third electrode conductor 10. The electrode conductor composite 7 is guided in an inner lumen of an electrode body 2. The first electrode conductor 8, the second electrode conductor 9 and the third electrode conductor 10 are identically structured. They each have seven strands 81, 91, 101, wherein each strand is made up of seven wires 82, 92, 102. For the sake of clarity, only individual strands and individual wires are labelled with the corresponding reference sign. The first electrode conductor 8 is surrounded by a first insulator 83, while the second electrode conductor 9 is surrounded by a second insulator 93 and the third electrode conductor 10 is surrounded by a third insulator 103.

[0066] The first electrode conductor 8, the second electrode conductor 9 and the third electrode conductor 10 are stranded together. This becomes clear in Figure 4B, which shows the first electrode conductor 8, the second electrode conductor 9 and the third electrode conductor 10 in a lateral view. It is clear that the first electrode conductor 8 and the third electrode conductor 10 wind around the centrally arranged second electrode conductor 9, forming the electrode conductor composite 7.

[0067] The first electrode conductor 8, the second electrode conductor 9 and the third electrode conductor 10 are not connected to each other in an integrally bond manner, but may be separated simply from each other. In the electrode conductor composite 7, however, they are initially connected to each other form-fittingly due to the stranding and also in a frictionally engaged manner due to the frictional forces that occur. Due to the first insulator 83, the second insulator 93 and the third insulator 103, the first electrode conductor 8, the second electrode conductor 9 and the third electrode conductor 10 are electrically insulated from each other.

[0068] Figure 5A shows a cross-sectional view through an electrode body 2 with a second electrode conductor composite 7. This second electrode conductor composite 7 consists of a first electrode conductor 8, a second electrode conductor 9, a third electrode conductor 10, a fourth electrode conductor 12 and a fifth electrode conductor 13. Each of these electrode conductors is surrounded by a corresponding insulator 83, 93, 103, 123, 133. The individual electrode conductors 8, 9, 10, 12, 13 are not connected to each other in an integrally bonded manner, but only form-fittingly and in a frictionally engaged manner, since they are stranded together - as are the electrode conductors of the electrode conductor composite shown in Figure 4A. This is shown in greater detail in the side view in Figure 5B. Here, the first electrode conductor 8, the third electrode conductor 10, the fourth electrode conductor 12 and the fifth electrode conductor 13 are shown stranded together. The second electrode conductor 9 is not visible in this illustration, as it is located in the centre of the stranded electrode conductors and the other electrode conductors are arranged around it. The individual electrode conductors shown in Figure 5A and Figure 5B are, like the electrode conductors in Figure 4A, made up of seven strands with seven wires each, wherein the respective reference signs are not shown in Figure 5A for the sake of clarity (but see Figure 4A for details).

[0069] Figure 6A shows a cross-sectional view through a third electrode conductor composite 7, which again comprises five individual electrode conductors, namely a first electrode conductor 8, a second electrode conductor 9, a third electrode conductor 10, a fourth electrode conductor 12 and a fifth electrode conductor 13. The individual electrode conductors 8, 9, 10, 12, 13 are surrounded by a common insulator 14, which on the one hand surrounds the respective electrode conductors 8, 9, 10, 12, 13 and on the other hand has a portion 141 common to all electrode conductors. The individual electrode conductors 8, 9, 10, 12, 13 are arranged in an outer cross- sectional region of the electrode conductor composite 7, while the common insulator 14 is arranged both in an outer cross-sectional region of the electrode conductor composite 7 (namely around the respective electrode conductors 8, 9, 10, 12, 13) and in a central cross-sectional region of the electrode conductor composite 7 (namely through the common portion 141).

[0070] This results in a star-shaped arrangement of the individual electrode conductors 8, 9, 10, 12, 13 around the common portion 141 of the common insulator 14. The common portion 141 may also have an additional lumen (not shown) to accommodate a guide wire (stylet) (see also embodiment according to Fig. 9). An alternative star-shaped arrangement of the individual electrode conductors 8, 9, 10, 12, 13 with a larger common portion 141 is shown in Fig. 10.

