There is increasing evidence that regular intense endurance exercise can promote structural and electrical remodeling of the right ventricle (RV). These physiological changes can be profound and are frequently accompanied by ECG changes in the right precordial leads, thereby mimicking features observed in arrhythmogenic right ventricular cardiomyopathy (ARVC). Because the 12-lead ECG is used as both a screening and diagnostic tool for the detection of conditions associated with sudden death in athletes, it is of fundamental importance to have a good understanding of the ECG features that distinguish physiological adaptations to endurance exercise from those related to RV pathology as well as their potential overlap. This article describes ECG findings observed in healthy endurance athletes versus athletes with underlying RV pathology and illustrates their differentiation using 4 case presentations.