Patent ID: 7729762

Claim:
A method for operating a cardiac device capable of delivering a plurality of therapies for each of a plurality of ventricular tachyarrhythmia types; the method comprising: sensing a cardiac electrical signal of an arrhythmia episode; measuring a cardiac rate of the sensed cardiac electrical signal; determining that the measured cardiac rate exceeds a tachyarrhythmia threshold rate; distinguishing between a tachycardia rate zone and a fibrillation rate zone using a fibrillation rate boundary; if the measured cardiac rate falls within the tachycardia rate zone, then: analyzing a morphology of the cardiac signal; further classifying the arrhythmia episode as one of a plurality of types of ventricular tachyarrhythmia (VT) based on the morphology analysis; if the measured cardiac rate falls within the fibrillation rate zone, then: initially classifying the arrhythmia episode as ventricular fibrillation (VF) based on the measured cardiac rate falling within the fibrillation rate zone; analyzing the morphology of the cardiac signal; based on the morphology analysis, either (a) maintaining the classification of the arrhythmia episode as VF, or (b) reclassifying the arrhythmia episode as a ventricular tachyarrhythmia (VT) that is terminable using anti-tachyarrhythmia pacing (ATP); if the arrhythmia episode is classified as one of the plurality of types of VT or as the VT that is terminable using ATP, then selecting a therapy from the plurality of therapies for the type of the VT based on a history of success of the selected therapy at terminating the type of the VT, and delivering the selected therapy; and if the arrhythmia episode is classified as VF, then delivering a cardioversion/defibrillation shock to terminate the VF.