Recent advances have been made in understanding Kawasaki disease, acute rheumatic fever and rheumatic heart disease, cardiomyopathy, and acquired immunodeficiency syndrome. Immune-mediated tissue injury in Kawasaki disease is likely caused by response to a superantigen. Persistent functional and anatomic coronary abnormalities may lead to silent ischemia and increase the risk of early atherosclerotic heart disease. Intravenous immunoglobulin therapy is clearly beneficial, but specific therapy awaits further definition of the etiology and pathophysiology of Kawasaki disease. Recently updated diagnostic criteria for Kawasaki disease and acute rheumatic fever are discussed. Advances in the understanding of genetically determined abnormal immune responses to streptococcal pharyngitis may help explain acute rheumatic fever manifestations. Further advances have been made in the elucidation of the pathophysiology of cardiomyopathy, particularly the role of viruses and genetic factors. Angiotensin-converting enzyme inhibitors appear to improve survival in dilated cardiomyopathy. Controversy regarding the possible myocardial depressant effect of zidovudine in human immunodeficiency virus infection is discussed.