What Are Congenital Atrial Septal Defects (ASD)?

The heart is divided into four chambers. The upper chambers, or atria, are divided by a wall called the septum. An atrial septal defect (ASD) is a hole in that septum. Atrial septal defects are one of the most common heart defects seen.

When an atrial septal defect is present, blood flows through the hole mostly from the left atrium to the right atrium. This blood flow pattern increases the blood volume in the right atrium. This means more blood flows through the lungs than would normally.

If left untreated, atrial septal defects may cause problems in adulthood. These problems may include pulmonary hypertension (which is high blood pressure in the lungs), congestive heart failure (weakening of the heart muscle), atrial arrhythmias ( abnormal rhythms or beating of the heart) and an increased risk of stroke.

Signs and Symptoms of ASD

In most children, atrial septal defects cause no symptoms. A large defect may allow too much blood flow through it. This can cause congestive heart failure symptoms. Symptoms include shortness of breath, getting tired easily, or poor growth. This is uncommon.

Most often an atrial septal defect is diagnosed when a doctor hears a heart murmur during a physical examination.

Diagnosis of ASD

Hearing a murmur on a physical exam is the most common reason an atrial septal defect is suspected. Echocardiography is the main method used to confirm that an atrial septal defect exists.

Echocardiography can show the hole and its size, and any enlargement of the right atrium and ventricle from the extra work they are doing.

An electrocardiogram (EKG) may show signs of thickening of the heart muscle. A chest X-ray may show enlargement of the heart and increased blood flow to the lungs.

Treatment for ASD

In some children, an ASD may close on its own without treatment. With a small atrial septal defect, the chance of the ASD closing on its own may be as high as 80 percent in the first 18 months of life. An ASD still present by 3 years of age will never close on its own.

Open-Heart Surgery

Although an atrial septal defect may be closed by open-heart surgery, this approach is not as common as it once was. If open heart surgery is necessary, the surgeon may be able to close the hole with stitches. It may need to be closed with a patch. Surgery is effective and carries a low risk.

Transcatheter Device Closure

Depending on the size and the area of the septum involved, many atrial septal defects may be closed by a device being put in during a cardiac catheterization. This device is put in through a catheter. It covers the ASD by attaching to the atrial septum. A catheter is a long thin tube, about as wide of a piece of spaghetti. This is directed to the heart through the large blood vessels in the groin.

The benefits of being able to close an atrial septal defect with a device is that it can be put in place without stopping the patient's heart or utilizing cardiopulmonary bypass. This reduces the trauma about open-heart surgery. It doesn't create a scar across the chest the way open-heart surgery does.

Two FDA-approved devices are available in the United States. The are used in the cardiac cath lab. These include the Amplatzer Septal Occluder and the Helex Septal Occluder.

Atrial Septal Defect Closure Results

Surgical closure of atrial septal defects doesn’t have problems in 99 percent of cases. The Amplatzer device has only been used for 10 years, but it is successful. After ASD closure in childhood, the heart size returns to normal over four to six months.

After the defect is closed, there should be no problems with activity and no restrictions. Regular follow-up appointments will be made with a cardiologist.

Adult and Adolescent Management

An atrial septal defect can be discovered for the first time in adult life. ASDs come in many sizes. A small ASD may have no significant effect on a person’s health. If ASDs are large enough to cause the right heart chambers to get larger, repair is recommended. Secundum ASDs are the most common form. These can usually be closed without surgery, using a device. The other forms of ASDs require surgical correction. These are typically low-risk procedures. Doctors with congenital surgical experience is important.

Adults with an ASD closed or repaired need periodic evaluation. Patients who have had device closure of ASDs should have an ECHO every five years to look for complications of the device. Patients who had some high blood pressure in their lungs (pulmonary hypertension) before the ASD was closed should be continue to see their cardiologist. Adults who have had rhythm problems such as atrial flutter or atrial fibrillation may need regular evaluation.

Learn more about the Adolescent and Adult Congenital Heart Disease Program.

Last Updated 08/2021

Reviewed By Marji Bretz, RN