Fault Tolerant System for an Implantable Cardioverter Defibrillator or Pulse Generator

• US 20120197330A1
• Filed: 01/27/2011
• Published: 08/02/2012
• Est. Priority Date: 01/27/2011
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Crutchfield, Randolph E., Cabelka, Lonny V.
• Granted Patent: US 9,061,163 B2
• Time in Patent Office: Days
• US Class Current: 607/7
• CPC Class Codes: A61N 1/3684 for stimulating the heart at multiple sites of the ventricle or the atrium
• CPC Class Codes: A61N 1/36842 Multi-site stimulation in the same chamber
• CPC Class Codes: A61N 1/36843 Bi-ventricular stimulation
• CPC Class Codes: A61N 1/3686 configured for selecting the electrode configuration on a lead A61N1/3688 takes precedence
• CPC Class Codes: A61N 1/3782 producing a voltage above the power source level
• CPC Class Codes: A61N 1/3931 Protecting, e.g. back-up systems
• CPC Class Codes: A61N 1/39622 Pacing therapy
• CPC Class Codes: A61N 1/3981 High voltage charging circuitry

Abstract

The disclosure describes circuits for providing therapy in an implantable medical device. The illustrative circuits include features that provide fault tolerance with graceful degradation as well as switching control methods that reduce component count and improves reliability.

Claims

1. An implantable medical device having a fault tolerant circuit for controlling delivery of a stimulus therapy signal, comprising:

a stimulus therapy generator for generating the stimulus therapy signal;

a therapy output circuit coupled to the stimulus therapy generator having;

a plurality of therapy output channels for coupling of said stimulus therapy signal to a patient;

a first switching array coupled to the plurality of therapy output channels, wherein one of the switches in the first switching array is controlled to couple one of the plurality of therapy output channels to the stimulus therapy generator; and

fault detection circuitry coupled to the therapy output circuit for generating a trigger signal to control the coupling between the plurality of therapy output channels and the stimulus therapy generator.

2. The implantable medical device of claim 1, wherein the therapy output circuit includes a plurality of hold capacitors and a plurality of tip capacitors.

3. The implantable medical device of claim 2, wherein the first switching array is operable to selectively couple one of the plurality of hold capacitors to one of the plurality of tip capacitors to define one of said therapy output channels.

4. The implantable medical device of claim 3, wherein the first switching array selectively couples one of the plurality of hold capacitors to one of the plurality of tip capacitors in response to the trigger signal generated by the fault detection circuitry.

5. The implantable medical device of claim 2, wherein the fault detection circuitry is operable to monitor the integrity of each of the hold capacitors and the tip capacitors.

6. The implantable medical device of claim 1, wherein the fault detection circuitry is operable to monitor the integrity of a component of the therapy output circuit.

7. The implantable medical device of claim 6, wherein the trigger signal is generated by the fault detection circuitry in response to failure of one of the components of the therapy output circuit.

8. The implantable medical device of claim 6, further comprising an alarm for generating a notification in response to detection of an abnormality of the monitored component, wherein the alarm is selected from the group consisting of a tactile signal, a vibratory signal, and an auditory signal.

9. The implantable medical device of claim 6, further comprising means for transmitting a notification to an external device in response to detecting an abnormality of the monitored component.

10. The implantable medical device of claim 2, wherein the fault detection circuitry further comprises:

means for charging one of the plurality of hold and tip capacitors; and

means for measuring a voltage across the charged hold or tip capacitor over a predetermined period of time.

11. The implantable medical device of claim 1, further comprising:

a second switching array disposed within the therapy output circuit; and

a plurality of leads coupled to the second switching array, the second switching array being operable to control the coupling of one of the plurality of leads to the therapy output channels.

12. The implantable medical device of claim 11, further comprising:

a third switching array coupled to the second switching array; and

a plurality of electrodes coupled to the third switching array, the third switching array being operable to control the coupling of one of the plurality of electrodes to the second switching array.

13. The implantable medical device of claim 12, wherein the third switching array comprises:

a plurality of transistors coupled to one of the plurality of electrodes; and

control circuitry coupled to the plurality of transistors, the control circuitry being operable to activate at least one of the plurality of transistors.

14. The implantable medical device of claim 12, wherein the third switching array is operable to control the coupling of the second switching array to at least two of the plurality of electrodes to define one or more pacing vectors.

15. An implantable medical device system, comprising

means for generating a stimulus therapy;

a therapy output circuit having a plurality of therapy output channels, the circuit being connected to the stimulus therapy generating means;

means for coupling one of the plurality of therapy output channels to the stimulus therapy generating means; and

means for detecting a fault in a component of the therapy output circuit and generating a trigger signal to control the coupling means.

16. The implantable medical device system of claim 15, further comprising means for generating an alarm in response to detection of the component failure.

17. The implantable medical device system of claim 15, wherein the plurality of therapy output channels are arranged to perform the same or similar function.

18. The implantable medical device system of claim 15, wherein the therapy output circuit comprises a plurality of hold capacitors and a plurality of tip capacitors.

19. The implantable medical device system of claim 18, wherein each of the plurality of therapy output channels includes a first hold capacitor selected from the plurality of hold capacitors and a first tip capacitor selected from the plurality of tip capacitors.

20. The implantable medical device system of claim 19, wherein the coupling means includes a plurality of switching arrays.

21. The implantable medical device system of claim 20, wherein the coupling of the first hold capacitor to the first tip capacitor comprises actuating one or more switches of one or more of the switching arrays.

22. A method comprising:

providing a plurality of hold capacitors and a plurality of tip capacitors;

selecting a first hold capacitor from the plurality of hold capacitors;

selecting a first tip capacitor from the plurality of tip capacitors;

coupling the first hold capacitor to the first tip capacitor; and

performing a test of the integrity of the plurality of hold capacitors and the plurality of tip capacitors to detect a failure.

23. The method of claim 22, further comprising switching the selection of the first hold capacitor to select a second hold capacitor in response to detection of a failure of the first hold capacitor and coupling the second hold capacitor to the first tip capacitor.

24. The method of claim 22, further comprising switching the selection of the first tip capacitor to select a second tip capacitor in response to detection of a failure of the first tip capacitor and coupling the first hold capacitor to the second tip capacitor.

25. The method of claim 22, further comprising providing a notification in response to detection of the failure.

26. The method of claim 22, further comprising coupling an energy delivery source to the first hold capacitor for delivery of a therapy to a patient through the first tip capacitor.

27. The method of claim 22, further comprising decoupling the first hold capacitor from the first tip capacitor in response to detection of the failure and directly coupling the first tip capacitor to the energy delivery source.

28. The method of claim 22, wherein the first tip capacitor is coupled to an electrode for delivery of a therapy to a patient.