Absence of viral nucleic acids in early and late dilated cardiomyopathy

Objective-To investigate whether viral infection acts as a trigger factor f or the development of dilated cardiomyopathy in genetically predisposed ind ividuals with a family history of disease. Setting-Patients attending the cardiomyopathy unit in a cardiac tertiary re ferral centre. Design-Nested polymerase chain reaction (nPCR) was used to determine whethe r enteroviral, adenoviral, or cytomegaloviral nucleic acids were detectable in the myocardium of 19 asymptomatic relatives of patients with dilated ca rdiomyopathy; all these relatives had echocardiographic abnormalities thoug ht to represent early disease. Explanted hearts from patients with end stag e dilated cardiomyopathy were also studied and were compared with 25 contro ls (ischaemic heart disease (21), valvar heart disease (2), hypertrophic ca rdiomyopathy (1), restrictive cardiomyopathy (1). Myocardial tissue from tw o fatal cases of culture positive coxsackie myocarditis was used as a posit ive control. Results-No viral nucleic acid was detected in any group other than in those with myocarditis. Spiking of random wells with purified recombinant viral nucleic acids confirmed the sensitivity and reproducibility of the assays. Conclusions-Myocardial viral infection is not detectable in relatives of pa tients with dilated cardiomyopathy who are suspected of having early diseas e. There is no evidence that viruses act as a trigger factor for initiating the dilated cardiomyopathy in these patients.