The medical history of the patient (endurance sports) and physical examination (bradycardia, and maybe a third or fourth heart sound), can give important hints. ECG – typical findings in resting position are, for example, sinus bradycardia, atrioventricular block (primary and secondary) and incomplete (IRBBB) or complete right bundle branch block (RBBB) – all those findings normalize during exercise. Echocardiography – differentiation between physiological and pathological increases of the hearts size is possible, especially by estimating the mass of the wall (not over 130 g/m2) and its end diastolic diameter (not much less 60 mm) of the left ventricle. X-ray examination of the chest may show increased heart size (mimicking other possible causes of enlargement). Cardiac MRI - In athletes heart, there is balanced atrioventricular remodeling, reduced thickening of the heart after detraining, no late gadolinium enhancement, low to normal T1 signal, and normal extracellular volume.
Although a link between intensive exercise and exercise-induced arythmogenic right ventricular cardiomyopathy exists.No treatment is required for people with athletic heart syndrome; it does not pose any physical threats to the athlete, and despite some theoretical concerns that the ventricular remodeling might conceivably predispose for serious arrhythmias, no evidence has been found of any increased risk of long-term events. Athletes should see a physician and receive a clearance to be sure their symptoms are due to athletes heart and not another heart disease, such as cardiomyopathy. If the athlete is uncomfortable with having athletes heart or if a differential diagnosis is difficult, deconditioning from exercise for a period of three months allows the heart to return to its regular size. However, one long-term study of elite-trained athletes found that dilation of the left ventricle was only partially reversible after a long period of deconditioning. This deconditioning is often met with resistance to the accompanying lifestyle changes. The real risk attached to athletes heart is if athletes or nonathletes simply assume they have the condition, instead of making sure they do not have a life-threatening heart illness. History
The athletes heart syndrome was first described in 1899 by Salomon Henschen. He compared the heart size of cross-country skiers to those who lived sedentary lives. He noticed that those who participated in competitive sports displayed symptoms of athletes heart syndrome. Henschen believed the symptoms were a normal adjustment to exercise, and felt concern was not needed.