Evidence of viral infection in the myocardium of American and Japanese patients with idiopathic dilated cardiomyopathy.

Enteroviruses have been implicated in the pathogenesis of idiopathic dilated cardiomyopathy (IDC). Recently, the association of adenovirus or parvovirus with IDC has been reported. Viral infection in the myocardium of American and Japanese patients with end-stage IDC was evaluated. Myocardial specimens from 30 American patients with IDC and 47 Japanese patients with IDC were analyzed for the presence of cardiotropic viruses. The strand-specific detection of enteroviral ribonucleic acid (RNA) was performed to determine viral activity in hearts with IDC. Established reverse transcription-polymerase chain reaction (PCR) or PCR techniques were used to detect genomic sequences of influenza viruses, mumps virus, adenovirus, parvovirus, herpes simplex viruses, varicella-zoster virus, and Epstein-Barr virus. Enteroviral RNA was detected in 7 of the 30 American patients (23%) and in 15 of the 47 Japanese patients (32%). Minus-strand enteroviral RNA, an indicator of active enteroviral RNA replication, was demonstrated in 5 of 7 plus-strand-positive American patients (71%) and in 12 of 15 plus-strand-positive Japanese patients (80%). Sequence analysis revealed that the viruses detected were Coxsackie B viruses. No genomic sequences of other viruses were detected in the myocardium of either American or Japanese patients with IDC. Therefore, active group B Coxsackie virus RNA replication in the myocardium was demonstrated in a significant proportion of American and Japanese patients with end-stage IDC. There was no evidence of persistent infection by other viruses in hearts with IDC. Specific therapy should be designed for Coxsackie virus positive patients with IDC.