Cases were categorized into 1 of 4 categories of CHD: single-ventricle (SV) physiology; 2-ventricle heart disease requiring complex repair (CR), defined as Risk Adjustment for Congenital Heart Surgery 1 class 3 or higher;2-ventricle heart disease requiring simple repair (SR), defined as Risk Adjustment for Congenital Heart Surgery class 1 or 2; and2-ventricle heart disease requiring no repair(NR).Cases were classified on the basis of indicated or planned repair at the last evaluable visit rather than whether repair had occurred at the time of the last evaluated visit. Chart review wasusedtodeterminetheageatrepair