Signal Analysis in Implantable Cardiac Treatment Devices
First Claim
1. A method of cardiac signal analysis in an implantable cardiac system comprising a plurality of implantable electrodes for sensing signals from implanted locations coupled to circuitry for analysis of sensed signals, the method comprising:
- capturing a cardiac signal by the use of the plurality of electrodes;
detecting a cardiac event;
conditioning a portion of the cardiac signal associated with the cardiac event; and
analyzing at least some parts of the conditioned portion of the cardiac signal to determine whether the patient is likely experiencing a malignant cardiac condition;
wherein the step of conditioning a portion of the cardiac signal associated with the cardiac event includes sampling the cardiac signal to generate a number of samples and comparing a selected sample to a sample threshold and, if the sample magnitude does not exceed the sample threshold, replacing the sample with a different value.
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Abstract
Methods and devices for cardiac signal analysis in implantable cardiac therapy systems. Several signal processing and/or conditioning methods are shown including R-wave detection embodiments including the use of thresholds related to previous peak amplitudes. Also, some embodiments include sample thresholding to remove extraneous data from sampled signals. Some embodiments include weighting certain samples more heavily than other samples within a sampled cardiac signal for analysis.
26 Citations
20 Claims
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1. A method of cardiac signal analysis in an implantable cardiac system comprising a plurality of implantable electrodes for sensing signals from implanted locations coupled to circuitry for analysis of sensed signals, the method comprising:
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capturing a cardiac signal by the use of the plurality of electrodes; detecting a cardiac event; conditioning a portion of the cardiac signal associated with the cardiac event; and analyzing at least some parts of the conditioned portion of the cardiac signal to determine whether the patient is likely experiencing a malignant cardiac condition; wherein the step of conditioning a portion of the cardiac signal associated with the cardiac event includes sampling the cardiac signal to generate a number of samples and comparing a selected sample to a sample threshold and, if the sample magnitude does not exceed the sample threshold, replacing the sample with a different value. - View Dependent Claims (2, 3, 4, 5, 6, 8, 9, 10)
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7. The method of claim 7, wherein the series of comparison values is performed by calculating a difference between a sample of the conditioned portion of the cardiac signal and a corresponding sample of the stored template.
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11. An implantable cardiac stimulus device (ICSD) comprising a plurality of implantable electrodes for sensing signals from implanted locations and operational circuitry coupled to the electrodes and configured to analyze sensed signals and, as determined by the analysis of sensed signals, deliver therapy to a patient, wherein the operational circuitry is configured to perform the following steps to analyze sensed signals:
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receive a cardiac signal captured by the use of the plurality of electrodes; detecting a cardiac event in the cardiac signal; conditioning a portion of the cardiac signal associated with the cardiac event; and analyzing at least some parts of the conditioned portion of the cardiac signal to determine whether the patient is likely experiencing a malignant cardiac condition by comparison of the conditioned portion of the cardiac signal to a stored template; wherein the step of conditioning a portion of the cardiac signal associated with the cardiac event includes sampling the cardiac signal to generate a number of samples and comparing a selected sample to a sample threshold and, if the sample magnitude does not exceed the sample threshold, replacing the sample with a different value. - View Dependent Claims (12, 13, 14, 15)
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16. A method of cardiac signal analysis in an implantable cardiac system comprising a plurality of implantable electrodes for sensing signals from implanted locations coupled to circuitry for analysis of sensed signals, the method comprising:
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capturing a cardiac signal by the use of the plurality of electrodes; detecting a cardiac event; sampling the cardiac signal, treating the sampled signal as a sample vector, and multiplying the sample vector by a weighting vector to yield a weighted sample vector; and analyzing the weighted sample vector to determine whether the patient is likely experiencing a malignant cardiac condition; wherein the step of analyzing the weighted sample vector to determine whether the patient is likely experiencing a malignant cardiac condition comprises comparing the weighted sample vector to a stored template to yield a score indicative of correlation between the cardiac signal and the stored template. - View Dependent Claims (17, 18, 19, 20)
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Specification