Methods and apparatus for discriminating polymorphic tachyarrhythmias from monomorphic tachyarrhythmias facilitating detection of fibrillation
First Claim
1. A method of discriminating between a monomorphic tachyarrhythmia and a polymorphic tachyarrhythmia of a heart of a patient having a cardiac signal, comprising the steps of:
- first deriving a plurality of data sets of signal amplitudes of at least a first number of measured time intervals of the cardiac signal satisfying a polymorphic tachyarrhythmia detection criteria;
thenderiving a corresponding plurality of sets of wavelet transform coefficients from the plurality of data sets of signal amplitudes;
comparing at least selected ones of the wavelet transform coefficients of each of the plurality of sets of wavelet transform coefficients to determine a match count of the plurality of sets of wavelet transform coefficients that match at least one other of the plurality of sets of wavelet transform coefficients within a predetermined match tolerance;
thendeclaring a monomorphic tachyarrhythmia if the match count is greater than a morphologic stability threshold; and
declaring a polymorphic tachyarrhythmia if the match count is less than a morphologic stability threshold.
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Abstract
Methods and apparatus are provided for discriminating high rate polymorphic QRS complexes from high rate monomorphic QRS complexes to increase the specificity of detection of polymorphic VT and VF employing wavelet transform signal processing of the QRS complexes are disclosed. Wavelet transforms are applied to the sampled amplitude values of a sequence of QRS complexes to develop wavelet transform coefficient (WTC) data sets. At least selected ones of the WTC data sets are processed and comparisons are made to determine a wavelet match score. A determination is made as a function of the wavelet match scores of the series of successive QRS complexes that characterizes the most recent QRS complex as more or less likely to signify polymorphic VT or VF.
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Citations
11 Claims
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1. A method of discriminating between a monomorphic tachyarrhythmia and a polymorphic tachyarrhythmia of a heart of a patient having a cardiac signal, comprising the steps of:
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first deriving a plurality of data sets of signal amplitudes of at least a first number of measured time intervals of the cardiac signal satisfying a polymorphic tachyarrhythmia detection criteria;
thenderiving a corresponding plurality of sets of wavelet transform coefficients from the plurality of data sets of signal amplitudes; comparing at least selected ones of the wavelet transform coefficients of each of the plurality of sets of wavelet transform coefficients to determine a match count of the plurality of sets of wavelet transform coefficients that match at least one other of the plurality of sets of wavelet transform coefficients within a predetermined match tolerance;
thendeclaring a monomorphic tachyarrhythmia if the match count is greater than a morphologic stability threshold; and declaring a polymorphic tachyarrhythmia if the match count is less than a morphologic stability threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification