| CPC A61B 5/352 (2021.01) [A61B 5/0245 (2013.01); A61B 5/076 (2013.01); A61B 5/287 (2021.01); A61B 5/333 (2021.01); A61B 5/363 (2021.01); A61B 5/686 (2013.01); A61B 5/7203 (2013.01); G16H 40/67 (2018.01); G16H 50/30 (2018.01)] | 20 Claims |
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1. A method for identifying ventricular sensed (VS) events from a signal indicative of cardiac electrical activity, and monitoring for an arrythmia and/or performing arrythmia discrimination based on the VS events, the method comprising:
(a) detecting when positive portions of the signal indicative of cardiac electrical activity cross a first dynamic sensing threshold to thereby detect first threshold crossings, each of which is indicative of a detected potential VS event;
(b) detecting when negative portions of the signal indicative of cardiac electrical activity cross a second dynamic sensing threshold to thereby detect second threshold crossings, each of which is indicative of a detected potential VS event;
(c) starting a positive signal refractory period in response to each said first threshold crossing, and ending each said positive signal refractory period after a first specified interval has elapsed;
(d) starting a negative signal refractory period in response to each said second threshold crossing, and ending each said negative signal refractory period after a second specified interval has elapsed;
(e) starting a shared signal refractory period in response to each said first threshold crossing that occurs outside of a previously started said positive signal refractory period that has not yet ended, if any, and outside of a previously started said shared signal refractory period that has not yet ended, if any;
(f) starting a shared signal refractory period in response to each said second threshold crossing that occurs outside of a previously started said negative signal refractory period that has not yet ended, if any, and outside of a previously started said shared signal refractory period that has not yet ended, if any;
(g) rejecting each said potential VS event detected within a said shared signal refractory period; and
(h) using the detected potential VS events that were not rejected to monitor for an arrythmia or to perform arrythmia discrimination, or both.
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9. An apparatus, comprising:
two or more electrodes;
a sensing circuit coupleable to at least two of the electrodes to thereby sense a signal indicative of cardiac electrical activity; and
at least one processor configured to
detect when positive portions of the signal indicative of cardiac electrical activity cross a first dynamic sensing threshold to thereby detect first threshold crossings, each of which is indicative of a detected potential VS event;
detect when negative portions of the signal indicative of cardiac electrical activity cross a second dynamic sensing threshold to thereby detect second threshold crossings, each of which is indicative of a detected potential VS event;
start a positive signal refractory period in response to each said first threshold crossing, and end each said positive signal refractory period after a first specified interval has elapsed;
start a negative signal refractory period in response to each said second threshold crossing, and end each said negative signal refractory period after a second specified interval has elapsed;
start a shared signal refractory period in response to each said first threshold crossing that occurs outside of a previously started said positive signal refractory period that has not yet ended, if any, and outside of a previously started said shared signal refractory period that has not yet ended, if any;
start a shared signal refractory period in response to each said second threshold crossing that occurs outside of a previously started said negative signal refractory period that has not yet ended, if any, and outside of a previously started said shared signal refractory period that has not yet ended, if any;
reject each said potential VS event detected within a said shared signal refractory period; and
use the detected potential VS events that were not rejected to monitor for an arrythmia or to perform arrythmia discrimination, or both.
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17. A method, comprising:
comparing a non-rectified far-field electrogram (EGM) or electrocardiogram (ECG) signal to a first dynamic sensing threshold and to a second dynamic sensing threshold to thereby detect first threshold crossings and second threshold crossings, each of which is indicative of a detected potential ventricular sensed (VS) event;
initiating a positive signal refractory period in response to each said first threshold crossing, and initiating a negative signal refractory period in response to each said second threshold crossing;
initiating a shared signal refractory period in response to each said first threshold crossing that occurs outside of a previously started said positive signal refractory period that has not yet ended, if any, and outside of a previously started said shared signal refractory period that has not yet ended, if any;
initiating a shared signal refractory period in response to each said second threshold crossing that occurs outside of a previously started said negative signal refractory period that has not yet ended, if any, and outside of a previously started said shared signal refractory period that has not yet ended, if any; and
monitoring for an arrythmia or performing arrythmia discrimination, or both, based on the detected potential VS events that were detected outside of the positive, the negative and the shared signal refractory periods.
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