System and method for selection of morphology templates

• US 20050192506A1
• Filed: 02/26/2004
• Published: 09/01/2005
• Est. Priority Date: 02/26/2004
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Bocek, Joseph, Kim, Jaeho
• Granted Patent: US 7,184,815 B2
• Time in Patent Office: Days
• US Class Current: 600/510
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/35 by template matching

Abstract

A template selection method involves providing a plurality of templates representing a type of cardiac event. One or more characteristics of each template are evaluated. The evaluations are compared and a template is selected as a current template based on the comparison.

Claims

1. A morphology template selection method, comprising:

providing a plurality of templates representing a type of cardiac event;

evaluating one or more characteristics of each template;

comparing the evaluations; and

selecting a template as a current template based on the comparison.

2. The method of claim 1, wherein providing the plurality of templates comprises retrieving at least one stored template from memory.

3. The method of claim 1, wherein providing the plurality of templates comprises generating at least one new template.

4. The method of claim 1, wherein the type of cardiac event comprises a sensed cardiac beat.

5. The method of claim 1, wherein the type of cardiac event comprises a paced cardiac beat.

6. The method of claim 1, wherein the type of cardiac event comprises a non-supraventricular conducted ventricular beat.

7. The method of claim 1, wherein the type of cardiac event comprises a supraventricular conducted ventricular beat.

8. The method of claim 1, wherein the type of cardiac event comprises a capture-related event.

9. The method of claim 1, wherein evaluating the one or more characteristics of each template comprises:

detecting cardiac signals associated with the type of cardiac event; and

evaluating each template using the cardiac signals.

10. The method of claim 1, wherein:

evaluating the one or more characteristics of each template comprises determining an accuracy of each template; and

comparing the evaluations comprises comparing the template accuracies.

11. The method of claim 10, wherein determining the accuracy of each template comprises determining a correlation between each template and one or more cardiac signals associated with the type of cardiac event.

12. The method of claim 1, wherein:

evaluating the one or more characteristics of each template comprises determining an accuracy of each template;

comparing the evaluations comprises comparing the accuracies; and

selecting the template as the current template comprises selecting a template having a higher accuracy.

13. A cardiac rhythm template selection method, comprising:

providing a plurality of templates representing a type of cardiac rhythm;

detecting one or more cardiac beats associated with the type of cardiac rhythm;

determining an accuracy of each template using the one or more cardiac beats;

comparing the accuracies of the plurality of templates; and

selecting a template as a current template representing the type of cardiac rhythm based on the comparison.

14. The method of claim 13, wherein providing the plurality of templates representing the type of cardiac rhythm comprises providing the plurality of templates representing a supraventricular rhythm.

15. The method of claim 13, wherein providing the plurality of templates comprises retrieving at least one template from memory and generating at least one new template.

16. The method of claim 13, wherein providing the plurality of templates comprises:

sensing cardiac signals using a first channel;

sensing cardiac signals using a second channel;

aligning the second channel signals using the first channel signals; and

forming a template using features selected from the aligned second channel signals.

17. The method of claim 16, wherein the first channel is a rate channel and the second channel is a shock channel.

18. The method of claim 13, wherein providing the plurality of templates representing the cardiac rhythm comprises providing at least one template comprising a set of feature points representing the type of cardiac rhythm.

19. The method of claim 13, wherein:

determining an accuracy of each template comprises determining correlation factors between the one or more cardiac beats and each template; and

comparing the accuracies comprises comparing the correlation factors.

20. A medical device, comprising:

a sensing system configured to sense electrical cardiac signals associated with cardiac events; and

a processor coupled to the sensing system and configured to provide a plurality of templates representing a type of cardiac event, evaluate one or more characteristics of each template, compare the evaluations, and select a template as a current template representing the type of cardiac event based on the comparison.

21. The medical device of claim 20, further comprising a memory and wherein the plurality of templates includes at least one template retrieved from the memory and at least one new template.

22. The medical device of claim 20, wherein the plurality of templates comprises a plurality of templates representing a supraventricular rhythm.

23. The medical device of claim 20, wherein the plurality of templates comprises a plurality of templates representing a capture-related event.

24. The medical device of claim 20, wherein the one or more characteristics of each template comprises an accuracy of each template.

25. The medical device of claim 24, wherein the processor is configured to evaluate an accuracy of each template based on correlation coefficients associated with a similarity of each template and cardiac signals representative of the type of cardiac event.

26. The medical device of claim 20, wherein:

the electrical cardiac signals include rate channel signals and shock channel signals; and

the sensing system comprises a rate channel configured to sense the rate channel signals and a shock channel configured to sense the shock channel signals.

27. The medical device of claim 26, wherein the plurality of templates comprises at least one template representing a supraventricular rhythm formed based on the rate channel signals and the shock channel signals.

28. A medical system, comprising:

means for providing a plurality of templates representing a type of cardiac event;

means for evaluating one or more characteristics of each template;

means for comparing the evaluations; and

means for selecting a template as a current template based on the comparison.

29. The system of claim 28, wherein means for providing the plurality of templates comprises means for storing at least one template and means for retrieving the at least one template from the storage means.

30. The system of claim 28, wherein means for providing the plurality of templates comprises means for generating at least one new template.

31. The system of claim 28, wherein the type of cardiac event comprises a sensed cardiac beat.

32. The system of claim 28, wherein the type of cardiac event comprises a paced cardiac beat.

33. The system of claim 28, wherein the type of cardiac event comprises a type of cardiac rhythm.

34. The system of claim 28, wherein the type of cardiac event comprises a capture-related event.

35. A medical system, comprising:

means for providing a plurality of templates representing a type of cardiac rhythm;

means for detecting one or more cardiac beats associated with the type of cardiac rhythm;

means for determining an accuracy of each template using the one or more cardiac beats;

means for comparing the accuracies of the plurality of templates; and

means for selecting a template as a current template representing the type of cardiac rhythm based on the comparison.