Patent ID: 7174209

Claim:
A cardiac rhythm management device, comprising: an atrial sensing channel for detecting atrial senses corresponding to atrial depolarizations; a ventricular sensing channel for detecting ventricular senses corresponding to ventricular depolarizations; a controller for detecting arrhythmias based upon the atrial and ventricular senses detected in the sensing channels, wherein the controller is programmed to: compute an AA interval corresponding to a cycle length between consecutive atrial senses, a VV interval corresponding to a cycle length between consecutive ventricular senses, an AV interval corresponding to a cycle length between an atrial sense and a next occurring ventricular sense with no intervening atrial sense, and a VA interval corresponding to a cycle length between a ventricular sense and a next occurring atrial sense with no intervening ventricular sense; compute variabilities for both the VA and AV intervals based upon their measured individual cycle lengths during a specified time window; and, if a 1:1 tachycardia condition is present, defined as when the AA and MV intervals are both within their tachycardia ranges and differ from one another by no more than a specified 1:1 limit value, discriminate between a supraventricular tachycardia and a ventricular tachycardia based upon a relative variability of the VA and AV intervals.