Cardiac rhythm management system with noise detector
First Claim
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1. A device for association with a heart using at least one electrode, the device comprising:
- a cardiac signal detector coupled to the first electrode, and including a detector output providing a sampled cardiac signal;
a signal processor circuit to determine, over a predetermined plurality of cardiac signal samples, whether an evaluation sample of the cardiac signal is a turning point with respect to previous and subsequent samples, and to deem a portion of the cardiac signal to be noisy if a number of turning points exceeds a threshold value for the predetermined plurality of cardiac signal samples; and
wherein, if the cardiac signal is deemed noisy, the cardiac signal detector is additionally coupled to a different second electrode for detecting depolarizations, and wherein the cardiac signal detector includes independent first and second sensing channels that are respectively coupled to the first and second electrodes for independently sensing a depolarization at each of the first and second electrodes to corroborate depolarizations sensed at the first electrode using corresponding depolarizations independently sensed at the second electrode.
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Abstract
A system, method, or device determines whether noise is present on a sampled and/or digitized sensed intrinsic cardiac signal based on a moving count of turning/inflection points of the signal. If noise is detected, the manner in which the cardiac signal is acquired, or the manner in which the device operates in response to the acquired cardiac signal (or both) is altered to reduce the risk of erroneously detecting noise as a heart depolarization and, therefore, inappropriately triggering or withholding therapy.
109 Citations
30 Claims
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1. A device for association with a heart using at least one electrode, the device comprising:
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a cardiac signal detector coupled to the first electrode, and including a detector output providing a sampled cardiac signal; a signal processor circuit to determine, over a predetermined plurality of cardiac signal samples, whether an evaluation sample of the cardiac signal is a turning point with respect to previous and subsequent samples, and to deem a portion of the cardiac signal to be noisy if a number of turning points exceeds a threshold value for the predetermined plurality of cardiac signal samples; and wherein, if the cardiac signal is deemed noisy, the cardiac signal detector is additionally coupled to a different second electrode for detecting depolarizations, and wherein the cardiac signal detector includes independent first and second sensing channels that are respectively coupled to the first and second electrodes for independently sensing a depolarization at each of the first and second electrodes to corroborate depolarizations sensed at the first electrode using corresponding depolarizations independently sensed at the second electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A device for association with a heart using at least one electrode, the device comprising:
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a cardiac signal detector coupled to the first electrode, and including a detector output providing a sampled cardiac signal; a signal processor circuit to determine, over a predetermined plurality of cardiac signal samples, whether an evaluation sample of the cardiac signal is a turning point with respect to previous and subsequent samples, and to deem a portion of the cardiac signal to be noisy if a number of turning points exceeds a threshold value for the predetermined plurality of cardiac signal samples; and wherein, if the cardiac signal is deemed noisy, the cardiac signal detector is additionally coupled to a different second electrode for detecting depolarizations, and in which the signal processor operates to repeat at different frequencies the determination of whether the evaluation sample is a turning point.
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22. A device for association with a heart using at least one electrode, the device comprising:
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a cardiac signal detector coupled to the first electrode, and including a detector output providing a sampled cardiac signal; means for determining, over a predetermined plurality of cardiac signal samples, whether an evaluation sample of the cardiac signal is a turning point with respect to previous and subsequent samples, and to deem a portion of the cardiac signal to be noisy if a number of turning points exceeds a threshold value for the predetermined plurality of cardiac signal samples; and wherein, if the cardiac signal is deemed noisy, the cardiac signal detector is additionally coupled to a different second electrode for detecting depolarizations and wherein the cardiac signal detector includes independent first and second sensing channels that are respectively coupled to the first and second electrodes for independently sensing a depolarization at each of the first and second electrodes to corroborate depolarizations sensed at the first electrode using corresponding depolarizations independently sensed at the second electrode. - View Dependent Claims (23, 24)
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25. A device for association with a heart using at least one electrode, the device comprising:
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a cardiac signal detector coupled to the first electrode, and including a detector output providing a sampled cardiac signal; a signal process or circuit to determine, over a predetermined plurality of cardiac signal samples, whether an evaluation sample of the cardiac signal is a turning point with respect to previous and subsequent samples, and to deem a portion of the cardiac signal to be noisy if a number of turning points exceeds a threshold value for the predetermined plurality of cardiac signal samples; and wherein, if the cardiac signal is deemed noisy, the cardiac signal detector is decoupled from the first electrode and instead coupled to a different second electrode for detecting depolarizations; and wherein the signal processor operates to determine first and second directions of the cardiac signal preceding and following the evaluation sample, respectively, and to deem the evaluation sample to be a turning point if the first direction is different from the second direction and each of the first and second directions manifest a slope of a magnitude that exceeds a corresponding first and second threshold value before deeming the evaluation sample to be a turning point. - View Dependent Claims (26, 27, 28, 29, 30)
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Specification