WO2023135054A1

WO2023135054A1 - Therapy system for providing a cardiac therapy

Info

Publication number: WO2023135054A1
Application number: PCT/EP2023/050204
Authority: WO
Inventors: Thomas Doerr; Ingo Weiss
Original assignee: Biotronik Se & Co. Kg
Priority date: 2022-01-17
Filing date: 2023-01-06
Publication date: 2023-07-20

Abstract

A therapy system for providing a cardiac therapy comprises a defibrillation device (1) comprising a generator device (10) having a control circuitry (102) and a shock generation circuitry (103) for generating an electrical shock signal for performing a defibrillation therapy, the defibrillation device (1) further comprising a shock electrode (115) for emitting said electrical shock signal. An implantable medical device (3) serves for emitting an electrical stimulation signal to perform a therapeutic action, the implantable medical device (3) comprising a processing circuitry (32) for generating said electrical stimulation signal. The shock generation circuitry (103) of the defibrillation device (1) is configured to produce and wirelessly transmit, using said shock electrode (115), an energy signal (TS) different than said electrical shock signal. The processing circuitry (32) of the implantable medical device (3) is configured to wirelessly receive said energy signal (TS) and to extract electrical energy from said energy signal (TS) to obtain extracted electrical energy and to produce said electrical stimulation signal using said extracted electrical energy.

Description

Therapy system for providing a cardiac therapy

The instant invention concerns a therapy system for providing a cardiac therapy and a method for operating a therapy system for providing a cardiac therapy.

A therapy system of this kind comprises a defibrillation device including a generator device having a control circuitry and a shock generation circuitry for generating an electrical shock signal for performing a defibrillation therapy. The defibrillation device further comprises a shock electrode for emitting the electrical shock signal. Furthermore, the therapy system includes an implantable medical device for emitting an electrical stimulation signal to perform a therapeutic action, the implantable medical device comprising a processing circuitry for generating the electrical stimulation signal.

The therapy system hence uses different devices, which cooperate to provide a cardiac therapy. The defibrillation device herein may be implantable or may be usable external to a patient. The defibrillation device is designed for providing for a defibrillation therapy and for this, in case a tachycardia or fibrillation is sensed, produces an electrical shock signal for providing for a defibrillation. The implantable medical device is designed for implantation, for example for intracardiac implantation, and shall provide for a therapy within or in the proximity of the patient’s heart, such as a pacing therapy.

A conventional implantable medical device comprises an (electrochemical) battery serving to supply electrical energy for operation of the implantable medical device over a prolonged span of life, typically in the order of multiple months or even years. When the battery is depleted, the implantable medical device may have to be explanted for replacing the battery or for replacing the implantable medical device as a whole. Approaches exist for employing passive implantable medical devices which do not comprise a battery, but are supplied with electrical energy using a separate transmitter device. An implantable medical device of this kind may for example be implanted intracardially, for example in the right or left ventricle or in the right or left atrium, in order to provide a therapeutic and/or diagnostic function within the patient’s heart, wherein the transmitter is for example subcutaneously implanted and transmits an energy signal for reception by the implantable medical device for supplying energy for the device’s operation.

There is a desire for providing a defibrillation device which at the same time is enabled to provide for a (painless) pacing therapy, in particular an antitachycardia pacing (in short ATP).

EP 2 769 750 Al describes a device for use in providing stimulation to cardiac tissue, the device having a flexible, elongated body and an arrangement of electrode poles for emitting stimulation signals. Energy may be transferred to the device using for example an inductive coupling by sending energy to magnetic coils arranged within the device. Alternatively, energy for example may be supplied by acoustic radiation, for example by transmitting ultrasound waves.

WO 2012/013201 Al describes an implantable electrode device, in particular for a cardiac pacemaker, the implantable electrode device being supplied with energy in an exclusively wireless manner via a time-variable magnetic field. The magnetic field is generated by an implanted control device.

US 2009/0018599 Al describes an implantable cardiac tissue excitation system including an implantable pacing controller unit with a pulse generation circuit. The system also includes a lead with a lead body extending between a proximal lead end attachable to the patient control unit and a distal lead end configured to be implanted within the heart. Furthermore, the system includes a leadless electrode assembly configured to be implanted within the heart that includes a receiver to receive a wireless transmission, a charge storage unit to store charge energy, and an electrical stimulation circuit to deliver an electrical stimulus to cardiac tissue using the pacing control information and the charge energy. It is an object of the instant invention to provide a therapy system for providing a cardiac therapy and a method for operating a therapy system which allow in an easy and efficient way to enable a defibrillation device to also perform a painless antitachycardia pacing (ATP) or temporary antibradycardia stimulation.

In one aspect, a therapy system for providing a cardiac therapy comprises: a defibrillation device comprising a generator device having a control circuitry and a shock generation circuitry for generating an electrical shock signal for performing a defibrillation therapy, the defibrillation device further comprising a shock electrode for emitting said electrical shock signal; and an implantable medical device for emitting an electrical stimulation signal to perform a therapeutic action, the implantable medical device comprising a processing circuitry for generating said electrical stimulation signal. The shock generation circuitry of the defibrillation device is configured to produce and wirelessly transmit, using said shock electrode, an energy signal different than said electrical shock signal. The processing circuitry of the implantable medical device is configured to wirelessly receive said energy signal and to extract electrical energy from said energy signal to obtain extracted electrical energy and to produce said electrical stimulation signal using said extracted electrical energy.

The therapy system includes a defibrillation device and an implantable medical device physically separate from the defibrillation device. The defibrillation device is configured for providing for a defibrillation therapy and for this comprises a generator device having a control circuitry and a shock generation circuitry. The defibrillation device further comprises a shock electrode for emission of an electrical shock signal.

The defibrillation device operates in combination with an implantable medical device which is configured for emission of an electrical stimulation signal to perform a therapeutic action. Whereas the defibrillation device shall provide for a defibrillation therapy, the implantable medical device for example may provide for a pacing therapy, e.g., for an antitachycardia pacing (ATP), for a temporary antibradycardia pacing or for a post-shock pacing. The implantable medical device serves for emitting an electrical stimulation signal to perform a therapeutic action. The implantable medical device in particular may be configured for an intracardiac implantation to provide e.g. a pacing action within the patient’s heart. The implantable medical device specifically may be designed for a ventricular implantation in the right or left ventricle of the patient’s heart or for an atrial implantation in the right or left atrium. Alternatively, the implantable medical device may be designed e.g. for an implantation in a coronary artery, e.g. of the left ventricle, of the patient’s heart.

The implantable medical device may be designed for a complete intravascular implantation, such that the implantable medical device, in an implanted state, fully rests within a vessel or body cavity, for example within the patient’s heart.

During operation, the defibrillation device produces and transmits an energy signal which is received by the implantable medical device and is processed by the implantable medical device for producing electrical energy for operating the implantable medical device. From extracted electrical energy as obtained from the transmit energy signal, the implantable medical device produces an electrical stimulation signal, which is emitted by the implantable medical device for providing for a therapeutic action, for example a cardiac pacing therapy.

The implantable medical device may, in one embodiment, be a passive implantable medical device not comprising an electrochemical battery. The term “passive” herein denotes that the implantable medical device receives energy for operation solely from the defibrillation device by means of an energy signal transmitted wirelessly by the defibrillation device towards the implantable medical device. The implantable medical device hence may be implanted without an energy storage unit in the shape of a battery equipping the implantable medical device for a prolonged span of operation. Rather, energy for operation is extracted from an energy signal received from a defibrillation device and is processed within the implantable medical device in order to generate and emit electrical stimulation signals at an implantation site for performing a desired therapeutic action, in particular an intracardiac pacing action.

