 Term infants with congenital heart disease CHD requiring neonatal surgery have an unusual susceptibility to white matter injury WMI, a neuropathology typically seen in preterm infants. The mechanism of this brain injury is unclear. Newborns with CHD may experience a dramatic peri-operative inflammatory response during critical periods of neurodevelopment. Experimental models suggest certain pro-inflammatory cytokines can be toxic to developing oligodendrocytes, resulting in white matter pathology. The consequence of exposure to the systemic inflammatory response SIR in this group of patients is unknown; however, neuroimaging abnormalities seen in approximately 40 and neurodevelopmental impairment noted in approximately 50 are both well established in children with CHD. We hypothesize that term newborns with complex CHD requiring neonatal surgery have WMI due to neurotoxicity from the profound peri-operative inflammatory response. These hypotheses will be tested in a prospective longitudinal study that will characterize the SIR Aim 1 in a heterogeneous group of congenital lesionssurgeries, assess brain injury in the post-operative period Aim 2, asses neurodevelopment outcomes at 1 and 2 years Aim 3, and determine whether inflammation plays a mechanistic role Aim 2a, 3a. 