Newer aspects of pathogenesis of heart failure: hepatitis C virus infection in myocarditis and cardiomyopathy.

Myocarditis is thought to be commonly caused by various viruses, and accumulating evidence links viral myocarditis with the eventual development of dilated cardiomyopathy. In many cases, however, the evidence is only circumstantial, and direct conclusive proof is not available. Polymerase chain reaction (PCR) has been used to detect enterovirus RNA in myocardial tissue, but the wide discrepancy in results emphasizes the need for further study. We evaluated patients with cardiomyopathy and myocarditis by PCR for the presence of various RNA and DNA viruses in the heart. Hepatitis C virus RNA was found in high frequency, but enterovirus RNA was detected only in low frequency. Therefore, we investigated hepatitis C virus infection in patients with dilated cardiomyopathy. Antihepatitis C virus antibody was present in the sera of 6 of 36 patients (16.7%) with dilated cardiomyopathy and in 1 of 40 patients (2.5%) with ischemic heart disease, showing a statistically significant (P < .05) difference. Hepatitis C virus RNA was present in the sera of four of the six patients, and all four had hepatitis C virus type II. The copy number of hepatitis C virus RNA in the serum was 8 x 10(2) to 2 x 10(3) genomes per 1 mL serum. Positive strands of hepatitis C virus were found in the hearts of three patients, and negative strands of hepatitis C virus were detected in the hearts of two patients. The results suggest that hepatitis C virus infection is frequently found in patients with dilated cardiomyopathy and that hepatitis C virus is an important causal agent in the pathogenesis of the disease. Antiviral therapy against hepatitis C virus may be indicated in these patients.