Methods and Systems for Managing Fusion and Noise in Cardiac Pacing Response Classification

• US 20100262207A1
• Filed: 06/24/2010
• Published: 10/14/2010
• Est. Priority Date: 04/28/2005
• Status: Active Grant

• Current Assignee: Clayton Scott Foster, David William Yost, Derek Daniel Bohn, Eric Keith Enrooth, John Michael Voegele, Kevin J. Stalsberg, Scott A. Meyers, Yanting Dong
• Original Assignee: Clayton Scott Foster, David William Yost, Derek Daniel Bohn, Eric Keith Enrooth, John Michael Voegele, Kevin J. Stalsberg, Scott A. Meyers, Yanting Dong
• Inventors: Meyer, Scott A., Dong, Yanting, Stalsberg, Kevin John, Bohn, Derek Daniel, Enrooth, Eric Keith, Foster, Clayton Scott, Yost, David William, Voegele, John Michael
• Granted Patent: US 8,290,591 B2
• Time in Patent Office: Days
• 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 managing fusion, indeterminate or possibly erroneous pacing responses, comprising:

delivering a first pacing pulse to a heart chamber;

delivering one or more pacing pulses to the heart chamber if a 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 a pacing energy greater than the first pacing pulse;

determining one or more cardiac responses respectively associated with the one or more pacing pulses; and

continuing to deliver the one or more pacing pulses if each of the one or more cardiac responses is at least one of fusion, indeterminate, and possibly erroneous.

2. The method of claim 1, further comprising terminating delivery of the one or more pacing pulses if a cardiac response associated with at least one of the one or more pacing pulses is classified as capture.

3. The method of claim 1, wherein continuing to deliver the one or more pacing pulses comprises, if the cardiac response associated with at least one of the one or more pacing pulses is classified as capture, classifying a cardiac response previous to the capture response as fusion.

4. The method of claim 1, wherein continuing to deliver the one or more pacing pulses comprises continuing to deliver the one or more pacing pulses until a predetermined number of the one or more pacing pulses has been delivered.

5. The method of claim 1, wherein continuing to deliver the one or more pacing pulses comprises terminating delivery of the one or more pacing pulses if none of a predetermined number of the one or more pacing pulses produces a capture response.

6. The method of claim 1, wherein:

continuing to deliver the one or more pacing pulses comprises continuing to deliver the one or more pacing pulses until a predetermined number of the one or more pacing pulses has been delivered; and

the method further comprises determining that a sensing channel for sensing the cardiac responses is unacceptably noisy if none of the predetermined number of the one or more pacing pulses produces a capture response.

7. 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 processor coupled to the sensing circuit and the pulse generator, the processor configured to deliver a first pacing pulse to the heart chamber, deliver one or more pacing pulses having a pacing energy greater than the first pacing pulse to the heart chamber if a cardiac response associated with the first pacing pulse is at least one of fusion, indeterminate, and possibly erroneous, determine one or more cardiac responses respectively associated with the one or more pacing pulses, and continue to deliver the one or more pacing pulses if each of the one or more cardiac responses is at least one of fusion, indeterminate, and possibly erroneous.

8. The device of claim 7, wherein the processor is configured to terminate delivery of the one or more pacing pulses if a cardiac response associated with at least one of the one or more pacing pulses is classified as capture.

9. The device of claim 7, wherein the processor is configured to classify a cardiac response produced previous to a capture response as fusion if the cardiac response associated with at least one of the one or more pacing pulses is classified as capture.

10. The device of claim 7, wherein the processor is configured to continue to deliver the one or more pacing pulses until a predetermined number of the one or more pacing pulses has been delivered.

11. The device of claim 7, wherein the processor is configured to terminate delivery of the one or more pacing pulses if none of a predetermined number of the one or more pacing pulses produces a capture response.

12. The device of claim 7, wherein the processor is configured to continue to deliver the one or more pacing pulses until a predetermined number of the one or more pacing pulses has been delivered, and to determine that a sensing channel for sensing the cardiac responses is unacceptably noisy if none of the predetermined number of the one or more pacing pulses produces a capture response.

