Method and apparatus for morphology-based arrhythmia classification using cardiac and other physiological signals
First Claim
1. A tachyarrhythmia detection and classification system, comprising:
- a cardiac sensing circuit configured to sense a cardiac signal;
a hemodynamic sensor configured to sense a hemodynamic signal;
a tachyarrhythmia detector coupled to the cardiac sensing circuit, the tachyarrhythmia detector configured to detect a tachyarrhythmia episode using the cardiac signal;
a physiological parameter generator coupled to the physiological sensor, the physiological parameter generator configured to measure an arrhythmic hemodynamic parameter from the hemodynamic signal during the detected tachyarrhythmia episode; and
a morphology-based tachyarrhythmia classification module coupled to the cardiac sensing circuit, the physiological parameter generator, and the tachyarrhythmia detector, the morphology-based tachyarrhythmia classification module configured to extract arrhythmic morphological features of an arrhythmic heart beat of the detected tachyarrhythmia episode from the cardiac signal, compute a measure of similarity between the extracted arrhythmic morphological features of the arrhythmic heart beat and template morphological features of a template heart beat, and compare the computed measure of similarity to a beat classification threshold to classify the arrhythmic heart beat, the morphology-based tachyarrhythmia classification module including a threshold generator configured to dynamically adjust the beat classification threshold using the arrhythmic hemodynamic parameter and a template hemodynamic parameter,wherein the hemodynamic signal comprises at least one of an impedance signal indicative of a transthoracic impedance or a cardiac impedance, a pressure signal indicative of an arterial pressure, a signal indicative of blood flow, a signal indicative of heart sounds, an oximetry signal indicative of blood oxygenation, a plethysmographic signal indicative of cardiac output, a respiratory signal, or a cardiac contractility signal, and the hemodynamic sensor comprises at least one of an impedance sensor configured to sense the impedance signal, a pressure sensor configured to sense the pressure signal, a flow sensor configured to sense the signal indicative of blood flow, a heart sound sensor configured to sense the signal indicative of heart sounds, a pulse oximetry sensor configured to sense the oximetry signal, a photoplethysmography sensor configured to sense the plethysmo graphic signal, a respiratory sensor configured to sense the respiratory signal, or a cardiac contractility sensor configured to sense the cardiac contractility signal.
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Abstract
A tachyarrhythmia detection and classification system classifies tachyarrhythmias based on an analysis of morphological features of a cardiac signal enhanced by using one or more physiological parameters indicative of hemodynamic stability and/or activity level. The tachyarrhythmia detection and classification system computes a measure of similarity between an arrhythmic waveform of the cardiac signal, a template waveform for that cardiac signal, such as a correlation coefficient representative of the correlation between morphological features of the arrhythmic waveform and morphological features of the template waveform. A detected tachyarrhythmia episode is classified by comparing the measure of similarity to a threshold that is dynamically adjusted using the one or more physiological parameters.
61 Citations
20 Claims
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1. A tachyarrhythmia detection and classification system, comprising:
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a cardiac sensing circuit configured to sense a cardiac signal; a hemodynamic sensor configured to sense a hemodynamic signal; a tachyarrhythmia detector coupled to the cardiac sensing circuit, the tachyarrhythmia detector configured to detect a tachyarrhythmia episode using the cardiac signal; a physiological parameter generator coupled to the physiological sensor, the physiological parameter generator configured to measure an arrhythmic hemodynamic parameter from the hemodynamic signal during the detected tachyarrhythmia episode; and a morphology-based tachyarrhythmia classification module coupled to the cardiac sensing circuit, the physiological parameter generator, and the tachyarrhythmia detector, the morphology-based tachyarrhythmia classification module configured to extract arrhythmic morphological features of an arrhythmic heart beat of the detected tachyarrhythmia episode from the cardiac signal, compute a measure of similarity between the extracted arrhythmic morphological features of the arrhythmic heart beat and template morphological features of a template heart beat, and compare the computed measure of similarity to a beat classification threshold to classify the arrhythmic heart beat, the morphology-based tachyarrhythmia classification module including a threshold generator configured to dynamically adjust the beat classification threshold using the arrhythmic hemodynamic parameter and a template hemodynamic parameter, wherein the hemodynamic signal comprises at least one of an impedance signal indicative of a transthoracic impedance or a cardiac impedance, a pressure signal indicative of an arterial pressure, a signal indicative of blood flow, a signal indicative of heart sounds, an oximetry signal indicative of blood oxygenation, a plethysmographic signal indicative of cardiac output, a respiratory signal, or a cardiac contractility signal, and the hemodynamic sensor comprises at least one of an impedance sensor configured to sense the impedance signal, a pressure sensor configured to sense the pressure signal, a flow sensor configured to sense the signal indicative of blood flow, a heart sound sensor configured to sense the signal indicative of heart sounds, a pulse oximetry sensor configured to sense the oximetry signal, a photoplethysmography sensor configured to sense the plethysmo graphic signal, a respiratory sensor configured to sense the respiratory signal, or a cardiac contractility sensor configured to sense the cardiac contractility signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for detecting and classifying tachyarrhythmia, the method comprising:
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sensing a cardiac signal; sensing a hemodynamic signal; detecting a tachyarrhythmia episode using the cardiac signal; measuring an arrhythmic hemodynamic parameter from the hemodynamic signal during the detected tachyarrhythmia episode; extracting arrhythmic morphological features of an arrhythmic heart beat of the detected tachyarrhythmia episode from the cardiac signal; computing a measure of similarity between the extracted arrhythmic morphological features of the arrhythmic heart beat and template morphological features of a template heart beat; comparing the computed measure of similarity to a beat classification threshold to classify the arrhythmic heart beat; dynamically adjusting the beat classification threshold using the arrhythmic hemodynamic parameter and a template hemodynamic parameter; and measuring the template hemodynamic parameter when hemodynamic performance is normal or stable. - View Dependent Claims (16, 17, 18)
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19. A method for detecting and classifying tachyarrhythmia, the method comprising:
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sensing a cardiac signal; sensing a hemodynamic signal; detecting a tachyarrhythmia episode using the cardiac signal; measuring an arrhythmic hemodynamic parameter from the hemodynamic signal during the detected tachyarrhythmia episode; extracting arrhythmic morphological features of an arrhythmic heart beat of the detected tachyarrhythmia episode from the cardiac signal; computing a measure of similarity between the extracted arrhythmic morphological features of the arrhythmic heart beat and template morphological features of a template heart beat; comparing the computed measure of similarity to a beat classification threshold to classify the arrhythmic heart beat; dynamically adjusting the beat classification threshold using the arrhythmic hemodynamic parameter and a template hemodynamic parameter; and empirically estimating the template hemodynamic parameter from the hemodynamic signal during hemodynamically tolerable tachyarrhythmia. - View Dependent Claims (20)
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Specification