Gray zones in cardiovascular adaptations to physical exercise: How to navigate in the echocardiographic evaluation of the athlete's heart

“Athlete's heart” represents a series of mechanisms through which cardiac chambers can adapt to physical activity. Echocardiography has a major role in sports cardiology and it can help physicians to investigate the so-called “grey zones”, defined as diagnostic overlaps between athlete's heart and several cardiac diseases: wall thickness and left ventricular size in hypertrophic and dilated cardiomyopathy, ventricular trabeculations in left ventricular non-compaction cardiomyopathy, left atrial size and atrial fibrillation, right ventricular systolic dysfunction in arrhythmogenic right ventricular cardiomyopathy. The use of advanced ultrasound methods such as tissue Doppler and two-dimensional strain can be added to the classic echocardiographic assessment to complete a multi-parametric evaluation, guiding the sports physician and cardiologist in the correct framing of these patients.