Cardiac pacing response classification using an adaptable classification interval

• US 20060129194A1
• Filed: 12/15/2004
• Published: 06/15/2006
• Est. Priority Date: 12/15/2004
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Zhang, Geng
• Granted Patent: US 7,908,006 B2
• Time in Patent Office: Days
• US Class Current: 607/17
• CPC Class Codes: A61N 1/3712 Auto-capture, i.e. automatic adjustment of the stimulation threshold

Abstract

Methods and systems involve the formation of a classification interval used for sensing a cardiac signal following a pacing pulse to determine a cardiac response to pacing. One or more cardiac signals associated with a type of cardiac pacing response are sensed. The timing of at least one feature of the cardiac signal may be used to define an initial cardiac response classification interval. The classification interval is adapted based on the variability of the timing of the feature. The classification interval may be adapted using a predetermined number of additional cardiac signals or until a predetermined stability criterion is achieved.

Claims

1. A method of forming a classification interval used for sensing a cardiac signal following a pacing pulse to determine a cardiac response to pacing, comprising:

sensing one or more cardiac signals associated with a type of cardiac pacing response;

determining a variability of a timing of one or more features of the cardiac signals; and

forming the cardiac response classification interval using the timing variability.

2. The method of claim 1, wherein the one or more features comprises a peak amplitude.

3. The method of claim 1, wherein the type of cardiac pacing response comprises a captured response.

4. The method of claim 1, wherein determining the timing variability comprises determining a standard deviation.

5. The method of claim 1, further comprising adapting the cardiac response classification interval using one or more additional cardiac signals.

6. The method of claim 1, wherein forming the cardiac response classification interval comprises:

determining values for the timing of a particular feature for each of the cardiac signals;

averaging the particular feature timing values;

determining a standard deviation of the particular feature timing values;

using the average feature timing value as a central point; and

defining a timing interval around the central point using the standard deviation; and

forming the cardiac response classification interval based on the timing interval.

7. The method of claim 1, further comprising using the classification interval to determine a cardiac response to a pacing pulse.

8. The method of claim 1, further comprising using the classification interval to discriminate between a captured or non-captured response and a fusion beat.

9. The method of claim 1, wherein forming the cardiac response classification interval comprises adapting an upper or lower bound of the classification interval based on a predetermined number of cardiac beats.

10. The method of claim 1, wherein forming the cardiac response classification interval comprises adapting an upper or lower bound of the classification interval until a predetermined stability criteria is achieved.

11. A medical system, comprising:

a pacing circuit configured to deliver pacing pulses to a heart chamber;

a sensing circuit configured to sense cardiac signals associated with the pacing pulses; and

a processor coupled to the sensing circuit, the processor configured to determine a cardiac response classification interval based on a timing variability of a feature of cardiac signals associated with a type of cardiac pacing response, the cardiac response classification interval defining a period of time after a pacing pulse that a cardiac signal is sensed to determine a response to the pacing pulse.

12. The system of claim 11, wherein the feature comprises a peak amplitude.

13. The system of claim 11, wherein the type of cardiac pacing response comprises a captured response.

14. The system of claim 11, wherein the processor is configured to determine the standard deviation of the feature timing.

15. The system of claim 11, wherein the processor is configured to determine values for the timing of the feature for each of the cardiac signals, average the feature timing values, determine a standard deviation of the feature timing values, and form the cardiac response classification interval based on the average feature timing and the standard deviation.

16. The system of claim 11, wherein the processor is further configured to adapt the cardiac response classification interval until a stability criterion is achieved.

17. The system of claim 11, further comprising a cardiac response classification processor configured to use the cardiac response classification interval to determine a cardiac response to a pacing pulse.

18. A system for forming a classification interval used for sensing a cardiac signal following a pacing pulse to determine a response to the pacing pulse, comprising:

means for sensing cardiac signals associated with a type of cardiac pacing response;

means for determining a variability of a timing of one or more features of the cardiac signals; and

means for forming the cardiac response classification interval using the timing variability.

19. The system of claim 18, further comprising means for modifying the cardiac response classification interval using one or more additional cardiac signals sensed during delivery of a pacing therapy.

20. The system of claim 18, further comprising means for using the cardiac response classification interval to detect capture.