SHORT CIRCUIT FAULT-TOLERANCE IN AN IMPLANTABLE MEDICAL DEVICE

• US 20130053911A1
• Filed: 08/30/2011
• Published: 02/28/2013
• Est. Priority Date: 08/30/2011
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Hareland, Scott A.
• Granted Patent: US 8,626,287 B2
• Time in Patent Office: Days
• US Class Current: 607/6
• CPC Class Codes: A61N 1/3918 characterised by shock pathway, e.g. by electrode configuration
• CPC Class Codes: A61N 1/3931 Protecting, e.g. back-up systems
• CPC Class Codes: A61N 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion

Abstract

A device includes an energy storage device, a plurality of electrodes, a memory, a switching circuit, and a processing module. The energy storage device stores electrical energy for delivery of defibrillation therapy to a heart. The memory stores N therapy configurations that define which of the plurality of electrodes are used to deliver defibrillation therapy and a waveform to be applied during delivery of defibrillation therapy. The switching circuit connects the plurality of electrodes to the energy storage device. The processing module controls the switching circuit to deliver defibrillation therapy according to a first therapy configuration of the N therapy configurations, detects a short circuit fault during delivery of the defibrillation therapy according to the first therapy configuration, and selects a second therapy configuration of the N therapy configurations based on when the short circuit fault was detected during delivery of the defibrillation therapy according to the first therapy configuration.

Claims

1. A medical device comprising:

an energy storage device configured to store electrical energy for delivery of defibrillation therapy to a heart;

a plurality of electrodes;

a memory that stores N therapy configurations, each of the N therapy configurations defining which of the plurality of electrodes are used to deliver defibrillation therapy and further defining a waveform to be applied during delivery of defibrillation therapy, wherein N is an integer that is greater than 1;

a switching circuit configured to connect the plurality of electrodes to the energy storage device; and

a processing module configured to;

control the switching circuit to deliver defibrillation therapy according to a first therapy configuration of the N therapy configurations;

detect a short circuit fault during delivery of the defibrillation therapy according to the first therapy configuration; and

select a second therapy configuration of the N therapy configurations based on when the short circuit fault was detected during delivery of the defibrillation therapy according to the first therapy configuration.

2. The medical device of claim 1, wherein the plurality of electrodes are coupled to the switching circuit using conductors, and wherein the short circuit fault includes a short circuit between the conductors.

3. The medical device of claim 1, wherein the short circuit fault includes a short circuit between at least two of the plurality of electrodes.

4. The medical device of claim 1, wherein the plurality of electrodes are coupled to the switching circuit using conductors, and wherein the short circuit fault includes a short circuit between one of the conductors and one of the plurality of electrodes.

5. The medical device of claim 1, wherein the switching circuit includes a plurality of switches, wherein the processing module is configured to instruct one of the plurality of switches to remain open during delivery of defibrillation therapy according to the first therapy configuration, and wherein the short circuit fault includes a malfunction in the one of the plurality of switches that causes the one of the plurality of switches to present a short circuit impedance when instructed to remain open.

6. The medical device of claim 1, wherein the processing module is configured to detect the short circuit fault based on an amount of current delivered by the energy storage device during delivery of defibrillation therapy according to the first therapy configuration.

7. The medical device of claim 1, wherein the first therapy configuration specifies the delivery of defibrillation therapy using a biphasic waveform, and wherein the second therapy configuration specifies the delivery of defibrillation therapy using a monophasic waveform.

8. The medical device of claim 1, wherein the first therapy configuration specifies the delivery of defibrillation therapy using a monophasic waveform, and wherein the second therapy configuration specifies the delivery of defibrillation therapy using a biphasic waveform.

9. The medical device of claim 1, wherein the first therapy configuration specifies the delivery of defibrillation therapy using three electrodes, and wherein the second therapy configuration specifies the delivery of defibrillation therapy using only two electrodes.

10. The medical device of claim 1, wherein the first therapy configuration specifies the delivery of defibrillation therapy using only two electrodes, and wherein the second therapy configuration specifies the delivery of defibrillation therapy using three electrodes.

