Myocarditis and sudden cardiac death in athletes. Diagnosis, treatment, and prevention

Myocarditis is the reason for sudden cardiac death in 5-22% of athletes < 35 years of age. Actually, parvovirus B19 and human herpes virus 6 are the most important pathogens. Clinical presentation of myocarditis is heterogeneous, with all courses between asymptomatic and fulminant reported. Especially in athletes it is important to take subtle discomforts seriously and initiate further evaluation. Electrocardiogram, laboratory parameters, serologic markers, and echocardiography are helpful in diagnosis of myocarditis, but are not specific. Magnetic resonance imaging (MRI) of the heart has become an important tool in the evaluation of patients with myocarditis and allows noninvasive appraisal of myocardial inflammation using late enhancement. However, MRI is not able to assess viral persistence. Therefore, endomyocardial biopsy (EMB) remains the gold standard in diagnosis of myocarditis. When considering EMB in these athletes one should not ignore spontaneous healing in 50% of patients with myocarditis. Contrariwise, specific therapy (e.g., immunosuppression, interferon, immunoglobulins) for myocarditis is only feasible after getting results of EMB. When myocarditis is verified, athletes have to withdraw from sport for at least 6 months. Before restarting physical activity, a detailed examination is necessary and most of the patients will undergo another EMB. For prevention of myocarditis and sudden cardiac death it is recommended to stop elite sport for 4 weeks after an unspecific infection. Whether moderate sport can be started earlier is unclear.