Patent ID: 8214038

Claim:
A cardiac rhythm management device, comprising: shock generation circuitry connectable to an electrode for delivering a cardioversion/defibrillation shock; a sensing amplifier connectable to an electrode for sensing ventricular electrical activity and generating a first electrogram signal; a controller interfaced to the sensing amplifier and the pulse generation circuitry, wherein the controller is programmed to measure a ventricular rate from sensed ventricular electrical activity and detect a tachyarrhythmia that may be either a supraventricular tachycardia (SVT) or a ventricular tachycardia (VT) if the measured ventricular rate is within a specified range; wherein the controller is programmed to utilize a morphology criterion derived from analysis of the first electrogram signal for discriminating between SVT and VT; wherein the controller is programmed to discontinue use of the morphology criterion for SVT/VT discrimination after delivery of a cardioversion/defibrillation shock; and, wherein the controller is programmed to resume use of the morphology criterion for SVT/VT discrimination when a first predetermined minimum number of ventricular beats has been judged as normally conducted.