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A Regular Narrow QRS Complex Tachycardia with Atrioventricular Dissociation

July 2001 PACE, Vol. 24 Case Report A 17-year-old woman was referred to this laboratory for the treatment of supraventricular tachycardia. She suffered from intermittent palpitation over the past 2 years. The 12-lead electrocardiograph (ECG) showed a regular narrow QRS complex tachycardia with atrioventricular (AV) dissociation (Fig. 1). During electrophysiological study, programmed stimulation demonstrated antegrade and retrograde dual AV nodal physiological properties. A single premature ventricular complex (PVC) could reproducibly induce a sustained supraventricular tachycardia with variable ventriculoatrial (VA) conduction time (Fig. 2). The tachycardia also could be induced by rapid high right atrial (HRA) pacing and terminated by ventricular burst pacing or a bolus of 12-mg adenosine (not shown). What is the mechanism of the tachycardia?