Atrial Septal Defect (ASD)
What is an atrial septal defect?
The atrial septum is the wall between the 2 upper chambers of the heart (right and
left atria). An atrial septal defect (ASD) is an abnormal hole in this wall. ASD is
a heart problem that is present at birth (congenital).
ASDs can happen on their own. Or they can happen in children born with other congenital
heart defects. Girls have ASDs twice as often as boys. Doctors don't know why this
ASDs are classified by their different location and development:
- Secundum ASD occurs in the middle part of the atrial septum.
- Primum ADS occurs in the lower part of the atrial septum close to the tricuspid and
- Sinus venosis occurs in the upper part of the atrial septum near the veins that drain
into the right atrium.
- Coronary sinus ASD occurs when there is a defect in the wall between the coronary
sinus and the left atrium.
Patent foramen ovale (PFO) is an opening between the right and left atria. However,
a PFO is not considered an ASD because no septal tissue is missing.
What causes an atrial septal defect?
The heart forms during the first 8 weeks of pregnancy. It starts as a hollow tube
and divides into 4 chambers. These chambers are separated by walls (septa). It's normal
for the walls to have openings as the fetus grows. The openings usually close shortly
before or just after birth. If they don't all close, the atrial septum will have a
hole in it. This is called an ASD.
Some congenital heart defects may be passed down in certain families. Most atrial
septal defects occur by chance. Doctors can find no clear reason why they occurred.
What are the symptoms of an atrial septal defect?
Many children have no symptoms and seem healthy. If the ASD is large, your child may
have symptoms. Your child may:
- Tire easily
- Have fast breathing
- Have shortness of breath
- Grow slowly
- Have respiratory infections often
- Have abnormal heart rhythm (arrhythmias)
Older children and adults with ASDs may have migraine headaches. But, it is unclear
if the ASD is the cause. A small blood clot that forms in the blood stream that causes
a stroke are also association with ASD in older children and adults. However, it does
not currently appear that closing the defect or taking anticoagulants (blood thinners)
The symptoms of ASD can be like other health conditions. Make sure your child sees
his or her healthcare provider for a diagnosis.
How is an atrial septal defect diagnosed?
Your child's healthcare provider may have heard a heart murmur when listening to
your child's heart with a stethoscope. The heart murmur is from the abnormal flow
of blood through the heart.
Your child may need to see a pediatric cardiologist for a diagnosis. This is a doctor
with special training to treat heart problems in children. The doctor will examine
your child and listen to your child's heart and lungs. The doctor will find out where
the murmur is best heard and how loud it is. Your child may have some tests, such
- Chest X-ray. This test may show an enlarged heart. Or it may show changes in your child's lungs
because of the blood flow changes caused by an ASD.
- Electrocardiogram (ECG). This test records the electrical activity of the heart. It shows abnormal rhythms
(arrhythmias) that may be caused by an ASD. It can also find heart muscle stress caused
by an ASD.
- Echocardiogram (echo). This test uses sound waves to make a moving picture of the heart and heart valves.
An echo can show the blood flow through the atrial septal opening and find out how
big the opening is.
- Cardiac catheterization. This tests uses a thin, flexible tube (catheter) put near the heart. Contrast dye
is used to get even clearer pictures. In some children, this procedure may be used
to close the ASD.
How is an atrial septal defect treated?
Treatment will depend on your child’s symptoms, age, and general health. It will also
depend on how severe the condition is. The most common type of ASD may close on its
own as your child grows.
Once an atrial septal defect is diagnosed, your child's cardiologist will check your
child to see if the defect is closing on its own. An ASD will usually be fixed if
it has not closed by the time a child starts school. The decision to close the ASD
may also depend on the size of the defect.
Treatment may include:
- Medicine. Many children have no symptoms and don't need medicine. But medicine can help some
children's hearts work better. For example, water pills (diuretics) help the kidneys
get rid of extra fluid from the body.
- Surgery. Your child's ASD may be repaired by surgery. The surgery is done under general anesthesia.
The defect may be closed with stitches or a special patch.
- Device closure. Some children are helped with this procedure. The doctor uses cardiac catheterization
to put a special device (septal occluder) in the open ASD. The device stops blood
from flowing through the ASD.
What are the complications of an atrial septal defect?
Large ASDs may cause lung problems over time if not treated. This is because the extra
blood passing through the defect and then into the lungs may harm the vessels in the
Living with an atrial septal defect
All children with an ASD need to be cared for by a pediatric cardiologist. Most children
who have had an ASD repair will live healthy lives. After the repair, your child's
doctor may want your child to take antibiotics. This will prevent an infection of
the heart lining (bacterial endocarditis).
With early diagnosis and repair of an ASD, children usually do very well. They don't
need much follow-up care. Children are more likely to have problems if an ASD is diagnosed
later in life and never repaired. Or they may have problems if complications occur
after closing the defect.
Some children develop high blood pressure in the lungs (pulmonary hypertension). These
children should have follow-up care at a center that specializes in congenital heart
Talk with your child's healthcare provider about the outlook for your child.
When should I call my child's healthcare provider?
Call your child's healthcare provider if your child has new symptoms or symptoms that
get worse. Symptoms may include:
- Tiredness that gets worse
- Troubled breathing
- Fast breathing
- Racing heartbeat or palpitations
Key points about atrial septal defect
- An atrial septal defect is an opening in the wall dividing the 2 upper chamber of
- Symptoms of an atrial septum defect include tiring easily, fast breathing, shortness
of breath, poor growth, arrhythmias, and respiratory frequent infections.
- Atrial septum defects range from small to large.
- Small atrial septum defects may close on their own.
- Atrial septum defects that are large or cause symptoms can be repaired.
- Most children who have had an atrial septal defect repair will live healthy lives.
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.