What is the physiologic basis of the cyanosis in CHD?

Right-to-left shunting with an admixture of deoxygenated blood
Truncus arteriosus (1: one common trunk)
Transposition of the great vessels (2: two-vessel switch)
Tricuspid atresia (3: tricuspid valve)
Tetralogy of Fallot (4: tetralogy)
TAPVR (5: five words)

5 T's