Method and apparatus for detecting arrhythmias in a subcutaneous medical device

• US 10,265,536 B2
• Filed: 09/20/2016
• Issued: 04/23/2019
• Est. Priority Date: 03/29/2006
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Stadler, Robert W., Ghanem, Raja N., Zhang, Xusheng
• Primary Examiner(s): Levicky, William J
• Application Number:
  US15/270,985
• Publication Number:
  US 20170007841A1
• Time in Patent Office: 945 Days
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/341 Vectorcardiography [VCG]
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/361 Detecting fibrillation
• CPC Class Codes: A61B 5/363 Detecting tachycardia or bradycardia
• CPC Class Codes: A61B 5/364 Detecting abnormal ECG interval, e.g. extrasystoles, ectopic heartbeats
• CPC Class Codes: A61B 5/4836 Diagnosis combined with treatment in closed-loop systems or methods A61B5/0036 takes precedence
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• CPC Class Codes: A61N 1/3621 for treating or preventing abnormally high heart rate
• CPC Class Codes: A61N 1/3925 Monitoring; Protecting
• CPC Class Codes: A61N 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion
• CPC Class Codes: A61N 1/3987 characterised by the timing or triggering of the shock
• CPC Class Codes: Y10S 128/901 Suppression of noise in electric signal
• CPC Class Codes: Y10S 128/902 Biological signal amplifier

Abstract

A method and system for use with an implantable medical device for subcutaneous implant within a patient to determine a likelihood of the patient experiencing a cardiac event that includes sensing a cardiac signal along a plurality of different sensing vectors, determining state information of each vector of the plurality of sensing vectors, determining a cross correlation of the determined state information of each vector of the plurality of sensing vectors, comparing the cross correlation of the determined state information of each vector of the plurality of sensing vectors to a threshold, and detecting the cardiac event in response to the comparing.

Claims

1. A system comprising:

a plurality of electrodes;

charge generation and storage circuitry configured to generate and store a charge for delivery as an anti-tachyarrhythmia shock to a patient via at least two of the plurality of electrodes;

sensing circuitry coupled to at least two of the plurality of electrodes and configured to sense, during each time period of a plurality of time periods, a first cardiac signal segment with a first sensing vector and a second cardiac signal segment with a second sensing vector; and

processing circuitry configured to;

classify each of the first cardiac signal segments and the second cardiac signal segments as shockable or not shockable;

determine a number of the first cardiac signal segments classified as shockable and a number of the second cardiac signal segments classified as shockable;

determine to deliver the anti-tachyarrhythmia shock to a patient based at least on the number of the first cardiac signal segments classified as shockable and the number of the second cardiac signal segments classified as shockable; and

control the charge generation and storage circuitry to deliver the anti-tachyarrhythmia shock to the patient in response to the determination to deliver the anti-tachyarrhythmia shock.

2. The system of claim 1, wherein the processing circuitry is further configured to classify, for each of the plurality of time periods, one of:

both the first cardiac signal segment and the second cardiac signal segment as shockable;

both the first cardiac signal segment and the second cardiac signal segment as not shockable;

or

only one of the first cardiac signal segment and the second cardiac signal segment as shockable and the other of the first cardiac signal segment and the second cardiac signal segment as not shockable.

3. The system of claim 2, wherein the processing circuitry is further configured to:

classify both the first cardiac signal segment and the second cardiac signal segment as corrupted by noise; and

classify both the first cardiac signal segment and the second cardiac signal segment as not shockable based on both the first cardiac signal segment being corrupted by noise.

4. The system of claim 2, wherein the processing circuitry is further configured to:

classify the first cardiac signal as not corrupted by noise and the second cardiac signal as corrupted by noise;

classify, based on the first cardiac signal segment not being corrupted by noise and the second cardiac signal segment being corrupted by noise, the first cardiac signal segment classified as not corrupted by noise as comprising regular RR intervals;

determine the first cardiac signal segment classified as not corrupted by noise as within a first shock zone based on classifying the first cardiac signal segment classified as not corrupted by noise as comprising regular RR intervals;

classify the first cardiac signal segment classified as not corrupted by noise as within a second shock zone, different from the first shock zone, based on classifying the first cardiac signal segment classified as not corrupted by noise as not comprising regular RR intervals; and

identify each of the first cardiac signal segment classified as not corrupted by noise and the second cardiac signal segment classified as corrupted by noise as shockable or not shockable based on the classification of the first cardiac signal segment as within the first shock zone or the classification of the first cardiac signal segment as within the second shock zone.

5. The system of claim 4, wherein the first shock zone comprises a ventricular tachycardia shock zone and the second shock zone comprises a ventricular fibrillation shock zone.

