Patent ID: 7515956

Claim:
A system for discriminating ventricular tachycardia (VT) from supraventricular tachycardia (SVT), the system comprising: a sensing circuit that senses an atrial electrogram indicative of atrial depolarizations and a ventricular electrogram indicative of ventricular depolarizations; a rate detector circuit, coupled to the sensing circuit, that detects an atrial rate based on the atrial electrogram and a ventricular rate based on the ventricular electrogram; a tachycardia detector circuit, coupled to the rate detector circuit, that detects a tachycardia based on at least one of the atrial rate and the ventricular rate; a rhythm classifier circuit, coupled to the rate detector circuit and the tachycardia detector circuit, that classifies the detected tachycardia as a 1:1 tachycardia in response to the atrial rate and the ventricular rate being substantially equal; and a tachycardia discriminator circuit coupled to the rhythm classifier circuit, the tachycardia discriminator circuit including: a time interval measurement circuit, coupled to the sensing circuit, that measures a tachycardia time interval between an atrial depolarization and an adjacent ventricular depolarization during the 1:1 tachycardia; and a VT comparator circuit coupled to the time interval measurement circuit, the VT comparator circuit having an output that indicates a VT detection in response to the VT comparator circuit determining that the tachycardia time interval differs from a template time interval by at least a predetermined percentage of the template time interval and that indicates a detection of SVT in response to the VT comparator circuit determining that the tachycardia time interval does not differ from the template time interval by at least the predetermined percentage of the template time interval, wherein the template time interval is a time interval between an atrial depolarization and an adjacent ventricular depolarization measured during a normal sinus rhythm.