Arrhythmogenic Cardiomyopathy or "Athlete's Heart"?: A Systematic Approach to Differential Diagnosis

Arrhythmogenic cardiomyopathy (ACM) is a heritable cardiac condition, which may lead to fatal arrhythmias, especially during intense exercise. Long-term regular exercise is associated with a spectrum of physiological cardiac adaptations, some of which may overlap with phenotypic features of ACM, thereby complicating the distinction between benign athletic remodeling and early disease expression. This overlap presents a significant diagnostic challenge, as misclassifying pathological changes as physiological can delay appropriate risk stratification and management. By contrast, overdiagnosis of cardiomyopathy in healthy athletes may lead to unnecessary restriction from sport and psychological distress. The complexities in the differential diagnosis may be mitigated by embracing a comprehensive and systematic approach, including a thorough assessment of family and personal history, and a careful interpretation of the electrocardiogram, with further investigations to be requested if suspicion of an underlying disease is raised. This review provides a comprehensive analysis of the differential diagnosis between physiological cardiac adaptations and pathological changes that raise the suspicion of ACM, highlighting red flags and benign findings to rationalize clinical management.