Postexertional Cardiac Asystole in a Young Man Without Organic Heart Disease

Abstract

jects after exhaustive exercise of short duration ( 1, 2). Persistent postexercise peripheral arterial vasodilitation coupled with impaired venous return have been implicat-ed as mediating events ( 3). Sinus pause with ventricular asystole is an unusual cause of postexercise syncope and has been ascribed to an excessive vagal response ( 4- 7). W e report a case of reproducible postexertional sinus pause with ventricular asystole and syncope and assess the effects of vagolytic and beta-adrenergic blocking agents. A previously healthy 22-year-old man had a syncopal episode several seconds after maximal exertion pedaling a bicycle up-hill. Results of physical examination were normal. The electro-cardiogram showed unifocal premature ventricular contractions and was otherwise normal. A two-dimensional echocardiogram