Adaptive windowing for cardiac waveform discrimination
First Claim
1. A method of operating an implantable medical device, comprising:
- defining at least one detection window;
sensing a cardiac signal;
detecting a feature of the sensed cardiac signal, the detected feature being disposed at a location relative to the detection window;
comparing the detected feature to the detection window;
determining a direction of change for the detection window based on comparison of the detected feature to the detection window; and
modifying the detection window to provide a modified detection window for use with a subsequent cardiac signal, comprising;
modifying the detection window using a first adjustment coefficient associated with a preferred direction in response to the direction of change corresponding to the preferred direction; and
modifying the detection window using a second adjustment coefficient associated with a second direction in response to the direction of change corresponding to the second direction, wherein modifying the detection window using the first adjustment coefficient modifies the detection window more aggressively than modifying the detection window using the second coefficient.
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Accused Products
Abstract
Cardiac devices and methods provide adaptation of detection windows used to determine a cardiac response to pacing. Adapting a detection window involves sensing a cardiac signal indicative of a particular type of cardiac pacing response, and detecting a feature of the sensed cardiac signal. The cardiac response detection window associated with the type of cardiac pacing response is preferentially adjusted based on the location of the detected cardiac feature. Preferential adjustment of the detection window may involve determining a direction of change between the detection window and the detected feature. The detection window may be adapted more aggressively in a more preferred direction and less aggressively in a less preferred direction.
109 Citations
24 Claims
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1. A method of operating an implantable medical device, comprising:
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defining at least one detection window; sensing a cardiac signal; detecting a feature of the sensed cardiac signal, the detected feature being disposed at a location relative to the detection window; comparing the detected feature to the detection window; determining a direction of change for the detection window based on comparison of the detected feature to the detection window; and modifying the detection window to provide a modified detection window for use with a subsequent cardiac signal, comprising; modifying the detection window using a first adjustment coefficient associated with a preferred direction in response to the direction of change corresponding to the preferred direction; and modifying the detection window using a second adjustment coefficient associated with a second direction in response to the direction of change corresponding to the second direction, wherein modifying the detection window using the first adjustment coefficient modifies the detection window more aggressively than modifying the detection window using the second coefficient. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A system, comprising:
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a sensing system configured to sense a cardiac signal following a pacing pulse delivered to a heart; and a processor coupled to the sensing system, the processor configured to (a) provide at least one detection window (b) detect a feature of the cardiac signal, the detected feature being disposed at a location relative to the detection window, (c) compare the detected feature to the detection window, (d) determine a direction of change for the detection window based on a comparison of the detected feature to the detection window, and (e) modify the detection window using a first adjustment coefficient associated with a preferred direction of change in response to the direction of change corresponding to the preferred direction and modify the detection window using a second adjustment coefficient associated with a second direction in response to the direction of change corresponding to the second direction, wherein the first coefficient provides a more aggressive modification of the detection window than the second coefficient. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. A system for adjusting a detection window used to detect a type of cardiac response, comprising:
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a detector configured to detect a feature of a cardiac signal; means for comparing the detected feature to a detection window, the detected feature being disposed at a location relative to the detection window; means for determining direction of change based on comparison of the detected feature to the detection window; and means for modifying the detection window to provide a modified detection window for use with a subsequent cardiac signal, comprising; means for modifying the detection window using the first adjustment coefficient associated with a preferred direction in response to the direction of change corresponding to the preferred direction; and means for modifying the detection window using a second adjustment coefficient associated with a second direction in response to the direction of change corresponding to the second direction, wherein the first coefficient provides a more aggressive modification of the detection window than the second coefficient. - View Dependent Claims (23, 24)
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Specification