The defibrillation device may, in one embodiment, be implantable to perform, in an implanted state, a defibrillation therapy within the patient. The defibrillation device may for example be a non-transvenous implantable cardioverter defibrillator device (in short non- transvenous ICD), which is designed for implantation external to a patient’s heart. In a non- transvenous implantable cardioverter defibrillator device, a generator device may for example be implanted subcutaneously in a patient. A lead, in a connected state, extends from the generator device, the lead being implanted such that it fully rests outside of the patient’s heart. The lead may for example extend from the generator device towards a location in the region of the patient’s sternum, the shock electrode hence being placed outside of the patient’s heart for emitting an electrical shock pulse at a location external to the patient’s heart.

The term “non-transvenous” in this respect in particular shall express that the lead of the non-transvenous implantable cardioverter defibrillator device does not extend transvenously into the heart, but fully rests outside of the patient’s heart.

In another embodiment, the defibrillation device may be designed as a defibrillator to be used external to a patient, or a life vest.

If the defibrillation device is operated externally to the patient, the defibrillation device may for example be placed in contact with the patient’s body for transmitting the energy signal into the body for reception by the implantable medical device.

In another embodiment, the energy signal may be coupled into the patient’s body by the defibrillation device without physically contacting the patient’s body, for example by using an electromagnetic induction technique for contactless energy transmission into the patient’s body.

The defibrillation device generally is configured to emit a shock pulse for achieving a defibrillation. The defibrillation device may serve for monitoring and treating potentially life-threatening arrhythmias of a patient's heart. If the defibrillation device is a non- transvenous implantable cardioverter defibrillator device, the shock electrode in an implanted state of the defibrillation device is placed outside of the heart of the patient, for example in the region of the sternum of the patient, such that a shock pulse for achieving a defibrillation is generated outside of the heart.

By operating the defibrillation device in combination with an implantable medical device the defibrillation device may be enabled for providing for a (painless) cardiac therapy in addition to a defibrillation therapy, for example for a pacing therapy, such as an antitachycardia pacing (ATP), a temporary antibradycardia pacing or a post-shock pacing. In that the implantable medical device receives its energy for operation from the defibrillation device, the implantable medical device may be implanted for example intracardially and may be operated within the patient’s heart over a prolonged period of time, without the need for replacing a battery of the implantable medical device.

In one embodiment, the defibrillation device comprises a sensing arrangement for sensing electrocardiogram signals. Sensed signals are forwarded to the control circuitry of the defibrillation device, which processes the signals in order to e.g. identify information relating to cardiac activity in a sensed electrocardiogram signal, for example to detect potentially life-threatening arrhythmias and to provide for a defibrillation therapy based on sensed signals.

The sensing arrangement may comprise multiple electrode poles. One or multiple electrode poles of the sensing arrangement herein may be placed on a lead carrying the shock electrode. For example, one electrode pole may be placed on the lead at a position proximal to the shock electrode. Another electrode pole may be placed on the lead at a position distal to the shock electrode.

Further electrode poles may be placed on further leads connected to the generator device. Alternatively or in addition, one or multiple electrode poles may be formed by a housing of the generator device. Yet alternatively or in addition, the shock electrode may be used as a sense electrode pole for sensing electrocardiogram signals.

In one embodiment, the sensing arrangement comprises three or more electrode poles. The three or more electrode poles form multiple pairs of electrode poles which may be used for sensing electrocardiogram signals. The different pairs span sense vectors which, each by itself, may be used to sense an electrocardiogram signal. The different sense vectors herein may exhibit a different spatial sensitivity with respect to electrocardiogram signals and hence may be used to sense information in a multichannel processing. Signals received by means of the different sense vectors as spanned by different pairs of electrode poles may be combined in order to sense ventricular activity and to derive information from electrocardiogram signals.

For emitting an electrical shock signal for providing for a defibrillation therapy, the shock electrode (for example placed on a lead connected to the generator device of the defibrillation device) in combination with an electrode pole also used by the sensing arrangement (such as an electrode pole formed by the housing of the generator device) may be employed. For transmission of the energy signal, for example the same pair of electrode poles, namely the shock electrode in combination with the further electrode pole also used for emitting the electrical shock signal, may be used. The electrical energy signal for transmission to the implanted medical device is produced by the shock generation circuitry that is also employed for producing the electrical shock signal, hence requiring a limited adaption of the circuitry of the defibrillation device for operating it in combination with the implantable medical device.

In one embodiment, the shock generation circuitry is configured to produce said energy signal at an elevated frequency, in particular in a predefined frequency range above 10 kHz, preferably about 30 kHz, for example at or around 100 kHz. The energy signal, in one embodiment, is at a frequency which does not cause a stimulation within the patient’s body, in particular for body tissue in the region of the thorax.

The shock generation circuitry in particular may be configured to produce the energy signal using a carrier signal at a predefined frequency, for example above 10 kHz, preferably about 30 kHz, for example at 100 kHz. The carrier signal may be a sinusoidal signal or may be a trapezoidal or rectangular signal. A duty cycle of the signal may lie in a range between 5% to 95%, e.g., based on a pulse width modulated signal employing rectangular or trapezoidal pulses of alternating polarity.

In one embodiment, the shock generation circuitry is configured to produce the energy signal to comprise a multiplicity of pulses formed by modulating the carrier signal. The pulses may be shaped to produce stimulation pulses at the implantable medical device for achieving a desired therapeutic action, such as a pacing action.

In one embodiment, the control circuitry of the generator device of the defibrillation device is configured to evaluate sensed information, e.g., as sensed by using the sensing arrangement of the defibrillation device, indicative of the electrical stimulation signal as produced by the implantable medical device. The defibrillation device hence is enabled to assess a therapy effect as produced by the electrical stimulation signal output by the implantable medical device. The defibrillation device hence may assess whether a signal produced by the implantable medical device has provided a desired success or may have to be adapted and repeated for achieving the desired success.

In one embodiment, the control circuitry is configured to control at least one of a pulse width, a pulse amplitude and/or a repetition interval of pulses of the energy signal for transmission to the implantable medical device. The control circuitry hence shapes the energy signal such that, based on the energy signal, a desired stimulation signal is produced by the implantable medical device.

If the implantable medical device is designed as a passive device which immediately converts the energy signal into an electrical stimulation signal and outputs the stimulation signal immediately and concurrently with receiving the energy signal, the shaping of the energy signal directly shapes the electrical stimulation signal as produced and output by the implantable medical device. By controlling the energy signal, hence, a therapeutic action of the implantable medical device may be controlled. In one embodiment, the control circuitry is configured to modulate the energy signal for transmitting information to the implantable medical device. For example, pulses of the energy signal may be modulated to carry information. For example, the pulse width of the pulses and/or a repetition rate of the pulses may be modulated in order to provide for a signaling of information from the defibrillation device to the implantable medical device. If the implantable medical device comprises its own timing circuitry for generating a simulation signal based on its own timing, operation of the implantable medical device may be controlled according to the signaling as transmitted from the defibrillation device. The implantable medical device hence may be enabled to process information as received by signaling from the defibrillation device.

The pulse width of pulses of the energy signal may in particular lie in a range between 0.05 ms and 10 ms.

A voltage level of the pulses of the energy signal as received by the implantable medical device may for example lie in a range between 0.1 V and 5 V. A voltage level of the pulses may be controlled by the defibrillation device such that a field strength at the location of the implantable medical device exceeds 0.1 V/cm. For example, a voltage level of the pulses may be controlled such that a voltage between electrode poles of the defibrillation device used for transmitting the energy signal exceeds 10 V and preferably lies in a range between 100 V to 1500 V. A source of the defibrillation device may function as a voltage source or a current source.

A repetition interval between neighboring pulses of the energy signal may for example lie in a range between 20 ms and 2 s.

