Abstract

Clenbuterol, a β2-adrenergic agonist, is often misused by athletes for its anabolic and lipolytic properties. When combined with supplements like L-carnitine, the risk of cardiovascular side effects may be amplified. We present the case of a 28-year-old female amateur bodybuilder who developed new-onset atrial fibrillation after the concurrent use of clenbuterol and L-carnitine. The patient had no prior history of structural heart disease. Electrocardiography showed rapid irregular rhythm consistent with atrial fibrillation. Sinus rhythm was restored with medical cardioversion. This case highlights the arrhythmogenic potential of β-agonist abuse in young athletes and emphasizes the importance of cardiovascular monitoring in supplement users.