11. The medical device of claim 1, wherein the waveform defined by each of the N therapy configurations includes one of a monophasic waveform or a biphasic waveform, wherein the biphasic waveform includes a first phase and a second phase, and wherein the processing module is configured to select the second therapy configuration based on which of the first and second phases included the short circuit fault.

12. The medical device of claim 1, wherein each of the N therapy configurations is associated with corresponding transition data that specifies one or more subsequent therapy configurations of the N therapy configurations to be selected by the processing module in the case that the processing module detects a fault.

13. The medical device of claim 12, wherein the processing module is configured to select the second therapy configuration based on the transition data associated with the first therapy configuration when the processing module detects the short circuit fault during delivery of the defibrillation therapy according to the first therapy configuration.

14. A medical device comprising:

an energy storage device configured to store electrical energy for delivery of defibrillation therapy to a heart;

a plurality of electrodes;

a switching circuit configured to connect the plurality of electrodes to the energy storage device; and

a processing module configured to;

control the switching circuit to deliver defibrillation therapy using a first set of the plurality of electrodes and using a biphasic waveform that includes first and second phases;

detect a short circuit fault during one of the first and second phases of the biphasic waveform; and

select a second set of the plurality of electrodes and one of a biphasic or monophasic waveform for delivery of a subsequent defibrillation therapy, wherein the selection is based on which one of the first and second phases of the biphasic waveform included the detected short circuit fault.

15. The medical device of claim 14, wherein the plurality of electrodes are coupled to the switching circuit using conductors, and wherein the short circuit fault includes a short circuit between the conductors.

16. The medical device of claim 14, wherein the short circuit fault includes a short circuit between at least two of the plurality of electrodes.

17. The medical device of claim 14, wherein the plurality of electrodes are coupled to the switching circuit using conductors, and wherein the short circuit fault includes a short circuit between one of the conductors and one of the plurality of electrodes.

18. The medical device of claim 14, wherein the switching circuit includes a plurality of switches, wherein the processing module is configured to instruct one of the plurality of switches to remain open during delivery of defibrillation therapy using the first set of the plurality of electrodes, and wherein the short circuit fault includes a malfunction in the one of the plurality of switches that causes the one of the plurality of switches to present a short circuit impedance when instructed to remain open.

19. The medical device of claim 14, wherein the processing module is configured to control the switching circuit to deliver defibrillation therapy according to the second set of the plurality of electrodes and the selected one of the biphasic or monophasic waveforms.

20. The medical device of claim 14, wherein the second set of the plurality of electrodes is the same as the first set of the plurality of electrodes.

21. The medical device of claim 14, wherein the first set of the plurality of electrodes includes three electrodes, and wherein the second set of the plurality of electrodes includes only two electrodes.

22. The medical device of claim 14, wherein the first set of the plurality of electrodes includes only two electrodes, and wherein the second set of the plurality of electrodes includes three electrodes.

23. The medical device of claim 14, wherein the first set of the plurality of electrodes includes three electrodes, and wherein the second set of the plurality of electrodes includes three electrodes.

24. The medical device of claim 14, wherein the fault is a short circuit path that shunts current away from the heart during delivery of defibrillation therapy.

25. A method comprising:

storing N therapy configurations in a memory of a medical device, each of the N therapy configurations defining which of a plurality of electrodes are used to deliver defibrillation therapy and further defining a waveform to be applied during delivery of defibrillation therapy, wherein N is an integer that is greater than 1;

controlling a switching circuit to deliver defibrillation therapy from an energy storage device according to a first therapy configuration of the N therapy configurations;

detecting a short circuit fault during delivery of the defibrillation therapy according to the first therapy configuration; and

selecting a second therapy configuration of the N therapy configurations based on when the short circuit fault was detected during delivery of the defibrillation therapy according to the first therapy configuration.

26. The method of claim 25, wherein the switching circuit includes a plurality of switches, wherein the plurality of electrodes are coupled to the switching circuit using conductors, and wherein the short circuit fault includes at least one of a short circuit between the conductors, a short circuit between at least two of the plurality of electrodes, a short circuit between one of the conductors and one of the plurality of electrodes, and a short circuit in one of the plurality of the switches.