Apple Watch Saves an Athlete: Unmasking Early Detection of Arrhythmogenic Cardiomyopathy.

Arrhythmogenic cardiomyopathy (ACM), encompassing arrhythmogenic right ventricular cardiomyopathy (ARVC), is an important cause of ventricular arrhythmias and sudden cardiac death in young individuals, particularly athletes. Early diagnosis remains challenging due to subtle or evolving structural and electrocardiographic findings, and the condition may initially mimic benign idiopathic ventricular tachycardia (VT). We report the case of a 33-year-old athletic male who presented with recurrent palpitations initially documented by a consumer wearable device and was managed as presumed idiopathic right ventricular outflow tract VT (RVOT VT). Despite initial endocardial ablation, he experienced recurrent VT. Subsequent multimodality assessment, including cardiac magnetic resonance imaging and electroanatomic mapping, demonstrated subepicardial fibrosis and extensive right ventricular epicardial scar, consistent with an ACM phenotype. Owing to recurrent ventricular arrhythmias and significant scar burden, a subcutaneous implantable cardioverter-defibrillator was implanted for secondary prevention. This case highlights the diagnostic overlap between idiopathic VT, myocarditis, and early ACM, and underscores the importance of ongoing diagnostic vigilance when arrhythmias recur after apparently successful ablation. It also illustrates the emerging role of wearable technology in the early detection of clinically significant ventricular arrhythmias and emphasises the value of longitudinal, multidisciplinary management in young patients with suspected ACM.