Conditions & Treatments
- A to Z Guide

Tetralogy of Fallot (ToF, Tet)

Disease Information

Overview

Surgery for tetralogy of Fallot, even 30 years ago, was very good, but we continue to improve our medical and surgical management of this condition. Recent advances made at Boston Children's and elsewhere have made the surgery safer and more effective, and promise to improve upon already excellent long-term results.

Thomas Kulik, MD

Tetralogy of Fallot (ToF) is a heart defect marked by a hole between the lower chambers of the heart and an obstruction from the heart to the lungs. With ToF patients, the aorta (blood vessel) lies over the hole in the lower chambers, and the muscle of the lower right chamber becomes thickened.

ToF is a combination of four cardiac anatomic characteristics:

Ventricular septal defect (VSD): This is a hole between the right and left pumping chambers (ventricles) of the heart.

Right ventricular outflow tract obstruction: The connection between the heart and the artery that goes to the lungs (pulmonary artery) is narrowed and blood flow to the lungs is reduced.

Overriding aorta: The major blood vessel from the heart to the body connects to the heart a bit further to the right than it normally does.

Hypertrophy of the right ventricle: The right-sided pumping chamber (ventricle) is thicker than normal because it’s pumping blood at a higher-than-normal pressure.

ToF is always present at birth (congenital).

Babies usually show a bluish tinge to skin (cyanosis ). This can become apparent shortly after birth but may take a few months to develop.

ToF affects about two in 10,000 children. It is the most common cyanotic heart defect.

ToF occurs equally in boys and girls.

Some babies have a severe degree of obstruction to blood flow to the lung, while others have less narrowing and only mild obstruction. The degree of obstruction generally becomes worse with time.

In most cases, surgery is used to repair the heart in ToF patients. The procedure usually takes place when the baby is 3 to 6 months.

Children with Down syndrome have a higher incidence of ToF.

How Boston Children’s Hospital approaches ToF

Thanks to technological innovations, people born with ToF now have a survival rate of more than 90 percent. Patients can lead normal lives, although in some cases other interventions will be required after the initial surgery.

At Boston Children’s Hospital, we’ve been successfully treating ToF since the 1940s. We offer a highly experienced staff and a multidisciplinary, team approach to caring for ToF. Over the years, we helped pioneer the use of early surgery to treat this condition, and our innovations and research efforts continue to contribute to overall improvements in quality of life for our patients.

Tetralogy of Fallot: Reviewed by Thomas J. Kulik, MD
© Boston Children’s Hospital; 2013

Boston Children’s history of heart care innovation
In 1938, Boston Children’s cardiac surgeon Robert Gross, MD, performed the world’s first successful surgery to correct a child’s heart defect. Since that time, we have gained recognition around the globe for our leadership in pediatric cardiology, and we continue to make critical advances in the field.