WO2024056249A1

WO2024056249A1 - Modular implantable therapy system for defibrillation therapy of a human or animal heart

Info

Publication number: WO2024056249A1
Application number: PCT/EP2023/070316
Authority: WO
Inventors: Thomas Doerr; Volker Lang; Bjoern Henrik Diem; Dominic WIST; Frank Becker; Daniel Krueger; Carsten Hennig
Original assignee: Biotronik Se & Co. Kg
Priority date: 2022-09-13
Filing date: 2023-07-21
Publication date: 2024-03-21

Abstract

A modular implantable therapy system (1) for defibrillation therapy of a human or animal heart (3) is described, comprising a non-transvenous defibrillator device (5) and an implantable sensing device (13). The non-transvenous defibrillator device (5) comprises an electrode arrangement (7) including at least one shock electrode (9) for applying electric defibrillation shocks to the heart (3) and at least one sensing electrode (11) for sensing electric cardiac signals. The implantable sensing device (13) is configured for sensing atrial activity signals relating to an atrial activity of the heart (3). The defibrillator device (5) and the sensing device (13) comprise a communication interface (15) for transmitting the atrial activity signals from the sensing device (13) to the defibrillator device (5). The defibrillator device (5) is configured for controlling the defibrillation therapy by applying a defibrillation shock to the heart (3) taking into account the atrial activity signals received from the sensing device (13). Using the atrial activity signals, a VT/SVT discrimination may be improved and specificity and sensitivity in applying defibrillation shocks may be increased.

Description

MODULAR IMPLANTABLE THERAPY SYSTEM FOR DEFIBRILLATION

THERAPY OF A HUMAN OR ANIMAL HEART

The present invention relates to an implantable therapy system for defibrillation therapy of a human or animal heart.

In defibrillation, a strong electric field is applied to cardiac tissue of a patient for treating a cardiac malfunction such as a tachycardia. Generally, a defibrillator device comprises a shock voltage generator and a shock electrode. The shock electrode is arranged at the patient such that an electric shock voltage generated by the shock voltage generator is applied such that the resulting strong electric field reaches the cardiac tissue.

In implantable therapy systems for defibrillation therapy, the defibrillator device generally furthermore comprises sensing electrodes. Using the sensing electrodes, the defibrillator device may acquire information about a cardiac status. Particularly, the defibrillator device may acquire information about a cardiac rhythm, a heart rate, abnormities in cardiac action, etc. and may use this information for determining, whether or not a defibrillation shock is to be applied.

Transvenous defibrillator devices comprise an electrode which is to be implanted into the heart of the patient upon passing through a blood vessel such as a vein. Using such electrode, the defibrillator device may acquire a precise information about the cardiac status. However, implanting such transvenous defibrillator device and particularly implanting its electrode into the heart may require extensive surgery and/or may result in risks for the patient. Accordingly, non-transvenous defibrillator devices such as non-transvenous implantable cardioverter defibrillator (ICD) devices have been developed. Such non-transvenous defibrillator devices are also referred to as subcutaneous or substemal defibrillator devices. They also comprise a shock voltage generator and a shock electrode as well as one or more sensing electrodes. However, in such non-transvenous defibrillator device, the shock electrode and the sensing electrodes are not implanted directly into the heart. Instead, these electrodes are typically provided on an electrode shaft which is to be implanted subcutaneous or substemal at the patient’s thorax in a position such that the electric field generated for example between the shock electrode and a counter electrode provided at an implanted housing of the defibrillator device reaches and therefore defibrillates cardiac tissue of the patient’s heart.