The energy signal may have a DC signal component or does not have a DC signal component.

In one embodiment, the shock generation circuitry is configured to produce a first energy signal in a first frequency range for transmission to a first implantable medical device and a second energy signal in a second frequency range different than the first frequency range for transmission to a second implantable medical device. In this embodiment, the system may comprise two implantable medical devices, wherein both implantable medical devices are designed for implantation and for providing for a therapeutic action, in particular a cardiac therapeutic action such as a pacing action. Both implantable medical devices herein are supplied from the defibrillation device with a dedicated energy signal in order to transmit energy to the respective implantable medical device. The energy signals are different in frequency, such that a first energy signal is transmitted to and processed by a first of the implantable medical devices, whereas a different, second energy signal is transmitted to and processed by a second of the implantable medical devices. The energy signals differ in frequency, such that by filtering each implantable medical device may receive and process a dedicated energy signal and may operate according to the received energy signal.

In one embodiment, the shock generation circuitry comprises an energy supply arrangement and an output circuit. The energy supply arrangement is formed by one or a multiplicity of energy storage devices, for example capacitors, which may be caused to discharge in order to supply energy to form the electrical shock signal as well as the energy signal. The energy supply arrangement is electrically connected to the output circuit, such that a current flows from the energy supply arrangement to the output circuit for causing a signal transmission.

In one embodiment, the output circuit is formed by an H bridge comprising switches to selectively form conduction paths for outputting e.g. a pulse signal (to form the electrical shock signal or the energy signal) in a first polarity or in a second, opposite polarity. In the H bridge, for example four switches may be used, wherein a first conduction path may be formed by a first pair of switches to connect terminals of the H bridge circuit to output an output pulse at a first polarity, and a second conduction path may be formed by a second pair of switches to connect the terminals of the H bridge to output an output pulse of a second, opposite polarity. By selectively switching the switches, the connection paths may be selectively opened or closed in order to selectively output an output pulse of a particular polarity.

By using the output circuit, in particular a carrier signal at a desired frequency may be produced and output to transmit the energy signal towards the implantable medical device via the shock electrode. For example, a rectangular, pulse-width modulated signal may be produced by switching switches of an H bridge of the output circuit according to the desired frequency of the carrier signal.

Instead of using an output circuit comprising an H bridge, a carrier signal at a desired frequency may be produced by using an oscillator, a resonating circuit, or an amplifier circuit such as a push-pull amplifier.

In one embodiment, the energy supply arrangement comprises a multiplicity of energy storage devices, for example in the shape of capacitors, functionally connected to at least one switching device. The control circuitry herein is configured to control the at least one switching device to supply energy for generating the output pulse using all of the multiplicity of energy storage devices or a combination of some of the multiplicity of energy storage devices. The output pulse in particular may be produced by causing energy storage devices in the shape of capacitors to discharge.

The energy storage devices of the energy supply arrangement, for example formed by capacitors, are charged using a primary or secondary energy storage of the defibrillation device, such as a battery. The battery may for example be a lithium-based battery. Primary energy storages may for example be LiMnO2 energy storing systems, secondary energy storages may for example be lithium-iones-based systems or LiPo systems.

A charging circuit may charge the energy storage devices of the energy supply arrangement during a transmission procedure in which an electrical shock pulse or an energy signal is transmitted, or independent and timely separated from a transmission procedure.

The energy storage devices, for example formed by capacitors, of the energy supply arrangement may for example be controlled such that approximately rectangular pulses or pulse trains containing pulses of approximately constant amplitude are produced by the shock generation circuitry. Herein, during a discharging of a capacitor a voltage level may decay over time, due to the discharging of the capacitor, wherein, when a certain discharging level is reached, another capacitor may be switched in order to add charge of the additional capacitor for producing the output pulse or pulse train. The switching of the energy storage devices of the energy supply arrangement may be controlled by the control circuit.

The control circuit may also monitor whether a voltage level of the energy supply arrangement drops below a predefined threshold in order to switch off an energy transmission if the voltage level is below the threshold.

The energy signal may exhibit a single phase. The energy signal may, in another embodiment, exhibit multiple phases. Within the multiple phases polarities of the pulse may change.

The defibrillation device may comprise a communication interface for communicating with an external device, for example within a home-monitoring system. The communication interface may for example employ a common communication scheme such as a MICS communication or a BLE communication.

In one embodiment, the implantable medical device comprises an electrode pole arrangement formed by a multiplicity of electrode poles configured to emit said electrical stimulation signal to perform said therapeutic action. The processing circuitry is configured to extract electrical energy from the energy signal received, using a first pair of electrode poles of said multiplicity of electrode poles, from the defibrillation device external to the implantable medical device to obtain extracted electrical energy and to produce said electrical stimulation signal using said extracted electrical energy for emission by a second pair of electrode poles of said multiplicity of electrode poles.

According to this embodiment, the implantable medical device comprises a processing circuitry configured to extract electrical energy from an energy signal received by means of a first pair of electrode poles of the multiplicity of electrode poles. The electrode poles of the electrode pole arrangement serve to emit electrical stimulation signals to perform a therapeutic action and, likewise, to receive an energy signal in order to provide energy for operation of the implantable medical device. Hence, an arrangement of electrode poles of the implantable medical device is used for signal emission and for signal reception, the signal emission being for providing for a therapeutic action and the signal reception serving to receive energy to operate the implantable medical device.

The electrode pole arrangement comprises at least two electrode poles. The electrode pole arrangement for example may comprise three electrode poles or more than three electrode poles.

Herein, a first pair of electrode poles of the multiplicity of electrode poles is used to receive the energy signal as transmitted by the defibrillation device. A second pair of electrode poles is used for emission of the electrical stimulation signal produced from extracted electrical energy as obtained from the energy signal. The first pair of electrode poles and the second pair of electrode poles, in one embodiment, have at least one electrode pole in common. The first pair of electrode poles and the second pair of electrode poles, in one embodiment, may use the same electrode poles. In another embodiment, if the multiplicity of electrode poles comprises at least three electrode poles, the first pair of electrode poles may for example use a first and a second electrode pole, whereas the second pair of electrode poles may use the first electrode pole and a third electrode pole different than the second electrode pole. In yet another embodiment, the two pairs may use completely different electrode poles.

In an implanted state, at least one of the electrode poles of the electrode pole arrangement or a multiplicity of the electrode poles generally are in contact with tissue within the patient. The pair of electrode poles for signal reception and the pair of electrode poles for signal emission herein may be designed and chosen to achieve a resulting body impedance as experienced by the respective pair of electrode poles. For example, the electrode poles of the first pair of electrode poles used for receiving the energy signal may be designed and chosen such that an effective body impedance for the first pair of electrode poles is smaller than 1000 Ohm, preferably smaller than 500 Ohm. The electrode poles of the second pair of electrode poles used for emission of the electrical stimulation signal may for example be designed and chosen such that an effective body impedance for the second pair of electrode poles is larger than 20 Ohm, preferably larger than 100 Ohm. In one embodiment, the implantable medical device comprises a body on which the multiplicity of electrode poles is arranged. The body may for example be made from an electrically insulating material. For example, the body may be made from a biocompatible plastics material, a silicone material, a polyurethane (PU) material, a ceramics material, or a combination of such materials. Alternatively, the body of the implantable medical device may at least partially be made from a metal material, wherein the metal material comprises a coating at its outside such that an outer surface of the body of the implantable medical device is electrically non-conductive. The coating for example may be made from a parylene coating, a silicone coating, a polyurethane (PU) coating or the like.

The body may provide for a hermetically tied sealing of components, in particular the processing circuitry, enclosed within the body.

