[Electrophysiologic effects of propafenone in subjects with pre-existing excito-conduction disorders].

Few data are currently available regarding the electrophysiological effects of Propafenon administration in patients with pre-existing excito-conduction system disturbances. We have performed electrophysiological evaluation in 18 patients (15 males and 3 females, mean age 61 +/- 9 years - 4 patients with sinus bradycardia, 5 pts with AVN block, 4 patients with bundle branch block and normal HV and 5 patients with bundle branch block and prolonged HV) before and after intravenous administration of Propafenon (1 mg/Kg B.W. in 5 minutes). Propafenone administration decreased the heart rate, significantly lengthened AH and HV intervals, lengthened atrial, ventricular and, above all, AVN refractory periods. In no cases sinus pauses, marked bradycardia, spontaneous A-V block or additional intraventricular conduction disturbances were observed. We conclude that: due to its marked electrophysiological effects on AVN and His-Purkinje system, Propafenon is electively indicated for the treatment of ventricular arrhythmias and paroxysmal supraventricular tachycardia with AVN reentry; Propafenon intravenous administration appears to be safe also in pts with preexisting excitation and conduction disturbances.