MANAGEMENT OF FUSION BEAT DETECTION DURING CAPTURE THRESHOLD DETERMINATION

• US 20130018433A1
• Filed: 07/11/2012
• Published: 01/17/2013
• Est. Priority Date: 07/15/2011
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Shome, Shibaji, Dong, Yanting, McCabe, Aaron R.
• Granted Patent: US 9,020,596 B2
• Time in Patent Office: Days
• US Class Current: 607/28
• CPC Class Codes: A61N 1/3712 Auto-capture, i.e. automatic adjustment of the stimulation threshold

Abstract

An improved technique is described for dealing with the detection of fusion beats when capture verification is performed by a cardiac pacing device such as during a capture threshold determination procedure. Schemes for classifying heart beats may misclassify beats as fusion beats due to feature/m orphology changes in the test electrogram waveform that may occur even when capture is achieved.

Claims

1. A method for operating a cardiac rhythm management device, comprising:

delivering a pacing pulse to a cardiac site;

recording a test electrogram after delivery of the pacing pulse;

classifying the test electrogram as representing a capture beat, a fusion beat, or a non-capture beat;

classifying the test electrogram as representing a capture beat if at least an amplitude criterion that specifies a peak amplitude and a location criterion that specifies a time window within which the peak amplitude must occur are both met;

classifying the test electrogram as representing a fusion beat if at least one of the amplitude criterion or the location criterion is not met; and

,

classifying the test electrogram as representing a capture beat if at least one of the amplitude and location criteria is met and a predetermined number of immediately preceding test electrograms have been classified as representing fusion beats,

2. The method of claim 1 wherein the predetermined number is zero.

3. The method of claim 1 further comprising, if only one of the amplitude and location criteria is met and a predetermined number of immediately preceding test electrograms have been classified as representing fusion beats, adjusting a blanking/recharge parameter used to define a blanking interval for a sensing channel used to record the test electrogram,

4. The method of claim 1 further comprising, if only one of the amplitude and location criteria is met and a predetermined number of immediately preceding test electrograms have been classified as representing fusion beats, modifying the amplitude criterion.

5. The method of claim 1 further comprising, if only one of the amplitude and location criteria is met and a predetermined number of immediately preceding test electrograms have been classified as representing fusion beats, decreasing the amplitude criterion.

6. The method of claim 1 further comprising, if only one of the amplitude and location criteria is met and a predetermined number of immediately preceding test electrograms have been classified as representing fusion beats, increasing the width of the time window specified by the location criterion.

7. The method of claim 1 further comprising, if:

1) the test electrogram exhibits a double peak,

     2) only one of the amplitude and location criteria is met, and

     3) a predetermined number of immediately preceding test electrograms have been classified as representing fusion beats, increasing the width of the time window specified by the location criterion to encompass the double peak.

8. The method of claim 1 further comprising performing a capture threshold procedure by successively decreasing the pacing energy of pacing pulses delivered to the cardiac site, classifying the recorded test electrogam recorded after each pacing pulse, and setting the capture threshold as the smallest pacing energy that achieves capture plus a specified safety margin.

9. The method of claim 8 further comprising, if:

1) the peak amplitude of the test electrogram has increased with decreasing pacing energy,

     2) only one of the amplitude and location criteria is met, and

     3) a predetermined number of immediately preceding test electrograms have been classified as representing fusion beats, adjusting a blanking/recharge parameter used to define a blanking interval for a sensing channel used to record the test electrogram.

10. The method of claim 8 further comprising, if:

1) the peak amplitude of the test electrogram has increased with decreasing pacing energy,

     2) only one of the amplitude and location criteria is met, and

     3) a predetermined number of immediately preceding test electrograms have been classified as representing fusion beats, increasing the amplitude criterion.

11. A cardiac rhythm management device, comprising:

pulse generation and sensing circuitry for connecting to electrodes and forming sensing and pacing channels;

a controller for controlling the delivery of pacing pulses by the pulse generation circuitry and for receiving electrogram signals from the sensing circuitry;

wherein the controller is programmed to;

deliver a pacing pulse to a cardiac site;

record test electrogram after delivery of the pacing pulse;

classify the test electrogram as representing a capture beat, a fusion beat, or a non-capture beat;

classify the test electrogram as representing a capture beat if at least an amplitude criterion that specifies a peak amplitude and a location criterion that specifies a time window within which the peak amplitude must occur are both met;

classify the test electrogram as representing a fusion beat if at least one of the amplitude criterion or the location criterion is not met; and

,

classify the test electrogram as representing a capture beat if at least one of the amplitude and location criteria is met and a predetermined number of immediately preceding test electrograms have been classified as representing fusion beats.

12. The device of claim 11 wherein the predetermined number is zero.

13. The device of claim 11 wherein the controller is further programmed to, if only one of the amplitude and location criteria is met and a predetermined number of immediately preceding test electrograms have been classified as representing fusion beats, adjust a blanking/recharge parameter used to define a blanking interval for a sensing channel used to record the test electrogram.

14. The device of claim 11 wherein the controller is further programmed to, if only one of the amplitude and location criteria is met and a predetermined number of immediately preceding test electrograms have been classified as representing fusion beats, modify the amplitude criterion.

15. The device of claim 11 wherein the controller is further programmed to, if only one of the amplitude and location criteria is met and a predetermined number of immediately preceding test electrograms have been classified as representing fusion beats, decrease the amplitude criterion.

16. The device of claim 11 wherein the controller is further programmed to, if only one of the amplitude and location criteria is met and a predetermined number of immediately preceding test electrograms have been classified as representing fusion beats, increase the width of the time window specified by the location criterion.

17. The device of claim 11 wherein the controller is further programmed to, if:

1) the test electrogram exhibits a double peak,

     2) only one of the amplitude and location criteria is met, and

     3) a predetermined number of immediately preceding test electrograms have been classified as representing fusion beats, increase the width of the time window specified by the location criterion to encompass the double peak.

18. The device of claim 11 wherein the controller is further programmed to perform a capture threshold procedure by successively decreasing the pacing energy of pacing pulses delivered to the cardiac site, classifying the recorded test electrogam recorded after each pacing pulse, and setting the capture threshold as the smallest pacing energy that achieves capture plus a specified safety margin.

19. The device of claim 18 wherein the controller is further programmed to, if:

1) the peak amplitude of the test electrogram has increased with decreasing pacing energy,

     2) only one of the amplitude and location criteria is met, and

     3) a predetermined number of immediately preceding test electrograms have been classified as representing fusion beats, adjust a blanking/recharge parameter used to define a blanking interval for a sensing channel used to record the test electrogram.

20. The device of claim 18 wherein the controller is further programmed to, if:

1) the peak amplitude of the test electrogram has increased with decreasing pacing energy,

     2) only one of the amplitude and location criteria is met, and

     3) a predetermined number of immediately preceding test electrograms have been classified as representing fusion beats, increase the amplitude criterion.