6. The system of claim 4, wherein the processing circuitry is further configured to:

identify, based on classifying the first cardiac signal segment classified as not corrupted by noise as comprising regular RR intervals and as within the first shock zone, both the first cardiac segment and the second cardiac segment as shockable; and

identify, based on classifying the first cardiac signal segment classified as not corrupted by noise as comprising regular RR intervals and as not within the first shock zone, both the first cardiac signal segment and the second cardiac signal segment as not shockable.

7. The system of claim 4, wherein the processing circuitry is further configured to:

identify, based on classifying the first cardiac signal segment classified as not corrupted by noise as not comprising regular RR intervals and as not within the second shock zone, both the first cardiac signal segment and the second cardiac signal segment as not shockable.

8. The system of claim 4, wherein the processing circuitry is further configured to:

classify, based on classifying the first cardiac signal segment classified as not corrupted by noise as not comprising regular RR intervals and as within the second shock zone, the second cardiac signal segment classified as corrupted by noise as within the second shock zone; and

identify, based on classifying the second cardiac signal segment classified as corrupted by noise as within the second shock zone, both the first cardiac signal segment and the second cardiac signal segment as shockable.

9. The system of claim 4, wherein the processing circuitry is further configured to:

classify, based on classifying the first cardiac signal segment classified as not corrupted by noise as not comprising regular RR intervals and as within the second shock zone, the second cardiac signal segment classified as corrupted by noise as within the second shock zone; and

identify, based on classifying the second cardiac signal segment classified as corrupted by noise as not within the second shock zone, the first cardiac signal segment classified as not corrupted by noise as being shockable, and the second cardiac signal segment classified as corrupted by noise as being not shockable.

10. The system of claim 2, wherein the processing circuitry is further configured to:

classify both the first cardiac signal segment and the second cardiac signal segment as not corrupted by noise;

classify, based on classifying both the first cardiac signal segment and the second cardiac signal segment as not corrupted by noise, both the first cardiac signal segment and the second cardiac signal segment as comprising regular RR intervals;

classify, based on classifying both the first cardiac signal segment and the second cardiac signal segment as comprising regular RR intervals, both the first cardiac signal segment and the second cardiac signal segment as within a first shock zone; and

classify, based on classifying both the first cardiac signal segment and the second cardiac signal segment as not comprising regular RR intervals, both the first cardiac signal segment and the second cardiac signal segment as within the second shock zone.

11. The system of claim 10, wherein the first shock zone comprises a ventricular tachycardia shock zone and the second shock zone comprises a ventricular fibrillation shock zone.

12. A non-transitory computer-readable medium storing a set of instructions which cause a processor to perform a method comprising:

sensing, during each time period of a plurality of time periods, a first cardiac signal segment with first sensing vector and a second cardiac signal segment with a second sending vector;

classifying each of the first cardiac signal segments and the second cardiac signal segments as shockable or not shockable;

determining a number of the first cardiac signal segments classified as shockable and a number of the second cardiac signal segments classified as shockable;

determining to deliver an anti-tachyarrhythmia shock to a patient based at least on the number of the first cardiac signal segments classified as shockable and the number of the second cardiac signal segments classified as shockable; and

controlling delivery of the anti-tachyarrhythmia shock to the patient via one or more electrodes.

13. The computer-readable medium of claim 12, wherein classifying each of the first cardiac signal segments and the second cardiac signal segments as shockable comprises, for each of the plurality of periods, one of:

classifying both the first cardiac signal segment and the second cardiac signal segment as shockable;

classifying both the first cardiac signal segment and the second cardiac signal segment as not shockable;

or

classifying only one of the first cardiac signal segment and the second cardiac signal segment as shockable and the other of the first cardiac signal segment and the second cardiac signal segment as not shockable.

14. A method comprising:

sensing, during each time period of a plurality of time periods, a first cardiac signal segment with a first sensing vector and a second cardiac signal segment with a second sensing vector;

classifying each of the first cardiac signal segments and the second cardiac signal segments as shockable or not shockable;

determining a number of the first cardiac signal segments classified as shockable and a number of the second cardiac signal segments classified as shockable;

determining to deliver an anti-tachyarrhythmia shock to a patient based at least on the number of the first cardiac signal segments classified as shockable and the number of the second cardiac signal segments classified as shockable; and

delivering the anti-tachyarrhythmia shock to the patient via one or more electrodes in response to the determination to deliver the anti-tachyarrhythmia shock.

15. The method of claim 14, wherein classifying each of the first cardiac signal segments and the second cardiac signal segments as shockable or not shockable comprises, for each of the plurality of time periods, one of:

classifying both the first cardiac signal segment and the second cardiac signal segment as shockable;

classifying both the first cardiac signal segment and the second cardiac signal segment as not shockable;

or

classifying only one of the first cardiac signal segment and the second cardiac signal segment as shockable, and the other of the first cardiac signal segment and the second cardiac signal segment sensing vector as not shockable.

