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1. WO2020142254 - METHOD AND DEVICE FOR DELIVERING MULTI-PHASE DEFIBRILLATION THERAPY

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[ EN ]

WHAT IS CLAIMED IS:

1 . A method, comprising:

sensing cardiac events of a heart;

utilizing one or more processors to perform:

declaring a ventricular fibrillation (VF) episode based on the cardiac events; charging a single charge storage capacitor;

delivering a multi-phase VF therapy that includes phase I and phase II therapies, wherein:

a) during the phase I therapy, a combination of two or more medium voltage (MV) shocks are delivered entirely from the single charge storage capacitor; and

b) during the phase II therapy, a low voltage pulse train is delivered at least partially from the single charge storage capacitor.

2. The method of claim 1 , wherein the multi-phase VF therapy further includes a phase III therapy and the delivering further comprises c) delivering pacing pulses during the phase III therapy.

3. The method of claim 1 , wherein an entirety of the phase I therapy is delivered from the single charge storage capacitor based on a single charge of the single charge storage capacitor.

4. The method of claim 1 , wherein the MV shock represents at least one of:

i) a defibrillation stimulus delivered at a select energy level that is at least one of i) no more than 25J or ii) has a maximum voltage of no more than 500V; or ii) a defibrillation stimulus delivered at a select energy level that is at least one of i) between 15J-25J or ii) has a maximum voltage of between 100V-475V.

5. The method of claim 1 , further comprising:

charging the single capacitor to a full voltage of between 400 V - 475 V; during the phase I therapy, delivering the combination of two or more MV shocks at first and second voltage levels, respectively, below the full voltage, such that the single capacitor retains a post phase I voltage following an end of the phase I therapy; and

delivering the low voltage pulse train at a low-voltage below the post phase I voltage.

6. The method of claim 1 , further comprising:

charging the single capacitor to a full charge of no more than 25 J;

managing an energy discharge from the single capacitor during the phase I therapy to retain a select post-phase I residual charge; and

during the phase II therapy delivering the low voltage pulse train utilizing the post-phase I residual charge, followed by pacing pulses.

7. The method of claim 1 , wherein the two or more MV shocks includes successive first and second MV shocks and the managing the energy discharge further comprises managing a trailing-edge voltage of the first MV shock to be substantially the same as a leading-edge voltage of the second MV shocks.

8. The method of claim 7, wherein the first and second MV shocks are delivered from the single charge storage capacitor during a single charge operation, without recharging the single charge storage capacitor between the first and second MV shocks.

9. An implantable medical device, comprising:

electrodes configured to sense cardiac events;

a battery and a single charge storage capacitor;

one or more processors configured to:

declare a ventricular fibrillation (VF) episode based on the cardiac events;

charge a single charge storage capacitor utilizing the battery;

deliver a multi-phase VF therapy that includes phase I and II therapies, wherein:

a) during the phase I therapy, a combination of two or more medium voltage (MV) shocks are delivered entirely from the single charge storage capacitor; and

b) during the phase II therapy, a low voltage pulse train is delivered at least partially from the single charge storage capacitor.

10. The device of claim 9, wherein the one or more processors are further configured to deliver, as part of the multi-phase VF therapy, a phase III therapy that includes pacing pulses.

11. The device of claim 9, wherein an entirety of the phase I is delivered from the single charge storage capacitor based on a single charge of the single charge storage capacitor.

12. The device of claim 9, wherein the MV shock represents at least one of:

i) a defibrillation stimulus delivered at a select energy level that is at least one of i) no more than 25J or ii) has a maximum voltage of no more than 500V; or ii) a defibrillation stimulus delivered at a select energy level that is at least one of i) between 15J-25J or ii) has a maximum voltage of between 100V-475V.

13. The device of claim 9, wherein the one or more processors are further configured to:

charge the single capacitor to a full voltage of between 400 V - 475 V;

during the phase I therapy, deliver the combination of two or more MV shocks at first and second voltage levels, respectively, below the full voltage, such that the single capacitor retains a post phase I voltage following an end of the phase I therapy; and

deliver the low voltage pulse train at a low-voltage below the post phase I voltage.

14. The device of claim 9, wherein the one or more processors are further configured to:

charge the single capacitor to a full charge of no more than 25 J;

manage an energy discharge from the single capacitor during the phase I therapy to retain a select post-phase I residual charge; and

during the phase II therapy, deliver the low voltage pulse train utilizing the post-phase I residual charge, followed by pacing pulses.

15. The device of claim 9, wherein the one or more processors are further configured to, after delivery of the phase I therapy and before delivery of the phase II therapy:

sense additional cardiac events; and when the additional cardiac events indicate that the VF episode has been terminated by the phase I therapy, suspend or cancel the phase II therapy before delivering the phase II therapy.

16. An output control system for use in an implantable medical device, comprising:

an output configured to be connected to a lead;

a charging circuit;

a capacitor switchably coupled to the charging circuit;

a switching circuit coupled between the capacitor and the output;

an output control circuit configured to generate a control signal that includes control pulses that control the switching circuit to switchably connect the capacitor to the output, the output control circuit configured to vary a duty cycle of the control pulses in a manner that defines a shape of an effective waveform for one or more shocks.

17. The output control system of Claim 16, wherein the shape of the effective waveform includes a positive phase segment that is defined by a collection of the control pulses, in which the duty cycle varies such that an initial portion of the collection includes a first duty cycle and a final portion of the collection includes a second duty cycle that is longer than the first duty cycle.

18. The output control system of claim 17, wherein the output control circuit is configured to vary the first and second duty cycles to define a leading edge profile having an ascending non-linear shape that transitions from a low voltage to a high voltage, and a steady-state profile at the high voltage for a duration of the positive phase segment.

19. The output control system of claim 16, wherein the output control circuit is configured to increase the duty cycle of the successive control pulses from an initial shorter duty cycle to a final longer duty cycle.

20. The output control system of claim 16, wherein the capacitor is configured to store a full charge with a voltage of at least 400V, and the output control circuit is configured to vary the duty cycle of the control pulses to define the effective waveform of a first shock to have a voltage of less than 300V.

21 . The output control system of claim 16, wherein the capacitor represents a single charge storage capacitor that is configured to store a full charge with a voltage of no more than 500V, and the output control circuit is configured to vary the duty cycle of the control pulses to define the effective

waveform for first and second shocks to be delivered from the single charge storage capacitor based on a single charge of the single charge storage capacitor.

22. The output control system of claim 16, wherein the capacitor represents a single charge storage capacitor that is configured to store a full charge with a voltage of no more than 500V, and the output control circuit is configured to vary the duty cycle of the control pulses to deliver a multi-phase VF therapy that includes first and second phase therapies, wherein:

a) during the first phase therapy, a combination of two or more medium voltage (MV) shocks are delivered entirely from the single charge storage capacitor; and

b) during the second phase therapy, a low voltage pulse train is delivered at least partially from the single charge storage capacitor.

23. An implantable medical device, comprising:

electrodes configured to sense cardiac events;

a charging circuit;

a capacitor switchably coupled to the charging circuit;

a switching circuit coupled between the capacitor and the output;

an output control circuit configured to generate a control signal that includes control pulses that control the switching circuit to switchably connect the capacitor to the electrodes, the output control circuit configured to vary a duty cycle of the control pulses in a manner that defines a shape of an effective waveform for one or more shocks.

24. The device of claim 23, wherein the shape of the effective waveform includes a positive phase segment that is defined by a collection of the control pulses, in which the duty cycle varies such that an initial portion of the collection includes a first duty cycle and a final portion of the collection includes a second duty cycle that is longer than the first duty cycle.

25. The device of claim 23, wherein the output control circuit is configured to linearly increase the duty cycle of the successive control pulses from an initial shorter duty cycle to a final longer duty cycle.

26. The device of claim 23, wherein the capacitor is configured to store a full charge with a voltage of at least 400V, and the output control circuit is configured to vary the duty cycle of the control pulses to define the effective waveform of a first shock to have a voltage of less than 300V.

27. The device of claim 23, wherein the capacitor represents a single charge storage capacitor that is configured to store a full charge with a voltage of no more than 500V, and the output control circuit is configured to vary the duty cycle of the control pulses to define the effective waveform for first and second shocks to be delivered from the single charge storage capacitor based on a single charge of the single charge storage capacitor.

28. The device of claim 23, wherein the capacitor represents a single charge storage capacitor that is configured to store a full charge with a voltage of no more than 500V, and the output control circuit is configured to vary the duty cycle of the control pulses to deliver a multi-phase VF therapy that includes first and second phase therapies, wherein:

a) during the first phase therapy, a combination of two or more medium voltage (MV) shocks are delivered entirely from the single charge storage capacitor; and

b) during the second phase therapy, a low voltage pulse train is delivered at least partially from the single charge storage capacitor.

29. The device of claim 23, wherein the output control circuit is configured to vary the first and second duty cycles to define a leading edge profile having an ascending non-linear shape that transitions from a low voltage to a high voltage, and a steady-state profile at the high voltage for a duration of the positive phase segment.

30. A method, comprising:

sensing cardiac events of a heart;

utilizing one or more processors to declare a ventricular fibrillation (VF) episode based on the cardiac events and initiate charge of a capacitor based on the declaration of the VF episode;

switchably connect the capacitor to the output based on a control signal; generate the control signal to includes control pulses having a duty cycle; varying the duty cycle of the control pulses in a manner that defines a shape of an effective waveform for one or more shocks.

31 . The method of claim 30, further comprising utilizing a collection of the control pulses to define the shape of the effective waveform to include a positive phase segment, in which the duty cycle varies such that an initial portion of the collection includes a first duty cycle and a final portion of the collection includes a second duty cycle that is longer than the first duty cycle.

