Atrioventricular (AV) Canal in Children
What are atrioventricular canal defects in children?
An atrioventricular (AV) canal defect is a congenital heart defect. This means that
your child is born with it. This condition includes the following heart problems:
- Atrial septal defect. This is an opening in the wall (septum) between the 2 upper chambers of the heart.
These are called the right and left atria.
- Ventricular septal defect. This is an opening in the wall between the 2 lower chambers of the heart. These are
called right and left ventricles.
- Improperly formed mitral or tricuspid valves. This is when the valves that separate the upper heart chambers from the lower heart
chambers aren’t formed right.
There are several types of this heart defect depending on how broad the defect is.
These conditions cause oxygen-rich (red) blood and oxygen-poor (blue) blood to mix.
This sends extra blood to your child's lungs.
What causes an AV canal defect in a child?
Genes and family history may play a part in AV canal defects. They may be caused by
Down syndrome or other chromosome problems.
What are the symptoms of an AV canal defect in a child?
The symptoms of AV canal defect may be similar to symptoms caused by other heart problems.
Infants with AV canal defects often have symptoms. They can include:
- Pale, cool skin
- Fast, heavy breathing
- Fast heart rate
- Chest congestion
- Poor feeding
- Poor weight gain
Your child’s symptoms depend on the size of his or her septal openings. The larger
the openings, the more blood is able to pass through them. This can overload your
heart and lungs. This means that your child’s symptoms may be more severe.
Over time, the pressure in your child’s lungs will force blood back to his or her
heart. This blood has low oxygen levels, and it’s sent to the rest body. This causes
your child’s lips, nailbeds, and skin to turn blue (cyanosis).
How is an AV canal defect diagnosed in a child?
Your child's healthcare provider may first suspect a heart defect when he or she
hears an abnormal sound (heart murmur) when listening to your child's heart with a
stethoscope. Your child may also have symptoms of a heart problem. Your child’s healthcare
provider may refer your child to a heart doctor for children (pediatric cardiologist).
The heart doctor will check your child and listen to his or her heart and lungs. The
location and loudness of the murmur will help the doctor make the diagnosis.
Your child’s doctor may then do tests to confirm the diagnosis. The tests your child
has depends on his or her age and condition, and the doctor’s preferences.
A chest X-ray may show changes in the heart and lungs caused by an AV canal defect.
This test records the electrical activity of the heart. It also shows abnormal rhythms
(arrhythmias) and spots heart muscle stress. These issues may be caused by caused
by an AV canal defect.
This test uses sound waves to make a moving picture of the heart and heart valves.
An echo can show the pattern of blood flow through the septal openings. It can also
show how large the openings are and how much blood is passing through them. Most AV
canal defects are diagnosed with an echo.
A cardiac catheterization gives very 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. Your child’s healthcare provider will inject your child with contrast dye to
see his or her heart more clearly. Your child’s healthcare provider will give him
or her medicine to help relax and prevent pain (sedation). Your child’s blood pressure
and oxygen levels will be checked during the procedure.
How is an AV canal defect treated in a child?
Treatment will depend on your child’s symptoms, age, and general health. It will also
depend on how severe the condition is.
All children with an AV canal defect will need to have surgery to fix it. They may
also need other treatments.
Many children will need medicine to help their heart and lungs work better, such as:
- Digoxin. This medicine helps the heart pump better.
- Diuretics. This medicine helps the kidneys remove extra fluid from the body.
- ACE (angiotensin-converting enzyme) inhibitors. These medicines make it easier for the heart to pump blood to the body.
Infants may become tired when feeding. This may stop them from eating enough to gain
weight. Your child may need the following:
- High-calorie formula or breastmilk. Your child may need special nutritional supplements added to his or her formula or
- Supplemental tube feedings. Your child may need to be fed through a tube. This small, flexible tube passes through
the nose, down into the esophagus, and into the stomach. Your child may have tube
feedings in addition to or instead of formula or breastmilk.
Children with heart problems are at risk for infections of the lining of the heart
and heart valves (bacterial endocarditis). Make sure that you tell all of your child’s
healthcare providers that your child has an AV canal defect. Your child may need to
take antibiotics before medical tests or procedures to prevent infections.
Your child will need surgery to repair the septal openings and heart valves. This
is done to stop his or her lungs from becoming damaged. Your child's heart doctor
will decide when the best time for surgery is. After the surgery, your child's heart
doctor may give him or her antibiotics. This is to prevent infections after he or
she leaves the hospital.
Most children have surgery by the age of 6 months. Children with Down syndrome may
develop lung problems earlier, and may need to have surgery at a younger age.
What are the complications of an AV canal defect in a child?
If left untreated, an AV canal defect can cause several problems.
This is because of higher than normal pressure in the blood vessels and lungs. This
lung damage doesn’t happen right away. The lungs are able to cope with extra volume
of blood for a while.
Blue coloring to your child’s skin, lips, and nailbeds
As the arteries in the lungs get thicker, less blood will flow from the left to the
right side of the heart and to the lungs. It will be easier for oxygen-poor (blue)
blood to flow from the right side into the left side of the heart, and on to the rest
of the body. This stops the body from getting enough oxygen. This causes a blue coloring
to your child’s skin, lips, and nailbeds.
Bacteria in the bloodstream can cause infections of the lining of the heart and heart valves.
How can I help my child live with an AV canal defect?
All children with an AV canal defect will need to have surgery to repair it. Before
their operation, it’s important to follow the recommended medicine and feeding schedules.
Many children who have had an AV canal defect will live active, healthy lives after
their surgery. Their activity levels, appetite, and growth will return to normal over
time. Some children will still have heart valve problems after surgery. They may eventually
need another operation to repair or replace the leaky or blocked valve or valves.
Ask your child's healthcare provider about your child’s outlook.
Key points about an AV canal defect in children
- An AV canal defect is a heart problem that children can be born with.
- An AV canal defect is a complex problem.
- Children with an AV canal defect need to have surgery to repair it.
- Many children who have had an AV canal defect will live active, healthy lives after
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.