VIRAL-INFECTION AND THE PATHOGENESIS OF DILATED CARDIOMYOPATHY

Long-term follow-up studies of patients with suspected viral myocardit is reveal progression to dilated cardiomyopathy (DCM) in a significant number of cases. Thus, an underlying viral etiology has been hypothes ized in the pathogenesis of ongoing heart disease that leads to DCM. R ecent application of molecular biology in clinical diagnosis has stren gthened this hypothesis. By use of probe hybridization and polymerase chain reaction, enteroviral RNA has been detected in the myocardium of patients at ail stages of the disease process: myocarditis, chronic h eart disease, and DCM. Experimental murine models of enterovirus-induc ed heart disease provide a framework for examining the pathogenic mech anisms. Viral cytotoxicity, immunological responses, viral RNA persist ence, and spasm of the coronary microvasculature are all implicated in the ongoing disease process. Abnormal cardiac function and heart fail ure are attributed to the pathological changes that occur.