How to approach the great mimic? Improving techniques for the diagnosis of myocarditis.

Myocarditis is characterized by inflammation of the myocardium, assessed by histological, immunological and immunohistochemical criteria, due to exogenous or endogenous causes. Abnormal QRS, increased troponin T and left ventricular regional or global dysfunction may be detected. Strain Doppler echocardiography can detect longitudinal segmental dysfunction of the myocardium, due to edema, which is in agreement with cardiac magnetic resonance imaging. Nuclear imaging shows a good sensitivity, but carries serious limitations. Somatostatin receptor positron emission tomography/computed tomography seems promising. Cardiac magnetic resonance imaging, using T2-weighted, early T1-weighted, delayed enhanced images and recently T2 and T1 mapping, has the best diagnostic capability. Endomyocardial biopsy has further contributed to the etiologic diagnosis of myocarditis. To conclude, cardiac magnetic resonance and endomyocardial biopsy have both significantly increased our diagnostic performance. However, further assessment by multicenter studies is needed to establish a clinically useful algorithm.