What is it?
The disorder happens because of a structural problem with the heart. Tetralogy of Fallot is caused by a combination of four heart defects that are present at birth.
What are the defects?
According to the Centers for Disease and Control, the defects are:
1. A hole in the wall between the two lower chamber – or ventricles – of the heart. This condition also is called a ventricular septal defect.
2. A narrowing of the pulmonary valve and main pulmonary artery. This condition also is called pulmonary stenosis.
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.
4. The muscular wall of the lower right chamber of the heart (right ventricle) is thicker than normal. This also is called ventricular hypertrophy.
What happens because of the problems?
The structure of the heart is affected and the defects cause blood that is oxygen-poor – meaning it has gone through the body and is being pumped back to the heart for recirculation – to be incorrectly routed through the body. Oxygen-poor blood is usually moved to the lungs to be infused with oxygen then routed through the heart to the brain and other organs.
With tetralogy of Fallot, the blood mixes in the heart, sending the oxygen-poor blood throughout the body. Because the blood does not have enough oxygen, it leaves a baby’s skin with a blue tinge.
What is the treatment?
Surgery is needed soon after birth. During the surgery, doctors widen or replace the pulmonary valve and place a patch over the ventricular septal defect to close the hole between the two lower chambers of the heart.
The surgery is incredibly delicate. Dr. Jennifer Ashton on “Good Morning America” Tuesday, offered this perspective on the complicated nature of the surgery: Try to imagine operating on an organ the size of a walnut with veins the diameter of angel-hair pasta.
Is it always diagnosed at birth?
No, not always, but usually. Sometimes it is diagnosed when the baby is still in the womb. Sometimes it is not diagnosed until later in life.
What about the other problem Kimmel mentioned – pulmonary atresia?
Pulmonary atresia (PULL-mun-airy ah-TREE-sha) is a birth defect of the pulmonary valve. That valve controls the blood flow from the right lower chamber of the heart into the blood vessel that carries blood from the heart to the lungs. Pulmonary atresia means that no pulmonary valve ever formed in the baby’s heart.
What caused these problems?
The cause of the defects is not known. Some are caused by gene or chromosome changes, some by something the mother and baby are exposed to – environmental factors or food, drinks or medication the mother uses.
What is the prognosis? Can children with this lead normal lives?
The baby needs surgery not long after birth to repair the problem if possible. When the defects are caught early and the child is treated, most lead fairly normal lives. Usually, three surgeries are required to fix the defects.
(Sources: Centers for Disease and Control, Mayo Clinic;
University of California San Francisco)