Implantable cardioverter defibrillator device having a shock generation circuitry

Abstract

An implantable cardioverter defibrillator device (1) comprises a generator device (10) comprising a processing circuitry (102) and a shock generation circuitry (103). The processing circuitry (102) is configured to control the shock generation circuitry (103) to produce a first shock pulse (Al) at a first peak voltage (PH1) by connecting, in a first initial time span (T1), a first group of energy storage devices of a multiplicity of energy storage devices (C1-C7) to an output circuitry (105) and, in at least one further time span (T2, T3) following said first initial time span (T1), a combination of the first group of energy storage devices and at least one further energy storage device to the output circuitry (105). The processing circuitry (102) is further configured to control the shock generation circuitry (103) to produce, subsequent to said first shock pulse (Al), a second shock pulse (A2) at a second peak voltage (PH2) larger than said first peak voltage (PH2) by connecting, in a second initial time span (T4), a second group of energy storage devices to the output circuitry (105).

Description

[0001] Implantable cardioverter defibrillator device having a shock generation circuitry

[0002] The instant invention relates to an implantable cardioverter defibrillator device according to the preamble of claim 1 and to a method for operating an implantable cardioverter defibrillator device.

[0003] An implantable cardioverter defibrillator device of the kind described herein may in particular be subcutaneously implanted and may comprise one or multiple leads carrying one or multiple electrodes and extending from the defibrillator into the patient's heart.

[0004] An implantable cardioverter defibrillator device generally comprises a generator device comprising a processing circuitry and a shock generation circuitry. The implantable cardioverter defibrillator device further comprises a shock electrode operatively connected to the generator device for emitting shock pulses. The shock generation circuitry is configured to generate shock pulses for emission using the shock electrode, the shock generation circuitry comprising a multiplicity of energy storage devices, an arrangement of switching devices and an output circuitry connected to the shock electrode. The processing circuitry is configured to control the shock generation circuitry to generate the shock pulses by selectively connecting, using the arrangement of switching devices, the multiplicity of energy storage devices to the output circuitry for delivering the shock pulses to the shock electrode.

[0005] In conventional defibrillators, an arrangement of energy storage devices, for example in the shape of capacitors, is used to generate shock pulses based on a discharging of the energy storage devices. As a capacitor generally exhibits an exponential decrease in its voltage during discharging, the shock pulse conventionally comprises an exponentially decaying waveform. This leads to the effect that the shock pulse, at its beginning, comprises a rather high peak voltage, for example in excess of 1300 V, making it necessary to use components within the implantable cardioverter defibrillator device which are capable of handling such high voltages.

[0006] There is a general desire to design an implantable cardioverter defibrillator device such that it may provide for an effective defibrillation, while reducing a peak voltage of the shock pulse and hence reducing the requirements for the components of the implantable cardioverter defibrillator device.

[0007] WO 2018 / 026922 Al discloses an implantable device including one or more leads adapted to be placed in the internal thoracic vein of a patient. The lead may include features to adapt the lead for such placement. An associated device for use with the lead may include operational circuitry adapted for use with a lead having an electrode for sensing and / or therapy purposes coupled thereto.

[0008] US 2016 / 0101293 Al discloses a cardiac defibrillator or cardioversion waveform energy control system employing transvenous ICDs or subcutaneous SICDs for treating cardiac arrhythmias. The system comprises differentially driven amplifier circuit operational modes to control the delivery of defibrillation or cardioversion electrical shocks, wherein the shock waveforms are constant current, constant voltage, or constant energy.

[0009] WO 2021 / 023506 Al discloses an implantable pulse generator comprising an electric circuit having a multiplicity of energy storage devices formed by capacitors, which may be selectively connected to an output circuit using an arrangement of switching devices to produce defibrillation pulses having an approximately rectangular shape.

[0010] It is an object of the instant invention to provide an implantable cardioverter defibrillator device and a method for operating an implantable cardioverter defibrillator device which allow for providing an effective shock therapy for achieving a defibrillation action. This object is achieved by an implantable cardioverter defibrillator device comprising the features of claim 1.

[0011] Accordingly, the processing circuitry is configured to control the shock generation circuitry to produce a first shock pulse at a first peak voltage by connecting, in a first initial time span, a first group of energy storage devices of the multiplicity of energy storage devices to the output circuitry and, in at least one further time span following the first initial time span, a combination of the first group of energy storage devices of the multiplicity of energy storage devices and at least one further energy storage device of the multiplicity of energy storage devices to the output circuitry. The processing circuitry further is configured to control the shock generation circuitry to produce, subsequent to the first shock pulse, a second shock pulse at a second peak voltage larger than the first peak voltage by connecting, in a second initial time span, a second group of energy storage devices of the multiplicity of energy storage devices to the output circuitry.

[0012] The shock generation circuit is particularly configured to produce shock pulses for defibrillation and / or inducing a fibrillation of the heart. The shock pulses produced by the shock generation circuit are particularly designed such that a defibrillation action and / or an action of inducing a fibrillation on the heart can be achieved when emitted via the shock electrode.

[0013] In an embodiment, the shock pulses produced by the shock generation circuitry are defibrillation pulses.

[0014] The implantable cardioverter defibrillator device (in short ICD) generally is configured to emit a shock pulse for achieving a defibrillation. The implantable cardioverter defibrillator device may serve for monitoring and treating potentially life-threatening arrhythmias of a patient's heart. The implantable cardioverter defibrillator device, for this, comprises a shock generation circuitry, which contains a multiplicity of energy storage devices, for example formed by capacitors or inductances, which serve to store electrical energy and, for producing shock pulses, are discharged. The energy storage devices, prior to the generation of a shock pulse, are charged using an energy supply of the implantable cardioverter defibrillator device, for example a battery, such that prior to the generation of a shock pulse the energy storage devices are in a charged state and may be discharged for producing the shock pulse.

[0015] Herein, the shock generation circuitry is configured, controlled by the processing circuitry, to produce shock pulses having a desired shape, e.g. an approximately rectangular shape. For this, the energy storage devices are selectively connected, using the arrangement of the switching devices, to the output circuitry, such that a group of energy storage devices may be connected to the output circuitry, and subsequently further energy storage devices may be added such that, after a partial discharge of the group and a resulting decay in the voltage of the shock pulse, the voltage of the shock pulse is raised to form a shock pulse having a desired shape.

[0016] The processing circuitry is configured to produce different shock pulses. Namely, the processing circuitry is configured to control the shock generation circuitry to produce a first shock pulse by switching a first group of energy storage devices and subsequently one or more further energy storage devices to the output circuitry. By using the first group of energy storage devices and by means of the subsequent switching of further energy storage devices to the first group, a first shock pulse at a first peak voltage is generated and is output, via the output circuitry, to the shock electrode for emission in a patient.

[0017] The first shock pulse may have a peak voltage, corresponding to the maximum voltage of the shock pulse, which is comparatively low, allowing for a defibrillation at a reduced voltage and e.g. at a reduced energy.

[0018] If it is found that, by means of the first shock pulse, a defibrillation action has not been sufficiently achieved, subsequently, the processing circuitry controls the shock generation circuitry to produce a second shock pulse at a second peak voltage larger than the first peak voltage of the first shock pulse. For this, a second group of energy storage devices, which provides for a combined larger peak voltage than the first peak voltage of the first shock pulse, is switched to the output circuitry. By means of the second shock pulse at the second peak voltage, a stronger defibrillation action may be achieved.

[0019] In that initially a first shock pulse is produced at a comparatively low peak voltage and, potentially, subsequently a second shock pulse at a higher peak voltage is produced, it becomes possible to first establish a defibrillation action at a rather low peak voltage in order to then, if it is found that the defibrillation action has not been sufficient yet, to produce another, second shock pulse to make sure that a desired defibrillation action is achieved. Subsequent to a first shock pulse, hence, a second shock pulse may be produced, in case the first shock pulse was, by itself, not successful for defibrillating the patient’s heart.

[0020] In one embodiment, the processing circuitry is configured to control the shock generation circuitry to produce the second shock pulse by connecting, in at least one further time span following the second initial time span, a combination of the second group of energy storage devices of the multiplicity of energy storage devices and at least one further energy storage device of the multiplicity of energy storage devices to the output circuitry. The shock generation circuitry, by selectively adding energy storage devices, is configured to produce a first shock pulse having e.g. an approximately rectangular shape. Likewise, by adding energy storage devices to the second group of energy storage devices, the processing circuitry may be configured to control the shock generation circuitry for producing a second shock pulse having e.g. an approximately rectangular shape. By successively adding energy storage devices for discharging via the output circuitry, both the first shock pulse and the second shock pulse may be shaped to approximate a desired pulse shape, in particular a rectangular shape.

[0021] In one embodiment, the second group of energy storage devices of the multiplicity of energy storage devices equals a combination of the first group of energy storage devices of the multiplicity of energy storage devices and at least one further energy storage device of the multiplicity of energy storage devices. Hence, for forming the second shock pulse, the energy storage devices of the first group, as used for producing the first shock pulse, and at least one additional energy storage device are used. The peak voltage, corresponding e.g. to the sum of the voltages across the individual energy storage devices, is larger for the second shock pulse than for the first shock pulse, as an increased number of energy storage devices is used in an initial time span at the beginning of the shock pulse.

[0022] In one embodiment, the multiplicity of energy storage devices is formed by capacitors or inductors. The energy storage devices serve to (temporarily) store energy and, by connecting the energy storage devices to the output circuitry using the arrangement of switching devices, may be caused to discharge such that a current is applied to the output circuitry for producing a corresponding shock pulse.

[0023] The energy storage devices may be charged, prior to producing a shock pulse, by means of an energy supply of the generator device, in particular an electrochemical battery. The energy storage devices hence, prior to producing a shock pulse, may be in a charged state such that the energy storage devices may be discharged by connecting them, using the arrangement of switching devices, to the output circuitry.

[0024] In one embodiment, the arrangement of switching devices is configured to selectively connect the energy storage devices in series to the output circuitry. The energy storage devices, for example formed by capacitors, hence form a series connection, such that the voltages across the individual energy storage devices add to each other. The sum of the voltages across the energy storage devices of the first group herein determines the peak voltage of the first shock pulse. The sum of the voltages across the energy storage devices of the second group in turn determines the peak voltage of the second shock pulse.

