Tetralogy of Fallot

Tetralogy of Fallot is a rare congenital (present at birth) heart defect caused by a combination of four heart defects. These defects, which affect the heart's structure, cause oxygen-poor blood to flow out of the heart and to the rest of the body.Infants with tetralogy of Fallot usually have bluish skin because their blood doesn't have enough oxygen.

The four defects that make up the tetralogy of Fallot include:

• Right ventricular hypertrophy: When the heart's working too hard, it causes the right ventricle's muscular wall to thicken. This causes the heart to stiffen and eventually fail.


• Pulmonary valve stenosis: This is a narrowing of the pulmonary valve. Narrowing the valve reduces blood flow to the lungs. In some severe cases, the pulmonary valve doesn't form properly (pulmonary atresia).


• Ventricular septal defect (VSD): A VSD is a hole (defect) in the wall (septum) that separates the left and right sides of the heart. The hole allows deoxygenated blood in the right ventricle to flow into the left ventricle's oxygenated blood. This reduces oxygen in the body and can weaken the heart.


• Overriding aorta: In tetralogy of Fallot, the aorta (the main artery leading out to the body) lies directly above the VSD. In this position, the aorta receives blood from both the right and left ventricles, mixing the oxygen-poor blood with oxygen-rich blood which reduces oxygen in the body.

What happens once you have tetralogy of Fallot?

Tetralogy of Fallot occurs when the baby's heart is developing in the mother's womb. It is usually diagnosed after birth, during infancy. Sometimes it is not diagnosed until adulthood if the defects and symptoms are not severe.

Symptoms depend on how obstructed the blood flow is into the lungs. Signs and symptoms may include:

• Fainting.


• Irritability.


• A heart murmur.


• Poor weight gain.


• Prolonged crying.


• Bluish skin (cyanosis).


• Tiring easily during play or exercise.


• Clubbing of fingers and toes—an abnormal, rounded shape of the nail bed.


• Shortness of breath and rapid breathing, especially during feeding or exercise.

Sometimes, babies will suddenly develop deep blue skin, nails, and lips after crying or feeding or when agitated. These episodes are called "tet spells." They are caused by a rapid drop in the amount of oxygen in the blood. If your baby becomes suddenly blue (cyanotic), lay him or her on their side and pull their knees up to his or her chest to increase blood flow to the lungs. Get emergency medical care immediately.

What causes tetralogy of Fallot?

In most cases, the cause of tetralogy of Fallot is unknown.

Factors that might increase the risk include:

• Alcoholism during pregnancy.


• A mother over the age of 40.


• Poor nutrition during pregnancy.


• A parent who has tetralogy of Fallot.


• The presence of Down syndrome or DiGeorge syndrome.


• A viral illness during pregnancy, such as rubella (German measles).

What types of tests are used to diagnose tetralogy of Fallot?

A doctor might suspect tetralogy of Fallot if they notice bluish skin or a heart murmur (an abnormal whooshing sound) when listening to the heartbeat. A cardiologist (heart doctor) will conduct a physical examination and use several tests to diagnose.

Tests may include:

• Echocardiogram: Sound waves bounce off the heart and produce moving images that can be viewed on a video screen. This can determine if there is a VSD and where it's located, if the pulmonary valve and pulmonary artery structure is normal, if the right ventricle is functioning properly, if the aorta is positioned properly, and if there are any other heart defects. This test can also help plan treatment.


• Electrocardiogram: An electrocardiogram records the electrical activity in the heart. This helps determine if the right ventricle is enlarged (right ventricular hypertrophy) if the right atrium is enlarged, and regular heart rhythm.


• Chest X-ray: A chest X-ray can show the structure of the heart and lungs. A common sign of tetralogy of Fallot on an X-ray is a "boot-shaped" heart because the right ventricle is enlarged.


• Pulse oximetry: This test uses a sensor to measure the amount of oxygen in the blood.


• Cardiac catheterization: Doctors use a catheter (thin, flexible tube) to evaluate the structure of the heart and plan surgical treatment.

What types of treatments and procedures are used to treat tetralogy of Fallot?

In some cases, your child may need medicine to maintain blood flow from the heart to the lungs before surgery. However, surgery is the most effective treatment for tetralogy of Fallot.

Most babies and older children have a type of surgery called intracardiac repair. This open-heart surgery is usually done during the first year after birth and involves several repairs. Adults might undergo this procedure if they didn't have surgical repair as children.

The surgeon places a patch over the VSD to close the hole between the heart's lower chambers (ventricles). They also repair or replace the narrowed pulmonary valve and widen the pulmonary arteries. Because the right ventricle won't need to work as hard, the right ventricle wall will go back to a normal thickness. The oxygen level in the blood will increase, and symptoms will lessen.

Arrhythmias are common after repair and may be treated with medications, a procedure to treat the arrhythmias (ablation), or a special pacemaker device that treats life-threatening heart rhythms (implantable cardioverter-defibrillator).

What can I do to support my health when I have tetralogy of Fallot?

While most babies and adults do well after intracardiac repair, there can be long-term complications. Infants, children, or adults with these complications might require additional surgeries. Some complications include:

• Sudden cardiac death.


• Coronary artery disease.


• Irregular heartbeats (arrhythmias).


• Aortic root dilation, in which the ascending aorta enlarges.


• Enlarged right ventricle or left ventricle that isn't working properly.


• Other heart valve problems, such as blood leaking back through the tricuspid valve.


• Chronic pulmonary regurgitation, blood leaks through the pulmonary valve back into the pumping chamber (right ventricle).


• Holes in the wall between the ventricles (VSDs) that continue to leak after repair.

Most adults with repaired tetralogy of Fallot may require another procedure or intervention during their lifetimes. It's very important to have regular follow-ups with a cardiologist trained in caring for people with congenital heart disease.

Sometimes, antibiotics are recommended during dental procedures to prevent infections that might cause endocarditis—an inflammation of the heart's lining. Antibiotics are especially important for those who have had prior endocarditis, have artificial valves, or have had repair with prosthetic material. Ask the doctor what's right for you or your child.

Why choose Presbyterian for tetralogy of Fallot?

Presbyterian’s Pediatric and Congenital Cardiology team has many different options to help you manage your or your child’s heart condition. The team performs various diagnostic tests and procedures to help form an accurate diagnosis and create individualized treatment plans. Depending on the type of heart condition your child has and its underlying cause, the team can recommend a wide variety of treatment options. Our pediatric cardiologists, pediatric interventional cardiologists, and pediatric cardiovascular surgeons work closely together for cases in which cardiac repair or surgery is the best treatment option.