[0071] Predetermined breaking points 142, 143, 144, 145 and 146 are provided to enable individual electrode conductors to be separated from the electrode conductor composite 7. These predetermined breaking points are formed in transition portions at which the common insulator transitions from the common portion 141 to the regions surrounding the individual electrode conductors 8, 9, 10, 12, 13. At these predetermined breaking points 142, 143, 144, 145, 146, the respective electrode conductors 8, 9, 10, 12, 13 may be mechanically separated from the portion 83, 93, 103, 123, 133 of the common insulator 14 directly surrounding them.

[0072] Figure 6B shows a configuration of the electrode conductor composite 7 comparable to Figure 6A, wherein only three electrode conductors are provided instead of five individual electrode conductors, namely a first electrode conductor 8, a second electrode conductor 9 and a third electrode conductor 10. This embodiment also results in a star-shaped arrangement of the individual electrode conductors 8, 9, 10 around a central common portion 141 of the common insulator 14. Here too, the common portion 141 may have an additional lumen (not shown) to accommodate a guide wire (stylet) (see also embodiment according to Fig. 9).

[0073] In addition, this embodiment also provides for the individual electrode conductors 8, 9, 10 to be separated from the electrode conductor composite 7 by means of predetermined breaking points 142, 143, 144 in order to be able to contact individual electrode poles of the electrode assembly.

[0074] Figure 7A shows a further possible embodiment of the electrode conductor composite 7. In this embodiment, the electrode conductor composite 7 does not have a star-shaped structure like the electrode conductor assemblies of Figures 6A and 6B, but a linear structure in which the individual electrode conductors 8, 9, 10, 12, 13 are arranged sequentially one behind the other or next to each other. Here, too, a common insulator 14 surrounds all the electrode conductors

[0075] 8, 9, 10, 12, 13. The common insulator 14 is formed from insulator portions 83, 93, 103, 123, 133, which directly surround the individual electrode conductors 8, 9, 10, 12, 13, and from webs 147, which connect the aforementioned portions to one another. These webs 147 represent transition portions between the individual electrode conductors 8, 9, 10, 12, 13. The first electrode conductor 8 and the fifth electrode conductor 13, which are each arranged terminally, are only connected to a single one of these webs 147. In contrast, the second electrode conductor

[0076] 9, third electrode conductor 10 and fourth electrode conductor 12, which are arranged in the central region of the sequential arrangement of the electrode conductor composite 7, are each connected to two of these webs 147.

[0077] A predetermined breaking point is again formed at the webs 147 to enable the individual electrode conductors 8, 9, 10, 12, 13 to be separated from the electrode conductor composite 7.

[0078] Figure 7B shows a cross-sectional view of a further electrode conductor composite 7, in which the individual electrode conductors 8, 9, 10 are again connected sequentially to each other. In contrast to the configuration shown in Figure 7A, however, only three electrode conductors 8, 9, 10 are present in the electrode conductor composite 7. Otherwise, the embodiment of the electrode conductor composite 7 corresponds to the embodiment of the electrode conductor composite 7 of Figure 7A.

[0079] Both the webs 147 of the electrode conductor composite 7 of Figure 7A and the webs 147 of the electrode conductor composite 7 of Figure 7B also serve to enable limited mobility between the individual electrode conductors of these electrode conductor assemblies 7. In this way, it is possible to arrange the electrode conductors 8, 9, 10, 12, 13 or 8, 9, 10 at an angle to each other and to convert the electrode conductor composite 7 into a rolled-up configuration if required.

[0080] Figure 8A shows a schematic perspective view of an exemplary embodiment of a ring electrode 42, which is intended for use in an electrode assembly 1 (see in particular Figures 1, 2A and 2B). This ring electrode 42 has a bulge 420 on its inner ring circumference 421, into which one of the electrode conductors of the electrode assembly 1 may be inserted and connected to the ring electrode 42 electrically conductively, for example by means of resistance welding or clamping. In this way, the corresponding electrode conductor then establishes an electrical line between the ring electrode 42 and a contact portion 31, 32, 33 (see Figures 3 A and 3B) of the electrode connector 3 of the electrode assembly 1 provided for this purpose.

