Methods and systems for managing fusion and noise in cardiac pacing response classification

• US 7,765,004 B2
• Filed: 04/28/2005
• Issued: 07/27/2010
• Est. Priority Date: 04/28/2005
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Voegele, John Michael, Meyer, Scott A., Dong, Yanting, Stalsberg, Kevin John, Bohn, Derek Daniel, Enrooth, Eric Keith, Foster, Clayton Scott, Yost, David William
• Primary Examiner(s): Bockelman; Mark W
• Assistant Examiner(s): Bertram; Eric D.
• Application Number:
  US11/116,565
• Publication Number:
  US 20060247695A1
• Time in Patent Office: 1,916 Days
• Field of Search: 607 27- 28
• US Class Current: 607/28
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7217 of noise originating from a therapeutic or surgical apparatus, e.g. from a pacemaker
• 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 1/371 Capture, i.e. successful stimulation
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems

Abstract

Methods and systems for detecting noise in cardiac pacing response classification processes involve determining that a cardiac response classification is possibly erroneous if unexpected signal content is detected. The unexpected signal content may comprise signal peaks that have polarity opposite to the polarity of peaks used to determine the cardiac response to pacing. Fusion/noise management processes include pacing at a relatively high energy level until capture is detected after a fusion, indeterminate, or possibly erroneous pacing response classification is made. The relatively high energy pacing pulses may be delivered until capture is detected or until a predetermined number of paces are delivered.

Claims

1. A method for detecting cardiac signal noise during capture verification, comprising:

delivering a pacing pulse to a heart chamber;

sensing a cardiac signal associated with the pacing pulse;

classifying a cardiac response to the pacing pulse based on the sensed cardiac signal, the cardiac response classification being one of a plurality of expected cardiac responses including capture and intrinsic activation;

sensing for unexpected signal content in the cardiac signal, the unexpected signal content being inconsistent with one or more of capture and intrinsic activation and comprising one or more of unexpected signal peaks, the one or more unexpected cardiac signal peaks having an opposite polarity relative to a polarity of one or more cardiac signal peaks indicative of capture or intrinsic activation; and

determining that the cardiac response classification is possibly erroneous if the unexpected signal content is detected, wherein at least one of delivering, classifying, and determining is implemented at least in part by circuitry.

2. The method of claim 1, wherein:

classifying the cardiac pacing response comprises;

detecting one or more cardiac signal peaks indicative of capture; and

classifying the cardiac pacing response as capture based on the one or more detected cardiac signal peaks; and

sensing for the unexpected signal content comprises sensing for one or more unexpected cardiac signal peaks, each of the one or more unexpected cardiac signal peaks having an opposite polarity relative to a polarity of a corresponding one of the one or more cardiac signal peaks indicative of capture.

3. The method of claim 1, wherein:

classifying the cardiac pacing response comprises;

detecting one or more cardiac signal peaks indicative of intrinsic activation; and

classifying the cardiac pacing response as noncapture with intrinsic activation based on the one or more detected signal peaks; and

sensing for the unexpected signal content comprises sensing for one or more unexpected cardiac signal peaks, each of the one or more unexpected cardiac signal peaks having an opposite polarity relative to a polarity of a corresponding one of the one or more cardiac signal peaks indicative of intrinsic activation.

4. The method of claim 1, wherein sensing the cardiac signal comprises sensing for cardiac signal behavior in one or more detection windows.

5. The method of claim 4, wherein detection windows has a finite time range and a finite amplitude range.

6. The method of claim 1, wherein sensing for the unexpected signal behavior comprises sensing for the unexpected cardiac signal behavior in one or more noise detection windows.

7. The method of claim 6, wherein each of the one or more noise detection windows has a finite time range and a finite amplitude range.

8. The method of claim 1, wherein:

sensing the cardiac signal comprises sensing for cardiac signal behavior indicative of a cardiac pacing response in one or more classification detection windows; and

sensing for the unexpected signal content comprises sensing for the unexpected signal content in one or more noise detection windows, each noise detection window associated with a particular one of the one or more classification windows.