However, while non-transvenous defibrillator devices are generally relatively easy to implant and/or reduce risks for the patient resulting from the implantation compared to transvenous defibrillator devices, their ability to specifically sense a cardiac status which is to be treated by defibrillation may be lower than for transvenous defibrillator devices. A reason for such reduced sensitivity may be seen in the fact that sensing electrodes of such non-transvenous defibrillator devices are generally not positioned at optimum locations for sensing the cardiac status, as they are provided on a same electrode shaft as the shock electrode and the position of such electrode shaft is mainly set such as to achieve optimum application of the electric shock field via the shock electrode. As a result of such nonoptimum positioning of the sensing electrodes, either a specificity of a decision on a defibrillation shock appliance or a sensitivity for a required cardiac defibrillation may be non-optimum. On the one hand, the non-optimum specificity of the decision on the defibrillation shock appliance may result in defibrillation shocks being applied in situations in which such defibrillation shocks are not required, such unnecessary defibrillation shocks being generally very unpleasant for the patient. On the other hand, the non-optimum sensitivity for a required cardiac defibrillation may result in defibrillation shocks not being applied even in situations, where they are required, thereby provoking critical or even lethal situations for the patient. It is an object of the instant invention to provide an implantable therapy system for defibrillation therapy which enables both, high specificity of a decision on a defibrillation shock appliance and high sensitivity for a required cardiac defibrillation.

This object may be achieved by the subject matter of the independent claim. Advantageous embodiments are disclosed in the dependent claims and the following specification as well as in the associated figures.

According to an aspect of the invention, a modular implantable therapy system for defibrillation therapy of a human or animal heart is disclosed. The system comprises (i) a non-transvenous defibrillator device comprising an electrode arrangement including at least one shock electrode for applying electric defibrillation shocks to the heart and at least one sensing electrode for sensing electric cardiac signals and (ii) an implantable sensing device configured for sensing atrial activity signals relating to an atrial activity of the heart. The defibrillator device and the sensing device comprise a communication interface for transmitting the atrial activity signals from the sensing device to the defibrillator device.

The defibrillator device is configured for controlling the defibrillation therapy by applying a defibrillation shock to the heart taking into account the atrial activity signals received from the sensing device.

Ideas underlying embodiments of the present invention may be interpreted as being based, inter alia, on the following observations and recognitions.

Briefly summarised in a non-limiting manner, embodiments of the present invention relate to the observation that, for optimising both the specificity of a decision on a defibrillation shock appliance and the sensitivity for a required cardiac defibrillation, an implantable therapy systems for defibrillation therapy should be enabled to distinguish between ventricular tachycardia (VT) and supraventricular tachycardia (SVT), i.e. for VT/SVT discrimination. Generally, isolated ventricular tachycardia, i.e. an elevated heartbeat rate at the ventricle without at the same time having an elevated heartbeat rate at the associated atrium, is more critical for a patient and may require defibrillation therapy. In contrast hereto, a tachycardia which originates from the atrium and which then induces a tachycardia at the ventricle is generally less critical for the patient and should generally not be treated with defibrillation therapy.

It has been found that conventional non-transvenous defibrillator devices may not in all cases reliably distinguish between VT and SVT with sufficient reliability, which may be mainly due to their sensing electrodes not being optimised for such purpose. Typically, conventional non-transvenous defibrillator devices use morphologic signal characteristics of a surface electrocardiogram (i.e. subcutaneous/substernal ECG) for VT/SVT discrimination, however without being able to analyse an isolated information about atrial activity in the heart. VT/SVT discrimination without being able to include information about the atrial rhythm is inferior to the known dual-chamber discrimination algorithms of transvenous ICDs with regard to the specificity of a therapy decision and leads in some patients to a need to exchange the non-transvenous ICD system for a transvenous ICD system or to adjust a detection setting in such a way that a significant reduction in sensitivity is to be expected (e.g., very high zone limit for the therapy zone).

