Effects of Propafenone on Induction and Maintenance of Atrioventricular Nodal Reentrant Tachycardia

Electrophysiologic studies were performed in 10 patients with atrioventriculur (A‐V) nodal reentrant paroxysmal supraventricular tachycardias (PSVT), before and after intravenous administration of propafenone (1.5 mg/kg). All patients utilized an A‐V nodal slow pathway for anterograde conduction and an A‐V nodal fast pathway for retrograde conduction of the reentrant impulse. Propafenone depressed retrograde fast pathway conduction which was manifested by: 1) complete V‐A block at all ventricular paced cycle lengths after propafenone in 3 cases; 2) increase In mean ± SD of ventricular paced cycle length producing V‐A block from