The body, for example on one end, may comprise a fixation device for fixing the body on tissue at an implantation site. The fixation device may for example be formed by a helical screw, by a stent-like structure or by an arrangement of fixation tines designed for engagement with tissue at the implantation site.

In one embodiment, the body may be flexibly bendable such that the body may be deformable in an implanted state and for example may adjust to a particular vessel shape at an implantation site. For providing such flexibility, the body may for example be formed from a silicone material.

In one embodiment, the body has an elongated shape generally extending along a longitudinal axis. For example, the body may have a length equal to or smaller than 10 cm and a cross-sectional diameter equal to or smaller than 10 mm. The body may comprise a circular cross section and may have a longitudinal, substantially cylindrical, tubular shape. Herein, at least some of the multiplicity of electrode poles of the electrode pole arrangement may be displaced with respect to one another along the longitudinal axis. Electrode poles hence are distributed along the longitudinal body of the implantable medical device to form spatially separated pairs of electrode poles for signal reception and/or transmission. In one embodiment, at least some electrode poles of the multiplicity of electrode poles are formed by ring electrodes arranged on the body. The ring electrodes preferably are displaced with respect to one another along the longitudinal axis along which the body of the implantable medical device extends. The ring electrodes circularly extend about the body and are designed for signal transmission and/or reception. In particular, by means of the ring electrodes therapeutic stimulation signals may be emitted, and/or sense signals relating to e.g., cardiac activity may be sensed. In addition, the energy signal as transferred from the defibrillation device may be received using the ring electrodes.

The energy signal is transferred from the defibrillation device external to the implantable medical device. The defibrillation device herein may be implanted, for example subcutaneously implanted, at an implantation site spatially separate from the implantation site of the implantable medical device. The defibrillation device and the implantable medical device do not comprise a direct galvanic connection by means of a dedicated connection line, but energy is transmitted by the defibrillation device to the implantable medical device in a wireless manner using the energy transferring (wireless) signal.

In one embodiment, the processing circuitry comprises a filter unit for performing a frequency filtering of the energy signal. The filter unit may for example be a bandpass filter which is designed to let a specific energy signal in a dedicated frequency range pass, but blocks signals outside of a passband. In this way energy may be specifically coupled into the implantable medical device, wherein different implantable medical devices may employ different frequency ranges and hence may be separately fed with energy by signal transmission from the defibrillation device. For example, multiple implantable medical devices may be implanted at different locations within the patient’s heart in order to provide e.g. a multi-chamber stimulation within the patient’s heart, wherein an energy transfer to the different medical devices may be conducted by using different energy signals at different frequency ranges.

In one embodiment, the processing circuitry comprises a demodulating circuit arrangement for demodulating the energy signal to obtain the extracted electrical energy. The demodulating circuit arrangement, in one embodiment, for example comprises an arrangement of one or multiple diodes, which serve to rectify the received energy signal and demodulate the signal in order to extract the electrical energy as carried by the modulated carrier signal.

In one embodiment, the processing circuitry may comprise a circuit arrangement for doubling or otherwise multiplying the voltage of the received signal for producing the stimulation signal.

In one embodiment, the processing circuitry comprises an energy storage circuit arrangement for storing the extracted electrical energy, the energy storage circuit arrangement comprising at least one capacitor. The at least one capacitor is charged by the extracted energy of the energy signal, such that operation of the implantable medical device for producing stimulation signals may be conducted by using energy as stored within the at least one capacitor.

The at least one capacitor of the energy storage circuit arrangement may, in cooperation with diodes of the demodulating circuit arrangement, be functional to provide for demodulation and energy extraction. By demodulating the energy signal the at least one capacitor is charged.

In one embodiment, an electrical stimulation signal may immediately, i.e., at the time of energy reception, be produced according to the charge of the capacitor, such that the implantable medical device substantially functions as a passive relay device without its own control. The therapeutic action hence takes place at the same time and is controlled by the transmission of the energy signal. The reception of the energy signal at the implantable medical device causes the production of a stimulation signal which is transmitted by means of the electrode pole arrangement. This may allow for a particularly easy construction of the implantable medical device, the implantable medical device not requiring any timing circuitry for timing stimulation signals. Rather, a control and timing may be conducted by the defibrillation device, the defibrillation device transferring energy to the implantable medical device for example in response to sense signals as sensed by the defibrillation device, the implantable medical device receiving the energy and converting the energy into stimulation signals for providing a therapeutic action at the implantation site of the implantable medical device.

In another embodiment, the processing circuitry comprises a timing unit for timing a therapeutic action by producing a stimulation signal. In such embodiment, energy is transferred from the defibrillation device to the implantable medical device, wherein the implantable medical device converts the energy and stores the energy in an energy storage arrangement, for example comprising one or multiple capacitors. Emission of stimulation signals however is controlled by the processing circuitry of the implantable medical device, for example according to a processing of sensed signals as sensed by the implantable medical device. The defibrillation device hence serves to supply energy, wherein operation subsequently is carried out by the implantable medical device in a substantially autarkic manner by using the energy as received from the defibrillation device to produce stimulation signals according to an internal control and timing at the implantable medical device.

Stimulation pulses of a stimulation signal as produced by the implantable medical device for performing a therapeutic action may for example have a pulse width in between 0.05 ms and 10 ms and may have a voltage level in between 0.1 V and 50 V. A repetition interval between pulses of the stimulation signal may for example lie in a range between 20 ms and 2 s.

If the implantable medical device serves as a passive relay device in that stimulation pulses are produced by immediate conversion of the energy signal as received from the defibrillation device, the stimulation pulses may substantially correspond to demodulated pulses as obtained by demodulation from the energy signal and hence may exhibit substantially the same pulse width, voltage level and repetition interval as the pulses of the energy signal.

In one embodiment, the processing circuitry comprises a signal generation circuit arrangement for producing an electrical stimulation signal from the extracted electrical energy. The signal generation circuit arrangement may for example comprise an output circuit, for example in the shape of a so-called H bridge, allowing to produce stimulation signals in the shape of pulses having a particular polarity. The output circuit for example comprises a multiplicity of switches which may be switched in a pairwise manner to produce a therapeutic current path to produce a stimulation pulse of a particular polarity.

The signal generation circuit arrangement may for example be controlled by a timing circuitry.

In one embodiment, the signal generation circuit arrangement may comprise at least one current limiting device for limiting a current for producing the electrical stimulation signal. By means of the current limiting device, which for example may be a current limiting diode or a Zener diode, a current for producing a stimulation signal may be limited, for example to produce a stimulation pulse having a voltage level equal to or smaller than 50 V and a current level equal to or smaller than 100 mA.

The body of the implantable medical device may have a volume smaller than 5 cm³.

The implantable medical device may be implantable using a venous access.

The implantation of the implantable medical device may take place by using a catheter system, in particular within a minimal invasive procedure.

The implantable medical device may be explantable, for example using a catheter system.

The implantable medical device may comprise an RFID tag for identifying the implantable medical device. The RFID tag may in particular be readable in an implanted state of the implantable medical device.

The defibrillation device may comprise an RFID reading device for reading information of the RFID tag of the implantable medical device.

The implantable medical device may be MRI compatible. In particular, the entire therapy system may be MRI compatible. The implantable medical device may be suitable to provide for a therapeutic action for providing for an antitachycardia pacing (ATP).

The implantable medical device may be configured for providing for a post-shock pacing, i.e., a pacing subsequent to a defibrillation action of a defibrillation device.

The defibrillation device may monitor and log information relating to the operation of the defibrillation device and/or the implantable medical device and may communicate such information to an external device, for example in the context of a home-monitoring system.

In another aspect, a method for operating a therapy system for providing a cardiac therapy comprises: providing a defibrillation device comprising a generator device having a control circuitry and a shock generation circuitry for generating an electrical shock signal for performing a defibrillation therapy, the defibrillation device further comprising a shock electrode for emitting said electrical shock signal; providing an implantable medical device for emitting an electrical stimulation signal to perform a therapeutic action, the implantable medical device comprising a processing circuitry for generating said electrical stimulation signal; producing, using said shock generation circuitry of the defibrillation device, and wirelessly transmitting, using said shock electrode, an energy signal different than said electrical shock signal; and wirelessly receiving said energy signal and extracting, using the processing circuitry of the implantable medical device, electrical energy from said energy signal to obtain extracted electrical energy and producing said electrical stimulation signal using said extracted electrical energy.

The advantages and advantageous embodiments described above for the therapy system equally apply also to the method, such that it shall be referred to the above in this respect.

The idea of the invention shall subsequently be described in more detail with reference to the embodiments as shown in the drawings. Herein: Fig. 1 shows a schematic drawing of a therapy system comprising an implantable medical device implanted intracardially and an implantable defibrillation device in an implanted state in a patient;

Fig. 2 shows a schematic drawing of a therapy system;

Fig. 3 shows a schematic drawing of an implantable medical device;

Fig. 4 shows a schematic drawing of another embodiment of an implantable medical device;

Fig. 5A shows an example of an energy signal as transmitted by a defibrillation device;

Fig. 5B shows a demodulated signal as obtained by the implantable medical device from the energy signal;

Fig. 6 shows an embodiment of a shock generation circuitry of the defibrillation device for producing an electrical shock signal for providing for a defibrillation therapy as well as an energy signal for supplying energy to the implantable medical device;

Fig. 7 shows another embodiment of a shock generation circuitry of the defibrillation device;

Fig. 8 shows a schematic drawing of a train of output pulses of an energy signal as produced and transmitted by the defibrillation device;

Fig. 9 shows a schematic circuit diagram of a processing circuitry of an implantable medical device;

Fig. 10 shows a schematic drawing of a processing circuitry of an implantable medical device; and Fig. 11 shows a schematic circuit diagram of an embodiment of a processing circuitry of an implantable medical device.

Subsequently, embodiments of the invention shall be described in detail with reference to the drawings. In the drawings, like reference numerals designate like structural elements.

It is to be noted that the embodiments are not limiting for the invention, but merely represent illustrative examples.

Referring to Fig. 1, in one embodiment a therapy system comprises an implantable medical device 3 and a defibrillation device 1 designed as a non-transvenous implantable cardioverter defibrillator device.

The defibrillation device 1 formed as a non-transvenous implantable cardioverter defibrillator device, in the shown setup, is implanted such that it is completely external to the heart H, the defibrillation device 1 comprising a generator device 10 encapsulated within a housing 100, and a lead 11 connected to the generator device 10 at a proximal end 111 and carrying electrode poles 113, 114 as well as a shock electrode 115 in the shape of a coil formed on a distal portion close to a distal end 112 of the lead 11. The electrode poles 113, 114, for example formed as ring electrodes on either side of the shock electrode 115, serve to sense cardiac signals for processing within the generator device 10 of the defibrillation device 1, such that based on sensed signals an arrhythmia may be identified and a shock pulse may be generated for providing for a defibrillation therapy.

The defibrillation device 1, in the embodiment of Fig. 1, is designed for a non-transvenous implantation, that is an implantation external to the patient’s heart H. In particular, the lead 11 connected to the connection block 101 of the generator device 10 shall rest outside of the patient’s heart H and shall not extend transven ously into the heart, the shock electrode 115 hence, in an implanted state, being placed outside of the heart H for providing for a defibrillation therapy. For example, the generator device 10 may be implanted subcutaneously in a patient. The lead 11, with a lead body 110, may extend from the generator device 10 towards the sternum of the patient, the lead 11 for example tunneling through tissue in the region of the sternum and being placed beneath the sternum of the patient.

The generator device 10 generally comprises a control circuitry 102 for controlling operation of the defibrillation device 1. In addition, the generator device 10 comprises a shock generation circuitry 103 and an energy storage 104, in particular in the shape of a battery. The control circuitry 102 serves to process signals sensed via a sensing arrangement formed by the electrode poles 113, 114 arranged on the lead 11 and additional poles, such as the shock electrode 115 and the housing 100 of the generator device 10.

The defibrillation device 1 may comprise a communication circuitry for communicating with a device 2 external to the patient, for example within the context of a home-monitoring system.

The implantable medical device 3, in the shown setup, is implanted intracardially within the patient’s heart H and is configured for providing a therapeutic action within the patient’s heart H. The implantable medical device 3 herein is configured for receiving an energy signal from the defibrillation device 1, which is implanted externally to the patient’s heart H.

By means of the implantable medical device 3 the defibrillation device 1 is enabled for providing a therapeutic function within the patient’s heart H, in particular a therapeutic pacing function, for example for providing an antitachycardia pacing (ATP). The defibrillation device 1 herein is configured to transmit an energy signal to the implantable medical device 3 to supply the implantable medical device 3 with energy, for example using a pair of electrodes formed by the shock electrode 115 and the housing 100 of the generator device 10.

In the embodiment of Fig. 1, the implantable medical device 3 comprises a body 30 having an elongated shape and an electrode pole arrangement 31 comprising electrode poles 310, 311, 312 which are placed on the body 30 and are displaced with respect to one another on the body 30. The implantable medical device 3 may be a passive device which receives energy for operation from the defibrillation device 1 spatially separated from the implantable medical device 3. In one embodiment, the implantable medical device 3 does not comprise an active control, but serves to passively convert and relay energy received from the defibrillation device 1 to output an electrical stimulation signal within the patient’s heart H. In another embodiment, the implantable medical device 3 may comprise a control circuit, namely a timing circuit, for controlling a timing of signal generation by the implantable medical device 3.

Referring now to Fig. 2, in a general setup the defibrillation device 1 is configured for providing for a defibrillation therapy by emitting, in case a life-threatening cardiac arrhythmia is detected, an electrical shock signal SP. In addition, the defibrillation device 1 is configured for wirelessly transmitting an energy signal TS towards the implantable medical device 3, which receives the energy signal TS wirelessly from the defibrillation device 1.

The defibrillation device 1 may be configured for transmitting energy to the implantable medical device 3 by means of the energy signal TS, wherein the implantable medical device 3 converts the energy signal TS for producing an electrical stimulation signal for providing for a therapeutic action at the implantation site of the implantable medical device 3, in particular for providing for a cardiac pacing.

In addition, information I may be modulated onto the energy signal TS by the defibrillation device 1 to transfer signaling information from the defibrillation device 1 to the implantable medical device 3.

The defibrillation device 1 comprises an RFID reading device 105. The implantable medical device 3 in turn comprises an RFID tag 34. By means of the RFID reading device 105 of the defibrillation device 1 information may be read from the RFID tag 34 of the implantable medical device 3, e.g., to identify the implantable medical device 3 towards the defibrillation device 1. Referring now to Fig. 3, the implantable medical device 3 generally comprises a body 30 which encapsulates a processing circuitry 32 which is in operative connection with the electrode pole arrangement 31, namely the electrode poles 310, 311, 312. The processing circuitry 32 of the implantable medical device 3 serves to process an energy signal TS received from the defibrillation device 1 to extract energy from that signal and to convert the energy for producing stimulation pulses to be output by the electrode poles 310, 311, 312 of the electrode pole arrangement 31.

Referring now to Fig. 4, the body 30 may have an elongated shape extending longitudinally along a longitudinal axis L. The body 30 may for example be made from an electrically insulating material such as a biocompatible plastics material, a silicone, a polyurethane (PU) material, a ceramics material, or a combination thereof. In another embodiment, the body 30 may be at least partially made from a metal material and may comprise an electrically insulating coating, for example a parylene coating, a silicone coating, a polyurethane (PU) coating or the like, such that an outer surface of the body 30 is electrically non-conductive but provides for an electrical insulation towards the outside.

