Methods and apparatuses for cardiac arrhythmia classification using morphology stability
First Claim
1. A system for classifying tachyarrhythmias, the system comprising:
- a correlation input to receive a plurality of feature correlation coefficient (Fcc) values each indicative of whether an arrhythmic heart beat of a 1;
1 tachyarrhythmia is morphologically correlated to a template heart beat of a known type cardiac rhythm;
a majority voting circuit coupled to the correlation input, the majority voting circuit adapted to classify the 1;
1 tachyarrhythmia as a first type tachyarrhythmia if a number of the arrhythmic heart beats that are correlated to the template heart beat equals or exceeds a predetermined threshold number, the majority voting circuit including;
a correlation comparator to receive each Fcc value of the plurality of Fcc values and indicate a correlated beat if the each Fcc value is greater than a predetermined detection threshold for the plurality of Fcc values;
a correlated beat counter circuit to count a number of the indicated correlated beats (NCORR); and
a first type tachyarrhythmia classification circuit to classify the 1;
1 tachyarrhythmia as the first type tachyarrhythmia if the NCORR equals or exceeds the predetermined threshold number; and
a morphology stability analysis circuit coupled to the majority voting circuit, the morphology stability analysis circuit adapted to further classify the 1;
1 tachyarrhythmia based on a stability associated with the Fcc values if the number of the arrhythmic heart beats that are correlated to the template heart beat is smaller than the predetermined threshold number.
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Abstract
An implantable cardioverter/defibrillator (ICD) includes a tachyarrhythmia detection and classification system that classifies tachyarrhythmias based on a morphological analysis of arrhythmic waveforms and a template waveform. Correlation coefficients each computed between morphological features of an arrhythmic waveform and morphological features of the template waveform provide for the basis for classifying the tachyarrhythmia. In one embodiment, morphological features are collected from a sensed arrhythmic waveform, and temporally corresponding morphological features are extracted a stored template waveform. In one embodiment, a correlation analysis takes into account the uncertainty associated with the production of the template waveform by using a template band that includes confidence intervals. In one embodiment, a correlation analysis produces Mahalanobis distance-based correlation coefficients for use in the classification of the tachyarrhythmia. In one embodiment, the stability of correlation coefficients are analyzed to classify the tachyarrhythmia.
176 Citations
16 Claims
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1. A system for classifying tachyarrhythmias, the system comprising:
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a correlation input to receive a plurality of feature correlation coefficient (Fcc) values each indicative of whether an arrhythmic heart beat of a 1;
1 tachyarrhythmia is morphologically correlated to a template heart beat of a known type cardiac rhythm;a majority voting circuit coupled to the correlation input, the majority voting circuit adapted to classify the 1;
1 tachyarrhythmia as a first type tachyarrhythmia if a number of the arrhythmic heart beats that are correlated to the template heart beat equals or exceeds a predetermined threshold number, the majority voting circuit including;a correlation comparator to receive each Fcc value of the plurality of Fcc values and indicate a correlated beat if the each Fcc value is greater than a predetermined detection threshold for the plurality of Fcc values; a correlated beat counter circuit to count a number of the indicated correlated beats (NCORR); and a first type tachyarrhythmia classification circuit to classify the 1;
1 tachyarrhythmia as the first type tachyarrhythmia if the NCORR equals or exceeds the predetermined threshold number; anda morphology stability analysis circuit coupled to the majority voting circuit, the morphology stability analysis circuit adapted to further classify the 1;
1 tachyarrhythmia based on a stability associated with the Fcc values if the number of the arrhythmic heart beats that are correlated to the template heart beat is smaller than the predetermined threshold number. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for classifying tachyarrhythmias, the method comprising:
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receiving a plurality of feature correlation coefficient (Fcc) values each indicative of whether an arrhythmic heart beat of a 1;
1 tachyarrhythmia is morphologically correlated to a template heart beat of a known type cardiac rhythm;indicating a correlated beat if each Fcc value of the plurality of Fcc values is greater than a predetermined detection threshold; counting a number of the indicated correlated beats (NCORR); classifying the 1;
1 tachyarrhythmia as the first type tachyarrhythmia if the NCORR equals or exceeds the predetermined threshold number;analyzing a stability of the Fcc values if the NCORR is smaller than the predetermined threshold number; and discriminating the 1;
1 tachyarrhythmia based on an outcome of the analyzing the stability of the Fcc values. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A system for classifying tachyarrhythmias, the system comprising:
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means for producing a plurality of feature correlation coefficient (Fcc) values each indicative of whether an arrhythmic heart beat of a 1;
1 tachyarrhythmia is morphologically correlated to a template heart beat of a known type cardiac rhythm;means for classifying the 1;
1 tachyarrhythmia based on whether a number of the arrhythmic heart beats that are correlated to the template heart beat equals or exceeds a predetermined threshold number; andmeans for discriminating the 1;
1 tachyarrhythmia by analyzing a stability of the Fcc values if the number of the arrhythmic heart beats that are correlated to the template heart beat is smaller than the predetermined threshold number, the means for discriminating the 1;
1 tachyarrhythmia including;means for computing a median Fcc being a median value of the plurality of Fcc values; means for counting an Fcc spread number being a number of Fcc values of the plurality of Fcc values that are within a window centered at the FccMED; and means for discriminating the 1;
1 tachyarrhythmia based on the number of the arrhythmic heart beats that are correlated to the template heart beat, the median Fcc, and the Fcc spread number. - View Dependent Claims (16)
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Specification