Diagnosis and treatment of myocarditis: The role of endomyocardial biopsy

Opinion statement

Viral infections often affect the heart. In the majority of cases, the course of the disease is benign and patients recover spontaneously. However, viral infection may persist and lead to acute cardiac failure or progress to dilated cardiomyopathy. Viral infections are considered to be the most common causes of myocarditis. There is evidence that intramyocardial viral persistence is associated with progressive ventricular dysfunction, even when the infiltrate is sparse or missing. The diagnosis of viral myocarditis necessitates the detection of viral genome by molecular biology techniques and the evaluation of myocardial inflammation by the immunohistochemistry on endomyocardial biopsy samples. Autoreactive myocarditis can also only be diagnosed by endomyocardial biopsy. Infiltration of leukocytes and a negative polymerase chain reaction on microbial agents are their hallmarks. Apart from symptomatic or supportive therapy, etiologic treatment strategies have to address the underlying causative virus or the autoimmune process. In symptomatic or deteriorating patients, targeted antiviral therapy is a reasonable algorithm to eradicate the virus, which will contribute to resolving inflammation or apoptosis, thus confining myocardial damage. The Marburg registry favors intravenous immunoglobulin treatment in biopsy-proven adenovirus and parvovirus B19 myocarditis combined with optimal conventional therapy to achieve virus clearance. In fulminant myocarditis, biopsy is mandatory to identify giant cell myocarditis and cardiac sarcoidosis to be treated by immunosuppression. In cardiogenic shock, the use of mechanical circulatory support by means of a ventricular assist device as a bridge to recovery may be a lifesaving approach. In perimyocarditis with dominant pericardial affection, colchicine over a period of 1 to 6 months can dissolve the pericardial effusion effectively in more than 80% of cases.