The purpose of the past prospective study, “Blood Markers of Brain Injury from Cardiopulmonary Bypass and Deep Hypothermic Circulatory Arrest in Infants and Children”, Emory #621-2004, was to observe the expression of blood markers of brain ischemia, NMDA receptor fragment (NR2) and antibody (NR2 ab) in infants with congenital heart disease before and after cardiac surgery.