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Pediatric Atrial Septal Defect (ASD)

What is an atrial septal defect?

Anatomy of the heart, normal

An atrial septal defect is an opening in the atrial septum, or dividing wall between the two upper chambers of the heart, known as the right and left atria. ASD can be a congenital (present at birth) heart defect, or it can result from the failure of normal postnatal closure of a hole that is present in the heart of every fetus.  

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

An atrial septal defect allows oxygen-rich (red) blood to pass from the left atrium, through the opening in the septum, and then mix with oxygen-poor (blue) blood in the right atrium.

Illustration of the anatomy of a heart with an atrial septal defect

Atrial septal defects occur in a small percentage of children born with congenital heart disease. For unknown reasons, girls have atrial septal defects twice as often as boys.


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Anatomy of the Heart

This animation presents the anatomy of the heart in detail. Learn about the organ's various parts and the roles that they play.

Frequently Asked Questions

Prevention and Risk Assessment

What causes an atrial septal defect in children?

What are the types of atrial septal defects in children?

Why is an atrial septal defect in children a concern?


What are the symptoms of an atrial septal defect in children?


What treatment is available for atrial septal defect in children?

What should I expect from my child's post-procedure care for an atrial septal defect?

How do I care for my child at home following an ASD repair?

What is the long-term outlook for my child after ASD repair?

Cardiology Treatment at Children's National Hospital

The pediatric heart experts at Children’s National in Washington, D.C., provide advanced care for unborn babies, children and young adults with heart conditions. 

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Providers Who Treat Atrial Septal Defect (ASD)

    Departments that Treat Atrial Septal Defect (ASD)

    Prenatal Cardiology Program

    Children diagnosed with heart conditions before they are born receive comprehensive, expert care from our fetal cardiology specialists. Learn more about our Prenatal Cardiology Program.

    Provider checking young boys breathing

    Pediatric Cardiac Surgery

    Our pediatric heart surgery team performs twice the number of surgeries of any other hospital in the region, with some of the best outcomes in the nation.

    Dr. Harahsheh checks pulse of patient.


    The pediatric heart experts at Children's National Hospital in Washington, D.C., provide advanced care for unborn babies, children and young adults with heart conditions.