[0025] In one embodiment, the processing circuitry is configured to control the arrangement of switching devices to produce the first shock pulse by connecting the first group of energy storage devices of the multiplicity of energy storage devices in series to the output circuitry and to successively connect at least one further energy storage device of the multiplicity of energy storage devices in series to the first group. By adding further energy storage devices to the first group, hence, the pulse voltage of the first shock pulse may be raised following a partial discharge of the first group of energy storage devices, such that a shock pulse having an approximately rectangular pulse shape is obtained. Likewise, in one embodiment, the processing circuitry is configured to control the arrangement of switching devices to produce the second shock pulse by connecting the second group of energy storage devices of the multiplicity of energy storage devices in series to the output circuitry and to successively connect at least one further energy storage device of the multiplicity of energy storage devices in series to the second group. By adding further energy storage devices to the second group, hence, the pulse voltage of the second shock pulse may be raised following a partial discharge of the second group of energy storage devices, such that a shock pulse having an approximately rectangular pulse shape is obtained.

[0026] In one embodiment, the second group of energy storage devices equals a combination of the first group of energy storage devices in series with at least one further energy storage device. To form the second shock pulse, hence, the same group of energy storage devices is used as for producing the first shock pulse, plus at least one further energy storage device, such that the peak voltage of the second shock pulse is increased by the voltage of the at least one further energy storage device in comparison to the first shock pulse.

[0027] In one embodiment, the processing circuitry is configured to control the shock generation circuitry to produce the first shock pulse to have a first pulse width and to produce the second shock pulse to have a second pulse width smaller than the first pulse width. In particular, the first shock pulse and the second shock pulse may be produced to have equal energy. Hence, as the second shock pulse exhibits an increased peak voltage, its pulse duration is shortened, such that the pulse energy of the second shock pulse may match the pulse energy of the first shock pulse.

[0028] It is to be noted that it also is conceivable that the first shock pulse and the second shock pulse may contain a different pulse energy.

[0029] For producing the first shock pulse and / or for producing the second shock pulse, e.g. a number of 1 to 3 further energy storage devices may be added to the first group of energy storage devices respectively the second group of energy storage devices. It however is also possible to add more energy storage devices, for example 4, 5 or 6 energy storage devices to the first group respectively the second group for producing the first shock pulse respectively the second shock pulse.

[0030] The peak voltage of the second shock pulse may be increased, in comparison to the peak voltage of the first shock pulse, by an amount in between 10% to 100%, in particular between 20% to 80%, 40% to 60% or of 50%, of the peak voltage of the first shock pulse. Other values, in particular smaller than 10% or larger than 100%, are however also conceivable.

[0031] Subsequent to producing the second shock pulse, further shock pulses at the peak voltage of the second shock pulse or another peak voltage may be produced. For example, a number in between 1 to 20, in particular 5 to 15 or 10 additional (second) shock pulses following an (unsuccessful) first shock pulse may be produced. After each shock pulse it herein may be checked whether a defibrillation of the patient’s heart has successfully been achieved or not.

[0032] If, even after one or more second shock pulses, no defibrillation of the patient’s heart has successfully been achieved, this may be communicated to an external device, for example in a home monitoring system. A (repeated) non-successful defibrillation may be an indication for a need for replacement of the implantable cardioverter defibrillator device.

[0033] In one embodiment, the implantable cardioverter defibrillator device comprises a sensing arrangement having an arrangement of electrode poles for sensing signals indicative of cardiac activity. The sensing arrangement in particular may be used to sense electrocardiogram signals, which may be analyzed by the processing circuitry in order to identify a cardiac activity, in particular cardiac contraction events relating to atrial and / or ventricular contractions. The electrode poles may be arranged on a lead connected to the generator device, the lead extending into the patient’s heart or being placed outside of the patient’s heart.

[0034] In one embodiment, the processing circuitry is configured to evaluate, based on signals sensed using the sensing arrangement, a defibrillation action achieved by the first shock pulse. Following the first shock pulse, cardiac activity is sensed, and based on sense signals relating to cardiac activity it is analyzed whether the defibrillation action caused by the first shock pulse has been successful in that a defibrillation of the patient’s heart has been achieved. If the defibrillation has been successfully achieved, it may be determined that no second shock pulse is required, such that no second shock pulse is produced. If, in contrast, it is determined that the first shock pulse has not been sufficient for achieving a defibrillation of the patient’s heart, the second shock pulse at an increased peak voltage is produced in order to defibrillate the patient’s heart.

[0035] The second shock pulse may be produced after a waiting period following the first shock pulse. During the waiting period it may be determined, using the sensing arrangement and by analyzing sensed signals using the processing circuitry, whether a defibrillation already has been achieved as a consequence of the first shock pulse. Only if this is not the case, the second shock pulse may be produced.

[0036] In one embodiment, the implantable cardioverter defibrillator device comprises a lead connected to the generator device. The lead may carry the shock electrode, wherein for example a housing of the generator device may serve as a counter-electrode for the shock electrode to produce shock pulses. In addition, sensing electrodes may be placed on the lead, for example at either side of the shock electrode.

