Tetralogy of Fallot (TOF)

What is Tetralogy of Fallot?

Illustration by Steven P. Goldberg, MD
Copyright © 2012 STS

Tetralogy of Fallot (TOF) is the most common form of congenital heart disease associated with children being blue (cyanosis). Tetralogy of Fallot means that there are four different conditions occurring in the heart at the same time (“tetralogy” is Latin for “four”). It was named after Fallot, the physician who identified it.

The four conditions are:

  1. Pulmonary stenosis (PS). PS is a narrowing (stenosis) at or around the pulmonary valve that blocks the flow of blood from the right ventricle to the pulmonary artery. Since the pulmonary artery is the main path for blood to travel from the heart to the lungs, this stenosis means that blood cannot get from the heart to the lungs easily to collect oxygen.
  2. Ventricular septal defect (VSD). A VSD is a hole (defect) in the wall (septum) separating the pumping chambers of the heart (the right and left ventricles). Patients usually have one VSD but may have more than one.
  3. Overriding aorta. Oxygen-rich blood is pumped to the body from the left ventricle of the heart through the aortic valve and aorta. An overriding aorta occurs when the aortic valve is located over the ventricular septal defect instead of the left ventricle, so that instead of receiving just the oxygen-rich blood from the left ventricle it can also receive oxygen-poor blood from the right ventricle. This anatomy means that both oxygen-poor and oxygen-rich blood is being pumped back to the body.
  4. Right ventricular hypertrophy (RVH). RVH is a thickening (hypertrophy) of the muscular walls of the right ventricle. The walls thicken because the right ventricle is pumping at high pressure to try to get blood to the lungs through the narrowing around the pulmonary valve.

Together, these conditions mean that there is not enough blood flow to the lungs so there is not enough oxygen in the blood, and the child appears blue.

Why do the surgery?

The surgery will repair the four conditions. Every child with TOF is different. Children with TOF do not have enough blood going to the lungs because of the narrowing around the pulmonary valve (pulmonary stenosis) and so do not have enough oxygen in their blood. If the narrowing is not very small, the blood flow to the lungs is more like normal, and the child will not appear blue. These children are sometimes called “pink tets.” If the narrowing is more severe, the oxygen level in the blood is lower and the child will appear blue (cyanosis).

If the pulmonary stenosis is left untreated, the right ventricle muscle gets thicker (right ventricular hypertrophy) to try to push blood through the narrowing around the pulmonary valve. When the right ventricle muscle is too thick, it also blocks the flow of blood to the pulmonary artery, and the amount of oxygen in the child’s blood continues to decrease. 

 Eventually, the child may have what are called “tet spells,” during which they may lose consciousness, experience seizures, have heart failure, and be at risk of death.

What to ask your surgeon

The following are questions that you should ask your surgeon before any surgical procedure is performed: 
  • What can happen if we do not do the surgery?
  • Will my child be in pain?
  • When should we do the surgery?
  • What is the experience of the surgical team?
  • Where will the incision be made? What will it look like?
  • Do you have specialized Intensive care staff?
  • How long does the surgery take?
  • Can I stay in the hospital with my child?
  • What is the risk of the surgery?
  • What should be bring to the hospital?
  • How long will my child be in the hospital?
  • Will my child be on any medications after surgery?
  • What will my child look like right after surgery?
  • Will my child need another surgery later on in life?
  • What can I expect during the hospital stay?

The surgical procedure

Illustration by Steven P. Goldberg, MD
Copyright © 2012 STS

Surgery is usually done when the child is between four and six months old. The surgeon makes an incision down the front of the chest (called a median sternotomy) and divides the breastbone (sternum) in half to get access to the heart. The heart is placed on cardiopulmonary bypass, meaning that a machine takes over the heart’s job of pumping of the blood so the surgeon can enter the heart to repair it.

The repair may consist of the following steps:

  1. Fixing the narrowing around the pulmonary valve (the pulmonary stenosis). The pulmonary artery may be cut open where it is too narrow, and a patch of material may be placed there to make the artery wider. If the narrowing is located at the pulmonary valve, it may be necessary to cut open the valve to make the repair. The child may require another surgery later in life to repair the valve.

