This patient was experiencing progressively decreasing cardiac function secondary to a congenital heart defect. Endocardial cushion defects are also known as atrioventricular septal defects or atrioventricular canal defects. They have a high incidence in Down syndrome patients. This patient's defect was partial, also known as ostium primum defect or PAVC. Partial defects usually consist of an ASD and an associated atrioventricular valve abnormality that often manifests with mitral regurgitation(present in this patient.) These congenital defects result in valve overload and the patient presents in congestive heart failure. This usually occurs in less than two months in complete defects and after 6 months in partial defects. Diagnosis is made by echocardiography with demonstration of the cleft in the anterior leaflet of the AV valve. In partial defects, surgical correction can usually be postponed until between 8-12 months of life. During bypass, an autologous pericardial patch is placed over the ASD.