Congenital Heart Defects - Tetralogy of Fallot

1.Right ventricular outflow obstruction. Typically multi-level: small, malformed pulmonic valve, hypoplastic proximal pulmonary artery, and muscular narrowing below the valve.

2. Right ventricular hypertrophy (thickened muscle wall) secondary to higher pressure load on this chamber.

3. The aorta "overrides" the VSD.

4. Ventricular septal defect. With significant obstruction in the right ventricular outflow tract, blood will shunt from right to left, bypassing the lungs and leading to cyanosis.

5.Muscular right ventricular outflow obstruction has been cut away as part of the repair.
6. Patch closure of the VSD.

7. Right ventricular outflow patch to address all levels of obstruction.

Tetralogy of Fallot is a cardiac anomaly that refers to a combination of four related heart defects that commonly occur together. The four defects include:

1.	Pulmonary stenosis (narrowing of the pulmonary valve and outflow tract or area below the valve, that creates an obstruction (blockage) of blood flow from the right ventricle to the pulmonary artery
2.	Ventricular Septal Defect/VSD
3.	Overriding aorta (the aortic valve is enlarged and appears to arise from both the left and right ventricles instead of the left ventricle as occurs in normal hearts)
4.	Right ventricular hypertrophy (thickening of the muscular walls of the right ventricle, which occurs because the right ventricle is pumping at high pressure)