As visible from Fig. 4, the electrode poles 310, 311, 312 are displaced with respect to one another along the longitudinal axis L. The electrode poles 310, 311, 312 may for example be formed by ring electrodes circumferentially extending about the body 30.

The body 30 may have a circular cross section and may have an overall cylindrical, tubular shape. The body in particular may have a length smaller than 10 cm and a cross-sectional diameter smaller than 10 mm.

At one end, the implantable medical device 3 comprises a fixation device 33 for providing for a fixation on tissue, for example intracardiac tissue. The fixation device 33 may for example have the shape of a helical screw which may be screwed into tissue in order to provide for a fixation. In another embodiment the fixation device 33 may comprise one or multiple flexible tines, for example made from a shape-memory alloy material, such as nitinol. In yet another embodiment, the implantable medical device 3 may be held at an implantation site due to its shape, for example by providing a kink or bent within the body 30 in order to provide for a fixation in a coronary vessel or the like.

The body 30 may be flexibly bendable. In another embodiment, the body 30 is rigid.

The implantable medical device 3 with its body 30 may for example have a volume smaller than 5 cm³.

Referring now to Fig. 5A, in one embodiment the defibrillation device 1 outputs an energy signal TS which comprises pulses S i-1, trans, Si. trans formed by modulation using a carrier signal CS at a defined frequency. The pulses may have an equal pulse width PWi-i, PWi, or may differ in their pulse width PWi-i, PWi. Likewise, a repetition rate RPi in between neighboring pulses may be constant or may vary.

The pulse width PWi-i, PWi may for example lie in a range between 0.05 ms to 10 ms. The pulses S i-1, trans, Si. trans may have a voltage level (as received by the implantable medical device 3) in between 0.1 V to 50 V. The pulse repetition interval RPi may lie in a range between 20 ms and 2 s.

As visible in Fig. 5B, the implantable medical device 3, using the processing circuitry 32, converts the received signal RS by demodulation such that, effectively, energy pulses Si-i,rec, Si, rec are extracted from the received signal. In particular, by demodulation the carrier signal CS is removed, and the signal is rectified such that the signal energy is extracted for producing an electrical stimulation signal to be output using the electrode arrangement 31.

The carrier frequency of the carrier signal CS for transmitting the energy signal TS by means of the defibrillation device 1 uses a carrier frequency above 10 kHz, preferably about 30 kHz, for example around 100 kHz. The frequency of the carrier signal is chosen such that a tissue stimulation by transmission of the energy signal is avoided.

The defibrillator device 1 is configured to produce an electrical shock signal for providing a defibrillation therapy in case a particular cardiac arrhythmia is detected requiring a defibrillation. In addition, the defibrillation device 1 is configured to produce the energy signal TS for transmission to the implantable medical device 3. Both for producing the electrical shock signal and for producing the energy signal TS the shock generation circuitry 103 is employed, and the respective signal is transmitted for example using the shock electrode 115 in combination with an electrode pole formed by the housing 100 of the generator device 10 (see Fig. 1).

Referring now to Fig. 6, the shock generation circuitry 103 may be implemented by an arrangement of energy storage devices formed by capacitors Cl to C7 and an arrangement of switching devices SI to S8. The capacitors Cl to C7 are in operative electrical connection to the energy storage 104, formed by a battery, of the generator device 10 and may be charged by the energy storage 104 in order to generate electrical output pulses for emission by the shock electrode 115.

The capacitors Cl to C7 herein form energy storage devices which, in combination, form an energy supply arrangement 106. The energy supply arrangement 106 is selectively switchable, by switches S5 to S8, to an output circuit 107 formed by an H bridge having switches SI to S4.

In the embodiment of Fig. 6, the capacitors Cl to C7 are connected to each other in an electrical series connection. Switching devices S5 to S8 selectively connect the capacitors Cl to C7 to a so-called H bridge formed by switching devices SI to S4. R represents an effective body impedance, the switching devices SI to S4 selectively forming therapeutic current paths for emitting electrical pulses of a desired polarity into the patient’s body to form an electrical shock signal or the energy signal.

By means of the switching devices S5 to S8 the electrical voltage of an electrical output pulse may be set. If only the switching device S5 is closed, the electrical pulse is formed by the charge of the capacitors Cl to C4, which discharge via the electrical path formed by the closed switching device S5. The electrical pulse is fed through the H bridge, wherein either the combination of switching devices S3, S2 or the combination of switching devices S4, SI is closed in order to form an electrical pulse at a particular polarity for emission into the body of the patient.

In order to set the voltage level of the electrical pulse, either one of the switching devices S5 to S8 is closed. If the switching device S6 instead of the switching device S5 is closed, the electrical pulse is formed by discharging the combination of the capacitors Cl to C5. If instead the switching device S7 is closed, the charge of the capacitor C6 is added. If the switching device S8 is closed, the electrical pulse is formed by the combination of all capacitors Cl to C7.

An output pulse may be formed by the combination of all capacitors Cl to C7 by closing the switching device S8 (and leaving the switching devices S5 to S7 open). For this, the capacitors Cl to C7 are charged by the energy storage 104 of the generator device 10 to such a level that the voltage of the output pulse is set to a desired level, e.g., for forming an electrical shock pulse or for forming the electrical energy signal for transmission to the implantable medical device 3.

Alternatively, an output pulse may be formed by using a subgroup of the capacitors Cl to C7. For example, an output pulse may be formed by closing (only) the switching device S5 in order to form the output pulse by discharging the capacitors Cl to C4. An output pulse of this kind may hence exhibit a reduced voltage level.

Referring now to Fig. 7, in another embodiment the shock generation circuitry 103 comprises energy storage devices in the shape of capacitors Cl to C7, which each may be charged with electrical energy supplied from the energy storage 104 (Fig. 1) in the shape of a battery. The shock generation circuitry 103 in addition comprises switching devices S5-S7, which serve to selectively couple the energy storage devices Cl to C7 to an output circuitry in the shape of an H bridge comprising switching devices SI to S4 for selectively forming a therapeutic current path via an associated diode D1-D3 for emitting an output signal into a patient, represented in the schematic circuit diagram of Fig. 7 by an effective body impedance R. In the embodiment of Fig. 7, electrical pulses may be formed by selectively switching the switching devices S5 to S7 to a closed position. Herein, if all switching devices S5 to S7 are open, an electrical pulse is formed by the combination of the capacitors Cl to C4. By closing the switching device S5, the capacitor C5 is added to the combination, such that an electrical pulse is formed by discharging the combination of the capacitors Cl to C5. By closing also the switching device S6, the capacitor C6 is added. By closing all switching devices S5 to S7, an electrical pulse of a maximum voltage level is produced from the combination of all capacitors Cl to C7 along the electrical conduction path via diode D3 towards the H bridge formed by the switching devices SI to S4.

By combining all capacitors Cl to C7 by closing all switching devices as S5 to S7, hence, a maximum voltage for an electrical output pulse may be set. As described above, an electrical output pulse may be formed by the combination of all capacitors Cl to C7 by closing the switching devices S5 to S7. The capacitors Cl to C7 may be charged by the energy storage 104 of the generator device 10 to such a level that the voltage of an output pulse is set to a desired level. Alternatively, an electrical output pulse may be formed by using a subgroup of the capacitors Cl to C7. For example, an electrical output pulse may be formed by keeping all switching devices S5 to S7 in the open state in order to form the electrical output pulse by discharging the capacitors Cl to C4.

