Summary Data on ventricular performance following “corrective” surgery for congenital heart disease at the present time are limited in number and scope. In isolated right and left heart pressure and volume overload lesions, information is available indicating suboptimal cardiac performance in many patients following successful corrective surgery. Patients with complex cyanotic lesions such as tetralogy of Fallot or transposition of the great arteries also have evidence for impaired myocardial function following “corrective” procedures. Histologic data show focal and diffuse myocardial fibrosis in most patients with long-standing hypertrophy. This fibrosis is probably a result of a discrepancy between myocardial oxygen demands and supply in patients with hypertrophy, and it may be the anatomical correlate of abnormal myocardial performance. Despite laboratory evidence for mild to moderate degrees of mechanical cardiac dysfunction, most patients are asymptomatic, lead useful lives, and are able to tolerate at least moderate levels of exercise without difficulty. Many questions which are of vital importance to the patient, the cardiologist, the primary physician, and the surgeon remain unanswered. What is the time reference over which irreversible changes in myocardial structure and function takes place for each congenital heart lesion? For what lesions will infant surgery prevent important residual cardiac-dysfunction? What are the long-term effects of outflow tract patches, ventriculotomy, pulmonary insufficiency, and residual pulmonary or aortic stenosis on cardiovascular function? Does hypothermia and total circulatory arrest ever permanently affect cardiac function? What are the time limits for anoxic arrest to prevent residual cardiac dysfunction in severe pressure overload lesions? Are mild degrees of abnormal pump function (ejection fraction 0.45–0.55) clinically important as regards morbidity, longevity, and “quality” of life for patients following surgery for congenital heart disease? These are only a few of the general questions for which very little data are available to attempt to answer. Obviously, each specific lesion and procedure will require study in an attempt to provide specific answers regarding optimal therapy. It is apparent that close liaisons must be formed and maintained between physicians who care primarily for children with heart disease and adult cardiologists in order to provide adequate longitudinal studies to evaluate current therapy for all patients with congenital heart disease.