WO2021028411A1

WO2021028411A1 - Implantable defibrillation system

Info

Publication number: WO2021028411A1
Application number: PCT/EP2020/072446
Authority: WO
Inventors: Thomas Dörr; Volker Lang; Gernot Kolberg
Original assignee: Biotronik Se & Co. Kg
Priority date: 2019-08-13
Filing date: 2020-08-11
Publication date: 2021-02-18
Also published as: DE102019121719A1

Abstract

An implantable defibrillation system comprises a defibrillation generator (1) and an electrode lead assembly with at least one electrode lead (2, 3) connectable to the defibrillation generator (1), the electrode lead assembly being intended to be implanted substernally in a patient and having an electrode array (20, 30). The electrode array (20, 30) has at least one first electrode pole (202, 204) for delivering stimulation energy for defibrillation, at least one second electrode pole (203, 205) for detecting ventricular signals and at least one third electrode pole (200, 201) for detecting atrial signals.

Description

IMPLANTABLE DEFIBRILLATION SYSTEM

Description

The present invention relates to an implantable defibrillation system according to the preamble of claim 1, to an electrode lead assembly for an implantable defibrillation system, and to a defibrillation generator for an implantable defibrillation system. Such a defibrillation system comprises a defibrillation generator and an electrode lead assembly having at least one electrode lead connectable to the defibrillation generator. The electrode lead assembly is to be implanted non-transvenously in a patient and comprises an electrode array. Such a defibrillation system, also known as an implantable cardioverter-defibrillator (ICD), is used to detect and treat potentially life-threatening cardiac arrhythmias (ventricular tachycardia, bradycardia, ventricular fibrillation). Such a defibrillation system is implanted in a patient in such a way that one or more electrode leads, starting from a defibrillation generator, extend to the human heart in order, on the one hand, to pick up signals for the purpose of detecting cardiac arrhythmias and, on the other hand, to emit stimulation energy, in particular to cause an electric shock (defibrillation). In this case both the electrode leads and the defibrillation generator are permanently implanted and remain in the patient for a relatively long period of time, usually several years. In conventional defibrillation systems, the defibrillation generator is implanted subcutaneously and electrode leads are laid directly into the heart via a vein access. Although such defibrillation systems have proven their worth in practice, it may be desirable to provide other defibrillation systems that are easier to implant and also easier to remove, in particular avoiding direct venous access to the heart.

However, in the case of an implantation in which electrode leads are laid outside the heart, i.e. non-transvenously, and do not extend into the heart, care must be taken to ensure that signals which may be used to identify cardiac arrhythmias and treat the heart may be recorded with sufficient sensitivity.

The object of the present invention is to provide an implantable defibrillation system, an electrode lead assembly and a defibrillation generator, which enable electrode leads to be laid outside the heart for the purpose of defibrillation, while at the same time allowing signals to be recorded for determining cardiac arrhythmias in different regions of the heart.

This object is achieved by a subject having the features of claim 1.

Accordingly, the electrode array has at least one first electrode pole for delivering stimulation energy for defibrillation, at least one second electrode pole for detecting ventricular signals and at least one third electrode pole for detecting atrial signals.

In the case of the implantable defibrillation system, the defibrillation generator should be implanted, for example, subcutaneously or under the patient's chest muscle. An electrode lead assembly comprises one or more electrode leads to be connected to the defibrillation generator and implanted in a patient in such a way that an electrode array created by the electrode lead assembly is implanted non-transvenously. Electrode leads are thus laid outside the patient's venous system and do not extend into the patient's heart. The electrode array created by the electrode leads allows signals to be picked up outside the heart and directed to the defibrillation generator, and also allows stimulation energy to be delivered to stimulate the heart.

The electrode array includes a first electrode pole for delivering stimulation energy for defibrillation. Electrical energy may be emitted via the at least one first electrode pole in order to cause an electric shock to the heart and thus, if a cardiac arrhythmia is detected, to initiate treatment.