[0037] In one embodiment, the implantable cardioverter defibrillator device is a non-transvenous implantable cardioverter defibrillator device. A non-transvenous implantable cardioverter defibrillator device is configured for non-transvenous implantation, that is an implantation such that no electrode leads transvenously are implanted within the heart of a (human or animal) patient. The non-transvenous implantable cardioverter defibrillator device hence is to be implanted in a patient such that a generator and an electrode arrangement, for example a shock electrode placed on a lead connected to the generator, are implanted extracardially and do not reach into the heart of the patient, that is into the right or left ventricle or the right or left atrium.

[0038] A non-transvenous implantable cardioverter defibrillator device may comprise a lead to be implanted extracardially and a shock electrode arranged on the lead. The shock electrode herein, in an implanted state of the defibrillator device, may be 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. Generally, the non- transvenous implantable cardioverter defibrillator device does not comprise any portions which extend transvenously into the heart, but the defibrillator device may be configured to achieve a sensing and emission of signals outside of the heart.

[0039] The generator device may be designed for a subcutaneous implantation in a patient.

[0040] The generator device and / or a lead may be designed for a substernal implantation in the patient.

[0041] In another aspect, in a method for operating an implantable cardioverter defibrillator device for performing a defibrillation shock therapy the implantable cardioverter defibrillator device comprises a generator device, having a processing circuitry and a shock generation circuitry, and a shock electrode operatively connected to the generator device for emitting shock pulses. The method comprises: generating, using the shock generation circuitry, shock pulses for emission using the shock electrode, the shock generation circuitry comprising a multiplicity of energy storage devices, an arrangement of switching devices and an output circuitry connected to the shock electrode; controlling, using the processing circuitry, said shock generation circuitry to generate said shock pulses by selectively connecting, using the arrangement of switching devices, the multiplicity of energy storage devices to said output circuitry for delivering the shock pulses to the shock electrode. Said controlling includes: controlling, using the processing circuitry, said shock generation circuitry to produce a first shock pulse at a first peak voltage by connecting, in a first initial time span, a first group of energy storage devices of said multiplicity of energy storage devices to said output circuitry and, in at least one further time span following said first initial time span, a combination of said first group of energy storage devices of said multiplicity of energy storage devices and at least one further energy storage device of said multiplicity of energy storage devices to said output circuitry. Said controlling further includes: controlling, using the processing circuitry, said shock generation circuitry to produce, subsequent to said first shock pulse, a second shock pulse at a second peak voltage larger than said first peak voltage by connecting, in a second initial time span, a second group of energy storage devices of said multiplicity of energy storage devices to said output circuitry.

[0042] The advantages and advantageous embodiments described above for the device equally apply also to the method.

[0043] Further features and advantages of the invention shall be described hereafter based on the description of exemplary embodiments shown in the figures. Herein:

[0044] Fig. 1 shows a schematic view of an implantable cardioverter defibrillator device;

[0045] Fig. 2 shows a schematic view of a shock generation circuitry of an implantable cardioverter defibrillator device;

[0046] Fig. 3 shows a schematic view of a shock generation circuitry, in another embodiment;

[0047] Fig. 4 shows a shock pulse waveform together with an effective defibrillation voltage;

[0048] Fig. 5 shows a schematic view of a first shock pulse at a first peak voltage and a second shock pulse at a second peak voltage larger than the first peak voltage; and

[0049] Fig. 6 shows a schematic view of a first shock pulse at a first peak voltage and a second shock pulse at a second peak voltage larger than the first peak voltage, produced by selectively adding energy storage devices to an output circuitry.

[0050] 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.

[0051] Referring to Fig. 1, in a setup of a therapy system a implantable cardioverter defibrillator device 1 is implanted such that the implantable cardioverter defibrillator device 1 rests externally to the heart H, the implantable cardioverter defibrillator 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 implantable cardioverter defibrillator 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.

[0052] The implantable cardioverter defibrillator 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 generator device 10 shall rest outside of the patient’s heart H and shall not extend transvenously 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.

[0053] 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.

[0054] The implantable cardioverter defibrillator device 1 may comprise a communication interface for communicating with an external device, for example within a home-monitoring system.

[0055] The generator device 10 generally comprises a processing circuitry 102 for controlling operation of the implantable cardioverter defibrillator device 1. In addition, the generator device 10 comprises a shock generation circuitry 103 and an energy supply 104, in particular in the shape of a battery.

[0056] The processing circuitry 102 in particular 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 different poles of the sensing arrangement form pairs of electrode poles in between which e.g. sense vectors are spanned, allowing to sense electrocardiogram signals from the patient’s heart H with a different spatial sensitivity.

[0057] The shock generation circuitry 103 comprises a circuitry for generating an electrical shock pulse. The shock generation circuitry 103 in particular comprises energy storage devices and an output circuitry for generating a high voltage shock pulse and for shaping the shock pulse in a way such that an effective therapeutic (defibrillation) action may be achieved within a patient.

[0058] Referring now to Fig. 2, 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 supply 104 (see Fig. 1), formed by a battery, of the generator device 10 and may be charged by the energy supply 104 in order to generate electrical pulses for emission by the shock electrode 115.

