Patent ID: 6748269
Filing Date: 2004-06-08
Classification: A61N

Abstract:
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; detect a supraventricular tachycardia (SVT) when: (a) the AA interval is within a tachycardia range defined as below an SVT threshold and (b) the VV interval is within normal limits; detect a ventricular fibrillation (VF) when the VV interval is below a VF threshold; detect a ventricular tachycardia (VT) when: (a) the VV interval is within a tachycardia range defined as above the VF threshold but below a VT threshold and (b) the AA interval is either within normal limits or differs from the VV interval by more than a specified dual tachycardia limit value; and, if a 1:1 tachycardia condition is present, defined as when the AA and VV 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.