The electrode array also comprises at least one second electrode pole, by means of which ventricular signals may be recorded. Via the at least one second electrode pole, signals which are generated in the region of the ventricles due, in particular, to intrinsic activity of the heart may thus be detected in order to conduct the signals to the defibrillation generator for evaluation in order to potentially detect cardiac arrhythmias. In addition, the electrode array comprises at least one third electrode pole, via which atrial signals, for example from the right atrium, may be recorded. Atrial signals may thus be included in diagnostics and therapy management. For example, this makes it possible to distinguish between supraventricular tachycardia (SVT) and ventricular tachycardia (VT) and allows a corresponding management of the treatment, in particular the delivery of stimulation energy.

Because the at least one electrode lead of the implantable defibrillation system is implanted non-transvenously and the electrode array is thus located outside the heart, the risk and expense of implantation for additional detection of atrial signals does not increase significantly.

The electrode lead assembly should preferably be implanted in a patient in such a way that an electrode array created by the electrode lead assembly is placed substernally, i.e. beneath the patient's sternum.

The at least one second electrode pole and/or the at least one third electrode pole may be designed as a ring electrode, for example. The at least one second electrode pole, which serves to pick up ventricular signals, and the at least one third electrode pole, which serves to pick up atrial signals, may be arranged in this case on the same electrode lead or on different electrode leads. If designed as a ring electrode, the electrode pole extends circumferentially on the outside of the associated electrode lead and enables electrical contact with surrounding tissue. The at least one first electrode pole, which is used to deliver stimulation energy, may be designed as a helix, for example. The at least one first electrode pole thus extends helically around an associated electrode lead. Due to the helical design, the surface area of the at least one first electrode pole is enlarged, so that electric shock energy may be delivered and introduced into the heart in an efficient manner, while still providing sufficient flexibility on the electrode lead for flexible, possibly curved arrangement in the patient.

The at least one first electrode pole may be arranged here on the same electrode lead as the at least one second electrode pole and the at least one third electrode pole. However, it is also conceivable that the at least one first electrode pole is arranged on an electrode lead which is different from an electrode lead having the at least one second electrode pole and/or the at least one third electrode pole.

In one embodiment, the at least one third electrode pole is located at a distal end of an electrode lead of the electrode lead assembly. Here, the distal end corresponds to the end of the electrode lead that is remote from the proximal end, the proximal end being the end that is connectable to the defibrillation generator. The at least one third electrode pole in this embodiment is thus placed distally from the defibrillation generator, and the at least one third electrode pole may be arranged directly at the distal end and in this case covers the tip of the electrode lead, for example. In the implanted state, the electrode lead with the at least one third electrode pole arranged thereon approaches the right atrium of the patient's heart, for example, so that atrial signals may be picked up via the at least one third electrode pole and may be fed to the defibrillation generator.

Additionally or alternatively, however, an electrode pole serving to pick up atrial signals may also be arranged proximally offset from the distal end of the electrode lead, although the at least one third electrode pole is arranged (clearly) distally from the proximal end of the electrode lead.

In one embodiment, the at least one first electrode pole, the at least one second electrode pole and the at least one third electrode pole are arranged on a common electrode lead of the electrode lead assembly. In this case, the implantable defibrillation system may, for example, comprise a single electrode lead on which all electrode poles are arranged. A single electrode lead thus has one or more first electrode poles for delivering stimulation energy, one or more second electrode poles for detecting ventricular signals and one or more third electrode poles for detecting atrial signals.

In an alternative embodiment, however, the at least one third electrode pole may also be arranged on a separate electrode lead. In this case, for example, the at least one first electrode pole and the at least one second electrode pole are arranged together on a first electrode lead, while the at least one third electrode pole for detecting atrial signals is arranged on a separate, second electrode lead of the electrode lead assembly. Both electrode leads may be connected to the defibrillation generator and, when implanted, are laid in such a way that stimulation energy may be delivered in a suitable manner and sensory signals in the region of the atrium and in the region of the ventricle may be recorded in a suitable manner.

