Feature of the shunts Left to right shunts Right to left shunts √ Generally no cyanosis Cyanosis appears early √ Increased pulmonary Pulmonary circulation circulation increase or decrease v Decreased systemic Deoxygenated blood mix circulation with oxygenated blood in systemic circulation √ Pulmonary arterial hypertention (hyperkinetic, obstructive) v Persistent cyanosis in late stage (Eissenmager 's syndrome)Feature of the shunts Left to right shunts Right to left shunts ✓Generally no cyanosis ✓ Cyanosis appears early ✓Increased pulmonary circulation ✓ Pulmonary circulation increase or decrease ✓Decreased systemic circulation ✓ Deoxygenated blood mix with oxygenated blood in systemic circulation ✓Pulmonary arterial hypertention (hyperkinetic、obstructive) ✓Persistent cyanosis in late stage (Eissenmager’s syndrome)