It is proposed herein to supplement the non-transvenous defibrillator device with an additional implantable sensing device. Such sensing device is configured for sensing atrial activity signals relating to an atrial activity of the heart. Based on such atrial activity signals, a clear distinction between VT and SVT is enabled. The atrial activity signals are transmitted from the sensing device to the defibrillator device. Thereby, the VT/SVT discrimination at the defibrillator device may be improved, enabling optimising the decision on a defibrillation shock appliance and the sensitivity for a required cardiac defibrillation. Thus, the therapy system described herein may allow offering established dual-chamber detection algorithms in non-transvenous ICD systems as well. Accordingly, embodiments of the idea described herein may be understood, inter-alia, as an upgrade option for patients in case of need to avoid a system change from a non-transvenous to a transvenous ICD system.

In the following, possible characteristics and advantages of embodiments of the present invention will be described in more detail. The modular implantable therapy system proposed herein shall comprise two main components, i.e. the non-transvenous defibrillator device and the implantable sensing device.

The non-transvenous defibrillator device may comprise same or similar structures and/or functionalities as conventional non-transvenous defibrillator devices for applying electric defibrillation shocks to a patient’s heart. Particularly, the defibrillator device generally comprises a shock generator for generating electric fields which are sufficiently strong for inducing defibrillation. Such shock generator may be comprised in a housing of the defibrillator device. Characteristics of such housing may be set such as to enable implanting the housing subcutaneously to the patient. The defibrillator device generally further comprises a shock electrode via which the defibrillation shocks may be applied to the heart. Such shock electrode may for example be provided as a coil. The shock electrode is typically arranged at an elongate electrode shaft which is to be connected with the housing of the defibrillator device. Furthermore, the defibrillator device generally comprises one, two or more sensing electrodes via which electric cardiac signals may be sensed. Such sensing electrodes are typically also arranged at the electrode shaft, for example one sensing electrode being positioned distal to the shock electrode and one sensing electrode being positioned proximal to the shock electrode.

Due to having a same or similar structure and functionality, the defibrillator device of the therapy system proposed herein may be operated in a same way as a conventional non- transvenous defibrillator device. Accordingly, it is possible to implant such defibrillator device to a patient without initially also implanting a sensing device and to operate the defibrillator device in a conventional manner in the patient. At a later point in time, for example when it is observed that the defibrillator device does not operate with a required specificity and/or sensitivity, the defibrillator device may be supplemented by implanting the sensing device, thereby completing the modular implantable therapy system described herein.

For such purpose, additional to the characteristics of a conventional defibrillator device, the non-transvenous defibrillator device of the implantable therapy system described herein shall comprise a communication interface enabling signal transmission between the sensing device and the defibrillator device. Upon the sensing device being implanted in the patient, the defibrillator device may then receive atrial activity signals from the sensing device.

Furthermore, as a difference to conventional defibrillator devices, the non-transvenous defibrillator device of the implantable therapy system described herein shall be specifically configured for controlling the defibrillation therapy by taking into account the atrial activity signals received from the sensing device. In other words, upon generating and applying the defibrillation shocks to the heart, the defibrillator device shall not only take into account signals sensed by its own sensing electrodes but shall also take into account the information comprised in the atrial activity signals received from the separate sensing device. Due to the additional information in the atrial activity signals, a VT/SVT discrimination at the defibrillator device may be significantly improved upon applying the defibrillation shock.

According to an embodiment, the sensing device is configured for being implanted in or at the atrium of the heart. Therein, at least a portion of the sensing device is arranged at the atrium or sufficiently close to the atrium such as to enable detecting atrial activity. For example, a sensor or a sensing electrode of the sensing device may be in direct contact with cardiac tissue of the atrium or may be arranged in close proximity to such tissue, for example within a maximum distance of less than 5 cm, less than 2 cm, less than 1 cm or even less than 3 mm. Particularly, a sensing surface of a sensor comprised in the sensing device may be arranged in or close to an atrium chamber wall. For example, the sensing device may be configured for being mechanically anchored at the atrium chamber wall. Due to being at or close to the atrium, the sensing device may detect physical characteristics of the atrial activity with high accuracy and/or reliability.

