SENSITIVITY AND SPECIFICITY OF A DUAL-CHAMBER ARRHYTHMIA RECOGNITION ALGORITHM FOR IMPLANTABLE DEVICES

Present ventricular rate-based arrhythmia detection algorithms lack sp ecificity. Using a training set of 109 endocardial electrogram recordi ngs, a sensitive and specific dual-chamber arrhythmia recognition algo rithm has been developed. The algorithm uses atrial and ventricular ra tes, irregularity, degree of beat-to-beat similarity, and measure of e lectrogram complex distinctiveness to arrive at a diagnostic conclusio n. A test set of 121 endocardial electrogram recordings obtained durin g provocative electrophysiology studies was then used for blinded vali dation of the algorithm. In normal rhythm, 1:1 tachycardia, atrial tac hycardia, atrial nutter, atrial fibrillation, ventricular tachycardia, and ventricular fibrillation, the percentages of sensitivity/specific ity were, respectively, 100/99, 100/99, 80/99, 89/98, 91/97, 92/100, a nd 100/98. Although ventricular rate alone can usually distinguish nor mal rhythm, ventricular tachycardia, and ventricular fibrillation, it is confounded by atrial arrhythmias and 1:1 tachycardias. When tested on a database, a ventricular rate-only algorithm resulted in sensitivi ty/specificity of 100/65, 90/78, and 100/99%, respectively, for these three rhythms. Therefore, the dual-chamber algorithm based on both tem poral and morphologic measures provides better distinction of normal r hythm and ventricular tachycardia than existing methods, without sacri ficing sensitivity.