Atrial Septal Defect (ASD)

Contact Information

(608) 263-1530

(608) 263-6420


Related Resources

Adult Congenital Heart Disease Program

Pediatric Congenital Heart Disease Program

UW Health Heart, Vascular and Thoracic Care doctors work with patients with atrial septal defect (ASD) to determine the best course of treatment.


About Atrial Septal Defects


The heart has a left and a right side, which are separated by a muscular wall called the septum. Each side of the heart also has two chambers: The atrium on top, and the ventricle on the bottom.


An atrial septal defect is an opening in the wall between the right and left atrium. If the defect is not repaired, oxygen-rich blood from the left atrium flows through the opening and mixes with oxygen-poor blood in the right atrium.


Concerns and Symptoms


An ASD results in a pathway for blood to travel between the right and left atrium. If clots or other masses (emboli) are present in the bloodstream, they can cross this pathway and flow through the left atrium to the body. Emboli that block blood vessels to the brain can cause a stroke or transient ischemic attack. Emboli that block the coronary artery can cause a heart attack.


Because an ASD causes the heart and lungs to handle more blood than normal, the pressure in the lung's blood vessels also can increase, a condition called pulmonary hypertension. This may cause the right side of the heart to enlarge, become damaged, and be less able to pump blood effectively. This leads to an increased risk of congestive heart failure.


Many adults with ASD exhibit few symptoms. The defect is often detected by a heart murmur or a noticeable delay in the closure of the pulmonary valve. If the defect is large, however, symptoms may include fatigue, sweating, shortness of breath, or rapid breathing. In women, an ASD may be first diagnosed during pregnancy, when the heart's output increases.


Imaging studies, such as a transesophageal echocardiogram (TEE), are required to diagnose an ASD.


Atrial Septal Defect Treatment and Recovery