Low heart rate, proportional enlargement of cardiac chambers, mild decrease in ejection fraction with preserved stroke volume are findings commonly seen in athletic heart syndrome. In some cases, a patchy LGE is seen in the inferoseptal and anteroseptal segments.

The athlete's heart syndrome refers to both heart enlargement and slow heart rate particularly seen in people exposed to high-performance and sustained exercise or sport (endurance sports, straight exercise, etc) that demands regular physical training program during any time of life.

It is induced by the changes the cardiovascular system has to make in order to be able to deliver the physical performance that is required. The heart tends to increase the size and strength of the ventricles (by hypertrophy and dilatation of the chambers) leading to a morphological big heart with conservated diastolic and systolic function;  heart ejection fraction is sometimes mildly decreased.

The diagnosis is usually made by echocardiography which is the first-line method in order to differentiate from other heart diseases. But the gold standard is cardiac MR, which is superior to echocardiography with 80% sensitivity and 90% specificity of cine CMR ¹.