32. The method of claim 30, further comprising varying the first and second duty cycles to define a leading edge profile having an ascending non-linear shape that transitions from a low voltage to a high voltage, and a steady-state profile at the high voltage for a duration of the positive phase segment.

33. The method of claim 30, further comprising storing a full charge on the capacitor with a voltage of at least 400V, and varying the duty cycle of the control pulses to define the effective waveform of a first shock to have a voltage of less than 300V.

34. The method of claim 30, wherein the capacitor represents a single charge storage capacitor that is configured to store a full charge with a voltage of no more than 500V, and the output control circuit is configured to vary the duty cycle of the control pulses to define the effective waveform for first and second shocks to be delivered from the single charge storage capacitor based on a single charge of the single charge storage capacitor.

35. The method of claim 30, further comprising storing a full charge of the capacitor in a single charge storage capacitor with a voltage of no more than 500V, and varying the duty cycle of the control pulses to deliver a multi-phase VF therapy that includes first and second phase therapies, wherein:

a) during the first phase therapy, a combination of two or more medium voltage (MV) shocks are delivered entirely from the single charge storage capacitor; and

b) during the second phase therapy, a low voltage pulse train is delivered at least partially from the single charge storage capacitor.

36. The method of claim 30, further comprising increasing the duty cycle of the successive control pulses from an initial shorter duty cycle to a final longer duty cycle.

37. An implantable medical device, comprising:

electrodes configured to sense cardiac events;

a charging circuit;

a reconfigurable capacitor bank that includes capacitors;

a switching circuit coupled between the reconfigurable capacitor bank and the output; and

a parallel/series reconfiguration (PSR) circuit that interconnects the capacitors in parallel and series configurations, the PSR circuit configured to switch between the parallel and series configurations during delivery of a shock to define an ascending stepped waveform.

38. The device of claim 37, wherein the shape of the ascending stepped waveform includes a positive phase segment that includes first and second waveform segments that are defined by the parallel and series configurations, respectively, of the capacitors.

39. The device of claim 37, wherein the ascending stepped waveform represents a biphasic waveform, the PSR circuit configured to connect the capacitors in the parallel configuration during the discharge of a first portion of a positive phase of the biphasic waveform, the PSR circuit configured to switch the capacitors from the parallel configuration to the series configuration during the discharge of a second portion of the positive phase of the biphasic waveform.

40. The device of claim 39, wherein the PSR circuit is configured to switch the capacitors from the series configuration back to the parallel configuration during the discharge of a negative phase of the biphasic waveform.

41 . The device of claim 37, wherein the PSR circuit is configured to switch the capacitors from the parallel configuration, to the series configuration and back to the parallel configuration at intermediate points during discharge of the shock.

42. The device of claim 37, wherein the reconfigurable capacitor bank includes first and second capacitors, each of which has an individual capacitance value of between 55 pF and 220 pF, the PSR circuit switching an effective capacitance of the reconfigurable capacitor bank between 27.5 pF and 440 pF when switching between the series configuration and the parallel configuration, respectively.

43. The device of claim 37, further comprising an output control circuit configured to generate a control signal that includes control pulses that control the switching circuit to switchably connect the configurable capacitor bank to the electrodes, the output control circuit configured to vary a duty cycle of the control pulses in a manner that defines a shape of one or more of first, second or third waveform segments of the shock.

44. A method, comprising:

sensing cardiac events of a heart;

utilizing one or more processors to declare a ventricular fibrillation (VF) episode based on the cardiac events and initiate charge of a reconfigurable capacitor bank based on the declaration of the VF episode;

switchably connect capacitor of the reconfigurable capacitor bank to the output to deliver a shock; and

during delivery of the shock, connecting the capacitors in a parallel configuration and switching from the parallel configuration to a series configuration to define an ascending stepped waveform for the shock.

45. The method of claim 44, wherein the shape of the ascending stepped waveform includes a positive phase segment that includes first and second waveform segments that are defined by the parallel and series configurations, respectively, of the capacitors.

46. The method of claim 44, wherein the ascending stepped waveform represents a biphasic waveform, the connecting further including connecting the capacitors in the parallel configuration during the discharge of a first portion of a positive phase of the biphasic waveform, and switching the capacitors from the parallel configuration to the series configuration during the discharge of a second portion of the positive phase of the biphasic waveform.

47. The method of claim 46, further comprising switching the capacitors from the series configuration back to the parallel configuration during the discharge of a negative phase of the biphasic waveform.

48. The method of claim 44 wherein the connecting comprises switching the capacitors from the parallel configuration, to the series configuration and back to the parallel configuration at intermediate points during the discharge of the shock.

49. The method of claim 44, further comprising generating a control signal that includes control pulses that control a switching circuit to switchably connect the configurable capacitor bank to the electrodes, the circuit signal varying a duty cycle of the control pulses in a manner that defines a shape of one or more of first, second or third waveform segments of the shock.