NONREENTRANT SUPRAVENTRICULAR TACHYCARDIA DUE TO DOUBLE VENTRICULAR RESPONSE VIA DUAL ATRIOVENTRICULAR NODAL PATHWAYS

Narrow and wide QRS tachycardias associated with various rhythm distur bances were recognized during 24-hour ambulatory electrocardiographic monitoring in a 65-year-old man with coronary artery disease. Laddergr am analysis revealed the presence of dual atrioventricular nodal pathw ays. Nonreentrant supraventricular tachycardia due to simultaneous fas t and slow conduction through the dual atrioventricular nodal pathways was confirmed by electrophysiologic study. The atrial rate determined the occurrence of simultaneous conduction, and extrastimulation faile d to induce a double ventricular response. Enhanced vagal activity was thought to play a critical role in provoking this phenomenon. Radiofr equency catheter ablation of the slow pathway eliminated the arrhythmi as.