[0081] Figure 8B shows a cross-sectional view through the ring electrode 42 of Figure 8A, wherein reference is made to the explanations for Figure 8A for an explanation of the individual elements.

[0082] Fig. 9 shows an electrode conductor composite 7, which again consists of five individual electrode conductors, namely a first electrode conductor 8, a second electrode conductor 9, a third electrode conductor 10, a fourth electrode conductor 12 and a fifth electrode conductor 13. The individual electrode conductors 8, 9, 10, 12, 13 are surrounded by a common insulator 14, which on the one hand surrounds the respective electrode conductors 8, 9, 10, 12, 13 and on the other hand has a portion 141 common to all electrode conductors. In this embodiment, the common portion 141 has an additional central lumen 150 for a guide wire (stylet).

Claims

Claims1. An electrode assembly for an implantable medical device, comprising- a tubular electrode body (2),- an electrode connector (3) arranged in a proximal end portion (5) of the electrode body (2),- at least three electrode poles (4, 41, 42, 43) arranged in a distal end portion (6) of the electrode body (2), and- at least three electrode conductors (8, 9, 10, 12, 13) which run within the electrode body (2), wherein in each case one electrode conductor (8, 9, 10, 12, 13) electrically conductively connects a contact portion (31, 32, 33, 34) of the electrode connector (3) to one of the electrode poles (41, 42, 43) characterised in that each electrode conductor (8, 9, 10, 12, 13) is surrounded by an electrically non-conductive insulator (83, 93, 103, 123, 133), wherein all the electrode conductors (8, 9, 10, 12, 13) form an electrode conductor composite (7) in which the individual electrode conductors (8, 9, 10, 12, 13) are mechanically connected to one another but electrically insulated from one another.

2. The electrode assembly according to claim 1, characterised in that the electrode conductors (8, 9, 10, 12, 13) are stranded together.

3. The electrode assembly according to claim 1 , characterised in that a plurality of electrode conductors (8, 9, 10, 12, 13) are surrounded by a common insulator (14) which insulates the electrode conductors (8, 9, 10, 12, 13) from one another and at the same time holds them in the electrode conductor composite (7).

4. The electrode assembly according to claim 3, characterised in that the electrode conductor composite (7) has a star-shaped structure in cross-section, in which the electrode conductors (8, 9, 10, 12, 13) are arranged only in an outer cross-sectional region and the common insulator (14) is arranged both around the electrode conductors (8, 9, 10, 12, 13) as well as in a central cross-sectional region (141), wherein the electrode conductors (8, 9, 10, 12, 13) are connected to one another via the common insulator (14) in the central cross- sectional region (141).

5. The electrode assembly according to claim 4, characterised in that the electrode conductor composite (7) has a lumen in the central cross-sectional region (141), wherein the lumen is suitable in particular for receiving a guide wire.

6. The electrode assembly according to claim 4 or 5, characterised in that the common insulator (14) has at least one predetermined breaking point (142, 143, 144, 145, 146) in order to enable at least one electrode conductor (8, 9, 10, 12, 13) to be separated from the other electrode conductors (8, 9, 10, 12, 13).

7. The electrode assembly according to claim 3, characterised in that the electrode conductor composite (7) has a structure which is linear in cross-section, in which the electrode conductors (8, 9, 10, 12, 13) are arranged sequentially one behind the other and a transition portion (147) formed by the common insulator (14) is formed between every two electrode conductors (8, 9, 10, 12, 13).

8. The electrode assembly according to claim 7, characterised in that the transition portion (147) is in the form of a web (147) which connects a first region (83, 93, 103, 123, 133) of the common insulator (14), which surrounds a first of the at least three electrode conductors (8, 9, 10, 12, 13), to a second region (83, 93, 103, 123, 133) of the common insulator (14), which surrounds a second of the at least three electrode conductors (8, 9, 10, 12, 13).