[0059] In the embodiment of Fig. 2, 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 an output circuitry 105 formed by a so-called H bridge using 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.

[0060] By means of the switching devices S5 to S8 the electrical voltage of an electrical shock 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.

[0061] 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.

[0062] By combining all capacitors Cl to C7 by closing (only) the switching device S8, a maximum voltage for the electrical pulse may be set (wherein it is conceivable that the shock generation circuitry 103 comprises more than the shown capacitors Cl to C7 such that further capacitors may be used for generating a shock pulse).

[0063] Referring now to Fig. 3, 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 supply 104 (see 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 105 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 injecting a shock pulse into a patient, represented in the schematic circuit diagram of Fig. 3 by an effective body impedance R.

[0064] In the embodiment of Fig. 3, 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.

[0065] The circuit arrangements of Figs. 2 and 3 allow to shape a shock pulse such that it may exhibit an approximately rectangular pulse waveform or another desired waveform.

[0066] In particular, for generating a shock pulse, e.g. in the embodiment of Fig. 3 the switching devices S5 to S7 in a first time span 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 the energy storage devices Cl to C4 discharge via the diode DI for supplying energy to the H bridge. In a subsequent, second time span, 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 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. 3.

[0067] By consecutively adding energy storage devices Cl to C7 in the different embodiments of Figs. 2 and 3 for the shaping of a shock pulse, the shock pulse may assume a waveform which substantially resembles a rectangular waveform, or another waveform, for example a rising ramp or the like. Referring now to Fig. 4, by consecutively adding energy storage devices Cl to C7 in the shock generation circuitry 103 of Fig. 2 or 3 for the shaping of a shock pulse, the shock pulse may assume a waveform Pl which approximately resembles a rectangular waveform P0.

[0068] Fig. 4 shows, in one example, discharging waveforms for the arrangement of first energy storage devices Cl to C4 (waveform P2), for the second energy storage device C5 (waveform P3), for the third energy storage device C6 (waveform P4) and for a fourth energy storage device C7 (waveform P5) in addition to the resulting overall waveform Pl.

[0069] As visible from Fig. 4, in a first phase Bl of a shock pulse the waveform Pl exhibits a toothed shape, due to the consecutive switching of the switching devices S5-S8 (in the embodiment of Fig. 2) respectively S5-S7 (in the embodiment of Fig. 3) for successively adding energy storage devices when generating an shock pulse.

[0070] In the first phase Bl herein the shock pulse assumes a first polarity, for example by forming a therapeutic current path in the output circuitry 105 by closing the switching devices S3, S2 and hence injecting a current in a first direction into the body impedance R. In a second phase B2 following the first phase Bl, in turn, the polarity of the shock pulse is reversed, by now forming a therapeutic current path in the output circuitry 105 by opening the switching devices S2, S3 and by closing the switching devices S4, SI, such that now a current is injected into the body impedance R via a path formed by the switching devices S4, SI.

[0071] During the first phase Bl, in the example of Fig. 4, the energy storage devices Cl to C7 are successively added, such that the toothed shape of the waveform Pl in the first phase Bl arises. In the second phase B2, in turn, no further energy storage devices are added, such that the waveform Pl in the second phase B2 exhibits a generally (exponentially) decaying shape.

[0072] In the first phase Bl, e.g. in the embodiment of Fig. 3, following a time point tO and prior to a time point tl the switching devices S5 to S7 are open, such that energy is supplied to the output circuitry 105 by the arrangement of first energy storage devices Cl to C4, as indicated in Fig. 4, via the diode DI placed therein. At the time point tO the generation of the shock pulse starts by suitably switching the shock generation circuitry 103 to the output circuitry 105. At the time point tl, 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, and energy is supplied via the diode D2 placed therein. At a time point t2, the switching device S6 is closed, such that the energy storage device C6 is connected in series to the energy storage devices Cl to C5 below, and energy is supplied via the diode D3 placed therein. At a time point t3, the switching device S7 is closed, such that the energy storage device C7 is connected in series to the energy storage devices Cl to C6 below, and energy is supplied to the output circuitry 105.

[0073] During each time span, the energy storage devices Cl to C7 respectively connected to the output circuitry 105 are discharged in a generally exponentially decaying manner. At the particular time points tl to t3, herein a sudden increase in the voltage waveform arises, due to the connection of a respective further energy storage device C5, C6, C7 to the output circuitry 105. Hence, a toothed waveform Pl in the first phase Bl is obtained.

[0074] At the time point t4, in the shown example the polarity of the shock pulse is reversed, wherein in the second phase B2 the pulse waveform Pl exhibits a generally exponentially decaying shape.

[0075] In Fig. 4 at the bottom a resulting transmembrane voltage of heart muscle cells is shown.

