Signal analysis in implantable cardiac treatment devices
AssigneeCameron Health, Inc.
InventorsAlan H. Ostroff, James W. Phillips, Venugopal Allavatam
Life of this patent
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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.
Claims19
A method of cardiac signal analysis, the method comprising:
- capturing a cardiac signal by the use of first and second electrodes disposed within a patient;
- detecting a cardiac event;
- conditioning a portion of the cardiac signal associated with the cardiac event;
- and
- analyzing at least some parts of the 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.
A method of cardiac signal analysis, the method comprising:
- capturing a cardiac signal by the use of first and second electrodes disposed within a patient;
- 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.
A method of determining whether a patient is undergoing a malignant cardiac condition, the method comprising:
- capturing a cardiac signal having a cardiac event from a patient using implanted electrodes;
- sampling the cardiac signal such that it is comprised of a number of signal samples;
- and
- comparing the cardiac signal to a stored template to yield a score indicative of correlation between the cardiac signal and the stored template, wherein at least some of the signal samples are provided with greater weight during the comparison and others of the signal samples are provided with a lesser weight during the comparison.
A method of cardiac signal analysis, the method comprising:
- capturing a cardiac signal by the use of first and second electrodes disposed within a patient;
- detecting a cardiac event;
- conditioning a portion of the cardiac signal associated with the cardiac event;
- and
- analyzing the portion of the cardiac signal to determine whether the patient is likely experiencing a malignant cardiac condition;
- wherein:
- the step of detecting a cardiac event includes observing whether a captured cardiac signal exceeds a threshold value in the following manner:
- a) after a previous cardiac event, selecting a refractory period;
- b) identifying peak signal amplitudes of one or more previous cardiac events and selecting first and second thresholds related to the peak signal amplitudes, the first threshold having a greater value than the second threshold;
- and
- c) generating the threshold value with a continuously decreasing value over a time following the refractory period and before sensing of a next cardiac event, the threshold value having a first value equal to the first threshold and, at a later point in time, having a value approaching the second threshold;
- and
- the step of analyzing includes comparing the cardiac signal to a stored template and providing greater weight to comparisons of first corresponding portions of the cardiac signal and the template, and lesser weight to comparisons of second corresponding portions of the cardiac signal and the template.
Dependencies are inferred from the claim text.