THERAPY AND PREVENTION ELECTROPHYSIOLOGY Sotalol in patients with Wolff-Parkinson-White syndrome

We evaluated the effects of intravenous and long-term oral sotalol treatment in 17 patients with an accessory atrioventricular (AV) pathway. All patients had a history of symptomatic supraventricular tachycardia. During electrophysiologic study intravenous (1.5 mg/kg body weight) and oral (240 to 320 mg/day) sotalol caused significant increases of sinus cycle length, AV nodal conduction time, and refractory periods of atrial and ventricular myocardium and accessory pathway. AV reciprocating tachycardia, which was inducible and sustained in 15 patients at control, was still inducible after intravenous sotalol in 14 patients, including one in whom it was not inducible at control. However, tachycardia became nonsustained in 10 patients. In seven patients who underwent repeat drug testing while on oral sotalol, results were the same as after intravenous sotalol. Sixteen patients were followed-up for 36 months (median value). Fifteen of them were clinically free of symptoms or experienced marked improvement, despite recurrences of tachycardia in two. In a third patient sotalol had to be withdrawn because of recurrent supraventricular tachycardia. Orthostatic hypotension occurred in five patients and required withdrawal of sotalol in one. To predict the long-term clinical outcome of patients, exercise testing and Holter monitoring were of little or no value. Programmed electrical stimulation predicted clinical outcome in 63% after intravenous and in 86% after oral sotalol. This study shows that long-term treatment with sotalol is highly effective in patients with the WolffParkinson-White syndrome and regular supraventricular tachycardia. Circulation 75, No. 5, 1050-1057, 1987. SOTALOL is a ,3-blocking agent without cardioselectivity, intrinsic sympathomimetic, or membrane-stabilizing effects. In addition to its class II antiarrhythmic properties, it prolongs action potential duration and increases atrial as well as ventricular effective refractory periods. This has initially been shown in animal preparations,1 2 and later on in electrophysiologic studies in humans.3 The additional class III mode of antiarrhythmic action' gave rise to the investigation of the effects of sotalol on supraventricular and ventricular tachyarrhythmias.>12 The aims of our study were to assess (1) the electrophysiologic effects of intravenous and oral sotalol in patients with an accessory atrioventricular pathway and recurrent paroxysmal supraventricular tachycardia, (2) the clinical effects of a long-term treatment with oral sotalol, and (3) the value of exercise testing, From the Department of Cardiology, University Hospital Eppendorf, Hamburg, F.R.G. Supported by a grant from the Werner-Otto-Stiftung, Hamburg, F.R.G. Address for correspondence: Karl-Heinz Kuck, M.D., Department of Cardiology, University Hospital Eppendorf, Martinistr. 52, 2000 Hamburg 20, F.R.G. Received July 29, 1986; revision accepted Jan. 15. 1987. Holter monitoring, and programmed electrical stimulation for prediction of the clinical outcome of patients receiving oral sotalol therapy.