[0076] Referring now to Fig. 5, the shock generation circuitry 103, in the embodiment of Fig. 2 or in the embodiment of Fig. 3, is controlled by the processing circuitry 102 to produce shock pulses Al, A2 for achieving a defibrillation action of the patient’s heart H. Based on an evaluation of signals sensed by means of the sensing electrodes 113, 114 and potentially further sensing electrodes it is identified whether the patient’s heart H is in an irregular, arrhythmic state, for example in a fibrillating state. As a consequence, shock pulses Al, A2 are produced, the shock pulses Al, A2 being designed such that the patient’s heart H is defibrillated. Herein, the processing circuitry 102 controls the shock generation circuitry 103 to first produce a first shock pulse Al having a peak voltage PHI and a pulse width PW1, corresponding to a pulse energy PEI . In a waiting period W following the first shock pulse Al, sense signals as obtained using the sensing arrangement of the sensing electrodes 113, 114 are analyzed, and it is established whether a defibrillation action resulting from the first shock pulse Al has been sufficient to defibrillate the patient’s heart H. If this is not the case, i.e., the patient’s heart H remains in a fibrillating state, a second shock pulse A2 is generated, the second shock pulse A2 having a peak voltage PH2 and a pulse width PW2, corresponding to a pulse energy PE2.

[0077] Herein, as visible from Fig. 5, the peak voltage PH2 of the second shock pulse A2 is larger than the peak voltage PHI of the first shock pulse Al . Hence, by means of the second shock pulse A2 a stronger defibrillation action is effected in order to cause the patient’s heart H to transition into a defibrillated, regular state.

[0078] As illustrated in Fig. 5, the pulse width PW2 of the second shock pulse A2 may be smaller than the pulse width PW 1 of the first shock pulse Al . This may result in the first shock pulse Al and the second shock pulse A2 having a similar, beneficially equal pulse energy PEI, PE2.

[0079] Referring now to Fig. 6, the shock pulses Al, A2 each are produced by causing the energy storage devices formed by the capacitors Cl to C7 to discharge. Herein, as described above in connection with Figs. 2 to 4, the energy storage devices formed by the capacitors Cl to C7 may successively be connected in series to the output circuitry 105, such that each shock pulse Al, A2 exhibits an approximately rectangular pulse shape at a maximum voltage corresponding to the peak voltage PHI respectively PH2.

[0080] Herein, the peak voltage PHI, PH2 is set by the combination of capacitors Cl to C7 at the beginning of the formation of the respective shock pulse Al, A2.

[0081] For example, for forming the first shock pulse Al, in the beginning a first group of capacitors Cl to C4 may be used, the peak voltage PHI hence corresponding to the sum of the voltages across the individual capacitors Cl to C4. By successively adding, in successive time spans T1-T3, further energy storage devices formed by the capacitors C5 to C7 to the first group of energy storage devices corresponding to the capacitors Cl to C4, a resulting pulse shape as illustrated in Fig. 6 for the first shock pulse Al is obtained.

[0082] After outputting the first shock pulse Al, the capacitors Cl and C7 are again charged using the energy supply 104.

[0083] For forming the second shock pulse A2, in contrast, in the beginning a second group of capacitors corresponding, for example, to the capacitors Cl to C5 in the embodiment of Figs. 2 and 3 may be used, the peak voltage PH2 of the shock pulse A2 at the beginning corresponding to the sum of the voltages across the individual capacitors Cl to C5 of the second group. By successively adding, in successive time spans T4-T6, further energy storage devices formed by the capacitors C6, C7 to the second group of energy storage devices corresponding to the capacitors Cl to C5, a resulting pulse shape as illustrated in Fig. 6 for the second shock pulse A2 is obtained.

[0084] Further shock pulses may be produced, if no successful defibrillation even after the second shock pulse A2 is observed.

[0085] The maximum number of further shock pulses however may be limited, for example to a number in between 1 to 20 further shock pulses, in order to avoid an excessive wear of the components of the implantable cardioverter defibrillator device 1.

[0086] In either of the embodiments of Figs. 2 and 3, the control of the switching devices S5-S8 for producing the first shock pulse and / or the second shock pulse may take place in a signal- controlled manner, based on a measurement of a voltage of the arrangement of first energy storage devices Cl to C4, or a measurement of a voltage on all energy storage devices Cl to C7. In particular, the control of the switching devices S5-S8 may be such that the waveform Pl of the shock pulse in the first phase Bl lies within a range bounded by a lower bound Z1 and an upper bound Z2, such that the waveform Pl in the first phase Bl approximates the ideal rectangular waveform P0, as illustrated in Fig. 4 in the graph at the top. In particular, for producing the first shock pulse and / or the second shock pulse a voltage of a group of energy storage devices be observed, and once it is found that the energy storage devices have discharged below a certain value, a further energy storage device may be added to increase the voltage of the shock pulse waveform Pl as indicated at the time point tl in Fig. 4 at the top. The control of the further switching may then take place by measurement of the overall voltage, or based on a time control based on a first time span Tl in between the time points tO and tl .

[0087] For example, the processing circuitry 102 may be configured to set a second time span T2 based on the following equation:

[0088] N

[0089] ?2“ N + 1 'T1where T2 indicates the second time span, N indicates the number of energy storage devices used for the first respectively the second group, and Ti indicates the initial time span.

[0090] A further time span for switching a further, mthswitching device may then be determined based on the following equation:

[0091] N

[0092] Tm= - ■ Ti m N + m - 11where Tmindicates a respective further time span, N indicates the number of energy storage devices used in the beginning, m may assume values between 2 and M+l, with M indicating the number of energy storage devices in addition to the first energy storage devices, and Ti indicates the first time span.

