Abstract
An accelerated idioventricular rhythm was seen on a routine preparticipation electrocardiogram of a 19-year-old healthy and symptom-free athlete. Family history was negative for cardiac disease. Additional investigations revealed a hypertrophic cardiomyopathy, confirmed with cardiac magnetic resonance imaging and genetic analysis. Accelerated idioventricular rhythm in young athletes warrants careful clinical evaluation. (Level of Difficulty: Advanced.).