16. The method of claim 15, further comprising classifying both the first cardiac signal segment and the second cardiac signal segment as corrupted by noise, wherein classifying both the first cardiac signal segment and the second cardiac signal segment as not shockable comprises classifying both the first cardiac signal segment and the second cardiac signal segment as not shockable based on both the first cardiac signal segment and the second cardiac signal segment being corrupted by noise.

17. The method of claim 15, further comprising:

classifying the first cardiac signal segment as not corrupted by noise and the second cardiac signal segment as corrupted by noise;

classifying, based on the first cardiac signal segment not being corrupted by noise and the second cardiac signal segment being corrupted by noise, the first cardiac signal segment classified as not corrupted by noise as comprising regular RR intervals;

classifying the first cardiac signal segment classified as not corrupted by noise as within a first shock zone based on classifying the first cardiac signal segment classified as not corrupted by noise as comprising regular RR intervals;

classifying the first cardiac signal segment classified as not corrupted by noise as within a second shock zone, different from the first shock zone, based on classifying the first cardiac signal segment classified as not corrupted by noise as not comprising regular RR intervals; and

identifying each of the first cardiac signal segment classified as not corrupted by noise and the second cardiac signal segment classified as corrupted by noise as shockable or not shockable based on the classification of the first cardiac signal segment as within the first shock zone or the classification of the first cardiac signal segment as within the second shock zone.

18. The method of claim 17, wherein the first shock zone comprises a ventricular tachycardia shock zone and the second shock zone comprises a ventricular fibrillation shock zone.

19. The method of claim 17, further comprising:

identifying, based on classifying the first cardiac signal segment classified as not corrupted by noise as comprising regular RR intervals and as within the first shock zone, both the first cardiac signal segment and the second cardiac signal segment as shockable; and

identifying, based on classifying the first cardiac signal segment classified as not corrupted by noise as comprising regular RR intervals and as not within the first shock zone, both the first cardiac signal segment and the second cardiac signal segment each as not shockable.

20. The method of claim 17, further comprising:

identifying, based on classifying the first cardiac signal segment classified as not corrupted by noise as not comprising regular RR intervals and as not within the second shock zone, both the first cardiac signal segment and the second cardiac signal segment as not shockable.

21. The method of claim 17, further comprising:

classifying, based on classifying the first cardiac signal segment classified as not corrupted by noise as not comprising regular RR intervals and as within the second shock zone, the second cardiac signal segment classified as corrupted by noise as within the second shock zone; and

identifying, based on classifying the second cardiac signal segment classified as corrupted by noise as within the second shock zone, both the first cardiac signal segment and the second cardiac signal segment as shockable.

22. The method of claim 17, further comprising:

classifying, based on classifying the first cardiac signal segment classified as not corrupted by noise as not comprising regular RR intervals and as within the second shock zone, the second cardiac signal segment classified as corrupted by noise as within the second shock zone; and

identifying, based on classifying the second cardiac signal segment classified as corrupted by noise as not within the second shock zone, the first cardiac signal segment classified as not corrupted by noise as being shockable, and the second cardiac signal segment classified as corrupted by noise as being not shockable.

23. The method of claim 15, further comprising:

classifying both the first cardiac signal segment and the second cardiac signal segment as not corrupted by noise;

classifying, based on classifying both the first cardiac signal segment and the second cardiac signal segment as not corrupted by noise, both the first cardiac signal segment and the second cardiac signal segment as comprising regular RR intervals;

classifying, based on classifying both the first cardiac signal segment and the second cardiac signal segment as comprising regular RR intervals, the first cardiac signal segment and the second cardiac signal segment as within a first shock zone; and

classifying, based on classifying both the first cardiac signal segment and the second cardiac signal segment as not comprising regular RR intervals, both the first cardiac signal segment and the second cardiac signal segment as within a second shock zone different from the first shock zone.

24. The method of claim 23, wherein the first shock zone comprises a ventricular tachycardia shock zone and the second shock zone comprises a ventricular fibrillation shock zone.

25. The method of claim 14, wherein delivering the anti-tachyarrhythmia shock to the patient via one or more electrodes in response to the determination to deliver the anti-tachyarrhythmia shock comprises:

determining the number of the first cardiac segments classified as shockable and the number of the second cardiac segments classified as shockable each satisfy a threshold value

controlling a medical device to deliver the anti-tachyarrhythmia shock to the patient in response to the determination that both the number of the first cardiac signal segments classified as shockable and the number of the second cardiac signal segments classified as shockable each satisfy a threshold value.