Evaluation of techniques for recognition of ventricular arrhythmias by implanted devices

Three methods of electrogram analysis have been investigated: rate, irregularity, and amplitude distribution. In 35 episodes in 19 patients, these three algorithms were applied to 15 s recorded passages of ventricular electrograms during supraventricular tachycardia (N=11), ventricular tachycardia (N=11), and ventricular fibrillation (N=13). Each was individually paired with a recording of sinus rhythm from the same patient. Each algorithm was successful at distinguishing the tachyarrhythmias from sinus rhythm at one or more levels of algorithm parameterization. Rate alone discriminated supraventricular tachycardia from ventricular fibrillation but did not distinguish between supraventricular and ventricular tachycardia. Rate combined with irregularity distinguished between ventricular tachycardia and ventricular fibrillation, but did not discriminate between ventricular and supraventricular tachycardia. It is concluded that algorithms based on rate, irregularity, and amplitude distribution analysis of ventricular electrograms may distinguish sinus rhythm from tachyarrhythmias, but may not distinguish among tachyarrhythmias.