Paediatrics:Tetralogy Of Fallot

The four abnormalities shown on the right characterize this fairly common condition:

1. There is a ventricular septal defect.
2. There is narrowing of the valve leading to the pulmonary arteries (pulmonic stenosis)
3. The aorta "overrides" the ventricular septal defect.
4. There is thickening (hypertrophy) of the right ventricle.



There is decreased flow of blood to the lungs, as well as mixing of the blood from each side of the heart. Despite its seeming complexity, it is quite common and often can be completely repaired.


Clinical Features:

Tetralogy of Fallot is a serious heart problem because it obstructs blood from reaching the lungs. Usually, the baby will have a bluish color called cyanosis. Although this may not be very severe at first, it generally increases over time. In some babies, the obstruction is severe causing significant cyanosis and very low oxygen levels soon after birth.

Usually the child's growth and development is not significantly affected.

Some babies with tetralogy of Fallot have periods where the cyanosis becomes very severe and the baby looks very blue. The baby may be upset at the time, and may actually pass out or even have a seizure. These periods are called "tetralogy spells" or hypoxic spells. The precise cause is not known but during a spell there is very little blood flow to the lungs. Hypoxic spells are more likely to happen when the baby is a little "dry" or dehydrated and may be prevented by careful attention to hydration particularly if the baby is having problems with vomiting or diarrhea. Spells are also more likely if the baby is anemic (low blood) so if this is noted the doctor may order an iron supplement.

During a spell, the baby turns very blue even though he or she is breathing rapidly. If a spells occurs, the baby should be placed in a knee-chest position (draw the baby’s knees up to their chest and hug them close to your body), attempt to calm the baby, and call the pediatric cardiologist or pediatrician. If a baby has even one spell, surgery will need to be scheduled to try to avoid another one that could possibly result in harm to the baby. Sometimes medicine is used to relax the right ventricle and hopefully prevent additional spells while the child is awaiting surgery.