Tetralogy of Fallot Defects

Tetralogy of Fallot is a congenital heart defect which is classically understood to involve four anatomical abnormalities of the heart (although only three of them are always present). It is the most common cyanotic heart defect and the most common cause of blue baby syndrome. Tetralogy of Fallot is made up of the following four defects of the heart and its blood vessels:
1) Ventricular septal defect (hole in the wall between the two lower chambers―or ventricles―of the heart)
2) Pulmonary stenosis (narrowing of the pulmonary valve and main pulmonary artery)
3) The aortic valves, which opens to the aorta, is enlarged and seems to open from both ventricles, rather than from the left ventricle only, as in a normal heart. In this defect, the aortic valve sits directly on top of the ventricular septal defect.
4) Ventricular hypertrophy (the muscular wall of the lower right chamber of the heart (right ventricle) is thicker than normal)