According to an embodiment, the sensing device is configured for sensing the atrial activity signals by measuring electric potentials within the heart. For example, the sensing device may detect an electrocardiogram (ECG) and/or an intracardiac electrogram (IEGM) as a basis for the atrial activity signal. Particularly, the sensing device may be configured for sensing and processing an ECG or IEGM at or close to the atrium. Accordingly, the atrial activity signals derived therefrom may reliably indicate an activity of the atrium and, specifically, may indicate an SVT.

According to an embodiment, the electrode arrangement of the non-transvenous defibrillator device is configured for being implanted subcutaneously. In other words, the electrode arrangement may for example be provided at an elongate electrode shaft which may be connected to a defibrillator housing, the shaft being bendable, being provided with the shock electrode and the sensing electrode and being adapted with its physical characteristics such as its length, width, bending characteristics, materials, etc. for being implanted under the skin of the patient. Such non-transvenous defibrillator device for a subcutaneous implantation may, inter-alia, reduce risks during and after surgical implantation.

According to an embodiment, the electrode arrangement is configured for being implanted substemally. Therein, the electrode shaft may be adapted with its physical characteristics for being implanted at or under the sternum of the patient. Such non-transvenous defibrillator device for a substernal implantation may, inter-alia, reduce risks during and after surgical implantation.

According to an embodiment, the sensing device is a leadless pacemaker. A leadless pacemaker is configured for being implanted directly into a cardiac chamber of the heart. Accordingly, the leadless pacemaker is miniaturized typically to a size of a few centimetres in length and a few millimetres in width or diameter. Generally, the leadless pacemaker comprises anchoring means such as tines for being attached to an inner surface of a cardiac wall. Furthermore, the leadless pacemaker comprises a sensor for sensing cardiac activity signals, particularly for sensing electric cardiac activity signals. As a main purpose, the leadless pacemaker is generally implanted into a patient’s heart for pacing the heart in case of bradycardia. However, the cardiac activity signals sensed by its sensor may also indicate tachycardia. Accordingly, such signals may be used as atrial activity signals in the therapy system proposed herein and may be transmitted to and used by the defibrillator device for improving VT/SVT discrimination.

According to an embodiment, the leadless pacemaker is configured to either (i) being implanted into an atrium of the heart and sensing the atrial activity signals by measuring electric cardiac potentials with an electrode in the atrium, or (ii) being implanted in a ventricle of the heart and sensing the atrial activity signals by measuring electric cardiac potentials with an electrode in the ventricle and analyzing the measured electric cardiac potentials for far-field potentials resulting from cardiac potentials in the atrium.

In the first alternative (i), the leadless pacemaker shall be sufficiently small to be accommodated within the atrium and shall comprise an electrode in the atrium for sensing atrial activity signals locally directly in the atrium. Such atrial leadless pacemaker may provide highly reliable atrial activity signals for indicating abnormities such as an atrial tachycardia.

In the second alternative (ii), the leadless pacemaker shall be configured for being accommodated within a ventricle. Due to the larger available space in the ventricle, such ventricular leadless pacemaker may be less miniaturized than an atrial leadless pacemaker. When being implanted in the ventricle, an electrode of such leadless pacemaker may generally be only in contact with a ventricular cardiac wall but not with an atrial cardiac wall. The ventricular leadless pacemaker may measure electric cardiac potentials with its electrode in the ventricle, wherein these local cardiac potentials are dominated by electric activity within cardiac tissue of the ventricle, but also include contributions of electric activity within cardiac tissue of a neighbouring atrium. In other words, the ventricular leadless pacemaker may be operated in a VDD sensing mode. Therefore, upon analysing the measured electric cardiac potentials for far-field potentials resulting from cardiac potentials in the atrium, the ventricular leadless pacemaker may provide information indicating abnormities such as an atrial tachycardia and may therefore be used for providing an atrial activity signal to the defibrillator device.

