What is the pathophysiology of tetralogy of fallot?

Tetralogy of fallot. Is a congenital malformation. Uneven septation of the embryological troncus: small PA, larger Aorta with overriding the VSD , RV hypertrophy, presence of a VSD, Obstruction of the RV outflow, diminished blood flow to the lungs, usually requires an arterial shunt to the PA to increase blood flow in to the lungs, the surgery is done as neonatal. Total repair by the age of 4-5 years.