Patent ID: 7991470

Claim:
A cardiac rhythm management device, comprising: one or more sensing channels for sensing cardiac electrical activity and for generating a first electrogram signal; pulse generation circuitry for delivering pacing pulses and/or shock pulses; a controller interfaced to the one or more sensing channels and the pulse generation circuitry, wherein the controller is programmed to: measure a ventricular rate from sensed ventricular electrical activity; 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; discriminate between SVT and VT with a test for SVT/VT discrimination that includes a morphology criterion based on an analysis of the first electrogram signal; deliver either a cardioversion/defibrillation shock or anti-tachycardia pacing to treat the tachyarrhythmia; and, if a cardioversion/defibrillation shock is delivered: discontinue use of the morphology criterion in the test for SVT/VT discrimination after delivery of the cardioversion/defibrillation shock for at least one ventricular beat; judge whether or not one or more ventricular beats that occur after delivery of the cardioversion/defibrillation shock are normally conducted; and, resume use of the morphology criterion in the test for SVT/VT discrimination when a first predetermined minimum number of ventricular beats occurring after delivery of the cardioversion/defibrillation shock has been judged as normally conducted.