Atrial Septal Defect

What is atrial septal defect?

Diagram of atrial septal defect showing the defectReprinted with permission from ©2009, American Heart Association, Inc.

Babies born with atrial (pronounced a-tree-ahl) septal defect (ASD) have an opening in the wall separating the 2 upper chambers of their heart: the right atrium and left atrium. The dividing wall is called the septum.

Normally, the heart works this way: 

  • Oxygen-poor (blue) blood returns from the body to the right atrium.
  • It flows into the right ventricle.
  • The right ventricle pumps it to the lungs, where it receives oxygen.
  • Oxygen-rich (red) blood returns from the lungs to the left atrium.
  • It flows into the left ventricle and is then pumped out to the body through the aorta

When there is an opening between the atria, oxygen-rich blood passes from the left atrium into the right atrium. With small openings, a small amount of blood passes between the atria and the child doesn’t have symptoms.

With larger openings, more blood passes to the right side of the heart. This causes the right side to be overworked and enlarged. Also, the lungs receive extra blood, which causes higher pressures than normal in the blood vessels of the lungs (pulmonary hypertension).

  • It is normal for babies to have a small opening, called the foramen ovale, between their atria while they are developing in the womb. This opening usually closes soon after birth.

    Some babies have an abnormal opening, an ASD. Most of the time, it’s unclear why it developed. Almost 4 in every 100,000 babies have an ASD. This defect is about twice as common in girls as it is in boys.

    Some children with ASD are born with other heart defects (congenital heart defects), such as ventricular septal defects. Children with certain genetic syndromes, such as Down syndrome, are at increased risk for developing an ASD

Atrial Septal Defect at Seattle Children’s

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Symptoms of Atrial Septal Defect

A small ASD may cause no symptoms at all until later in childhood or adulthood.

A larger defect may cause symptoms soon after birth, such as: 

  • Feeling tired quickly when playing
  • Breathing fast
  • Having to work hard to breathe (shortness of breath)
  • Having abnormal heartbeats
  • Feeding problems
  • Poor weight gain
  • Frequent lung (respiratory) infections such as pneumonia or bronchitis 

Large defects that aren’t treated can increase the risk for certain heart or blood problems later in life, such as heart failure, stroke and high blood pressure in the lungs (pulmonary hypertension).

Diagnosing Atrial Septal Defect

To diagnose this condition, your doctor will examine your child, check their heartbeat and use a stethoscope to listen to their heart. In children with ASD, doctors can often hear an abnormal heart sound or heart murmur – a noise caused by the flow of blood through the opening from the left side of the heart to the right. The doctor will ask for details about your child’s symptoms, their health history and your family health history.

The doctor will then ask for diagnostic tests such as a chest X-rayechocardiogram or electrocardiogram. Your child may need other tests that provide more information about the ASD, size of the heart or blood vessel connections to the heart. These tests may include cardiac catheterization or an MRI (magnetic resonance imaging).

Your child may need other tests that provide more information about how their heart looks and works. These might include an MRI of the heart and cardiac catheterization.

Treating Atrial Septal Defect

Your child may not need treatment for ASD. In some children, it does not cause any problems. If the opening is small, it may close up on its own as your child grows. In this case, your doctor may simply recommend monitoring your child’s condition.

Some children need treatment because of the size of the defect, its effect on the heart or the symptoms it causes. The most common type of ASD is taken care of before school age and before the child has symptoms.

  • ASD PatchReprinted with permission from ©2009, American Heart Association, Inc.

    Some ASDs are treated with a device that covers the opening in the septum. The device is placed through a large blood vessel in the groin using a long, thin tube (catheter) through a large blood vessel in the groin up to the heart. This is called cardiac catheterization.

    Other children need surgery to close the hole with stitches (sutures) or a patch.

    The position and size of the defect are important factors in deciding the mode of treatment. Children need to reach a certain age and weight in order to have catheterization. If the defect is large and close to a heart valve, doctors may not be able to close it using a device; instead, the child will need surgery.

Transitioning to Adult Care

To meet your child’s long-term healthcare needs, we have a special Adult Congenital Heart Disease Program to transition your child to adult care when they’re ready.

Contact Us 

Contact the Heart Center at 206-987-2515 to request an appointment, a second opinion or more information.

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