SYSTEM AND METHOD FOR CLASSIFYING CARDIAC DEPOLARIZATION COMPLEXES WITH MULTI-DIMENSIONAL CORRELATION
First Claim
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1. A method for classifying a sensed cardiac depolarization complex, comprising:
- sensing a plurality of depolarization waveforms resulting from a cardiac depolarization complex with a plurality of separate electrodes and generating digital samples of the sensed waveforms over a defined period of time to result in a sample set for each sensed waveform;
storing the sample set of each sensed waveform in a sensed sample array and subtracting a mean waveform value from each array member;
storing a sample set of each corresponding waveform of a template depolarization complex in a template sample array and subtracting a mean waveform value from each array member;
computing a correlation sum for the sensed depolarization complex and the template depolarization complex by multiplying each sensed sample array member by a corresponding template sample array member and summing the results of each such multiplication;
computing an autocorrelation sum for the sensed complex by multiplying each sensed sample array member by itself and summing the results of each such multiplication;
computing an autocorrelation sum for the template complex by multiplying each template sample array member by itself and summing the results of each such multiplication;
computing a multi-dimensional correlation between the sensed and template depolarization complexes by dividing the correlation sum for the sensed and template complexes by the square root of the product of the autocorrelation sum for the sensed complex and the autocorrelation sum for the template complex; and
, wherein the sensed depolarization complex is classified as being equivalent to the template complex if the multi-dimensional correlation exceeds a specified value.
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Abstract
A system and method for classifying cardiac depolarization complexes in which waveforms of a depolarization complex are sensed by separate electrodes and correlated with template waveforms of a template depolarization complex. The system is particularly suitable for incorporation into a cardiac rhythm management device such as an implantable cardioverter/defibrillator or pacemaker in order to facilitate arrhythmia prediction and/or prevention.
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Citations
20 Claims
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1. A method for classifying a sensed cardiac depolarization complex, comprising:
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sensing a plurality of depolarization waveforms resulting from a cardiac depolarization complex with a plurality of separate electrodes and generating digital samples of the sensed waveforms over a defined period of time to result in a sample set for each sensed waveform;
storing the sample set of each sensed waveform in a sensed sample array and subtracting a mean waveform value from each array member;
storing a sample set of each corresponding waveform of a template depolarization complex in a template sample array and subtracting a mean waveform value from each array member;
computing a correlation sum for the sensed depolarization complex and the template depolarization complex by multiplying each sensed sample array member by a corresponding template sample array member and summing the results of each such multiplication;
computing an autocorrelation sum for the sensed complex by multiplying each sensed sample array member by itself and summing the results of each such multiplication;
computing an autocorrelation sum for the template complex by multiplying each template sample array member by itself and summing the results of each such multiplication;
computing a multi-dimensional correlation between the sensed and template depolarization complexes by dividing the correlation sum for the sensed and template complexes by the square root of the product of the autocorrelation sum for the sensed complex and the autocorrelation sum for the template complex; and
,wherein the sensed depolarization complex is classified as being equivalent to the template complex if the multi-dimensional correlation exceeds a specified value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 12)
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11. A cardiac rhythm management device having incorporated therein a system for classifying sensed cardiac depolarization complexes, comprising:
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a plurality of sensing channels for sensing waveforms of a cardiac depolarization complex and for converting the sensed waveforms into digitized samples;
a processor and associated memory interfaced to the sensing channels; and
,wherein the processor is programmed to;
store digital samples of the sensed waveforms for each sensed waveform over a defined period of time to result in a sample set;
store the sample set of each sensed waveform in a sensed sample array and subtracting a mean waveform value from each array member;
store a sample set of each corresponding waveform of a template depolarization complex in a template sample array and subtracting a mean waveform value from each array member;
compute a correlation sum for the sensed depolarization complex and the template depolarization complex by multiplying each sensed sample array member by a corresponding template sample array member and summing the results of each such multiplication;
compute an autocorrelation sum for the sensed complex by multiplying each sensed sample array member by itself and summing the results of each such multiplication;
compute an autocorrelation sum for the template complex by multiplying each template sample array member by itself and summing the results of each such multiplication;
compute a multi-dimensional correlation between the sensed and template depolarization complexes by dividing the correlation sum for the sensed and template complexes by the square root of the product of the autocorrelation sum for the sensed complex and the autocorrelation sum for the template complex; and
,classify the sensed depolarization complex as being equivalent to the template complex if the multi-dimensional correlation exceeds a specified value. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification