What is Tetralogy of Fallot?
Tetralogy of Fallot is a name given to a complex of four cardiac malformations when they appear together:
- Ventricular Septal Defect (VSD)
- Pulmonary Stenosis (narrowing)
- Right Ventricular Hypertrophy (enlargement)
- Overriding Aorta
For practical purposes, however, the signs and symptoms of Tetralogy of Fallot depend on the Ventricular Septal Defect and the degree of Pulmonary Stenosis. The VSD is a large hole in the wall between the ventricles. Pulmonary Stenosis is a narrowing in the outlet from the right ventricle to the pulmonary artery. With more severe degrees of Pulmonary Stenosis, the right ventricle delivers less and less blood to the arteries to the lungs for oxygenation. With increasing degrees of pulmonary stenosis, more and more of this blue blood (lacking oxygen) is directed away from the lungs, through the Ventricle Septal Defect, and back to the left ventricle and out to the body. Thus, as the Pulmonary Stenosis becomes increasingly narrowed, the patient becomes more blue.
What are the warning signs and symptoms of Tetralogy of Fallot?
The most common warning signs and symptoms of Tetralogy appear in a newborn or young infant and include:
- Bluish coloring around the mouth, lips, tongue, and fingertips (called cyanosis)
- Presence of a heart murmur
Occasionally, early on, the degree of Pulmonary Stenosis will be very mild and the symptoms will be that of a Ventricular Septal Defect, including labored breathing, poor feeding, and poor weight gain.
How is Tetralogy of Fallot detected?
Usually Tetralogy patients are initially referred for evaluation because of a heart murmur or cyanosis. This leads to performing an echocardiogram and the diagnosis of Tetralogy is documented. Occasionally, a cardiac catheterization with angiography is needed prior to surgery to obtain more detailed anatomical information.
What are the treatment options for Tetralogy of Fallot?
Patients with Tetralogy of Fallot generally undergo surgery in infancy. Most often a complete repair is performed with patch closure of the Ventricular Septal Defect and widening of the outflow from the right ventricle to the pulmonary artery. Occasionally it is too dangerous to perform open-heart surgery on a particular infant and a temporizing surgery is performed called a shunt, which allows more blood to flow to the lungs. The open-heart repair is then deferred until the patient gets bigger.
Occasionally infants will have periods of inconsolable crying accompanied by a severe increase in cyanosis (called "Tet Spells") requiring immediate notification to the child's physician.