Tetralogy of Fallot is a heart condition in which a baby is born with four abnormalities in how their heart developed. These issues make it hard for the baby’s heart to send enough oxygen to their entire body.
Normally, your blood travels a specific route through your heart with every heartbeat. Because of the structural abnormalities in a heart with tetralogy of Fallot, some blood that doesn’t have oxygen in it can go into the aorta and out to the body instead of to the pulmonary artery to get oxygen.
What are the symptoms of tetralogy of Fallot?
Tetralogy of Fallot symptoms can be mild, moderate or severe. They usually get worse over time without treatment.
Tet spells
Babies who haven’t gotten treatment for tetralogy of Fallot can get “tet spells” when their oxygen level drops without warning while or after feeding, crying or pooping. Tet spells can be as short as a few minutes to as long as several hours. Your baby may sleep a lot after a tet spell.
Healthcare providers don’t know what causes tetralogy of Fallot.
Possible causes include:
Something in your child’s DNA may have changed, and that change rarely comes from a parent. A parent who’s had a heart abnormality since birth doesn’t normally pass it to their child. However, the risk may be higher if both parents have the heart issue.
Having rubella or diabetes, drinking alcohol or eating a poor diet while pregnant can put the fetus at a higher risk of a congenital heart problem.
Being pregnant after age 40 may be a risk factor.
A rare condition called phenylketonuria (a buildup of an amino acid) can increase your child’s risk of a heart issue.
How do I manage my baby’s symptoms?
Until your baby has surgery, you can help them through tet spells. When your baby has trouble breathing, put them into a squatting position (pushing their knees to their chest). Your provider can help with extra oxygen and beta-blocker medicine to improve blood flow.
Other things you can do to help your child include making sure they:
Are drinking enough fluids.
Aren’t exercising too hard.
Are taking prescribed medicines.
How is tetralogy of Fallot treated?
Without tetralogy of Fallot surgery, symptoms usually get worse. Soon after birth, your baby can have surgery that will make blood move through their heart the way it should. A surgeon can make the pulmonary valve and the path to the pulmonary artery bigger. And they can patch the hole between the two ventricles so the blood without oxygen doesn’t mix with the blood that has oxygen in it.
If your baby is too small or weak for the surgery, their provider can do a simpler procedure until they can do the complete repair. Your provider can put a shunt or tube between one of the aorta’s large arteries and the pulmonary artery to help blood get to the lungs or do a catheter procedure.
These techniques can relieve symptoms for a number of years — well into adulthood — until a provider can do a more complete repair surgery.
Complications of the treatment
Often, after the complete tetralogy of Fallot surgery, the pulmonary valve leaks. If this happens, your child may need to limit their physical activity. Sometimes, a provider will need to replace the pulmonary valve. If your child’s pulmonary valve is fine, they may be able to do normal activities. Your child may also have a higher risk of abnormal heart rhythms after surgery.
How is tetralogy of Fallot surgically repaired in an adult?
To perform a complete repair, a surgeon who specializes in adult congenital heart disease closes the ventricular septal defect with a patch. They open the passageway out of the right ventricle, and repair or replace the pulmonary valve. They enlarge the pulmonary arteries to both lungs. Sometimes, they place a tube between the right ventricle and the pulmonary artery to improve blood flow.
Are there tetralogy of Fallot complications in adults who have the surgery?
Although the surgical treatment of tetralogy of Fallot is very effective in correcting the structural defects and blood flow through the heart, it can cause some ongoing abnormalities in your heart’s function. If these issues develop, additional surgery can treat them.
Many adults who undergo repair for tetralogy of Fallot don’t need further surgical treatment. One study found that 10% to 15% of people needed a reoperation over 20 years.
The potential tetralogy of Fallot complications in adults who have the surgical repair include:
Electrical disturbances: Having a patch on the ventricular septal defect can block your atria from sending electrical signals to your ventricles. A pacemaker can correct this.
Rhythm disturbances (arrhythmias): Atrial fibrillation or atrial arrhythmias in general are common complications after heart surgery. You can treat them with medication or a nonsurgical procedure. A rarer but more serious arrhythmia is ventricular tachycardia.
Leaking valves: The most common valve problem after a tetralogy of Fallot repair is a leaking pulmonary valve, but your aortic and tricuspid heart valves can also leak. Heart valves are designed to allow blood to flow in one direction. When a valve leaks, blood can flow backward. A surgeon or structural cardiologist can repair a leaky valve.
Residual ventricular septal defect: Sometimes the ventricular septal defect doesn’t seal completely and there’s some leaking around the patch. A surgeon can repair the leak if it’s large or causes major symptoms.
Aneurysm: Patches that repair a ventricle can cause weak sections of the ventricle to bulge out, forming an aneurysm. There’s also an increased risk of developing aneurysms of the ascending aorta. A large aneurysm requires surgical repair.
How is tetralogy of Fallot diagnosed?
Your healthcare provider can diagnose tetralogy of Fallot during pregnancy or after your baby is born. They usually find it in the first few weeks or months of life.
Tests before birth
During prenatal tests, your healthcare provider may see something in an ultrasound image that looks like it could be tetralogy of Fallot. From 18 to 22 weeks into your pregnancy, your provider will be able to use a fetal echocardiogram or ultrasound image of the fetus’s heart to see if the heart’s structure is normal.
Tests in infancy
If your baby has tetralogy of Fallot, your provider will most likely hear a heart murmur when listening to your baby’s heart. They can easily check your newborn baby’s oxygen level with pulse oximetry (pulse ox). If it shows a low oxygen level, your provider can do an echocardiogram (ultrasound of the heart). These tests are painless and don’t go through the surface of your baby’s skin.
Pulse oximetry: Before you take your baby home, your provider will put sensors on your newborn’s feet or hands to find out how much oxygen is in their blood.
Echocardiogram: uses sound waves to show your baby’s heart structure and how well their heart is working.
Chest X-ray or CT (computed tomography): This may show a heart that has the abnormal shape of a boot.
Tests in childhood or adulthood
To diagnose tetralogy of Fallot in a child or adult, a provider may use the above methods, as well as an electrocardiogram (EKG) and cardiac catheterization.
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