The four main components are (1) malaligned VSD, (2) obstruction to RV outflow, (3) aorta that overrides the VSD, and (4) RV hypertrophy (RVH). Degree of RV outflow obstruction largely determines clinical presentation; when severe, the large right-to-left shunt causes cyanosis and systemic hypoxemia. ECG shows RVH. CXR demonstrates “boot-shaped” heart with prominent RV. Echocardiography delineates VSD, overriding aorta, and RVH and quantitates degree of RV outflow obstruction.