9. The method of claim 8, further comprising:

forming the one or more classification detection windows, each of the one or more classification detection windows formed based on one or more cardiac signals representative of a particular type of cardiac pacing response; and

forming the one or more noise detection windows, each of the one or more noise detection windows formed in part based on a corresponding one of the classification detection windows.

10. The method of claim 9, further comprising:

adapting the one or more classification detection windows based on one or more additional cardiac signals indicative of the particular type of cardiac pacing response; and

adapting the one or more noise detection windows based on a corresponding one of the one or more adapted classification windows.

11. The method of claim 8, further comprising:

forming the one or more classification detection windows, each of the one or more classification detection windows formed based on one or more cardiac signals representative of a particular type of cardiac pacing response; and

forming the one or more noise detection windows, each of the one or more noise detection windows formed in part based on a feature of the sensed cardiac signals.

12. The method of claim 1, further comprising initiating a fusion/noise management process if the cardiac response classification is determined to be at least one of a fusion beat, an indeterminate response, and possibly erroneous.

13. The method of claim 1, wherein the classifying classifies the cardiac response based on at least one first feature of the sensed cardiac signal, and the unexpected signal content includes at least one second feature of the sensed cardiac signal, the unexpected signal content being inconsistent with capture and intrinsic activation if the at least one first and second features are collectively inconsistent with capture and intrinsic activation.

14. A cardiac rhythm management device, comprising:

a pulse generator configured to deliver pacing pulses to a heart chamber;

a sensing circuit configured to sense cardiac signals of the heart chamber, the sensed cardiac signals respectively associated with the pacing pulses; and

a cardiac response classification processor, the processor coupled to the sensing circuit and configured to classify a cardiac response to a pacing pulse based on a sensed cardiac signal associated with the pacing pulse and to determine that the cardiac response classification is possibly erroneous if unexpected signal content is detected in the sensed cardiac signal, the cardiac response classification is one of a plurality of expected cardiac responses that the processor is configured to classify including capture, fusion, and intrinsic activation, and wherein the unexpected signal content is inconsistent with one or more of capture, fusion, and intrinsic activation.

15. The device of claim 14, wherein the processor is configured to classify the cardiac pacing response based on one or more cardiac signal peaks indicative of the cardiac pacing response and to determine that the cardiac pacing response classification is possibly erroneous based on one or more unexpected cardiac signal peaks.

16. The device of claim 14, wherein the processor is configured to classify the cardiac pacing response as a particular type of cardiac pacing response based on one or more peaks of the cardiac signal detected in one or more classification detection windows and the processor is configured to determine that the cardiac response classification is possibly erroneous if one or more unexpected cardiac signal peaks are detected in one or more noise detection windows.

17. The device of claim 16, wherein the processor is configured to form the one or more classification detection windows and the one or more noise detection windows.

18. The device of claim 16, wherein the processor is configured to adapt the one or more classification detection windows and the one or more noise detection windows.

19. The device of claim 16, wherein each of the one or more classification detection windows has a finite time range and a finite amplitude range.

20. The device of claim 16, wherein each of the one or more noise detection windows has a finite time range and a finite amplitude range.

21. The device of claim 14, wherein the processor is configured to classify the cardiac pacing response as capture based on the sensed cardiac signal and to determine that the captured response classification is possibly erroneous based on the unexpected signal content.

22. The device of claim 14, wherein the processor is configured to determine that the cardiac response classification is possibly erroneous based on the unexpected signal content comprising one or more of unexpected signal peaks having an opposite polarity relative to a polarity of one or more cardiac signal peaks indicative of capture or intrinsic activation.

23. The device of claim 14, wherein the processor is configured to classify the cardiac pacing response as noncapture with intrinsic activation based on the sensed cardiac signal and to determine that the noncapture with intrinsic activation response classification is possibly erroneous based on the unexpected signal content.

