Anatomy of tetralogy of Fallot

Tetralogy of Fallot is characterized by a large VSD, an aorta that overrides the left and right ventricles, obstruction of the right ventricular outflow tract, and right ventricular hypertrophy. As a result of the substantial obstruction of the right ventricular outflow tract, there is right-to-left shunting through the VSD, resulting in cyanosis.