The prevalence study was one of three subprojects with the common failure due to chronic opportunistic pulmonary infection, primarily Pneumocystis carinii pneumonia. Drugs such as azidothymidine (AZT) and trimetrexate showed some effectiveness in prolonging the lives of some AIDS patients. With increased survival, it was believed that cardiac diseases might well become an important complication of AIDs. Reports described a syndrome of rapidly progressive cardiomyopathy associated with AIDS. The etiology of AIDS-associated cardiomyopathy was yet unknown although immunologic theme of the immunopathogenesis of AIDS-associated cardiomyopathy. The other two subprojects dealt with immunopathology studies in endomyocardial biopsies and autopsy tissues and serologic studies. The AIDS Clinical Research Center at Johns Hopkins Hospital served as the source of patients. All patients underwent serologic testing and echocardiography at time of entry and at six and twelve months. The screening electrocardiogram identified 40 to 50 patients per year with AIDS-associated cardiomyopathy. Approximately 30 patients per year had no contraindications for endomyocardial biopsy. Comprehensive tissue studies and cellular immune studies were performed on the cohort and autopsies, if possible. Immunohistochemical techniques and in situ hybridization of biopsy and autopsy material were used to determine if AIDS-associated cardiomyopathy was associated with HIV infection of the heart or with some other viral or opportunistic non-viral infection. Indirect immunofluorescence and a Western immunoblotting assay using patient sera determined the prevalence of heart autoimmunity.