In one embodiment, the electrode array has two third electrode poles that form a dipole for detecting atrial signals. The two third electrode poles may be arranged on a common electrode lead, for example in the region of the distal end of the electrode lead. It is also possible, however, that the third electrode poles are arranged at a distance from each other on a common electrode lead or on different electrode leads. Between the two third electrode poles, signals may be recorded that originate from atrial activity of the heart and thus enable the detection of atrial sensory signals.

In one embodiment, at least one second electrode pole and at least one third electrode pole are arranged on different sides of the at least one first electrode pole (reference is made here to the axial extension length of the flexible, elongate electrode lead). For example, a third electrode pole for receiving atrial signals may be located on a distal side of the first electrode pole, while a second electrode pole for receiving ventricular signals is located on a proximal side of the first electrode pole. However, other arrangements are also conceivable. For example, two third electrode poles may be arranged on different sides of a first electrode pole. Likewise, two second electrode poles may be arranged on different sides of a first electrode pole. It is also conceivable that a second electrode pole and/or a third electrode pole is arranged between two first electrode poles. One or more second and/or third electrode poles are thus arranged between a pair of first electrode poles for the delivery of stimulation energy.

In one embodiment, the at least one electrode lead has a plug that may be plugged into a connector of the defibrillation generator to connect the electrode lead to the defibrillation generator. For example, all electrode poles of the electrode lead may be functionally connected to the defibrillation generator via a single plug. The plug may, for example, have connection poles which, when the plug is plugged into the connector of the defibrillation generator, make electrical contact with associated contact elements of the connector, so that electrical supply lines of the electrode lead are connected to the defibrillation generator.

The plug may be, for example, have two poles, four poles, six poles, eight poles or even more.

In one embodiment, the defibrillation generator has a control device which forms a first receiving channel for processing ventricular signals received via the electrode lead assembly and a second receiving channel for processing atrial signals received via the electrode lead assembly. A separate receiving channel is thus provided for picking up and processing atrial signals, with the atrial signals being processed separately in said receiving channel. In particular, the second receiving channel for processing the atrial signals may have a different gain and a different filter characteristic than the first receiving channel for processing the ventricular signals. In this way, atrial signals may be received with higher sensitivity, for example with a sensitivity of less than 1 mV, preferably less than 0.1 mV, more preferably less than 0.05 mV. Atrial signals may be filtered here in a special way, especially to suppress other, possibly interfering signals, for example ventricular signals, for example by using a cyclic time window in which interfering signals are suppressed (a so-called "blanking window"). Atrial signals may also be processed here in order to analyse signal characteristics, such as a maximum (positive and/or negative) amplitude, peak-to-peak value, pulse width or average value (positive and/or negative).

In one embodiment, the control device is designed to receive atrial signals via a plurality of different dipoles created by electrode poles of the electrode array.

Atrial signals may, for example, be received via a dipole created by two third electrode poles. However, atrial signals may also be received between other electrode poles, for example between two first electrode poles and/or between two second electrode poles or combinations thereof. In addition, a dipole may be created to receive atrial signals between, for example, a third electrode pole and the defibrillation generator housing. The defibrillation generator may be designed in this case to receive and evaluate atrial signals using a dipole, it being possible to choose from different available dipoles. Alternatively, the defibrillation generator may be designed to switch cyclically between two or more dipoles during operation. Atrial signals may, however, also be received and evaluated simultaneously using two or more dipoles.

Received atrial signals may be used to distinguish between VT and SVT, for example.

Additionally or alternatively, atrial signals may be used for atrial cardioversion.

Again, additionally or alternatively, atrial signals may be used for atrial-synchronised ventricular stimulation.

Additionally or alternatively, atrial stimulation signals may also be delivered via third electrode poles, for example for antibradycardia atrial stimulation and/or antitachycardia atrial stimulation. Additionally or alternatively, atrial signals may be recorded, stored and, if necessary, transmitted remotely to an external device, for example by telemetry, for the purpose of atrial rhythm diagnosis. Atrial signals may also be included in the ventricular therapy delivery.

An electrode lead on which a third electrode pole is arranged, in particular the plug of the electrode lead, and/or the defibrillation generator may have a marking indicating the configuration of the defibrillation system, for example by using text or a factory marking.

