Abstract

In most cases inflammatory changes of the myocardium are asymptomatic. If inflammatory changes of the myocardium manifest with clinical symptoms, the condition is termed myocarditis. Myocarditis is regarded as a major cause for sudden death of young adults and accounts for up to 20% of the cases. In Europe viral infections represent the most important cause of myocarditis. In chronic myocarditis, viremia is often absent and myocardial fibrosis and dilated cardiomyopathy (DCM) resulting in heart failure can occur. The role of cardiac MRI in chronic myocarditis is not yet well understood. MRI is a sensitive tool detecting myocardial fibrosis on late images after application of paramagnetic contrast agents. The region of contrast accumulation is defined as "late enhancement" (LE). Data are available now suggesting that differentiating fibrosis due to myocardial infarction from inflammatory causes is facilitated using MRI late images. Fibrosis after ischemic infarction includes the subendocardial layer of the myocardium. If the subendocardial layer of the myocardium is not involved in the fibrosis, infarction is unlikely and can be reliably excluded as an important differential diagnosis in the vast majority of affected patients.