Clinical and prognostic significance of detection of enteroviral RNA in the myocardium of patients with myocarditis or dilated cardiomyopathy.

BACKGROUND: Enteroviral RNA sequences have been demonstrated in the myocardium of patients with myocarditis or dilated cardiomyopathy from presentation to end-stage disease. The prognosis of heart muscle disease has not previously been evaluated in relation to the detection of enterovirus in myocardial biopsy tissue. METHODS AND RESULTS: We studied 123 consecutive patients with heart muscle disease prospectively. Multiple endomyocardial biopsy samples taken from all patients during diagnostic cardiac catheterization were classified histologically and were examined for enteroviral RNA by use of an enterovirus group-specific hybridization probe. Three enterovirus-negative patients with cardiac amyloidosis were excluded from subsequent analysis. Enteroviral RNA sequences were detectable in 41 (34%) of the remaining 120 patients (group A), while 79 (66%) had no virus detected (group B). The groups did not differ significantly in age, sex, symptomatic presentation, or hemodynamic characteristics; duration of symptoms was significantly shorter in group A (7.8 +/- 9.6 versus 14.9 +/- 19.0 months, P < .05). At follow-up (mean, 25 months; range, 11 to 50 months), patients from group A had an increased mortality compared with those in group B (25% versus 4%, respectively; P = .02). Mortality was also statistically greater in patients with symptomatic cardiac failure (P = .02), those with elevated left ventricular end-diastolic pressures (P = .03), and those in New York Heart Association functional classes III and IV (P = .05). Multivariate regression analysis, however, showed that only the presence of enterovirus RNA and symptomatic heart failure were of independent prognostic value. CONCLUSIONS: These data demonstrate that the detection of enterovirus RNA in the myocardium of patients with heart muscle disease at the time of initial investigation is associated with an adverse prognosis and that the presence of enterovirus RNA is an independent predictor of clinical outcome.

Molecular probes for detection of persisting enterovirus infection of human heart and their prognostic value.

Enteroviruses are well recognized in the aetiology of myocarditis. Molecular hybridization using enterovirus group-specific probes shows that virus can be detected in endomyocardial biopsies and persists in myocardium after the inflammation heals. Virus persistence is associated with the subsequent development of dilated cardiomyopathy, progressing to end-stage disease requiring cardiac transplantation. Infectious virus cannot usually be isolated from myocardium nor can virus-specific antigens be detected after the initial inflammatory stage. Patients with healed myocarditis or dilated cardiomyopathy may have no histological evidence of inflammation despite detection of virus-specific RNA sequences by molecular hybridization. Persisting enterovirus RNA in dilated cardiomyopathy is the strongest known predictor of poor prognosis. The molecular mechanism of virus persistence is the selection of defective virus mutants during the initial phase of disease.