METHOD AND APPARATUS FOR DETECTING ARRHYTHMIAS IN A SUBCUTANEOUS MEDICAL DEVICE

• US 20190314637A1
• Filed: 04/22/2019
• Published: 10/17/2019
• 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
• Granted Patent: US 11,291,849 B2
• Time in Patent Office: 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 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;

determining whether each of the first cardiac signal segments and the second cardiac signal segments is shockable or not shockable; and

determining whether to deliver an anti-tachyarrhythmia shock to a patient based on a number of the first cardiac signal segments determined to be shockable and a number of the second cardiac signal segments determined to be shockable.

2. The method of claim 1, wherein determining whether each of the first cardiac signal segments and the second cardiac signal segments is shockable or not shockable comprises, for each of the plurality of time periods, one of:

determining that both the first cardiac signal segment and the second cardiac signal segment are shockable;

determining that both the first cardiac signal segment and the second cardiac signal segment are not shockable;

or

determining that only one of the first cardiac signal segment and the second cardiac signal segment is shockable, and the other of the first cardiac signal segment and the second cardiac signal segment sensing vector is not shockable.

3. The method of claim 2, further comprising determining that both the first cardiac signal segment and the second cardiac signal segment are corrupted by noise, wherein determining that both the first cardiac signal segment and the second cardiac signal segment are not shockable comprises determining that both the first cardiac signal segment and the second cardiac signal segment are not shockable based on both the first cardiac signal segment and the second cardiac signal segment being corrupted by noise.

4. The method of claim 2, further comprising:

determining that the first cardiac signal segment is not corrupted by noise and the second cardiac signal segment is corrupted by noise;

determining, based on the first cardiac signal segment not being corrupted by noise and the second cardiac signal segment being corrupted by noise, whether the first cardiac signal segment determined not to be corrupted by noise comprises regular RR intervals;

determining whether the first cardiac signal segment determined not to be corrupted by noise is within a first shock zone based on determining that the first cardiac signal segment determined not to be corrupted by noise comprises regular RR intervals;

determining whether the first cardiac signal segment determined not to be corrupted by noise is within a second shock zone, different from the first shock zone, based on determining that the first cardiac signal segment determined not to be corrupted by noise does not comprise regular RR intervals; and

identifying each of the first cardiac signal segment determined not to be corrupted by noise and the second cardiac signal segment determined to be corrupted by noise as shockable or not shockable based on the determination of whether the first cardiac signal segment is within the first shock zone or the determination of whether the first cardiac signal segment is within the second shock zone.

5. The method 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 method of claim 4, further comprising:

identifying, based on determining that the first cardiac signal segment determined not to be corrupted by noise comprises regular RR intervals and is within the first shock zone, both the first cardiac signal segment and the second cardiac signal segment as shockable; and

identifying, based on determining that the first cardiac signal segment determined not to be corrupted by noise comprises regular RR intervals and is not within the first shock zone, both the first cardiac signal segment and the second cardiac signal segment each as not shockable.

7. The method of claim 4, further comprising:

identifying, based on determining that the first cardiac signal segment determined not to be corrupted by noise does not comprise regular RR intervals and is not within the second shock zone, both the first cardiac signal segment and the second cardiac signal segment as not shockable.

8. The method of claim 4, further comprising:

determining, based on determining that the first cardiac signal segment determined not to be corrupted by noise does not comprise regular RR intervals and is within the second shock zone, whether the second cardiac signal segment determined to be corrupted by noise is within the second shock zone; and

identifying, based on determining that the second cardiac signal segment determined to be corrupted by noise is within the second shock zone, both the first cardiac signal segment and the second cardiac signal segment as shockable.

9. The method of claim 4, further comprising:

determining, based on determining that the first cardiac signal segment determined not to be corrupted by noise does not comprise regular RR intervals and is within the second shock zone, whether the second cardiac signal segment determined to be corrupted by noise is within the second shock zone; and

identifying, based on determining that the second cardiac signal segment determined to be corrupted by noise is not within the second shock zone, the first cardiac signal segment determined not to be corrupted by noise as being shockable, and the second cardiac signal segment determined to be corrupted by noise as being not shockable.

