Tetralogy of Fallot refers to a type of congenital heart defect. Congenital means present at birth.
Tetralogy of Fallot is classified as a cyanotic heart defect because the condition causes low oxygen levels in the blood. This leads to cyanosis (a bluish-purple color to the skin).
The classic form of tetralogy includes four related defects of the heart and its major blood vessels:
At birth, infants may not show signs of cyanosis. However, later they may develop sudden episodes (called "Tet spells") of bluish skin from crying or feeding.
Tetralogy of Fallot is rare, but it is the most common form of cyanotic congenital heart disease. Patients with tetraology of Fallot have a higher incidence of major non-heart congenital defects.
The cause of most congenital heart defects is unknown. Many factors seem to be involved.
Factors that increase the risk for this condition during pregnancy include:
There is a high incidence of chromosomal disorders in children with tetralogy of Fallot, such as Down syndrome and DiGeorge syndrome (a condition that causes heart defects, low calcium levels, and immune deficiency).
A physical examination with a stethoscope almost always reveals a heart murmur.
Tests may include:
Surgery to repair tetralogy of Fallot is done when the infant is very young. Sometimes more than one surgery is needed. When more than one surgery is used, the first surgery is done to help increase blood flow to the lungs.
Surgery to correct the problem may be done at a later time. Often only one corrective surgery is performed in the first few months of life. Corrective surgery is done to widen part of the narrowed pulmonary tract and close the ventricular septal defect.
Most cases can be corrected with surgery. Babies who have surgery usually do well. Ninety percent survive to adulthood and live active, healthy, and productive lives. Without surgery, death usually occurs by the time the person reaches age 20.
Patients who have continued, severe leakiness of the pulmonary valve may need to have the valve replaced.
Regular follow-up with a cardiologist to monitor for life-threatening arrhythmias (irregular heart rhythms) is recommended.
Call your health care provider if new unexplained symptoms develop or the patient is having an episode of cyanosis (blue skin).
If a child with tetralogy of Fallot becomes blue, immediately place the child on his or her side or back and put the knees up to the chest. Calm the baby and seek medical attention immediately.
There is no known prevention.
Zipes DP, Libby P, Bonow RO, Braunwald E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 8th ed. St. Louis, Mo; WB Saunders; 2007.