  2. Cutting out some of the muscle in the right ventricle if it has gotten too thick and is blocking the flow of blood to the pulmonary artery.
  3. Fixing the ventricular septal defect. The hole(s) between the right and left ventricles are usually closed with a patch of fabric made of Gore-Tex™ or Dacron™.  Both fabrics are strong woven materials that are accepted by the body. The child’s own heart cells will grow over the patch, making it part of the child’s body.

When the breastbone is put back together, stainless steel wires are usually wrapped around the bone to make it very sturdy. The surgery will take an average of four hours from start to finish.

Risks and benefits of the surgery

The benefit of the surgery is for the child to have a better functioning heart.

Risks of any heart surgery include: bleeding, infection, stroke, organ damage, requirement for a temporary or permanent pacemaker, or possibly death. For 99% of all pediatric heart disease surgical procedures, the risk of these occurring is 5% or less. Some children may have a fast heartbeat for a few days (supraventricular tachycardia or SVT). SVT is treated with medication and is almost always temporary. The ventricular septal defect patch can come loose, requiring another operation to repair it, but this is extremely rare. Some children have a leaky pulmonary valve following surgery. While this leak should not interfere with most activities, these children may have some restrictions placed on them by their cardiologist. Further surgery may be necessary later in life to address this leaky pulmonary valve.

What to expect during the hospital stay

The length of the hospital stay usually varies from five to 14 days, depending on how quickly the heart recovers. The child may need to be in the hospital for more than seven days if they experience any of the following: 
  • A fast heart beat (supraventricular tachycardia or SVT), requiring medications to slow down the heart
  • Fluid in the chest (pleural effusions), requiring a chest tube that is put in place at the end of surgery to stay in longer or additional chest tubes to be added
  • Needing help from a machine (ventilator) to breathe for a few days
  • These challenges are part of the normal recovery after surgery in a child with TOF.

Just after surgery, the child will be sleepy while recovering from anesthesia and will be under the influence of strong pain medications. It is normal for a child to be confused, thirsty, and nauseated. The child may have nothing but glue over the outside over the surgical incision in the chest and will have many tubes and wires attached, including a chest tube.

Over the several days, the child’s chest will be x-rayed daily and more of the wires and tubes will be removed. Over time, the primary focus of care will involve getting the child moving, making sure the child is breathing well, and comfortable.  Pain medication may be given, such as morphine, acetaminophen, or ibuprofen.

Going home

The hospital will supply specific discharge instructions, and all instructions from the hospital, cardiac surgeon, and cardiologist should be strictly followed. The child should get back to his or her normal routine upon arrival at home. For the first week, the child may wish to take more frequent naps or wake up occasionally at night, and will need to take acetaminophen or ibuprofen every six hours or so. The child should be seen by his or her cardiologist within two weeks after discharge from the hospital. After that visit, the child should be able to return to daycare or school. The incision should be kept clean and dry until it is healed. It should also be protected from the sun for a full year. The child should not be picked up under the arms for four weeks following surgery. Any of the following symptoms should be reported immediately to the cardiologist: (1) fever greater than 101, (2) redness, puffiness, discharge from the incision, or (3) unusual nausea or flu-like symptoms.

Long-term prognosis

It is important that the child be in the care of a cardiologist through his or her life so that physician can monitor the growth of the pulmonary artery and the function of the heart. Many children will never need another surgery. However, if the first surgery involved cutting open of the pulmonary valve, it is likely that the child will need additional surgery sometime during childhood or early adulthood so the pulmonary valve can be replaced. Once recovered from the surgery and cleared by the cardiologist, the child can usually be treated as any other healthy child, without restrictions, with one exception. Children who have leaky pulmonary valves after surgery should not participate in competitive heavy weight lifting.
Written by Jeffrey P. Jacobs, MD and Heidi Hess, RN - Reviewed September 2012