24. The device of claim 14, wherein the processor is configured to control delivery of a first pacing pulse to the heart chamber, determine that the cardiac response associated with the pacing pulse is at least one of fusion, indeterminate, and possibly erroneous, deliver one or more pacing pulses to the heart chamber if the cardiac response associated with the first pacing pulse is at least one of fusion, indeterminate, and possibly erroneous, the one or more pacing pulses having an energy greater than the first pacing pulse, the processor further configured to determine a cardiac response associated with each of the one or more pacing pulses, and to continue delivery of the one or more pacing pulses if the cardiac response to the one or more pacing pulses is at least one of fusion, indeterminate, and possibly erroneous.

25. The device of claim 24, wherein the processor is configured to terminate delivery of the one or more pacing pulses if the cardiac response to at least one of the one or more pacing pulses is classified as capture.

26. The device of claim 14, wherein the processor is configured to classify the cardiac response to the pacing pulse based on the cardiac signal sensed in a classification interval following the pacing pulse and the processor is configured to detect noise in a noise interval following the classification interval.

27. The device of claim 14, wherein the processor is configured to classify the cardiac response based on at least one first feature of the sensed cardiac signal, and the unexpected signal content includes at least one second feature of the sensed cardiac signal, the unexpected signal content being inconsistent with capture and intrinsic activation if the at least one first and second features are collectively inconsistent with capture and intrinsic activation.

28. A system for detecting cardiac signal noise during capture verification, comprising:

a pulse generator for delivering a pacing pulse to a heart chamber;

a sensing circuit for sensing a cardiac signal associated with the pacing pulse;

means for classifying a cardiac response to the pacing pulse based on the sensed cardiac signal using one or more classification detection windows, the cardiac response classification being one of a plurality of expected cardiac responses including capture and intrinsic activation;

means for sensing for unexpected signal content in the cardiac signal using one or more noise detection windows, the unexpected signal content being inconsistent with capture and intrinsic activation; and

means for determining that the cardiac response classification is possibly erroneous if the unexpected signal content is detected, wherein the one or more classification detection windows are different from the one or more noise detection windows.

29. The system of claim 28, wherein

the means for classifying classifies the cardiac response using one or more classification detection windows, each of the one or more classification detection windows formed based on one or more cardiac signals representative of a particular type of cardiac pacing response;

and

the means for sensing senses for unexpected signal content using one or more noise detection windows, each of the one or more noise detection windows formed in part based on a corresponding one of the classification detection windows.

30. The system of claim 29, further comprising:

means for adapting the one or more classification detection windows based on one or more additional cardiac signals indicative of the particular type of cardiac pacing response; and

means for adapting the one or more noise detection windows based on a corresponding one of the one or more adapted classification windows.

31. The system of claim 29, wherein each of the one or more classification detection windows has a finite time range and a finite amplitude range.

32. The system of claim 29, wherein each of the one or more noise detection windows has a finite time range and a finite amplitude range.

33. The system of claim 28, wherein:

the means for classifying classifies the cardiac response using one or more classification detection windows, each of the one or more classification detection windows formed based on one or more cardiac signals representative of a particular type of cardiac pacing response; and

the means for sensing senses for unexpected signal content using one or more noise detection windows, each of the one or more noise detection windows formed in part based on a feature of the sensed cardiac signals.

34. The system of claim 28, further comprising means for initiating a fusion/noise management process if the cardiac response classification is determined to be at least one of a fusion beat, an indeterminate response, and possibly erroneous.

35. The system of claim 28, wherein the classifying means classifies the cardiac response based on at least one first feature of the sensed cardiac signal, and the unexpected signal content includes at least one second feature of the sensed cardiac signal, the unexpected signal content being inconsistent with capture and intrinsic activation if the at least one first and second features are collectively inconsistent with capture and intrinsic activation.