The object is also achieved by an electrode lead assembly for an implantable defibrillation system. The electrode lead assembly comprises at least one electrode lead which may be connected to a defibrillation generator and which is to be implanted non-transvenously, preferably substernally, in a patient and has an electrode array. It is provided here that the electrode array has at least one first electrode pole for delivering stimulation energy for defibrillation, at least one second electrode pole for detecting ventricular signals and at least one third electrode pole for detecting atrial signals.

The object is also achieved by a defibrillation generator for an implantable defibrillation system, to which an electrode lead assembly which comprises at least one electrode lead and which is to be implanted non-transvenously, preferably substernally in a patient, may be connected. It is provided here that the defibrillation generator has a control device which forms a first receiving channel for processing ventricular signals received via the electrode lead assembly and a second receiving channel for processing atrial signals received via the electrode lead assembly.

With regard to the electrode lead assembly and the defibrillation generator, the same advantages and advantageous embodiments apply as described above for the defibrillation system, and therefore, in this respect, full reference should be made to the description provided above. Within the scope of a method for implanting an implantable defibrillation system, a defibrillation generator and an electrode lead assembly comprising at least one electrode lead connectable to the defibrillation generator are implanted in a patient. The at least one electrode lead is implanted here substernally in a patient in such a way that an electrode array of the electrode lead assembly comes to lie substernally in the patient. The electrode array has at least one first electrode pole for delivering stimulation energy for defibrillation, at least one second electrode pole for detecting ventricular signals and at least one third electrode pole for detecting atrial signals. Implantation is thus performed in the body outside the heart by laying one or more electrode leads outside the heart and placing an electrode array substernally in a patient. The defibrillation generator is implanted here subcutaneously or under the chest muscle of the patient. The concept underlying the invention will be explained in greater detail hereinafter with reference to the embodiments shown in the drawings, in which:

Fig. 1 shows a view of a defibrillation system with a substernally implanted electrode lead;

Fig. 2 shows a view of the defibrillation system in the region of the patient's heart;

Fig. 3 shows a view of an embodiment of an electrode lead; Fig. 4 shows a view of a defibrillation generator of the defibrillation system;

Fig. 5 shows a functional, schematic view of a control device of the defibrillation generator; Fig. 6 shows a schematic view of two receiving channels of the control device; and Fig. 7 shows a view of an embodiment of a defibrillation system with different electrode leads.

In an embodiment shown in Fig. 1 and 2, an implantable defibrillation system comprises a defibrillation generator 1, which is to be implanted, for example, subcutaneously or under the chest muscle of a patient and to which an electrode lead 2 (or a plurality of electrode leads, as will be described hereinafter) is connected. The electrode lead 2 extends here in the implanted state from the defibrillation generator 1 to the region of the patient's sternum S (breastbone) and is placed - as viewed from the outside - behind the sternum S.

As shown in Fig. 2, the electrode lead 2 thus runs outside the patient's heart H and does not extend into the patient's heart H. An electrode array 20 arranged in the distal region on the electrode lead 2 approaches the heart H from the outside, so that signals from the heart H may be recorded via the electrode array 20 and, in addition, electrical signals may be delivered to the heart H for the purpose of stimulation.

The electrode array 20 of the electrode lead 2, in the implanted state, in particular approaches the right atrium RA and the right ventricle RV of the heart H. The electrode array 20 may be used to record both atrial signals from the right atrium RA and ventricular signals from the right ventricle RV and also to deliver stimulation energy for the purpose of stimulation, in particular for the treatment of cardiac arrhythmias.

An electrode lead 2 shown in an embodiment in Fig. 3 comprises an electrode array 20 formed by a plurality of electrode poles 200-205 and arranged in the region of a distal end of the electrode lead 2. At a proximal end, the electrode lead 2 has a plug 21, on which connection poles 210 are arranged and which may be plugged into the defibrillation generator 1 in order to thus connect the electrode poles 200-205 to the defibrillation generator 1, to feed received signals to the defibrillation generator 1 and to feed stimulation energy to the electrode array 20.

The electrode array 20 has a plurality of electrode poles 200-205. Each electrode pole 200- 205 in this case may be assigned a connection pole 210, and in this case each electrode pole 200-205 is connected to its assigned connection pole 210 via a supply line. In this case (in contrast to the embodiment shown), the number of connection poles 210 corresponds to the number of electrode poles 200-205. Alternatively, individual electrode poles 200, 205 may also be connected jointly to just one assigned connection pole 210.

In the embodiment shown, the plug 21 has four connection poles 210 and is therefore of a four-pole design. Alternatively, plug 21 may also have a higher number of connection poles 210 and, for example, may be designed with six or eight poles.

The electrode poles 200-205 are differently designed and perform different functions.

First electrode poles 202, 204 are used to deliver stimulation energy and are arranged helically on the electrode lead 2. In the embodiment shown, the electrode lead 2 has two first electrode poles 202, 204, to which stimulation energy from the defibrillation generator

1 may be supplied in order to deliver stimulation energy to the heart H for the purpose of defibrillation and to thus treat detected cardiac arrhythmias.

Second electrode poles 203, 205 are used to detect ventricular signals, i.e. signals that have a ventricular origin and are due to ventricular activity at the heart H. Such ventricular signals may be intrinsic, i.e. they may be due to an intrinsic activity of the heart. However, such ventricular signals may also be stimulated.

In the embodiment shown, the second electrode poles 203, 205 are arranged on different sides of a first electrode pole 204 and are thus spaced apart from each other along the axial direction of extent of the electrode lead 2.

Third electrode poles 200, 201 are arranged in the region of the distal end of electrode lead

2 in the embodiment shown in Fig. 3. The third electrode poles 200, 201 are used to detect atrial signals and, when the electrode lead 2 is in the implanted state, are located in the immediate vicinity of the right atrium RA of the heart H, for example. While the first electrode poles 202, 204 are formed by helices, the second electrode poles 203, 205 and the third electrode poles 200, 201 are formed as ring electrodes, for example, which extend annularly around the electrode lead 2.

In each case, the electrode poles 200-205 may be exposed outwardly and may thus make electrical contact with surrounding tissue of the patient.

The third electrode poles 200, 201 together form a dipole through which atrial signals may be received.

The electrode lead 2 may be connected by means of the plug 21 to a connector 110 of a connector block 11 of the defibrillation generator 1, so that the connection poles 210 of the plug 21 make electrical contact with contact elements 111 of the plug connector 110. The contact elements 111 are functionally connected to a control device 12 of the defibrillation generator 1, so that signals received via the electrode lead 2 may be fed to the control device 12 via the contact elements 111 and, in addition, signals from the control device 12 may be delivered to the contact elements 111 and fed via same into the electrode lead 2.

The defibrillation generator 1 also has an energy store 13, especially in the form of a battery. The defibrillation generator 1 may be implanted in a patient and is intended to remain in the patient for a long period of time, for example several years. All components of the defibrillation generator 1 are encapsulated via a housing 10 and are thus sealed against moisture.

As shown in Fig. 5, the control device 12 has a ventricular receiving channel 121 and an atrial receiving channel 122. Ventricular signals and atrial signals are received and processed via the receiving channels 121, 122 and are fed to a control unit 120 for the purpose of diagnostics and therapy management. The control device 12 also has, in the embodiment shown, a ventricular stimulation unit 123, an atrial stimulation unit 124 and a cardioversion/defibrillation unit 125 for the purpose of defibrillation therapy. Ventricular signals received via the second, ventricular electrode poles 203, 205 of the electrode lead 2 are processed via the ventricular receiving channel 121. By contrast, atrial signals received, for example, via the third electrode poles 200, 201 are processed via the atrial receiving channel 122.

As shown in the schematic view according to Fig. 6, the different signals are processed here in different channels with possibly different gain 121A, 122A, different filtering 121B, 122B and different signal analysis 121C, 122C. In particular, the atrial receiving channel 122 should have an increased sensitivity so as to be able receive and process also weak atrial signals. Filtering 122B in the atrial receiving channel 122 is tuned to atrial signals, and the filtering may include, for example, a rectification, a smoothing (in the sense of a continuous averaging) and a suppression of interfering signals (in the sense of a "blanking window"). Via the filtering 122B, atrial signals are separated from other signals, for example, so that even weak atrial signals may be processed and evaluated.

With a signal analysis 122C, characteristics of atrial signals may be evaluated, for example to determine a maximum (positive and/or negative) amplitude, a peak-to-peak value, a (positive and/or negative) average value and/or a pulse width.

Pre-processed signals and/or characteristic values for signal characteristics may be fed to the control unit 120 of the control device 12 in order to carry out diagnostics and therapy management on the basis of the pre-processed signals and signal characteristics.

As described above, an electrode lead 2, in one embodiment, may have a pair of third electrode poles 200, 201, which form a dipole via which atrial signals may be received. Atrial signals may be received here additionally or alternatively via further dipoles, for example a dipole between one of the third electrode poles 200, 201 and a first electrode pole 202, 204 or a second electrode pole 203, 205 or also between one of the third electrode poles 200, 201 and the (electrically conductive) housing 10 of the defibrillation generator 1. Atrial signals may also be received via dipoles that are independent of the third electrode poles 200, 201, for example between the two first electrode poles 202, 204, which in themselves are intended to deliver stimulation energy.

During operation, a dipole may be selected via which atrial signals are received. It is also conceivable, however, to switch cyclically between different dipoles, or atrial signals may be received simultaneously via a plurality of dipoles.

In the embodiment shown in Fig. 3, all electrode poles 200-205 are arranged on a (single) electrode lead 2, so that 2 ventricular and atrial signals may be received and stimulation energy may also be delivered via just one electrode lead.

By contrast, in an embodiment shown in Fig. 7, in addition to a first electrode lead 2 with an electrode array 20 arranged thereon, a second electrode lead 3 with an electrode array 30 arranged thereon is connected to the defibrillation generator 1, which accordingly has a plurality of connectors for connecting the electrode leads 2, 3. For example, the first electrode poles 202, 204 for emitting stimulation energy and the second electrode poles 203, 205 for receiving ventricular signals may be arranged on the first electrode lead 2, while the electrode array 30 of the second electrode lead 3 is designed for receiving atrial signals.

The second electrode lead 3 is in this case advantageously implanted likewise outside the heart H and is thus arranged with the electrode array 30 substernally outside the heart H. It is also conceivable and possible, however, to implant the second electrode lead 3 in the heart H via a venous access.

The concept forming the basis of the invention is not limited to the above embodiments, but may also be realised in other ways.

A defibrillation system may have one or more electrode leads, the electrode leads together forming an electrode array for receiving ventricular and atrial signals and for delivering stimulation energy. Third electrode poles for receiving atrial signals may be arranged here on a common electrode lead or distributed over a plurality of electrode leads.

More than two third electrode poles may also be present here, in particular to create multiple dipoles (vectors) between third electrode poles to receive atrial signals.

Third electrode poles may also be used to deliver stimulation energy, in particular for antibradycardia atrial stimulation and/or antitachycardia atrial stimulation. Atrial sensory signals may be recorded, stored and transmitted to an external device for the purpose of atrial rhythm diagnostics. Atrial sensory signals may be used in particular for distinguishing between VT and SVT, for atrial cardioversion and/or for atrial synchronised ventricular stimulation (VDD).

LIST OF REFERENCE SIGNS

1 Defibrillation generator

10 Housing 11 Connector block

110 Connector 111 Contact element 12 Control device 120 Control unit 121 Ventricular receiving channel 121A Reinforcement 121B Filter unit 121C Analysis unit 122 Atrial receiving channel 122 A Reinforcement 122B Filter unit 122C Analysis unit

123 Ventricular stimulation unit

124 Atrial stimulation unit 125 Cardioversion/defibrillation unit

13 Energy source (battery)

2 Electrode lead

20 Electrode array

200-205 Electrode pole 21 Connector

210 Connection pole 3 Electrode lead

30 Electrode array

H Heart RA Right atrium RV Right ventricle S Sternum

Claims

CLAIMS What is claimed is

1. An implantable defibrillation system with a defibrillation generator (1) and an electrode lead assembly comprising at least one electrode lead (2, 3) connectable to the defibrillation generator (1), the electrode lead assembly being intended to be implanted non-transvenously in a patient and having an electrode array (20, 30), characterised in that the electrode array (20, 30) has at least one first electrode pole (202, 204) for delivering stimulation energy for defibrillation, at least one second electrode pole (203, 205) for detecting ventricular signals and at least one third electrode pole (200, 201) for detecting atrial signals.

