Therapy delivery for identified tachyarrhythmia episode types

• US 20080125824A1
• Filed: 03/07/2007
• Published: 05/29/2008
• Est. Priority Date: 11/29/2006
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Li, Dan, Cazares, Shelley Marie, Sauer, William H.
• Granted Patent: US 7,941,208 B2
• Time in Patent Office: Days
• US Class Current: 607/14
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy

Abstract

Methods and systems for identifying tachyarrhythmia episode types and delivering therapy to mitigate the identified tachyarrhythmia episode types are described. Electrogram signals of cardiac activity are sensed and stored by an implantable cardiac device. Tachyarrhythmia episodes are detected and tachyarrhythmia episode types are identified based on characteristics of the electrogram signals. In preparation for performing ablation, a tachyarrhythmia episode is induced. The features of the induced tachyarrhythmia episode are compared to characteristics of the identified episode types. A similarity between the induced tachyarrhythmia episode and at least one of the episode types identified from the stored electrogram signals is indicated to facilitate performing the ablation.

Claims

1. A method of operating a cardiac system, comprising:

sensing and storing electrogram signals of cardiac electrical activity in an implantable cardiac device;

detecting tachyarrhythmia episodes using the electrogram signals;

identifying tachyarrhythmia episode types based on characteristics of the electrogram signals;

inducing a tachyarrhythmia episode in preparation for performing ablation;

comparing characteristics of the induced tachyarrhythmia episode to characteristics of the identified episode types; and

indicating a similarity between the induced tachyarrhythmia episode and at least one of the episode types identified from the stored electrogram signals to facilitate performing the ablation.

2. The method of claim 1, further comprising:

counting a number of stored tachyarrhythmia episodes associated with each episode type; and

displaying a number of tachyarrhythmia episodes counted for each episode type.

3. The method of claim 1, further comprising ranking the episode types based on the number of tachyarrhythmia episodes counted for each episode type, a rank of an episode type corresponding to a tachyarrhythmia burden of the episode type.

4. The method of claim 1, further comprising performing ablation to prevent future occurrences of one or more of the identified episode types.

5. The method of claim 1, further comprising comparing episode types identified from tachyarrhythmia episodes stored before ablation to episode types identified from tachyarrhythmia episodes stored after ablation.

6. The method of claim 1, wherein the characteristics of the tachyarrhythmia episodes of each episode type are associated with a conduction pattern of the episode type.

7. The method of claim 1, wherein the characteristics of the tachyarrhythmia episodes comprise one or more morphological characteristics of the tachyarrhythmia episodes.

8. The method of claim 1, wherein the characteristics of the tachyarrhythmia episodes comprise one or more interval characteristics of the tachyarrhythmia episodes.

9. The method of claim 1, further comprising ranking the tachyarrhythmia episode types, wherein the criteria used for the ranking is user programmable.

10. The method of claim 1, further comprising determining a number of distinct episode types.

11. The method of claim 1, wherein determining the number of distinct episode types comprises:

identifying, by a user, one or more episodes defining boundary episodes between the episode types; and

grouping the tachyarrhythmia episodes based on the boundary episodes.

12. The method of claim 1, wherein a number of distinct episode types is determined by a user.

13. The method of claim 1, wherein a number of distinct episode types is determined algorithmically.

14. The method of claim 1, wherein:

sensing the electrogram signals comprises sensing a far field electrogram signal using a far field sensing vector and a near field electrogram signal using a near field sensing vector; and

identifying the tachyarrhythmia episode types comprises identifying the tachyarrhythmia types based on morphological or interval characteristics determined using the far field signal and the near field signal.

15. The method of claim 1, wherein:

sensing the electrogram signals comprises sensing a plurality of near field electrogram signals and a plurality of far field electrogram signals; and

identifying the tachyarrhythmia episode types comprises identifying the tachyarrhythmia types based on morphological or interval characteristics determined using at least one of the plurality of far field signals and at least one of the plurality of near field signals.

16. The method of claim 1, further comprising determining exit sites of the identified episode types using the electrogram signals.

17. A cardiac system, comprising:

an implantable sensing system configured to sense and store electrogram signals;

a tachyarrhythmia detector configured to detect tachyarrhythmia episodes using the electrogram signals and to determine characteristics of the tachyarrhythmia episodes from the electrogram signals;

a data processor configured to identity episode types based on the characteristics of the tachyarrhythmia episodes, the data processor further configured to determine a similarity between a tachyarrhythmia episode induced in preparation for performing ablation and at least one identified episode type; and

a display configured to present information related to the similarity between the induced tachyarrhythmia episode and the at least one identified episode type to facilitate performing the ablation.

18. The system of claim 17, wherein the data processor is configured to rank the episode types, a rank of an episode type corresponding to a tachyarrhythmia burden of the episode type.

19. The system of claim 17, wherein the data processor is configured to rank each episode type based on a number of tachyarrhythmia episodes counted for the episode type.

20. The system of claim 17, wherein the characteristics of the tachyarrhythmia comprise morphological characteristics.

21. The system of claim 17, wherein the characteristics of the tachyarrhythmia episodes of each episode type characterize timing interval characteristics.

22. The system of claim 17, wherein the data processor is further configured to determine a number of distinct episode types.

23. The system of claim 17, wherein the data processor is configured to discriminate a first type of ventricular tachyarrhythmia episode from a second type of ventricular tachyarrhythmia episode.

24. The system of claim 17, wherein:

the sensing system comprises;

a first pair of cardiac electrodes configured to sense a far field electrogram signal; and

a second pair of cardiac electrodes configured to sense a near field electrogram signal; and

the tachyarrhythmia detector is configured to determine the characteristics of the tachyarrhythmia episodes using the far field electrogram signal and the near field electrogram signal.

25. The system of claim 17, wherein:

the sensing system comprises;

a plurality of far field cardiac electrode pairs, each far field electrode pair configured to sense a far field electrogram signal; and

a plurality of near field cardiac electrode pairs, each near field electrode pair configured to sense a near field electrogram signal; and

the tachyarrhythmia detector is configured to determine the characteristics of the tachyarrhythmia episodes using at least one of the plurality of far field electrogram signals and at least one of the plurality of near field electrogram signals.

26. The system of claim 17, wherein the data processor is further configured to determine an exit site of one or more of the identified episode types based on the electrogram signals.

27. The system of claim 17, wherein the data processor is further configured to compare characteristics of the tachyarrhythmia episodes to electrogram signals of paced beats to determine an exit site of one or more identified episode types.

28. A system, comprising:

an implantable sensing system configured to sense electrogram signals;

a tachyarrhythmia detector configured to detect tachyarrhythmia episodes using the electrogram signals and to determine characteristics of the tachyarrhythmia episodes from the electrogram signals;

means for identifying episode types based on the characteristics of the tachyarrhythmia episodes; and

means for determining a similarity between an induced tachyarrhythmia episode and one or more identified episode types.

29. The system of claim 28, further comprising means for determining a number of distinct episode types.

30. The system of claim 28, further comprising means for determining an exit site for each episode type based on the electrogram signals.