Atrial Septal Defect (ASD) in Children

What is an atrial septal defect in children?

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 is.

ASDs are classified by their different location and development:

  • Secundum ASD occurs in the middle part of the atrial septum.
  • Primum ASD occurs in the lower part of the atrial septum close to the tricuspid and mitral valves.
  • 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 in a child?

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 in a child?

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) decreases risk.
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 in a child?

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 as:

  • 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.