Tetralogy

Tetralogy (often called Fallot's Tetralogy after the physician who first described it) is a complex condition comprising these defects:

· a ventricular septal defect
· pulmonary (or right ventricular outflow tract) obstruction - a muscular obstruction in the right ventricle, just below the pulmonary valve, that decreases the normal flow of blood. The pulmonary valve may also be small.
· overriding aorta - the aorta is shifted towards the right side of the heart so that it sits over the ventricular septal defect.
· A fourth problem arises when the right ventricle is unable to cope with the extra work it is forced to do to overcome the outflow obstruction, and it becomes enlarged