[Syncopal episodes in healthy young athletes. Report of 3 cases in the course of ergometric evaluation].

We report the occurrence of syncope in three healthy athletes during exercise stress testing. In two subjects the syncope occurred in the late recovery stage and was due to inhibition of sinus activity. In the third case a Mobitz type II A-V block developed during hyperventilation, which was followed by a complete A-V block with ventricular asystole and subsequent sinoatrial arrest. We discuss the probable pathophysiological mechanisms of these arrhythmias and their implications in sports practice.