Output pulses for forming the energy signal in particular may be formed by employing a pulse width modulation technique. For this, the switching devices SI to S4 of the H bridge may be used. For example, if the H bridge is switched to form an electrical conduction path via switching devices S3, S2 to generate a pulse of a desired polarity, the switching device S3 may repeatedly be opened in order to open the conduction path for achieving a pulse width modulation.

The circuit arrangements of Figs. 6 and 7 allow to shape an output pulse or a train of output pulses such that output pulses may exhibit an approximately rectangular pulse waveform or another desired waveform or an envelope of a train of output pulses exhibits an approximately rectangular form or another desired form. In particular, referring now to Fig. 8, for generating a train of output pulses S i-l, trans, Si, trans for producing the energy signal TS e.g. by using the embodiment of Fig. 7, the switching devices S5 to S7 in a first time span T1 may be in an open state, such that the arrangement of energy storage devices Cl to C4 are connected to the H bridge, the energy storage devices Cl to C4 being connected in series. During the first time span T1 the energy storage devices Cl to C4 discharge via the diode DI for supplying energy to the H bridge for producing pulses S i-l, trans, Si. trans- In a subsequent, second time span T2 the switching device S5 is closed, such that the energy storage device C5 is connected in series to the energy storage devices Cl to C4, such that energy now is supplied to the H bridge via the diode D2 (due to the voltage being supplied from the energy storage device C5, the diode DI assumes a blocking state, the diode D2 in turn assuming a conducting state such that the energy is supplied via the diode D2 to the H bridge circuit). In a third time span T3 the switching device S6 is closed (while the switching device S5 remains closed), such that the further energy storage device C6 is connected in series to the energy storage devices Cl to C5, and energy is supplied to the H bridge via diode D3 (when the switching devices S5, S6 are closed, the diodes DI, D2 are in a blocking state, such that energy is supplied via the diode D3 to the H bridge). Further energy storage devices C7 beyond the energy storage devices Cl to C6 may be added, which are connected each via an associated switching device S7 in series to the energy devices Cl to C6 below, as illustrated in Fig. 7.

By consecutively adding energy storage devices Cl to C7 for the shaping of a train of output pulses Si-i, trans, Si, trans, an envelope E according to which the amplitude of the output pulses Si-i, trans, Si, trans is defined follows a sawtooth shape as visible in Fig. 8, due to the discharging of the capacitors Cl to C7 of the energy supply arrangement 106. By consecutively adding energy storage devices Cl to C7 for forming the train of output pulses S i-l, trans, Si, trans, for example by controlling the switching of the capacitors Cl to C7 according to a decay of the voltage level while producing the output pulses Si-i, trans, Si, trans, a train of output pulses Si- 1, trans, Si, trans may be formed which exhibit a substantially constant amplitude.

In one embodiment, the implantable medical device 3 comprises no active control of its own. In another embodiment, the implantable medical device 3 may be formed passive only in that it receives energy for operation from the defibrillation device 1, but comprises an active control of its own to provide for a timing for producing a stimulation signal.

Referring now to Fig. 9, in one embodiment the processing circuitry 32 is formed as a passive circuitry not requiring any energy supply arrangement such as an electrochemical battery and also having no control circuitry of its own. The processing circuitry 32 comprises diodes D31, D32 and capacitors Cl, C2 which in combination form a demodulating circuit arrangement 321 and an energy storage circuit arrangement 322. Energy is received from the defibrillation device 1, which is modeled in the circuit diagram of Fig. 9 by the voltage source VI on the left. The energy signal is received via an effective body impedance, modeled in the circuit diagram of Fig. 9 by the resistance Rl. The energy signal, in the embodiment of Fig. 9, is received via a pair of electrode poles 310, 312, which feed the signal to a diodes D31, D32 and capacitors C31, C32.

By means of the diodes D31, D32 in combination with the capacitors C31, C32 the signal received from the external defibrillation device is converted and output via a pair of electrode poles 311, 312 connected to the capacitor Cl. In this way a stimulation pulse is generated and output into body tissue, modeled in the circuit diagram of Fig. 9 by an effective body impedance R2.

When supplying an energy signal in the shape of a voltage pulse modulated by a carrier frequency to the processing circuitry 32 substantially formed by the diodes D31, D32 in combination with the capacitors C31, C32, the energy signal is demodulated and converted into an output signal, similarly as shown in Fig. 5B. Namely, the capacitor Cl is charged and, while energy reception still goes on, is discharged across the electrode poles 311, 312 such that a series of substantially rectangular electrical stimulation pulses is output across the electrode poles 311, 312 for performing a therapeutic action within the patient.

In the circuit diagram as depicted in Fig. 9, it is assumed that the implantable medical device 3 functions as a passive device which does not comprise an active control circuitry, in particular a timing function, and an energy storage for a prolonged storage of electrical energy, such as an electrochemical battery. Rather, in the embodiment of Fig. 9 the received energy is directly converted to produce an output electrical stimulation signal for performing a therapeutic action at the implantation site of the implantable medical device 3. Therapeutic parameters herein are controlled by the signal transmission of the defibrillation device 1.

This however is not restrictive for the instant invention. Rather, the implantable medical device 3 may comprise a timing function to control a therapeutic action. In such embodiments, therapeutic parameters are not controlled by the signal transmission of the defibrillation device 1, but by the implantable medical device 3 itself. In such embodiments, energy is received at the implantable medical device 3 from the defibrillation device 1, wherein the energy is converted and stored at the implantable medical device 3 and is used for operation of the implantable medical device 3.

Referring now to Fig. 10, in a general embodiment of an implantable medical device 3 comprising advanced control circuitry, the processing circuitry 32 comprises a filter unit 320 for filtering an energy signal received via the electrode pole arrangement 31. The filter unit 320 may for example be a bandpass filter for passing a signal in a particular frequency range, but blocking signal components outside of that frequency range. By using such a filter unit 320, a particular energy signal may be received at the implantable medical device 3, wherein different implantable medical devices 3 may be configured to receive energy signals at different frequencies, hence allowing to use multiple implantable medical devices 3 in parallel, for example to achieve a multi-chamber stimulation within a patient’s heart H.

The filter unit 320 passes the received signal to a demodulating circuit arrangement 321 at which the signal is demodulated and fed to an energy storage circuit arrangement 322 at which energy extracted from the received signal is stored.

In a signal generation circuit arrangement 323, electrical stimulation signals are produced from the energy as stored in the energy storage circuit arrangement 322 and output by means of the electrode pole arrangement 31.

Referring now to Fig. 11, in a particular embodiment the demodulating circuit arrangement may comprise diodes D31, D32 and a capacitor C32, similar as in the embodiment of Fig. 9, for receiving an energy signal using a pair of electrode poles 310, 312 and for demodulating the energy signal. The demodulating circuit arrangement 321 may be selectively coupled to the capacitor C31, which forms an energy storage circuit arrangement 322, by means of switches S31, S32. The energy storage circuit arrangement 322 of the capacitor C31 in turn may be selectively coupled, using a switch S33, to a signal generation circuit arrangement 323 comprising an arrangement of switches S34 to S37 forming an H bridge for producing electrical stimulation signals to be output via a pair of electrode poles 311, 312.

During operation, energy is received via the demodulating circuit arrangement 321 and is used for charging the capacitor C31 of the energy storage circuit arrangement 322 while the switches S31, S32 are in a closed position and the switch S33 is in an open position. When the capacitor C31 is charged, the switches S31, S32 may be opened. For producing an electrical stimulation signal, then, the switch S33 may be closed and, using the signal generation circuit arrangement 323, output pulses of a desired polarity may be generated by selectively closing a pair of switches S34, S37 respectively S35, S36 to form a therapeutic current path via the electrode poles 311, 312.

The switches S31-S37 may be controlled by an electronic control circuitry, which is operated by the energy as received from the defibrillation device 1.