9. The electrode assembly according to claim 7 or 8, characterised in that the transition portion (147) has a predetermined breaking point in order to enable separation of the electrode conductors (8, 9, 10, 12, 13) connected by the transition portion (147).

10. The electrode assembly according to any one of the preceding claims, characterised in that each electrode conductor (8, 9, 10, 12, 13) has a plurality of electrode strands, wherein each electrode strand (81, 91, 101) is surrounded by an electrically non-conductive strand insulator.

11. The electrode assembly according to claim 10, characterised in that each electrode strand (81, 91, 101) comprises a plurality of wires (82, 92, 102).

12. The electrode assembly according to any one of the preceding claims, characterised in that a first of the at least three electrode poles (41 , 42, 43) is embodied as a screw electrode (43), in that a second of the at least three electrode poles (41, 42, 43) is embodied as a ring electrode (42), and in that a third of the at least three electrode poles (41, 42, 43) is embodied as a defibrillation electrode (41).

13. The electrode assembly according to any one of the preceding claims, characterised in that the electrode conductor composite (7) extends from a region of the electrode body (2) lying distally of the electrode connector (3) to the most proximally arranged electrode pole (41) of the at least three electrode poles (4, 41, 42, 43).

14. The electrode assembly according to claim 13, characterised in that one of the at least three electrode conductors (8, 9, 10, 12, 13) extends beyond the most proximally arranged electrode pole (41) of the at least three electrode poles (4, 41, 42, 43) to the most distally arranged electrode pole (43), and in that the remaining electrode conductors (8, 9, 10, 12, 13) each extend to one of the at least three electrode poles (4, 41, 42, 43) which is arranged between the most proximally arranged electrode pole (41) and the most distally arranged electrode pole (43).

15. An implantable medical device for stimulating the human or animal heart, comprising a stimulation unit for stimulating a cardiac region of a human or animal heart and a detection unit for detecting an electrical signal of the same heart, characterised in that the stimulation unit and / or the detection unit has at least one electrode assembly (1) according to any one of the preceding claims, wherein the at least one electrode assembly (1) has a tubular electrode body (2), an electrode connector (3) arranged in a proximal end portion (5) of the electrode body (2), at least three electrode poles (4, 41, 42, 43) arranged in a distal end portion (6) of the electrode body (2) and at least three electrode conductors (8, 9, 10, 12, 13) which run inside the electrode body (2), wherein a respective electrode conductor (8, 9, 10, 12, 13) electrically conductively connects a contact portion (31, 32, 33) of the electrode connector (3) to one of the electrode poles (4, 41, 42, 43), wherein each electrode conductor (8, 9, 10, 12, 13) is covered by an electrically non-conductive insulator (83, 93, 103, 123, 133), wherein all the electrode conductors (8, 9, 10, 12, 13) form an electrode conductor composite (7) in which the individual electrode conductors(8, 9, 10, 12, 13) are mechanically connected to one another but electrically insulated from one another.

16. A method for producing an electrode assembly (1) according to any one of the preceding claims, wherein the electrode assembly (1) comprises a tubular electrode body (2), an electrode connector (3) arranged in a proximal end portion (5) of the electrode body (2), at least three electrode poles (4, 41, 42, 43) arranged in a distal end portion (6) of the electrode body (2) and at least three electrode conductors (8, 9, 10, 12, 13) which run within the electrode body (2), wherein in each case one electrode conductor (8, 9, 10, 12, 13) electrically conductively connects a contact portion (31, 32, 33) of the electrode connector (3) to one of the electrode poles (4, 41, 42, 43), wherein each electrode conductor (8, 9, 10, 12, 13) is surrounded by an electrically non-conductive insulator (83, 93, 103, 123, 133), wherein all of the electrode conductors (8, 9, 10, 12, 13) form an electrode conductor composite (7) in which the individual electrode conductors (8, 9, 10, 12, 13) are mechanically connected to one another but electrically insulated from one another, wherein the method comprises the following step:- drawing together the at least three electrode conductors (8, 9, 10, 12, 13) into the electrode body (2) in the form of the electrode conductor composite (7).

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