BACKGROUND: Human immunodeficiency virus (HIV) infection is increasingly recognized as an important cause of dilated cardiomyopathy. However, the pathogenesis of the heart-muscle disease in the acquired immunodeficiency syndrome is unclear.
METHODS: We performed a prospective, long-term clinical and echocardiographic follow-up study of 952 asymptomatic HIV-positive patients to assess the incidence of dilated cardiomyopathy and to analyze the clinical variables associated with the development of cardiomyopathy. All patients with an echocardiographic diagnosis of dilated cardiomyopathy underwent endomyocardial biopsy for histologic, immunohistologic, and virologic assessment.
RESULTS: During a mean (+/-SD) follow-up period of 60+/-5.3 months, an echocardiographic diagnosis of dilated cardiomyopathy was made in 76 patients (8 percent), with a mean annual incidence rate of 15.9 cases per 1000 patients. The incidence of dilated cardiomyopathy was higher in patients with a CD4 count of less than 400 cells per cubic millimeter (as compared with a CD4 count of > or =400 cells per cubic millimeter) and in those who received therapy with zidovudine. A histologic diagnosis of myocarditis was made in 63 of the patients with dilated cardiomyopathy (83 percent). Inflammatory infiltrates were predominantly composed of CD3 and CD8 lymphocytes, with staining for major histocompatibility complex class I antigens in 71 percent of the patients. In the myocytes of 58 patients, HIV nucleic acid sequences were detected by in situ hybridization, and active myocarditis was documented in 36 of the 58. Among these 36 patients, 6 were also infected with coxsackievirus group B (17 percent), 2 with cytomegalovirus (6 percent), and 1 with Epstein-Barr virus (3 percent).
CONCLUSIONS: Dilated cardiomyopathy may be related either to a direct action of HIV on the myocardial tissue or to an autoimmune process induced by HIV, possibly in association with other cardiotropic viruses.