Atrial Septal Defect: Overview

What is atrial septal defect (ASD)?

If your child has an atrial septal defect, or ASD, he or she has a hole in the wall of the heart that separates its two upper chambers, the left and right atrium. The hole is formed when the heart wall, called the atrial septum, does not seal completely during a baby’s development. This condition is sometimes known as “a hole in the heart.” ASD is a congenital heart defect, which means children are born with it.

The location on the septum (wall) and size of the hole can vary from child to child. Some ASDs are so small they heal themselves as a child grows, but others may require closure with either a heart catheterization or surgery.

Rarely, an atrial septal defect is part of a more complicated heart condition that might involve other heart defects.

Why is ASD a health concern?

Normally, the septum seals off the two atria from each other completely. But the presence of an ASD allows blood from the higher-pressure left atrium to seep into the right atrium. This causes extra blood to be sent from the right side of the heart back into the lungs.

If your child has ASD, he or she may have an increased risk of stroke and lung infections caused by the extra blood pushing through the lungs.

ASD is more common in girls, although the reason why is still unknown. ASD is usually diagnosed before a child is old enough to go to school.