Ventricular Flutter and Pleomorphic Ventricular Tachycardia-Induced Syncope in Borderline Arrhythmogenic Right Ventricular Cardiomyopathy.

A 20-year-old female competitive collegiate swimmer presented after 2 postexercise syncopal episodes and 1 episode while actively swimming. Ambulatory monitoring and exercise testing revealed nonsustained ventricular tachycardia. Electroanatomic mapping demonstrated multifocal premature ventricular contractions and ventricular flutter originating from the right ventricular outflow tract, consistent with borderline arrhythmogenic right ventricular cardiomyopathy. (Level of Difficulty: Intermediate.).