Unexplained Syncope in Athletes

Evaluation of syncope in athletes can be challenging, with a vast array of potential explanations ranging from vasovagal to ventricular arrhythmias secondary to an arrhythmogenic cardiomyopathy. The evaluation of syncope requires a thorough history and physical examination, electrocardiogram, and in many cases further diagnostic testing and imaging including stress testing, transthoracic echocardiography, and cardiac magnetic resonance imaging. In this case series, we report 4 cases of previously unexplained syncope in athletes of various levels, with the underlying mechanism of left ventricular outflow tract obstruction (LVOTO). Our findings indicate that LVOTO can cause syncope with or without the presence of significant left ventricular hypertrophy. These cases demonstrate the utility of stress transthoracic echocardiography in eliciting LVOTO and how detecting LVOTO can drastically change clinical management for athletes, especially with respect to implantable cardioverter-defibrillator placement.