10. The method of claim 2, further comprising:

determining that both the first cardiac signal segment and the second cardiac signal segment are not corrupted by noise;

determining, based on determining that both the first cardiac signal segment and the second cardiac signal segment are not corrupted by noise, whether both the first cardiac signal segment and the second cardiac signal segment comprise regular RR intervals;

determining, based on determining that both the first cardiac signal segment and the second cardiac signal segment comprise regular RR intervals, whether the first cardiac signal segment and the second cardiac signal segment are within a first shock zone; and

determining, based on determining that both the first cardiac signal segment and the second cardiac signal segment do not comprise regular RR intervals, whether both the first cardiac signal segment and the second cardiac signal segment are within a second shock zone different from the first shock zone.

11. The method 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. The method of claim 1, further comprising:

controlling a medical device to deliver the anti-tachyarrhythmia shock to the patient in response to determining that both the number of the first cardiac signal segments determined to be shockable and the number of the second cardiac signal segments determined to be shockable each exceed the threshold value.

13. A system comprising:

a plurality of electrodes;

sensing circuitry coupled to 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;

determine whether each of the first cardiac signal segments and the second cardiac signal segments is shockable or not shockable; and

determine whether to deliver an anti-tachyarrhythmia shock to a patient based on a number of the first cardiac signal segments determined to be shockable and a number of the second cardiac signal segments determined to be shockable.

14. The system of claim 13, wherein the processing circuitry is further configured to determine, for each of the plurality of time periods, one of:

that both the first cardiac signal segment and the second cardiac signal segment are shockable;

that both the first cardiac signal segment and the second cardiac signal segment are not shockable;

or

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

15. The system of claim 14, wherein the processing circuitry is further configured to:

determine that both the first cardiac signal segment and the second cardiac signal segment are corrupted by noise; and

determine that both the first cardiac signal segment and the second cardiac signal segment are not shockable based on both the first cardiac signal segment being corrupted by noise.

16. The system of claim 14, wherein the processing circuitry is further configured to:

determine that the first cardiac signal is not corrupted by noise and the second cardiac signal is corrupted by noise;

determine, based on the first cardiac signal segment not being corrupted by noise and the second cardiac signal segment being corrupted by noise, whether the first cardiac signal segment determined not to be corrupted by noise comprises regular RR intervals;

determine whether the first cardiac signal segment determined not to be corrupted by noise is within a first shock zone based on determining that the first cardiac signal segment determined not to be corrupted by noise comprises regular RR intervals;

determine whether the first cardiac signal segment determined not to be corrupted by noise is within a second shock zone, different from the first shock zone, based on determining the first cardiac signal segment determined not to be corrupted by noise does not comprise regular RR intervals; and

identify each of the first cardiac signal segment determined not to be corrupted by noise and the second cardiac signal segment determined to be corrupted by noise as shockable or not shockable based on the determination of whether the first cardiac signal segment is within the first shock zone or the determination of whether the first cardiac signal segment is within the second shock zone.

17. The system of claim 16, wherein the first shock zone comprises a ventricular tachycardia shock zone and the second shock zone comprises a ventricular fibrillation shock zone.

18. The system of claim 16, wherein the processing circuitry is further configured to:

identify, based on determining that the first cardiac signal segment determined not to be corrupted by noise comprises regular RR intervals and is within the first shock zone, both the first cardiac segment and the second cardiac segment as shockable; and

identify, based on determining that the first cardiac signal segment determined not to be corrupted by noise comprises regular RR intervals and is not within the first shock zone, both the first cardiac signal segment and the second cardiac signal segment as not shockable.

19. The system of claim 16, wherein the processing circuitry is further configured to:

identify, based on determining that the first cardiac signal segment determined not to be corrupted by noise does not comprise regular RR intervals and is not within the second shock zone, both the first cardiac signal segment and the second cardiac signal segment as not shockable.

20. The system of claim 16, wherein the processing circuitry is further configured to:

determine, based on determining that the first cardiac signal segment determined not to be corrupted by noise does not comprise regular RR intervals and is within the second shock zone, whether the second cardiac signal segment determined to be corrupted by noise is within the second shock zone; and

identify, based on determining that the second cardiac signal segment determined to be corrupted by noise is within the second shock zone, both the first cardiac signal segment and the second cardiac signal segment as being shockable.