Termination of a long RP supraventricular tachycardia by carotid sinus massage

Carotid sinus massage is a useful diagnostic and therapeutic maneuver in patients with supraventricular tachycardia. Abrupt tachycardia termination with carotid sinus massage typically indicates a mechanism dependent on the atrioventricular node. Here, we present the case of a 79-year-old patient presenting with a long-RP supraventricular tachycardia terminated with carotid sinus massage that was proven invasively to be due to a focal atrial tachycardia. We discuss mechanistic explanations for this unusual phenomenon and review the literature.