[0093] If the switching does not take place in a signal-controlled manner, but in a time-controlled manner, the processing circuitry 102 may be configured to set the first time span based on the following equation: where Ti is the first time span, R corresponds to a value of a body impedance, C is a capacitance value indicative of a capacitance of the energy storage devices C1-C7 (assuming that all energy storage devices Cl to C7 have approximately the same capacitance), Uo represents a peak voltage value at the beginning of the first time span Tl, and Uerepresents a voltage value at the end of the first time span Tl, Uo and Uebeing known in advance for example by suitable electrical modelling).

[0094] In the embodiments of Figs. 2 and 3, the storage devices Cl to C7 may all comprise equal capacitances, that is a capacitance value within a range of + / - 20% around a nominal capacitance. Alternatively, the energy storage devices Cl to C7 may have unequal capacitances.

[0095] In the embodiments of Figs. 2 and 3, the switching devices S1-S8 are for example formed by electronic switches, such as IGBTs or AGTs. In one embodiment, the switching devices S1-S8 may in part be formed by AGTs and in part by IGBTs.

[0096] The implantable cardioverter defibrillator device 1 may comprise a home monitoring function.

[0097] The implantable cardioverter defibrillator device 1 may be MR compatible, when viewed alone and in an implanted state when connected to one or multiple leads 2.

[0098] The idea underlying the invention is not limited to the embodiments described above, but may be implemented in an entirely different fashion.

[0099] An implantable cardioverter defibrillator device may comprise one or multiple leads, with one or multiple electrode poles arranged on each lead. The leads are configured for implantation external to the patient’s heart, such that no portions of the implantable cardioverter defibrillator device extend transvenously into the heart. Alternatively, at least one lead may be designed for an implantation internally in the patient’s heart. List of reference numerals

[0100] I (Non-transvenous) Implantable cardioverter defibrillator device

[0101] 10 Generator device

[0102] 100 Housing

[0103] 101 Connection block

[0104] 102 Processing circuitry

[0105] 103 Shock generation circuitry

[0106] 104 Energy supply (battery)

[0107] 105 Output circuitry

[0108] I I Electrode lead

[0109] 110 Lead body

[0110] I I I Proximal end

[0111] 112 Distal end

[0112] 113, 114 Electrode pole

[0113] 115 Shock electrode (coil)

[0114] Al, A2 Shock pulse

[0115] Bl, B2 Phase

[0116] C1-C7 Capacitors

[0117] D1-D3 Diode

[0118] H Heart

[0119] P0-P5 Waveform

[0120] PEI, PE2 Pulse energy

[0121] PHI, PH2 Peak voltage

[0122] PW1, PW2 Pulse width

[0123] R Body impedance

[0124] S1-S8 Switches t0-t4 Time point

[0125] T1-T6 Time span

[0126] W Waiting period

[0127] Z1, Z2 Bound

Claims

Claims1. An implantable cardioverter defibrillator device (1) for performing a defibrillation shock therapy on a human or animal heart, comprising: a generator device (10) comprising a processing circuitry (102) and a shock generation circuitry (103); and a shock electrode (115) operatively connected to the generator device (10) for emitting shock pulses; wherein the shock generation circuitry (103) is configured to generate shock pulses for emission using the shock electrode (115), the shock generation circuitry (103) comprising a multiplicity of energy storage devices (C1-C7), an arrangement of switching devices (S5-S8) and an output circuitry (105) connected to the shock electrode (115), wherein the processing circuitry (102) is configured to control said shock generation circuitry (103) to generate said shock pulses by selectively connecting, using the arrangement of switching devices (S5-S8), the multiplicity of energy storage devices (C1-C7) to said output circuitry (105) for delivering the shock pulses to the shock electrode (115), characterized in that the processing circuitry (102) is configured to control said shock generation circuitry (103) to produce a first shock pulse (Al) at a first peak voltage (PHI) by connecting, in a first initial time span (Tl), a first group of energy storage devices of said multiplicity of energy storage devices (C1-C7) to said output circuitry (105) and, in at least one further time span (T2, T3) following said first initial time span (Tl), a combination of said first group of energy storage devices of said multiplicity of energy storage devices (C1-C7) and at least one further energy storage device of said multiplicity of energy storage devices (C1-C7) to said output circuitry (105), wherein the processing circuitry (102) is configured to control said shock generation circuitry (103) to produce, subsequent to said first shock pulse (Al), a second shock pulse (A2) at a second peak voltage (PH2) larger than said first peak voltage (PH2) by connecting, in a second initial time span (T4), a second group ofenergy storage devices of said multiplicity of energy storage devices (C1-C7) to said output circuitry (105).

2. The implantable cardioverter defibrillator device (1) according to claim 1, characterized in that the processing circuitry (102) is configured to control said shock generation circuitry (103) to produce the second shock pulse (A2) by connecting, in at least one further time span (T5, T6) following said second initial time span (T4), a combination of said second group of energy storage devices of said multiplicity of energy storage devices (C1-C7) and at least one further energy storage device of said multiplicity of energy storage devices (C1-C7) to said output circuitry (105).

