The histopathologic pattern in the Central Nervous System in 12 out of 21 new-borns and young infants, below 2 months of age, operated for various congenital heart defects, is that of recent necroses in the deep and subcortical white matter of the pallium, seen from a few hours to 8 days following completion of surgery. Type and location of these lesions of ischemic coagulative necrosis, resembling findings in the perinatal respiratory distress syndrome, seem to depend on shock-like states, the low output syndrome of the left heart with hypovolemia and hypotension. The cause of death in all these infants was cardio-respiratory failure. The question to what extent glial scars replacing necroses within the mostly non-myelinated fiber systems of the pallium will lead to defective maturation of the brain in later infancy and childhood remains a challenge for neurologic and psychological investigation, even if the heart defect has been successfully repaired by the surgeon. Post-mortem data of the CNS in 24 older infants and children below 9 years of age in association with cardia surgery include thrombembolic infarctions, also, after catheterization alone, diffuse or segmental cortical necroses, and cortical scars, especially in children older than 1 year, confirming data recently reported from this laboratory.