What is Tetralogy of Fallot?
Tetralogy of Fallot is a congenital heart defect with four abnormalities in the heart affecting blood flow to the lungs. Fortunately, only two of these defects require surgery.
The Four Abnormalities in Tetralogy of Fallot
- Ventricular septal defect (VSD)
- There is a hole between the two bottom chambers (ventricles) of the heart. This is usually a single, large hole.
- Overriding aorta
- Due to the location of the ventricular septal defect, the relationship of the aorta to the ventricular septum is slightly different than usual, and is referred to as an “overriding aorta.”
- Pulmonary stenosis
- The pulmonary valve allows blood to flow from the right ventricle to the lungs. Pulmonary stenosis refers to narrowing in this area. Narrowing can occur below the valve, at the valve, or in the pulmonary arteries, the blood vessels that go to the lungs. This narrowing can range from minor to severe. In some cases there is no connection from the right ventricle to the pulmonary arteries (pulmonary atresia).
- Right ventricular hypertrophy
- Like any muscle that has to work harder than usual, the right ventricle becomes more muscular and the walls are thicker than normal.
How is Tetralogy of Fallot diagnosed and managed during pregnancy?
If your doctor suspects a fetal heart anomaly after reviewing your routine ultrasound, he or she may request a fetal echocardiogram (echo), an ultrasound of the fetus’s heart. This safe, noninvasive test shows the structure of the heart and how it is functioning, which can help us confirm the diagnosis of Tetralogy of Fallot and discuss possible options for treatment after delivery. Our Fetal Heart Team will monitor the baby closely for the remainder of the pregnancy.
How will Tetralogy of Fallot affect delivery and after birth?
Most babies with Tetralogy of Fallot can be delivered vaginally unless otherwise indicated by your obstetrician. It is best for these babies to be delivered at a medical center where there is access to a team of pediatric cardiologists and neonatologists, along with an established Neonatal Intensive Care Unit (NICU).
If the pulmonary stenosis is severe, after delivery, the baby will need prostaglandin (PGE), an intravenous medication that keeps the patent ductus arteriosus (a normal connection present in babies in the womb) open. The patent ductus arteriosus (PDA) will allow blood to get to the lungs.
Babies with Tetralogy of Fallot may have bluish skin because of decreased oxygen in the blood. Other symptoms may include difficulty feeding, poor weight gain and blue (TET) spells. Tetralogy of Fallot can be associated with other conditions such as Down Syndrome or DiGeorge Syndrome.
What are the treatments and surgeries for Tetralogy of Fallot?
The type of treatments and surgery necessary depends on the severity of the pulmonary stenosis.
- Less severe stenosis: These babies can go home from the hospital with close cardiology follow up as an outpatient. Depending on the oxygen levels, complete repair is typically performed around 4-6 months of age. The surgeon closes the ventricular septal defect with a patch, and relieves the blockage of blood flow to the lungs.
- More severe stenosis: Prostaglandins will be continued until surgery.
- Blalock Taussig shunt or central shunt: This surgery is done before leaving the hospital after birth. An artificial tube is placed between the aorta and the pulmonary arteries to allow more blood flow to the lungs.
- Complete repair: This surgery is typically performed around four to six months of age. The surgeon takes down the previously placed shunt, closes the ventricular septal defect with a patch, and relieves the blockage of blood flow to the lungs.
What happens after surgery?
These children will need lifelong follow-up visits with a cardiologist to monitor their progress. Depending on the function of the pulmonary valve long-term, additional surgeries, medications, or other treatments may be required later in life.
What is the long-term prognosis for children with Tetralogy of Fallot?
The long-term prognosis after surgery for Tetralogy of Fallot is very good in most cases. After total surgical repair, many patients lead normal lives. In fact, Olympic snowboarder Shaun White and Australian cricketer Beau Casson are two examples of children born with Tetralogy of Fallot who are now world-class athletes!