Patent ID: 8532762

Claim:
A method of arrhythmia discrimination for implementation by an implantable cardiac rhythm management device, comprising: detecting cardiac beats associated with an arrhythmia episode; forming a plurality of templates of the arrhythmia episode using morphological features of the cardiac beats of the arrhythmia episode, wherein forming the plurality of templates includes: forming at least one template of the arrhythmia episode; measuring similarity between morphological features of a cardiac beat of the arrhythmia episode and each previously formed template of the arrhythmia episode; using the cardiac beat to modify a previously formed template of the arrhythmia episode in response to a measure of similarity between the cardiac beat and the previously formed template being greater than a similarity threshold; and forming an additional template of the arrhythmia episode in response to measures of similarity between the cardiac beat and each previously formed template being less than a similarity threshold; determining the number of templates formed from the arrhythmia episode; and discriminating between monomorphic tachyarrhythmia and polymorphic tachyarrhythmia based on the number of templates determined to be formed using the cardiac beats of the arrhythmia episode.