What Is an Atrial Septal Defect?

An atrial septal defect (ASD) is a hole in the wall (septum) that separates the heart's upper chambers (atria). Sometimes, the hole may not cause any problems and doesn’t need treatment. Larger holes can cause too much blood to flow from the left side of the heart to the right side of the heart, which can lead to heart failure.

ASDs are usually present at birth (congenital) and are fairly common. Some small ASDs close without treatment before birth or during the first few years of life.

For most people, treatment for an ASD isn't needed right away. But treatment might eventually be needed for large or symptomatic defects. Treatment options include surgically stitching the hole closed, using a device to plug the hole, and medications to treat complications of ASDs, such as heart failure or arrhythmias.