In the embodiment of Fig. 11, the signal generation circuit arrangement 323 comprises a current limiting component 324, for example in the shape of a current limiting diode or a Zener diode, which serves to limit a current and/or voltage of an electrical stimulation pulse as output via the H bridge formed by the switches S34 to S37. By means of the current limiting component 324 it can be avoided that an output signal comprises an excessive voltage level and/or current beyond a defined maximum. For example, using the current limiting component 324 an output voltage and current may be limited to a value equal to or below 50 V respectively equal to or below 100 mA.

The idea underlying the invention is not limited to the embodiments described above, but may be implemented in an entirely different fashion. The implantable medical device is used in combination with a defibrillation device which may be implantable or may be designed for use external to a patient. The defibrillation device functions to transmit an energy signal to the implantable medical device, such that energy is supplied to the implantable medical device from the defibrillation device.

List of reference numerals

1 Defibrillation device (non-transvenous implantable cardioverter defibrillator device)

10 Generator device

100 Housing

101 Connection block

102 Control circuitry

103 Shock generation circuitry

104 Energy storage (battery)

105 RFID reading device

106 Energy supply arrangement

107 Output circuit

11 Electrode lead

110 Lead body

111 Proximal end

112 Distal end

113, 114 Electrode pole

115 Shock electrode (coil)

2 External device

3 Implantable medical device

30 Body

31 Electrode pole arrangement

310-312 Electrode pole

32 Processing circuitry

320 Filter unit

321 Demodulating circuit arrangement

322 Energy storage circuit arrangement

323 Signal generation circuit arrangement

324 Current limiting device

33 Fixation device

34 RFID tag C1-C7 Capacitor

C31, C32 Capacitor cs Carrier signal

D1-D3 Diode

D31, D32 Diode

E Envelope

H Heart

I Information

L Longitudinal axis

OS Output signal

PWi-i, PWi Pulse width

R, Rl, R2 Resistor (effective body impedance)

RP, Repetition interval

RS Received signal

S1-S8 Switches

S31-S37 Switches

Si- Imrans, Si. trans Transmit pulses

Si-l^rec, Si. rec Energy pulses

SP Shock pulse

Tl, T2 Time point

TS Energy signal

VI Voltage source

Claims

- 36 - Claims

1. A therapy system for providing a cardiac therapy, comprising: a defibrillation device (1) comprising a generator device (10) having a control circuitry (102) and a shock generation circuitry (103) for generating an electrical shock signal for performing a defibrillation therapy, the defibrillation device (1) further comprising a shock electrode (115) for emitting said electrical shock signal; and an implantable medical device (3) for emitting an electrical stimulation signal to perform a therapeutic action, the implantable medical device (3) comprising a processing circuitry (32) for generating said electrical stimulation signal; wherein said shock generation circuitry (103) of the defibrillation device (1) is configured to produce and wirelessly transmit, using said shock electrode (115), an energy signal (TS) different than said electrical shock signal; wherein the processing circuitry (32) of the implantable medical device (3) is configured to wirelessly receive said energy signal (TS) and to extract electrical energy from said energy signal (TS) to obtain extracted electrical energy and to produce said electrical stimulation signal using said extracted electrical energy.

2. The system according to claim 1, characterized in that the defibrillation device (1) is an implantable cardioverter defibrillator device, in particular a non-transvenous implantable cardioverter defibrillator device, comprising at least one lead (11) on which the shock electrode (115) is arranged.

3. The system according to claim 2, characterized in that the defibrillation device (1) comprises a sensing arrangement having a multiplicity of electrode poles (113, 114) for sensing electrocardiogram signals, wherein at least one electrode pole (113, 114) of said sensing arrangement is arranged on said at least one lead (11).

4. The system according to one of the claims 1 to 3, characterized in that the shock generation circuitry (103) is configured to produce said energy signal (TS) using a carrier signal (CS) in a pre-defined frequency range above 10 kHz, preferably above 30 kHz. - 37 - The system according to claim 4, characterized in that the shock generation circuitry (103) is configured to produce said energy signal (TS) to comprise a multiplicity of pulses (Si-i, trans, Si, trans) formed by modulating said carrier signal (CS). The system according to one of the preceding claims, characterized in that the control circuitry (102) is configured to evaluate sensed information indicative of said electrical stimulation signal and to control at least one of a pulse width (PWi-i, PWi), a pulse amplitude and/or a repetition interval (RPi) of pulses of the said energy signal (TS) for transmission to the implantable medical device (3). The system according to one of the preceding claims, characterized in that the control circuitry (102) is configured to modulate said energy signal (TS) for transmitting information to the implantable medical device (3). The system according to one of the preceding claims, characterized in that the shock generation circuitry (103) is configured to produce a first energy signal in a first frequency range for transmission to a first implantable medical device and a second energy signal in a second frequency range different than the first frequency range for transmission to a second implantable medical device. The system according to one of the preceding claims, characterized in that the shock generation circuitry (103) comprises an energy supply arrangement (106) containing at least one energy storage device (C1-C7) for supplying energy to form said energy signal (TS) and an output circuit (107) for outputting said energy signal (TS) to the shock electrode (115). The system according to claim 9, characterized in that the output circuit (107) is formed by an H bridge comprising switches (S1-S4) to selectively form conduction paths for outputting said energy signal (TS) in a first polarity or in a second, opposite polarity. The system according to claim 9 or 10, characterized in that the energy supply arrangement (106) comprises a multiplicity of energy storage devices (C1-C7) functionally connected to at least one switching device (S5-S8), wherein the control circuitry (102) is configured to control the at least one switching device (S5-S8) to supply energy for generating said energy signal using all of said multiplicity of energy storage devices (C1-C7) or a combination of some of said multiplicity of energy storage devices (C1-C7). The system according to one of the preceding claims, characterized in that the implantable medical device (3) comprises an electrode pole arrangement (31) comprising a multiplicity of electrode poles (310-312) configured to emit said electrical stimulation signal, wherein the processing circuitry (32) is configured to extract electrical energy from said energy signal (TS) received via a first pair of electrode poles of said multiplicity of electrode poles (310-312) to obtain said extracted electrical energy and to produce said electrical stimulation signal using said extracted electrical energy for emission by a second pair of electrode poles of said multiplicity of electrode poles (310-312). The system according to one of the preceding claims, characterized in that the processing circuitry (32) of the implantable medical device (3) comprises a demodulating circuit arrangement (321) for demodulating said energy signal (TS) to obtain said extracted electrical energy, the demodulating circuit arrangement (321) comprising at least one diode (D31, D32). The system according to one of the preceding claims, characterized in that the processing circuitry (32) of the implantable medical device (3) comprises an energy storage circuit arrangement (322) for storing said extracted electrical energy, the energy storage circuit arrangement (322) comprising at least one capacitor (C31, C32). A method for operating a therapy system for providing a cardiac therapy, the method comprising: providing a defibrillation device (1) comprising a generator device (10) having a control circuitry (102) and a shock generation circuitry (103) for generating an electrical shock signal for performing a defibrillation therapy, the defibrillation device (1) further comprising a shock electrode (115) for emitting said electrical shock signal; providing an implantable medical device (3) for emitting an electrical stimulation signal to perform a therapeutic action, the implantable medical device (3) comprising a processing circuitry (32) for generating said electrical stimulation signal; producing, using said shock generation circuitry (103) of the defibrillation device (1), and wirelessly transmitting, using said shock electrode (115), an energy signal (TS) different than said electrical shock signal; and wirelessly receiving said energy signal (TS) and extracting, using the processing circuitry (32) of the implantable medical device (3), electrical energy from said energy signal (TS) to obtain extracted electrical energy and producing said electrical stimulation signal using said extracted electrical energy.