3. The implantable cardioverter defibrillator device (1) according to claim 1 or 2, characterized in that the second group of energy storage devices of said multiplicity of energy storage devices (C1-C7) equals a combination of said first group of energy storage devices of said multiplicity of energy storage devices (C1-C7) and at least one further energy storage device of said multiplicity of energy storage devices (C1-C7).

4. The implantable cardioverter defibrillator device (1) according to one of claims 1 to 3, characterized in that the multiplicity of energy storage devices (C1-C7) are formed by capacitors or inductors.

5. The implantable cardioverter defibrillator device (1) according to one of the preceding claims, characterized in that the arrangement of switching devices (S5-S8) is configured to selectively connect the energy storage devices (C1-C7) in series to the output circuitry.

6. The implantable cardioverter defibrillator device (1) according to one of the preceding claims, characterized in that the processing circuitry (102) is configured to control the arrangement of switching devices (S5-S8) to produce the first shock pulse (Al) by connecting the first group of energy storage devices of said multiplicity of energy storage devices (C1-C7) in series to the output circuitry (105) and to successivelyconnect at least one further energy storage device of said multiplicity of energy storage devices (C1-C7) in series to said first group.

7. The implantable cardioverter defibrillator device (1) according to one of the preceding claims, characterized in that the processing circuitry (102) is configured to control the arrangement of switching devices (S5-S8) to produce the second shock pulse (A2) by connecting the second group of energy storage devices of said multiplicity of energy storage devices (C1-C7) in series to the output circuitry (105) and to successively connect at least one further energy storage device of said multiplicity of energy storage devices (C1-C7) in series to said second group.

8. The implantable cardioverter defibrillator device (1) according to one of the preceding claims, characterized in that the second group equals a combination of the first group in series with at least one further energy storage device of said multiplicity of energy storage devices (C1-C7).

9. The implantable cardioverter defibrillator device (1) according to one of the preceding claims, characterized in that the processing circuitry (102) is configured to control said shock generation circuitry (103) to produce the first shock pulse (Al) to have a first pulse width (PW1) and to produce the second shock pulse (A2) to have a second pulse width (PW2) smaller than the first pulse width (PW1).

10. The implantable cardioverter defibrillator device (1) according to one of the preceding claims, characterized by a sensing arrangement (113, 114) comprising an arrangement of electrode poles for sensing signals indicative of cardiac activity.

11. The implantable cardioverter defibrillator device (1) according to claim 10, characterized in that the processing circuitry (102) is configured to evaluate, based on signals sensed using said sensing arrangement (113, 114), a defibrillation action achieved by said first shock pulse (Al).

12. The implantable cardioverter defibrillator device (1) according to claim 11, characterized in that the processing circuitry (102) is configured to control said shock generation circuitry (103) to produce said second shock pulse (A2) based on said evaluation of the defibrillation action achieved by said first shock pulse (Al).

13. The implantable cardioverter defibrillator device (1) according to one of the preceding claims, characterized by a lead (11) connected to the generator device (10) and carrying said shock electrode (115).

14. The implantable cardioverter defibrillator device (1) according to one of the preceding claims, characterized in that the implantable cardioverter defibrillator device (1) is a non-transvenous implantable cardioverter defibrillator device (1) device configured for implantation external to the patient’s heart (H).

15. Method for operating an implantable cardioverter defibrillator device (1) for performing a defibrillation shock therapy, the implantable cardioverter defibrillator device (1) comprising a generator device (10), having a processing circuitry (102) and a shock generation circuitry (103), and a shock electrode (115) operatively connected to the generator device (10) for emitting shock pulses, the method comprising: generating, using the shock generation circuitry (103), shock pulses for emission using the shock electrode (115), the shock generation circuitry (103) comprising a multiplicity of energy storage devices (C1-C7), an arrangement of switching devices (S5-S8) and an output circuitry (105) connected to the shock electrode (115); controlling, using the processing circuitry (102), said shock generation circuitry (103) to generate said shock pulses by selectively connecting, using the arrangement of switching devices (S5-S8), the multiplicity of energy storage devices (C1-C7) to said output circuitry (105) for delivering the shock pulses to the shock electrode (115); characterized in that said controlling includes: controlling, using the processing circuitry (102), said shock generation circuitry (103) to produce a first shock pulse (Al) at a first peak voltage (PHI) by connecting, in a first initial time span (Tl), a first group of energy storage devices of said multiplicity of energy storage devices (C1-C7) to said output circuitry (105) and, in at least one further time span (T2, T3) followingsaid first initial time span (Tl), a combination of said first group of energy storage devices of said multiplicity of energy storage devices (C1-C7) and at least one further energy storage device of said multiplicity of energy storage devices (C1-C7) to said output circuitry (105), wherein said controlling further includes: controlling, using the processing circuitry(102), said shock generation circuitry (103) to produce, subsequent to said first shock pulse (Al), a second shock pulse (A2) at a second peak voltage (PH2) larger than said first peak voltage (PH2) by connecting, in a second initial time span (T4), a second group of energy storage devices of said multiplicity of energy storage devices (C1-C7) to said output circuitry (105).

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