One of the diagnostic criteria in order to differentiate between physiological and pathological left ventricular hypertrophy is the wall thickness reduction after at least 3-month detraining period, which is considered a marker of the athlete’s heart. This report describes detraining-related regression of LV hypertrophy and improvement in myocardial deformation in a junior athlete likely to have hypertrophic cardiomyopathy.

• Hypertrophic cardiomyopathy in adolescent athletes can be discovered by 12-lead ECG

• Physical training is an important trigger for the clinical presentation of hypertrophic cardiomyopathy

• Reverse LV remodeling (wall thickness reduction) with detraining is a common echocardiographic finding in athletes with physiological hypertrophy

• This report demonstrates that reverse remodeling can also be found in adolescent athletes likely to have hypertrophic cardiomyopathy