Patent ID: 8086308

Claim:
An implantable medical device, comprising: a pulse generator configured to provide atrial and ventricular pacing pulses on demand, the pulse generator timing delivery of the ventricular pacing pulses based on an AV pacing interval; an AV hysteresis module that extends an AV interval from a base AV interval to an extended AV interval to promote intrinsic heart activity; a refractory module that establishes a PVARP interval equal to a base PVARP interval following at least one of the ventricular pacing pulses, the refractory module lengthening the PVARP interval by adding a PVARP extension to the base PVARP interval to provide an extended PVARP interval; and a reentrant conduction detector identifying an intrinsic reentrant tachycardia based, in part, on a retrograde P wave occurring during the PVARP extension of the extended PVARP interval.