According to an embodiment, the sensing device is a conventional pacemaker comprising a lead for implantation into the heart. Such conventional pacemaker typically comprises a housing which is to be implanted subcutaneously external to the heart. Furthermore, such conventional pacemaker typically comprises an elongate lead electrode extending from such housing, an end of which is to be implanted into a cardiac chamber within the heart. Using such lead electrode, the pacemaker may sense electric cardiac potentials within the heart and, based thereon, may provide atrial activity signals to the defibrillator device.

According to an embodiment, the sensing device is configured for transmitting the atrial activity signals to the defibrillator device in a beat-to-beat rhythm. In other words, the sensing device may provide the atrial activity signals as PP-intervals indicating a time period between two successive heartbeats. Such atrial activity signals may be acquired with a relatively simple sensor and/or circuitry. Furthermore, such atrial activity signals may be easily transmitted to the defibrillator device with very low energy consumption, thereby preserving an energy supply in the sensing device.

Generally, it may be assumed that sensing the atrial activity in the sensing device requires less energy than permanently transmitting the sensed atrial activity signal to the defibrillator device and that reducing energy consumption for such signal transmission may significantly help enhancing a service life of an energy supply for the sensing device.

According to an embodiment, the sensing device is configured for accumulating the atrial activity signals during a predetermined period and then transmitting accumulated atrial activity signals to the defibrillator device. Expressed differently, the sensing device may register the atrial rhythm in a block-wise manner, for example during a predetermined period of e.g. 5 s, and may then transmit the registered results as the atrial activity signal to the defibrillator device. Due to such accumulating or block-wise acquisition of information about atrial activity and transmitting the result only periodically, an energy consumption for signal transmission may be reduced, thereby preserving the energy supply in the sensing device.

According to an embodiment, the sensing device is configured for sensing an information on an atrial rhythm and an information on a ventricular rhythm in the heart and for discriminating between a ventricular tachycardia and a supraventricular tachycardia based on processing the information on the atrial rhythm and the information on the ventricular rhythm and for transmitting a result of such processing as the atrial activity signals. In other words, the sensing device may register the atrial and ventricular rhythms and may process this information in an algorithm for VT/SVT discrimination and may signal the discrimination result to the defibrillator device. Thereby, the VT/SVT discrimination capability of the defibrillator device may be further improved.

According to an embodiment, the sensing device is configured for transmitting the atrial activity signals only upon a heartbeat rate in one of the atria and the ventricles exceeds a predetermined rate limit. Expressed differently, the atrial activity signals may not be transmitted from the sensing device to the defibrillator device continuously or with a static periodicity all the time, even in long periods where there is no increased heartbeat rate detected. Instead, such transmission of the atrial activity signals may be initiated only as soon as the sensing device detects that the heartbeat rate in the atrium or the ventricle becomes higher than a predetermined limit and therefore indicates an occurrence of a tachycardia in the respective heart chamber. By limiting signal transmission only to periods when a tachycardia is indicated to the sensing device, energy consumption for the signal transmission between the sensing device and the defibrillator device may be reduced.

According to an embodiment, the communication interface is configured for transmitting the atrial activity signals using a power-saving signal transmission technique including for example one of impedance modulated signal transmission, BLE, MICS, MEDS, ZigBee, ISM, coil telemetry and resonant coil telemetry.

As already indicated further above, signal transmission contributes to a significant extent to an overall energy consumption of a sensing device. For example, when the sensing device is a leadless pacemaker, only a small battery may provide energy for the operation of such pacemaker. Accordingly, energy consumption should be minimised. Furthermore, it is to be noted that replacing a sensing device implanted in or at the atrium or replacing its energy supply such as its battery is generally more troublesome than replacing the defibrillator device housing or an energy source accommodated therein. By using power- saving signal transmission techniques for transmitting the atrial activity signals to the defibrillator device, energy consumption on the side of the sensing device may be preserved.

