Method and apparatus for detecting and discriminating arrhythmias

• US 20050080347A1
• Filed: 10/10/2003
• Published: 04/14/2005
• Est. Priority Date: 10/10/2003
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Hess, Michael F., Warman, Eduardo N., Sheth, Nirav V.
• Granted Patent: US 7,076,290 B2
• Time in Patent Office: Days
• US Class Current: 600/515
• CPC Class Codes: A61B 5/361 Detecting fibrillation
• CPC Class Codes: A61B 5/363 Detecting tachycardia or bradycardia
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/39622 Pacing therapy
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems

Abstract

An apparatus and method for discriminating arrhythmias that includes sensing a heart rate indicative of an arrhythmia associated with a first portion of a heart, determining regularity of the sensed heart rate, determining an event interval variability associated with a second portion of the heart, and classifying the arrhythmia in response to the determined event interval variability.

Claims

1. An implantable medical device, comprising:

means for sensing a heart rate indicative of an arrhythmia associated with a first portion of a heart;

means for determining regularity of the sensed heart rate;

means for determining an event interval variability associated with a second portion of the heart; and

means for classifying the arrhythmia in response to the determined event interval variability.

2. The device of claim 1, further comprising:

means for determining whether a therapy is being delivered to the second portion of the heart; and

means for varying the therapy prior to determining the event interval variability in response to the therapy being delivered.

3. The device of claim 2, further comprising means for determining whether sensing is present in the second portion of the heart, and wherein the means for varying the therapy includes reducing the therapy until one of determining sensing is present and the therapy being delivered at a predetermined minimum rate.

4. The device of claim 3, wherein the means for determining whether sensing is present determines the frequency of the therapy during a predetermined time interval and disables the means for determining an event interval variability and the means for classifying the arrhythmia.

5. The device of claim 1, further comprising means for determining R-R intervals, wherein the means for determining the event interval variability determines a difference between maximum R-R intervals and minimum R-R intervals occurring during a predetermined number of consecutive R-R intervals.

6. The device of claim 5, wherein the means for determining the event interval variability determines whether the difference between maximum R-R intervals and minimum R-R intervals is less than a regularity threshold, wherein the means for classifying the arrhythmia determines the arrhythmia is a first arrhythmia in response to the difference between maximum R-R intervals and minimum R-R intervals being less than the regularity threshold.

7. The device of claim 6, wherein the means for determining the event interval variability determines whether events associated with the second portion of the heart are associated with events associated with the first portion of the heart, wherein the means for classifying the arrhythmia determines the arrhythmia is the first arrhythmia in response to events associated with the second portion of the heart being associated with events associated with the first portion of the heart.

8. The device of claim 7, wherein the arrhythmia is classified as a second arrhythmia different from the first arrhythmia in response to events associated with the second portion of the heart not being associated with events associated with the first portion of the heart.

9. The device of claim 8, wherein the arrhythmia is classified as the first arrhythmia in response to events associated with the second portion of the heart being associated with events associated with the first portion of the heart such that intervals of events associated with the second portion of the heart are approximately equal an integer multiple of intervals of events associated with the first portion of the heart.

10. A method of detecting and classifying an arrhythmia, comprising:

sensing a heart rate indicative of an arrhythmia associated with a first portion of a heart;

determining regularity of the sensed heart rate;

determining an event interval variability associated with a second portion of the heart; and

classifying the arrhythmia in response to the determined event interval variability.

11. The method of claim 10, further comprising:

determining whether a therapy is being delivered to the second portion of the heart; and

varying the therapy prior to determining the event interval variability in response to the therapy being delivered.

12. The method of claim 11, further comprising determining whether sensing is present in the second portion of the heart, and wherein varying the therapy includes reducing the therapy until one of determining sensing is present and the therapy being delivered at a predetermined minimum rate.

13. The method of claim 12, wherein determining whether sensing is present includes determining the frequency of the therapy during a predetermined time interval and disabling the method in response to the determined frequency having a predetermined value.

14. The method of claim 10, further comprising sensing R-R intervals, wherein determining the event interval variability includes determining a difference between maximum R-R intervals and minimum R-R intervals occurring during a predetermined number of consecutively sensed R-R intervals.

15. The method of claim 14, further comprising determining whether the difference between maximum R-R intervals and minimum R-R intervals is less than a regularity threshold, wherein the arrhythmia is classified as a first arrhythmia in response to the difference between maximum R-R intervals and minimum R-R intervals being less than the regularity threshold.

16. The method of claim 15, further comprising determining whether events associated with the second portion of the heart are associated with events associated with the first portion of the heart, wherein the arrhythmia is classified as the first arrhythmia in response to events associated with the second portion of the heart being associated with events associated with the first portion of the heart.

17. The method of claim 16, wherein the arrhythmia is classified as a second arrhythmia different from the first arrhythmia in response to events associated with the second portion of the heart not being associated with events associated with the first portion of the heart.

18. The method of claim 17, wherein the arrhythmia is classified as the first arrhythmia in response to events associated with the second portion of the heart being associated with events associated with the first portion of the heart such that intervals of events associated with the second portion of the heart are approximately equal an integer multiple of intervals of events associated with the first portion of the heart.

19. An implantable medical device, comprising:

means for sensing a heart rate indicative of an arrhythmia associated with a first portion of a heart;

means for determining regularity of the sensed heart rate;

means for determining an event interval variability associated with a second portion of the heart;

means for classifying the arrhythmia in response to the determined event interval variability;

means for determining whether a therapy is being delivered to the second portion of the heart;

means for varying the therapy prior to determining the event interval variability in response to the therapy being delivered; and

means for determining whether sensing is present in the second portion of the heart, wherein the means for varying the therapy includes reducing the therapy until one of determining sensing is present and the therapy being delivered at a predetermined minimum rate, and the means for determining whether sensing is present determines the frequency of the therapy during a predetermined time interval and disables the means for determining an event interval variability and the means for classifying the arrhythmia.

20. The device of claim 19, further comprising means for determining R-R intervals, wherein the means for determining the event interval variability determines a difference between maximum R-R intervals and minimum R-R intervals occurring during a predetermined number of consecutive R-R intervals.

21. The device of claim 20, wherein the means for determining the event interval variability determines whether the difference between maximum R-R intervals and minimum R-R intervals is less than a regularity threshold, wherein the means for classifying the arrhythmia determines the arrhythmia is a first arrhythmia in response to the difference between maximum R-R intervals and minimum R-R intervals being less than the regularity threshold.

22. The device of claim 21, wherein the means for determining the event interval variability determines whether events associated with the second portion of the heart are associated with events associated with the first portion of the heart, wherein the means for classifying the arrhythmia determines the arrhythmia is the first arrhythmia in response to events associated with the second portion of the heart being associated with events associated with the first portion of the heart.

23. The device of claim 22, wherein the arrhythmia is classified as a second arrhythmia different from the first arrhythmia in response to events associated with the second portion of the heart not being associated with events associated with the first portion of the heart.

24. The device of claim 23, wherein the arrhythmia is classified as the first arrhythmia in response to events associated with the second portion of the heart being associated with events associated with the first portion of the heart such that intervals of events associated with the second portion of the heart are approximately equal an integer multiple of intervals of events associated with the first portion of the heart.