Overview

An atrial septal defect (ASD) is a hole in the wall (septum) between the two upper chambers of your heart (atria). The condition is present at birth (congenital).

Small defects might be found by chance and never cause a problem. Some small atrial septal defects close during infancy or early childhood.

The hole increases the amount of blood that flows through the lungs. A large, long-standing atrial septal defect can damage your heart and lungs. Surgery or device closure might be necessary to repair atrial septal defects to prevent complications.