Impedance modulated signal transmission is one form of power-saving signal transmission. Therein, signals are not transmitted by actively emitting for example electromagnetic energy from a signal-generating device to a signal-receiving device. Instead, information is provided by modifying a local impedance in the signal-generating device, i.e. a device serving as a signal source. Such modified impedance may then be detected by an external device by analyzing resonances upon irradiating electromagnetic energy interacting with the modified impedance. Accordingly, in the therapy system described herein, energy consumption on the side of the sensing device may be reduced upon using impedance modulated signal transmission therein. Examples and further details of such transmission techniques are disclosed, inter-alia, in the applicant’s prior patent applications US 9,370,663 B2 and US 9,375,581 B2, the content of which is to be incorporated herein by reference.

BLE (Bluetooth low energy), MICS (medical implant communication service), MEDS (medical data service), ZigBee, ISM, coil telemetry and resonant coil telemetry are further examples of power-saving signal transmission techniques which may be used for data transmission between implanted devices and which may be particularly suitable for establishing power-saving signal transmission between the sensing device and the defibrillator device in the therapy system described herein.

According to an embodiment, the defibrillator device and the sensing device are configured for data transmission to a programming device such that the programming device is enabled to receiving data from and/or transmitting data to the defibrillator device as well as the sensing device in a common programming session. In other words, both implantable devices may be programmed and/or data may be retrieved therefrom using a same programming device. Accordingly, information regarding both implantable devices may be depicted and/or programmed in a common programming device session in parallel for example on a common user interface. Embodiments of such technique are described in the applicant’s prior patent application PCTZEP2022/064221 having the title “method for controlling the operation of at least two implantable medical devices”, the content of which is to be incorporated herein by reference. Using such technique, both, the defibrillator device and the sensing device may be beneficially handled in a common session for programming and/or data retrieval.

It shall be noted that possible features and advantages of embodiments of the invention are described herein with respect to various embodiments of the therapy system. One skilled in the art will recognize that the features may be suitably transferred from one embodiment to another and features may be modified, adapted, combined and/or replaced, etc. in order to come to further embodiments of the invention.

In the following, advantageous embodiments of the invention will be described with reference to the enclosed drawing. However, neither the drawing nor the description shall be interpreted as limiting the invention.

Fig. 1 shows a modular implantable therapy system for defibrillation therapy according to an embodiment of the present invention.

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

Fig. 1 shows modular implantable therapy system 1 for defibrillation therapy of a heart 3 of a patient 27. The therapy system 1 comprises an implanted non-transvenous defibrillator device 5 and an implanted sensing device 13.

In the example shown, the defibrillator device 5 is implemented as an ICD pulse generator. The defibrillator device 5 comprises an electrode arrangement 7 including a shock electrode 9 for applying electric defibrillation shocks to the heart 3 and two sensing electrodes 11’, 11” for sensing cardiac signals. The shock electrode 9 is provided on an elongate electrode shaft 10 and the sensing electrodes 11’, 11” are arranged proximal and distal to the shock electrode 9 at this electrode shaft 10. The electrode shaft 10 with its electrode arrangement 7 arranged thereon is adapted for being implanted subcutaneously along a sternum of the patient 27. Therein, none of the components of the defibrillator device 5 is to be directly implanted into the heart 3. A proximal end of the electrode shaft 10 is connected to a defibrillator housing 12. This defibrillator housing 12 accommodates a shock generator for generating strong electric shock potentials and transmitting them to the shock electrode 9 for applying defibrillation shocks. Furthermore, a circuitry comprised in the defibrillator housing 12 is connected to the sensing electrodes 11’, 11” and may use them for sensing electric cardiac signals indicating a cardiac status. The defibrillator housing 12 may serve as a sensing and/or defibrillation electrode. Accordingly, the sensing electrodes 11’, 11”, the shock coil 9 and the defibrillator housing 12 may form possible perception vectors to be used for sensing electrical signals from the heart 3.

However, based on these possible perception vectors, an electrical activity of the atria (P wave) may be inadequately mapped, so that especially in the case of an atrial tachyarrhythmia, no reliable VT/SVT discrimination may be possible. This is first realized by means of a morphology analysis of the QRS complex.

Generally, shock delivery is always between the generator housing 12 and the shock electrode 9 on the electrode shaft 10.

In order to significantly improve VT/SVT discrimination in patients in whom QRS morphology analysis is not sufficient, the therapy system described herein comprises the additional sensing device 13 which may be implanted for atrial ECG perception. This sensing device 13 is preferably positioned directly as a wireless sensor implant in the right atrium.

In the example shown in the figure, the sensing device 13 is a leadless pacemaker 21. Therein, the leadless pacemaker 21 is implanted into the atrium 17. Due to being anchored at an atrium wall, an electrode 23 of the leadless pacemaker 21 is in direct mechanical and electrical contact to cardiac tissue at the atrium and may therefore acquire electrocardiogram data directly relating to the atrial activity. Accordingly, such data may be used as atrial activity data. As an alternative (not shown in the figure), the leadless pacemaker 21 may be implanted into the ventricle 19 such that its electrode 23 contacts a ventricle wall. In such configuration, the leadless pacemaker 21 may be specifically configured for also sensing far-field potentials resulting from cardiac potentials at the atrium 17. Thus, sensed data relating to such far-field potentials may be used as atrial activity data.

As another alternative (not shown in the figure), the sensing device 13 may be a conventional pacemaker having a lead which is to be implanted into one of the chambers of the heart 3. Preferably, such lead comprises an electrode to be located within the atrium 17 such as to enable directly acquiring ECG data in the atrium 17 which may then be used as atrial activity data.

In order to enable data and signal transmission between the devices, the defibrillator device 5 and the sensing device 13 comprise a communication interface 15. This interface 15 is configured for transmitting atrial activity signals from the sensing device 13 to the defibrillator device 5. Communication between the defibrillator device 5 and the sensing device 13 may be performed here, for example, via very low-current coil telemetry at relatively low frequencies (e.g., 30-870 kHz). Alternatively, other power-saving signal transmission techniques such as impedance modulated signal transmission, BLE, MICS, MEDS, ZigBee or ISM may be used to save energy in signal transmission between the sensing device 13 and the defibrillator device 5.

To further save energy, information is exchanged only when the atrial rhythm exceeds a pre-programmed frequency limit. If it remains below the frequency limit, intra-body communication in the implanted sensing device 13 is switched off. Alternatively or additionally, the sensing device 13 may transmit the atrial activity signals in a beat-to-beat rhythm to the defibrillator device 5 and/or may accumulate the atrial activity signals during a predetermined period and then transmit accumulated atrial activity signals to the defibrillator device 5. Upon having transmited the atrial activity signals from the sensing device 13 to the defibrillator device 5, the defibrillator device 5 may control the defibrillation therapy by applying defibrillation shocks to the heart via the shock electrode 9, thereby taking into account the received atrial activity signals. Using the atrial activity signals, a VT/SVT discrimination may be improved and specificity and sensitivity in applying defibrillation shocks may be increased.

The defibrillator device 5 and/or the sensing device 13 may be programmable. Furthermore, each or both devices may be configured for transmitting data to external devices. For such programming and/or data transmission, each or both of the devices may exchange data with a programming device 25. The programming device 25 may be an external device, i.e. may be located outside the patient’s body. Preferably, the defibrillator device 5 and the sensing device 13 may both exchange data with the programming device 25 in a way such that the programming device 25 may receive data from and transmit data to the defibrillator device 5 and the sensing device 13 in a common programming session. Accordingly, both implanted devices 5, 13 may be polled by the same programming device 25. Furthermore, both implanted devices 5, 13 may for example be represented on a user interface simultaneously and/or may be programmed in a common programming session.

