Tetralogy of Fallot (TOF)
Tetralogy of Fallot (TOF) is a set of 4 congenital heart defects that
occur together. "Tetralogy" refers to the number 4. Congenital means that a baby is
with them. The set of 4 defects are:
Narrowing (stenosis) of the pulmonary artery.
This is the artery that carries blood from the heart to the lungs to pick up
Ventricular septal defect. This is an
opening in the wall between the 2 lower chambers of the heart (right and left
Overriding aorta. The artery that carries oxygen-rich blood to the
body (aorta) is shifted toward the right side of the heart. It should be on the
left side. In this condition, the aorta sits over the ventricular septal
Enlargement (hypertrophy) of the right
The right lower chamber of the heart (ventricle) is
bigger than normal.
In a healthy heart, oxygen-poor
(blue) blood returns to the right chamber of the heart (right atrium) from the body.
Next, it travels through the tricuspid valve to the right ventricle of the heart.
it’s pumped through the pulmonary valve to the pulmonary artery and into the lungs for
oxygen. Oxygen-rich (red) blood comes back to the left upper chamber of the heart
atrium) from the lungs. Then it passes through the mitral valve and into the left
ventricle of the heart. Finally, it’s pumped through the aortic valve to the aorta
out to the body.
Some children with TOF may only have slightly lower than normal
oxygen levels in their blood. These children have minimal narrowing of the pulmonary
artery. They don’t usually have bluish skin (cyanosis). Other children with TOF will
have low oxygen levels in their blood. These children have more severe narrowing of
pulmonary artery. They have bluish skin. This is from the low oxygen levels in their
Genes and family history may play a part in TOF. It may also be caused by Down syndrome
or 22q11.2 deletion syndrome (DiGeorge syndrome). Most of the time, this heart defect
occurs by chance, with no cause.
Symptoms can show up a bit differently in each child. The most common
symptom is a bluish color of the skin, lips, and nail beds. This may come on in sudden
spells, called TET spells. It happens when blood oxygen level drops quickly. During
spell, babies may have a hard time breathing. They may also be tired and fussy. In
most severe cases, they may lose consciousness.
The symptoms of TOF may be similar to symptoms caused by other problems. Make sure
that your child sees a healthcare provider for a diagnosis.
Your child will need to see a heart
doctor (pediatric cardiologist.) They will check your baby and listen to their heart
lungs. The details about your child’s heart murmur will also help the doctor make
Tests may be done to confirm the
diagnosis. The tests your child has depends on their age and condition, and the doctor’s
An echo uses sound
waves to make a moving picture of the heart and heart valves. This test will
show structural changes caused by TOF.
A chest X-ray may show changes
in the heart and lungs caused by TOF. The heart on an X-ray may be enlarged or have
the shape of a boot.
This test records the electrical
activity of the heart. It also shows abnormal rhythms (arrhythmias or dysrhythmias)
and spots heart muscle stress. These issues may be caused by TOF.
Cardiac catheterization (cardiac or heart cath)
A cardiac catheterization gives
detailed information about the structures inside the heart. In this test, a small,
thin, flexible tube (catheter) is put into a blood vessel in your child’s groin. Then
the healthcare provider guides it to your child’s heart. They will inject your child
with contrast dye to see their heart more clearly. This test measures your child’s
blood pressure and oxygen in the 4 chambers of the heart. It also measures blood
pressure and oxygen in the pulmonary artery and aorta. Your child will get medicine
to help them relax and prevent pain (sedation).
Treatment will depend on your child’s symptoms, age, and general health. It will also
depend on how severe the condition is.
Some children will need a small tube called a shunt put into the
pulmonary artery. This helps create stable pulmonary blood flow until a permanent repair
can be done at a later age.
All children with TOF need to have
surgery to fix it. Most children have it before they turn 1 year old. It’s often done
around age 6 months. A team of heart surgeons will do your child’s surgery. To fix
TOF, a surgeon may use a patch to close the ventricle septal defect (VSD). The surgeon
will enlarge the right ventricular outflow tract. This can be done by removing excess
heart muscle or using a patch to enlarge narrowed pulmonary arteries.
Fixing the heart defects will allow
oxygen-poor blood to travel its normal route. This is through the pulmonary artery
the lungs to pick up oxygen.
If left untreated, it can cause
- Blood clots (which may be in the brain
- Infection in the lining of the heart
and heart valves (bacterial endocarditis)
- Abnormal heart rhythms (arrhythmias)
- Heart failure
The heart doctor may give your
child antibiotics to prevent infections after leaving the hospital. Your child may
need medicine before other surgeries or dental tests.
After surgery, your child may become tired easily and sleep more.
Over time, most children are able to be active. Most children’s appetite and growth
become normal soon after surgery. Some children who had surgery for TOF can have
problems learning or growing normally.
Most children who have surgery for
this condition will live healthy lives. They may need more surgeries throughout their
lives. Your child might need a pulmonary valve replacement surgery when they are an
adult. This will help prevent heart complications. These include enlargement of the
right ventricle, abnormal heart rhythms, and heart failure. Women who want to have
children should be checked by a heart doctor before they get pregnant.
Ask your child's healthcare
provider about your child’s outlook.
When to Call a Healthcare Provider
Call your child’s healthcare provider if they have trouble breathing,
eating, or being active.
- Tetralogy of Fallot is a set of 4
congenital heart defects. Children are born with this condition.
- This condition causes problems with
the heart’s ability to pump oxygen-rich blood to the body.
- All children with TOF need to have
surgery to fix it.
- After surgery, most children will live healthy lives.
- Most children who have had surgery for
TOF will need more surgery when they are an adult.
Tips to help you get the most from a visit to your child’s healthcare provider:
- Know the reason for the visit and what you want to happen.
- Before your visit, write down questions you want answered.
- At the visit, write down the name of a new diagnosis, and any new medicines, treatments,
or tests. Also write down any new instructions your provider gives you for your child.
- Know why a new medicine or treatment is prescribed and how it will help your child.
Also know what the side effects are.
- Ask if your child’s condition can be treated in other ways.
- Know why a test or procedure is recommended and what the results could mean.
- Know what to expect if your child does not take the medicine or have the test or procedure.
- If your child has a follow-up appointment, write down the date, time, and purpose
for that visit.
- Know how you can contact your child’s provider after office hours. This is important
if your child becomes ill and you have questions or need advice.