Wolff-Parkinson-White syndrome. Circus movement tachycardia dependent on procainamide.

Abstract

A patient with Wolff-Parkinson-White syndrome was disabled by rapid ventricular rates during atrial arrhythmia and by periods of asystole. Circus tachycardia was induced by atrial stimulation only after the administration of procainamide. Nevertheless, treatment with this drug controlled the ventricular rate and spontaneous circus tachycardia did not occur.The effects of antiarrhythmic drugs on conduction through accessory atrioventricular pathways and on the induction of tachycardia by atrial or ventricular stimulation have recently been recorded (Wellens and Durrer, 1974;Mandel et al., 1975 However, monitoring indicated that the spontaneous cessation of paroxysmal atrial flutter or, at times, fibrillation was followed by asystole which was often of sufficient duration to cause loss of consciousness. That digitalis was a factor in causing sinus node dysfunction was proved by withdrawal and subsequent rechallenge with digoxin. Verapamil also delayed recovery (Fig. 1)