Method and apparatus for rate-dependent morphology-based cardiac arrhythmia classification
First Claim
1. A system for classifying cardiac arrhythmias, the system comprising:
- a template waveform input to receive template data representative of a template waveform associated with a template heart beat of a known cardiac rhythm;
an arrhythmic waveform input to receive arrhythmic data representative of an arrhythmic waveform associated with an arrhythmic heart beat of an arrhythmia episode;
an arrhythmic heart rate input to receive an arrhythmic heart rate parameter representative of an arrhythmic heart rate associated with the arrhythmic waveform;
a rate-dependent feature locator coupled to the template waveform input, the arrhythmic waveform input, and the arrhythmic heart rate parameter input, the rate-dependent feature locator adapted to determine morphological feature locations using at least the arrhythmic heart rate parameter, the morphological feature locations including template feature locations of a plurality of template morphological features on the template waveform and arrhythmic feature locations of a plurality of corresponding arrhythmic morphological features on the arrhythmic waveform; and
a feature extracting module coupled to the rate-dependent feature locator, the feature extracting module adapted to extract the plurality of template morphological features from the template waveform and the plurality of corresponding arrhythmic morphological features from the arrhythmic waveform based on the morphological feature locations.
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Abstract
An implantable medical device includes a tachyarrhythmia detection and classification system that classifies tachyarrhythmias based on a morphological analysis of template and arrhythmic waveforms. The morphological analysis takes effect of heart rate on the morphological characteristics of the template and arrhythmic waveforms into consideration. Correlation between morphological features of the template waveform and corresponding morphological features of an arrhythmic waveform provides for the basis for classifying the tachyarrhythmia. In one embodiment, corresponding morphological features are extracted from the template and arrhythmic waveforms at locations determined by the heart rate associated with a detected arrhythmia episode. In another embodiment, weighting factors each being a function of the heart rate are applied to the template and arrhythmic morphological features before a correlation coefficient is calculated.
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Citations
35 Claims
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1. A system for classifying cardiac arrhythmias, the system comprising:
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a template waveform input to receive template data representative of a template waveform associated with a template heart beat of a known cardiac rhythm;
an arrhythmic waveform input to receive arrhythmic data representative of an arrhythmic waveform associated with an arrhythmic heart beat of an arrhythmia episode;
an arrhythmic heart rate input to receive an arrhythmic heart rate parameter representative of an arrhythmic heart rate associated with the arrhythmic waveform;
a rate-dependent feature locator coupled to the template waveform input, the arrhythmic waveform input, and the arrhythmic heart rate parameter input, the rate-dependent feature locator adapted to determine morphological feature locations using at least the arrhythmic heart rate parameter, the morphological feature locations including template feature locations of a plurality of template morphological features on the template waveform and arrhythmic feature locations of a plurality of corresponding arrhythmic morphological features on the arrhythmic waveform; and
a feature extracting module coupled to the rate-dependent feature locator, the feature extracting module adapted to extract the plurality of template morphological features from the template waveform and the plurality of corresponding arrhythmic morphological features from the arrhythmic waveform based on the morphological feature locations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for classifying cardiac arrhythmias, the method comprising:
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detecting an arrhythmia episode;
producing a heart rate parameter representative of an arrhythmic heart rate associated with the arrhythmic episode;
determining morphological feature locations using at least the heart rate parameter, the morphological feature locations including template feature locations of a plurality of template morphological features on a template waveform associated with a template heart-beat of a known cardiac rhythm and arrhythmic feature locations of a plurality of corresponding arrhythmic morphological features on an arrhythmic waveform associated with an arrhythmic heart beat of the arrhythmia episode; and
extracting the plurality of template morphological features from the template waveform and the plurality of corresponding arrhythmic morphological features from the arrhythmic waveform based on the morphological feature locations. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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23. A system for classifying cardiac arrhythmias, the system comprising:
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a template feature input to receive a plurality of template morphological features of a template waveform associated with a template heart beat of a known cardiac rhythm;
an arrhythmic feature input to receive a plurality of arrhythmic morphological features of an arrhythmic waveform associated with an arrhythmic heart beat of an arrhythmia episode, the arrhythmic morphological features each corresponding to one of the template morphological features;
an arrhythmic heart rate input to receive an arrhythmic heart rate parameter representative of an arrhythmic heart rate associated with the arrhythmic waveform;
a rate-dependent weighting module coupled to the template feature input, the arrhythmic feature input, and the arrhythmic heart rate input, the rate-dependent weighting module adapted to produce weighted template morphological features and weighted arrhythmic morphological features using at least the plurality of template morphological features, the plurality of arrhythmic morphological features, and the arrhythmic heart rate parameter; and
a correlation coefficient calculator, coupled to the rate-dependent weighting module, to calculate at least one correlation coefficient representative of a correlation between the weighted arrhythmic morphological features and the weighted template morphological features. - View Dependent Claims (24, 25, 26, 27, 28, 29)
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30. A method for classifying cardiac arrhythmias, the method comprising:
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receiving a plurality of template morphological features of a template waveform associated with a template heart beat of a known cardiac rhythm;
receiving a plurality of arrhythmic morphological features of an arrhythmic waveform associated with an arrhythmic heart beat of an arrhythmia episode, the arrhythmic morphological features each corresponding to one of the template morphological features;
receiving an arrhythmic heart rate parameter representative of an arrhythmic heart rate associated with the arrhythmic waveform;
producing a plurality of weighting factors using at least the arrhythmic heart rate parameter;
producing weighted template morphological features and weighted arrhythmic morphological features by applying a weighting factor of the plurality of weighting factors to each of the template morphological features and each of the arrhythmic morphological features;
analyzing a correlation between the weighted template morphological features and the weighted arrhythmic morphological features; and
classifying the arrhythmia episode based on the correlation. - View Dependent Claims (31, 32, 33, 34, 35)
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Specification