2. The implantable defibrillation system according to claim 1, characterised in that the at least one second electrode pole (203, 205) and/or the at least one third electrode pole (200, 201) are designed as ring electrodes.

3. The implantable defibrillation system according to claim 1 or 2, characterised in that the at least one first electrode pole (202, 204) is designed as a helix.

4. The implantable defibrillation system according to any one of claims 1 to 3, characterised in that the at least one third electrode pole (200, 201) is arranged at a distal end of an electrode lead (2, 3) of the electrode lead assembly, the distal end being remote from a proximal end connectable to the defibrillation generator (1).

5. The implantable defibrillation system according to any one of claims 1 to 4, characterised in that the at least one first electrode pole (202, 204), the at least one second electrode pole (203, 205) and the at least one third electrode pole (200, 201) are arranged on a common electrode lead (2) of the electrode lead assembly.

6. The implantable defibrillation system according to any one of claims 1 to 4, characterised in that the at least one first electrode pole (202, 204) and/or the at least one second electrode pole (203, 205) are arranged on a first electrode lead (2) of the electrode lead assembly and the at least one third electrode pole (200, 201) is arranged on a second electrode lead (3) of the electrode lead assembly.

7. The implantable defibrillation system according to any one of the preceding claims, characterised in that the electrode array (20, 30) comprises two third electrode poles (200, 201), which form a dipole for detecting atrial signals.

8. The implantable defibrillation system according to any of the preceding claims, characterised in that at least one second electrode pole (203, 205) and at least one third electrode pole (200, 201) are arranged on different sides of the at least one first electrode pole (202, 204).

9. The implantable defibrillation system according to any one of the preceding claims, characterised in that at least one second electrode pole (203, 205) and/or at least one third electrode pole (200, 201) are arranged between two first electrode poles

(202, 204).

10. The implantable defibrillation system according to any one of the preceding claims, characterised in that the at least one electrode lead (2, 3) has a plug (21) and the defibrillation generator (1) has a connector (110) for connecting the plug (21).

11. The implantable defibrillation system according to any one of the preceding claims, characterised in that the defibrillation generator (1) comprises a control device (12) which forms a first receiving channel (121) for processing ventricular signals received via the electrode lead assembly and a second receiving channel (122) for processing atrial signals received via the electrode lead assembly.

12. The implantable defibrillation system according to claim 11, characterised in that the first receiving channel (121) and the second receiving channel (122) have a different gain (121 A, 122 A) from one another.

13. The implantable defibrillation system according to claim 11 or 12, characterised in that the control device (12) is designed to receive atrial signals via a plurality of different dipoles created by electrode poles (200-205) of the electrode array (20, 30).

14. An electrode lead assembly for an implantable defibrillation system, having at least one electrode lead (2, 3) which is connectable to a defibrillation generator (1), the electrode lead assembly being intended to be implanted substernally in a patient and having an electrode array (20, 30), characterised in that the electrode array (20, 30) has at least one first electrode pole (202, 204) for delivering stimulation energy for defibrillation, at least one second electrode pole (203, 205) for detecting ventricular signals and at least one third electrode pole (200, 201) for detecting atrial signals.

15. A defibrillation generator (1) for an implantable defibrillation system, to which an electrode lead assembly which is to be implanted substernally in a patient and comprises at least one electrode lead (2, 3) is connectable, characterised in that the defibrillation generator (1) has a control device (12) which forms a first receiving channel (121) for processing ventricular signals received via the electrode lead assembly and a second receiving channel (122) for processing atrial signals received via the electrode lead assembly.