Exercise-associated cardiac asystole in persons without structural heart disease.

Exercise-associated cardiac asystole (EACA) in patients without structural heart disease is uncommonly encountered. Two patients who developed prolonged asystolic arrest associated with exercise are described; both demonstrated a positive head-up tilt table response, absence of underlying heart disease, and a history of vagotonia. A review of this condition in the literature suggests the occurrence of this syndrome of EACA in young men with atheletic inclination who developed syncope usually after a strenuous exercise at a high heart rate. Although the described patients usually responded by avoiding maximal exercise and the use of beta-blockade, vagolytic agent, and permanent pacing, EACA may be the link for some cases of exercise-related asystolic deaths.