Beware of regression of electrocardiographic abnormalities on detraining - It may not always mean 'athlete's heart'.

Hypertrophic cardiomyopathy is one of the main causes of sudden cardiac death in young athletes. Differentiating between this pathological condition and 'athlete's heart' can be quite challenging, warranting a thorough clinical and imaging assessment. Clinicians often rely on detraining-induced attenuation of electrocardiographic and echocardiographic findings as a means of distinguishing between pathological and physiological cardiac remodeling. This report describes detraining-related regression of left ventricular hypertrophy in a young soccer player with a diagnosis of hypertrophic cardiomyopathy. It challenges the dogma that regression of electrocardiographic abnormalities and left ventricular hypertrophy is exclusive to physiological remodeling and questions the impact of exercise training in the phenotypic expression and progression of hypertrophic cardiomyopathy.