Chronic variant of myocarditis associated with hepatitis C virus infection

Although molecular biological studies suggest a pathogenic link between enterovirus infection and dilated cardiomyopathy (DCM), the frequency of detection of enteroviral RNA is not consistently high in myocardial tissue from patients with DCM. A recent study has suggested that hepatitis C virus (HCV) may also be involved in the development of DCM.

We performed genomic analysis for HCV in three patients with chronic active myocarditis. In all three patients, serum aminotransferase activities remained within normal ranges until the terminal stage of heart failure. At necropsy, all three livers showed evidence of tissue damage caused by chronic congestion, and one liver had evidence of chronic hepatitis. Routinely processed, paraffin-embedded tissue blocks of myocardium and liver were analyzed. Renal specimens were also analyzed to exclude the possibility of myocardial contamination with HCV material from the circulating blood. RNA extracted from the heart, liver, and kidney was subjected to strand-specific reverse transcription and amplified by semi-nested polymerase chain reaction. The target nucleotide sequence was a 178-bp fragment of the highly conserved 5'-noncoding region. Both positive- (genomic) and negative-strand RNA (replicative intermediates) were present in myocardial and liver tissue samples from all three patients. However, negative-strand RNA was undetectable in renal tissue from one patient.

These findings suggest that HCV replicated in myocardial tissue of these patients with myocarditis. Thus, HCV infection may contribute to the development of this unusual form of myocarditis.