Overview of tetralogy of Fallot in children
Tetralogy of Fallot (TOF) is a cardiac anomaly that refers to a combination of four related heart defects that commonly occur together. The four defects are:
- Ventricular septal defect (VSD): a hole between the right and left pumping chambers of the heart.
- The overriding aorta is the aortic valve is enlarged and appears to arise from both the left and right ventricles instead of the left ventricle as in normal hearts.
- Pulmonary stenosis: narrowing of the pulmonary valve and outflow tract or area below the valve that creates an obstruction (blockage) of blood flow from the right ventricle to the pulmonary artery.
- Right ventricular hypertrophy thickening of the muscular walls of the right ventricle, which occurs because the right ventricle is pumping at high pressure.
A small percentage of children with tetralogy of Fallot may also have additional ventricular septal defects, an atrial septal defect (ASD) or abnormalities in the branching pattern of their coronary arteries. Some patients with tetralogy of Fallot have complete obstruction to flow from the right ventricle or pulmonary atresia. Tetralogy of Fallot may be associated with chromosomal abnormalities, such as 22q11 deletion syndrome.
The pulmonary stenosis and right ventricular outflow tract obstruction are seen with tetralogy of Fallot usually limit blood flow to the lungs. When blood flow to the lungs is restricted, the combination of the ventricular septal defect and overriding aorta allows oxygen-poor blood (“blue”) returning to the right atrium and right ventricle to be pumped out the aorta to the body.
Causes of Tetralogy of Fallot (TOF) in children
Genes and family history can influence TOF. It can also be caused by Down syndrome or 22q11.2 deletion syndrome. Most of the time, this heart defect occurs by chance, without cause.
Symptoms of Tetralogy of Fallot (TOF) in children
Cyanosis is a very common sign. Healthy babies can sometimes also have bluish skin around their mouth or eyes due to the prominent veins under the skin, but their lips and tongue appear pink. Babies who have low oxygen levels in their blood usually have blue lips and tongue in addition to blue skin.
A child with TOF may have sudden episodes of deep cyanosis, called “hypercyanotic episodes” or “Tet episodes,” during crying or feeding. Older children who have episodes of TOF often instinctively bend over, helping to stop the spell.
Other signs include:
- Heart murmur
- Laboured breathing
- Fast heartbeat
Prenatal tests are performed to check for birth defects and other conditions. Tetralogy of Fallot in children might be seen during an ultrasound. If your doctor suspects your baby may have tetralogy of Fallot, a fetal echocardiogram (a cardiac ultrasound) will be ordered to evaluate any issues with the structure of the heart and how it’s functioning with this defect.
A pediatric cardiologist will listen to your baby’s heart and lungs, feel the baby’s pulses, measure the oxygen level in the blood (non-invasively) and use several tests to determine the diagnosis, including:
- Electrocardiogram (EKG or ECG)
- Cardiac magnetic resonance imaging (MRI)
- Chest x-ray: A conventional chest x-ray will evaluate the size and spatial relationships of the heart within the child’s chest.
- Cardiac catheterization
- Pulse oximetry: A non-invasive test that measures the amount of oxygen in the blood.
Treatment for tetralogy of Fallot
Surgery is required to repair the tetralogy of Fallot in children. Typically in the first few months of life, we will perform open-heart surgery to patch the hole (VSD) and widen the pulmonary valve or artery.
In some cases, depending on the unique needs of the patient, we will perform a temporary repair until a complete repair can be done. The temporary repair involves connecting the pulmonary arteries (which carry blood from the heart to the lungs) with one of the large arteries that carry blood away from the heart to the body. This increases the amount of blood that reaches the lungs, and so increases the amount of oxygen in the blood.
While the exact cause of tetralogy of Fallot in children is unknown, several factors can increase the risk of a baby being born with this condition. These risk factors include:
- A viral illness throughout pregnancy, such as rubella.
- Alcoholism during pregnancy.
- A mother over 40
- A parent who has tetralogy of Fallot
- The presence of Down syndrome.
All babies with tetralogy of Fallot need remedial surgery. Without treatment, your baby may not grow and develop suitably.
Your baby may also be at increased risk for serious complications, such as infective endocarditis, an infection of the inner lining of the heart or the heart valve caused by a bacterial infection.
Untreated cases of tetralogy of Fallot in children generally develop serious complications over time, which can result in death or disability in early adulthood.
Lifestyle and home remedies
As your child grows, you might have some concerns about how best to care for him or her, including:
- Preventing infection. A child who has severe heart defects might need to take preventive antibiotics before certain dental and surgical procedures. Your child’s doctor can tell you if this is necessary. Maintaining good oral hygiene and getting regular dental checkups are excellent ways to help prevent infection.
- Exercising and play. Parents of children who have congenital heart defects often worry about the risks of rough play and vigorous activity even after successful treatment.
Although some children might need to limit the amount or type of exercise, many can lead normal or near-normal lives. Decisions about exercise need to be made on a case-by-case basis, so ask your child’s doctor which activities are safe for your child.
If you have congenital heart disease, discuss family planning with your doctor. Your doctor may recommend that you receive care before and during your pregnancy from doctors trained in congenital heart disease, genetics and high-risk obstetric care. Some heart medications aren’t safe during pregnancy and might need to be stopped or adjusted before you become pregnant.