The clinical course of cardiac disease in Down's syndrome.

There was 230 patients with heart disease among 369 infants and children with Down's syndrome. The majority exhibited defects of the endocardial cushion variety and approximately one quarte had complete atrioventricular canals (CAVC). Pulmonary artery hypertension was uniform in catheterized patients in this latter group and frequent in all left-to-right shunts. Medical and surgical mortality was high (33%) in these 230 children and especially in those with CAVC and tetralogy of Fallot. Only 4% (76 of 1,916) of infants with critical heart disease in New England had Down's syndrome and the most frequent lesion encountered was complete atrioventricular canal.