13. A cardiac signal noise detection method, comprising:

sensing a cardiac signal in one or more classification intervals following delivery of a pacing pulse;

using the cardiac signal sensed in the one or more classification intervals to classify a cardiac response to the pacing pulse;

sensing the cardiac signal in a noise detection interval following the one or more classification intervals; and

detecting noise based on the cardiac signal sensed in at least one of the one or more classification intervals and the noise detection interval.

14. The method of claim 13, comprising computing an estimate of a signal-to-noise ratio based on a magnitude of the cardiac signal sensed during at least one of the classification intervals and a magnitude of the cardiac signal sensed during the noise detection interval.

15. The method of claim 14, comprising

comparing the signal-to-noise ratio to a threshold;

and

detecting cardiac signal noise based on the signal-to-noise ratio exceeding the threshold.

16. The method of claim 13, wherein detecting the noise comprises:

determining a signal level of the cardiac signal in at least one of the classification intervals;

determining a noise level of the cardiac signal in the noise interval;

comparing the classification interval signal level to the noise interval noise level; and

detecting cardiac signal noise based on the comparison.

17. The method of claim 13, wherein detecting the noise comprises:

determining a noise level of the cardiac signal in the noise interval;

comparing the noise level to a threshold;

detecting cardiac signal noise based on the noise level of the cardiac signal exceeding the threshold; and

determining the cardiac signal to be unusable for cardiac response classification in response to detecting the cardiac signal noise.

18. The method of claim 13, wherein a last classification interval of the one or more classification intervals is followed by a delay period, and the noise detection interval follows the delay period.

19. 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 processor coupled to the sensing circuit and the pulse generator, the processor configured to sense a cardiac signal in one or more classification intervals following delivery of a pacing pulse, classify a cardiac response to the pacing pulse using the cardiac signal sensed in the one or more classification intervals, sense the cardiac signal in a noise detection interval following the one or more classification intervals, and detect noise based on the cardiac signal sensed in at least one of the one or more classification intervals and the noise detection interval.

20. The device of claim 19, wherein the processor is configured to compute an estimate of a signal-to-noise ratio based on a magnitude of the cardiac signal sensed during at least one of the classification intervals and a magnitude of the cardiac signal sensed during the noise detection interval.

21. The device of claim 20, wherein the processor is configured to compare the signal-to-noise ratio to a threshold and detect cardiac signal noise based on the signal-to-noise ratio exceeding the threshold.

22. The device of claim 19, wherein the processor is configured to detect the noise by determining a signal level of the cardiac signal in at least one of the classification intervals, determining a noise level of the cardiac signal in the noise interval, comparing the classification interval signal level to the noise interval noise level, and detecting cardiac signal noise based on the comparison.

23. The device of claim 19, wherein the processor is configured to detect the noise by determining a noise level of the cardiac signal in the noise interval, compare the noise level to a threshold, detect cardiac signal noise based on the noise level of the cardiac signal exceeding the threshold, and determine the cardiac signal to be unusable for cardiac response classification in response to detecting the cardiac signal noise.

24. The device of claim 19, wherein a last classification interval of the one or more classification intervals is followed by a delay period, and the noise detection interval follows the delay period.

25. A system for managing fusion, indeterminate or possibly erroneous pacing responses, comprising:

means for determining that a cardiac response associated with a first pacing pulse is at least one of fusion, indeterminate, and possibly erroneous;

means for delivering one or more pacing pulses having a pacing energy greater than that of the first pacing pulse if the cardiac response associated with the first pacing pulse is at least one of fusion, indeterminate, and possibly erroneous;

means for determining a cardiac response associated with each of the one or more pacing pulses; and

means for continuing to deliver the one or more pacing pulses if the cardiac response associated with each of the one or more pacing pulses is at least one of fusion, indeterminate, and possibly erroneous.

26. The system of claim 25, further comprising means for terminating delivery of the one or more pacing pulses if a cardiac response associated with at least one of the one or more pacing pulses is classified as capture.

27. The system of claim 25, further comprising means for continuing to deliver the one or more pacing pulses until a predetermined number of pacing pulses have been delivered.