Method and apparatus for detecting arrhythmias in a medical device
First Claim
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1. A method of detecting a cardiac event in a medical device, comprising:
- sensing a cardiac signal from a plurality of electrodes, the plurality of electrodes forming a first sensing vector and a second sensing vector different from the first sensing vector;
determining first amplitudes of the sensed cardiac signal sensed along the first sensing vector during a predetermined sensing window;
determining second amplitudes of the sensed cardiac signal sensed along the second sensing vector during the predetermined sensing window;
determining a first noise to signal ratio corresponding to the determined first amplitudes;
determining a second noise to signal ratio corresponding to the determined second amplitudes;
comparing the first noise to signal ratio to a noise to signal ratio threshold;
identifying the first sensing vector as noisy in response to the comparing the first noise to signal ratio to the noise to signal ratio threshold;
comparing the second noise to signal ratio to the noise to signal threshold;
identifying the second sensing vector as noisy in response to the comparing the second noise to signal ratio to the noise to signal threshold; and
delivering therapy in response to the identifying.
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Abstract
A method of detecting a cardiac event in a medical device that includes sensing a cardiac signal from a plurality of electrodes, determining amplitudes of the sensed cardiac signal during a predetermined sensing window, determining a noise to signal ratio corresponding to the determined amplitudes, and determining the sensed cardiac signal during the predetermined sensing window is corrupted by noise in response to the determined noise to signal ratio being greater than a noise to signal ratio threshold.
201 Citations
15 Claims
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1. A method of detecting a cardiac event in a medical device, comprising:
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sensing a cardiac signal from a plurality of electrodes, the plurality of electrodes forming a first sensing vector and a second sensing vector different from the first sensing vector; determining first amplitudes of the sensed cardiac signal sensed along the first sensing vector during a predetermined sensing window; determining second amplitudes of the sensed cardiac signal sensed along the second sensing vector during the predetermined sensing window; determining a first noise to signal ratio corresponding to the determined first amplitudes; determining a second noise to signal ratio corresponding to the determined second amplitudes; comparing the first noise to signal ratio to a noise to signal ratio threshold; identifying the first sensing vector as noisy in response to the comparing the first noise to signal ratio to the noise to signal ratio threshold; comparing the second noise to signal ratio to the noise to signal threshold; identifying the second sensing vector as noisy in response to the comparing the second noise to signal ratio to the noise to signal threshold; and delivering therapy in response to the identifying. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of detecting a cardiac event in a medical device, comprising:
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sensing a cardiac signal from a plurality of electrodes, the plurality of electrodes forming a first sensing vector and a second sensing vector different from the first sensing vector; determining amplitudes of the sensed cardiac signal during a predetermined sensing window for each of the first sensing vector and the second sensing vector; determining a first noise to signal ratio associated with the first sensing vector and a second noise to signal ratio associated with the second sensing vector corresponding to the determined amplitudes as a ratio of a highpass mean rectified amplitude corresponding to the sensed cardiac signal during the predetermined sensing window to a lowpass mean rectified amplitude corresponding to the sensed cardiac signal during the predetermined sensing window; comparing the first noise to signal ratio and the second noise to signal ratio to a noise to signal ratio threshold; determining a first metric of signal energy content associated with the sensed cardiac signal during the predetermined sensing window for the first sensing vector; determining a second metric of signal energy content associated with the sensed cardiac signal during the predetermined sensing window for the second sensing vector; comparing the first metric of signal energy content and the second metric of signal energy content to a first signal energy content threshold and a second signal energy content threshold, the first signal energy content threshold corresponding to a value greater than a signal energy content associated with the detected cardiac event and the second signal energy content threshold corresponding to asystole episodes; and identifying the detected cardiac event as a shockable event in response to the comparing. - View Dependent Claims (12, 13)
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14. A non-transitory computer readable medium having computer executable instructions for performing a method comprising:
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sensing a cardiac signal from a plurality of electrodes, the plurality of electrodes forming a first sensing vector and a second sensing vector different from the first sensing vector; determining first amplitudes of the sensed cardiac signal sensed along the first sensing vector during a predetermined sensing window; determining second amplitudes of the sensed cardiac signal sensed along the second sensing vector during the predetermined sensing window; determining a first noise to signal ratio corresponding to the determined first amplitudes; determining a second noise to signal ratio corresponding to the determined second amplitudes; identifying the first sensing vector as noisy in response to the comparing the first noise to signal ratio to the noise to signal ratio threshold; comparing the second noise to signal ratio to the noise to signal threshold; identifying the second sensing vector as noisy in response to the comparing the second noise to signal ratio to the noise to signal threshold; and delivering therapy in response to the identifying. - View Dependent Claims (15)
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Specification