ELECTROPHYSIOLOGICAL EFFECTS OF INTRAVENOUS DIPRAFENONE IN PATIENTS WITH SUPRAVENTRICULAR TACHYCARDIA

Diprafenone is a new class IC antiarrhythmic drug, chemically similar to propafenone. Diprafenone was evaluated in 25 patients with supraventricular tachycardias (12 pat. AV-nodal reentry tachycardja, 8 pat. AV reentry tachycardia, 4 pat. atrial flutter, 1 pat. incessant atrial tachycardia). Electrophysiologic study was performed before and after i.v. diprafenone (1.5 mg/kg body weight). Diprafenone produced a prolongation in all parts of the conduction system, it produced a significant increase in sinus cycle length, AH- and HV intervall, Wenckebach point and effective refractory period of the AV node and right ventricle. Supraventricular tachycardia was no longer inducible in 9/12 patients with AV-nodal reentry tachycardia and in 4/8 pat. with AV reentry tachycardia. In the nonresponder, the tachycardia cycle length increased significantly. Diprafenone was administered during atrial flutter in 4 patients, none converted to sinus rhythm, but the cycle length increased. Diprafenone prevents the induction of supraventricular tachycardias in 2/3 of patients.