In addition, pulmonary atresia with and without a ventrical septal defect is a complex condition which often requires early surgical intervention. Each is briefly described below with its preferred therapeutic approach. Tetralogy of Fallot Tetralogy of Fallot is perhaps the best known of the cyanotic heart lesions. Cyanosis varies with the degree of outflow tract obstruction and the size of the ventricular septal defect. Right to left shunting through the ventricular septal defect causes cyanosis.
Infundibular spasm is thought to play a role in initiation of Tet spells.
Early repair is favored over palliation unless birth weight is low or if the patient's condition is suboptimal. At surgery, the ventricular septal defect is closed with a patch, and any obstructing right ventricular muscle is removed. All other sites of outflow tract obstruction, including the valve and pulmonary arteries must also be addressed. Transposition of the Great Arteries Transposition of the Great Arteries is the most common cyanotic condition that requires hospitalization in the first two weeks of life. Anatomically, the aorta arises from the right ventricle and carriers deoxygenated blood to the systemic vasculature.