Narrowing of the pulmonary outflow tract (the valve and artery that connect the heart with the lungs)
Overriding aorta (the artery that carries oxygen-rich blood to the body) that is shifted over the right ventricle and ventricular septal defect, instead of coming out only from the left ventricle
Thickened wall of the right ventricle (right ventricular hypertrophy)
Tetralogy of Fallot is rare, but it is the most common form of cyanotic congenital heart disease. It occurs equally as often in males and females. People with tetralogy of Fallot are more likely to also have other 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:
Alcoholism in the mother
Mother who is over 40 years old
Poor nutrition during pregnancy
Rubella or other viral illnesses during pregnancy
Children with tetralogy of Fallot are more likely to have chromosome disorders, such as Down syndrome, Alagille syndrome, and DiGeorge syndrome (a condition that causes heart defects, low calcium levels, and poor immune function).
Surgery to repair tetralogy of Fallot is done when the infant is very young, typically before 6 months of age. 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 with a patch.
Most cases can be corrected with surgery. Babies who have surgery usually do well. More than 90% survive to adulthood and live active, healthy, and productive lives. Without surgery, death often occurs by the time the person reaches age 20.
People who have continued, severe leakiness of the pulmonary valve may need to have the valve replaced.
Regular follow-up with a cardiologist is strongly recommended.
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Fraser CD, Kane LC. Congenital heart disease. In: Townsend CM Jr, Beauchamp RD, Evers BM, Mattox KL, eds. Sabiston Textbook of Surgery: The Biological Basis of Modern Surgical Practice. 20th ed. Philadelphia, PA: Elsevier; 2017:chap 58.
Webb GD, Smallhorn JF, Therrien J, Redington AN. Congenital heart disease in the adult and pediatric patient. In: Zipes DP, Libby P, Bonow RO, Mann DL, Tomaselli GF, Braunwald E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 11th ed. Philadelphia, PA: Elsevier; 2019:chap 75.
Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.