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

1 implantable therapy system

3 heart 5 non-transvenous defibrillator device

7 electrode arrangement

9 shock electrode

10 electrode shaft

11 sensing electrode 12 defibrillator housing

13 sensing device

15 communication interface

17 atrium

19 ventricle 21 leadless pacemaker

23 electrode

25 programming device

27 patient

Claims

1. A modular implantable therapy system (1) for defibrillation therapy of a human or animal heart (3), comprising: a non-transvenous defibrillator device (5) comprising an electrode arrangement (7) including at least one shock electrode (9) for applying electric defibrillation shocks to the heart (3) and at least one sensing electrode (11) for sensing electric cardiac signals, an implantable sensing device (13) configured for sensing atrial activity signals relating to an atrial activity of the heart (3), wherein the defibrillator device (5) and the sensing device (13) comprise a communication interface (15) for transmitting the atrial activity signals from the sensing device (13) to the defibrillator device (5), wherein the defibrillator device (5) is configured for controlling the defibrillation therapy by applying a defibrillation shock to the heart (3) taking into account the atrial activity signals received from the sensing device (13).

2. The therapy system (1) according to claim 1, wherein the sensing device (13) is configured for being implanted one of in and at the atrium (17) of the heart (3).

3. The therapy system (1) according to one of the preceding claims, wherein the sensing device (13) is configured for sensing the atrial activity signals by measuring electric potentials within the heart (3).

4. The therapy system (1) according to one of the preceding claims, wherein the electrode arrangement (7) is configured for being implanted subcutaneously.

5. The therapy system (1) according to one of the claims 1 to 3, wherein the electrode arrangement (7) is configured for being implanted substemally. The therapy system (1) according to one of the preceding claims, wherein the sensing device (13) is a leadless pacemaker (21). The therapy system (1) according to claim 6, wherein the leadless pacemaker (21) is configured to one of

- being implanted into an atrium (17) of the heart (3) and sensing the atrial activity signals by measuring electric cardiac potentials with an electrode (23) in the atrium (17),

- being implanted in a ventricle (19) of the heart (3) and sensing the atrial activity signals by measuring electric cardiac potentials with an electrode (23) in the ventricle (19) and analyzing the measured electric cardiac potentials for far-field potentials resulting from cardiac potentials in the atrium (17). The therapy system (1) according to one of claims 1 to 5, wherein the sensing device (13) is a conventional pacemaker comprising a lead for implantation into the heart (3). The therapy system (1) according to one of the preceding claims, wherein the sensing device (13) is configured for transmitting the atrial activity signals to the defibrillator device (5) in a beat-to-beat rhythm. The therapy system (1) according to one of the preceding claims, wherein the sensing device (13) is configured for accumulating the atrial activity signals during a predetermined period and then transmitting accumulated atrial activity signals to the defibrillator device (5). The therapy system (1) according to one of the preceding claims, wherein the sensing device (13) is configured for sensing an information on an atrial rhythm and an information on a ventricular rhythm in the heart (3) and for discriminating between a ventricular tachycardia and a supraventricular tachycardia based on processing the information on the atrial rhythm and the information on the ventricular rhythm and for transmitting a result of such processing as the atrial activity signals. The therapy system (1) according to one of the preceding claims, wherein the sensing device (13) is configured for transmitting the atrial activity signals only upon a heartbeat rate in one of the atria (17) and the ventricles (19) exceeds a predetermined rate limit. The therapy system (1) according to one of the preceding claims, wherein the communication interface (15) is configured for transmitting the atrial activity signals using a power-saving signal transmission technique including one of impedance modulated signal transmission, BLE, MICS, MEDS, ZigBee, ISM, coil telemetry and resonant coil telemetry. The therapy system (1) according to one of the preceding claims, wherein the defibrillator device (5) and the sensing device (13) are configured for data transmission to a programming device such that the programming device (25) is enabled to at least one of receiving data from and transmitting data to the defibrillator device (5) and the sensing device (13) in a common programming session.