Dilated cardiomyopathy in a zidovudine-treated AIDS patient

The pathogenesis of dilated cardiomyopathy in acquired immunodeficiency syndrome (AIDS) is poorly understood. We report a case of an HIV-positive, 45-year-old homosexual male treated with high-dose azidothymidine (AZT, 1,200 mg/day) for two years prior to development of AIDS. He subsequently manifested symptoms of congestive heart failure with left ventricle dilation and a 20% ejection fraction. An endomyocardial biopsy showed no active myocarditis, but intramyocytic vacuoles were found. Transmission electron microscopy revealed mitochondrial cristae with distortion and myofibrillar loss. The clinical consideration was dilated cardiomyopathy in AIDS. His AIDS worsened and he died in October 1991. Autopsy revealed a 100-ml pericardial effusion, cardiomegaly, and biventricular dilation. Vacuolar changes in cardiac myocytes were present. Pathologic findings support a diagnosis of AZT-induced cardiotoxicity. Potential mechanisms are discussed.