Atrial septal defect (ASD)

Date Updated: 03/01/2022

Overview

An atrial septal defect (ASD) is a hole in the heart between the upper chambers (atria). The hole increases the amount of blood that flows through the lungs. The condition is present at birth (congenital heart defect).

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

A large, long-term atrial septal defect can damage the heart and lungs. Surgery may be needed to repair an atrial septal defect and to prevent complications.

Types

Types of atrial septal defects include:

Secundum. This is the most common type of ASD. It occurs in the middle of the wall between the upper heart chambers (atrial septum).
Primum. This type of ASD affects the lower part of the atrial septum and might occur with other congenital heart defects.
Sinus venosus. This rare type of ASD usually occurs in the upper part of the wall separating the heart chambers. It's also associated with other heart structure changes present at birth.
Coronary sinus. In this rare type of ASD, part of the wall between the coronary sinus — which is part of the vein system of the heart — and the left upper heart chamber (left atrium) is missing.

Symptoms

Many babies born with atrial septal defects have no signs or symptoms. Signs or symptoms can begin in adulthood.

Atrial septal defect signs and symptoms can include:

Shortness of breath, especially when exercising
Fatigue
Swelling of legs, feet or belly (abdomen)
Irregular heartbeats (arrhythmias)
Sensation of a rapid, pounding heartbeat (palpitations) or skipped beats
Whooshing sound that can be heard through a stethoscope (heart murmur)

When to see a doctor

Serious congenital heart defects, including large atrial septal defects, are often diagnosed before or soon after a child is born.

Contact your health care provider if you or your child has:

Shortness of breath
Easy tiring, especially after activity
Swelling of legs, feet or belly (abdomen)
Sensations of a rapid, pounding heartbeat (palpitations) or skipped beats

Causes

The cause of atrial septal defect is unclear. Atrial septal defect is a structure problem that occurs during heart development while a baby is still in the womb.

Genetics, certain medical conditions, use of certain medications, and environmental or lifestyle factors, such as smoking or alcohol misuse, may play a role.

How the heart works

To understand the cause of atrial septal defect, it may be helpful to know how the heart typically works.

The typical heart is made of four chambers — two upper chambers (atria) and two lower chambers (ventricles).

The right side of the heart moves blood to the lungs. In the lungs, blood picks up oxygen and then returns it to the heart's left side. The left side of the heart then pumps the blood through the body's main artery (aorta) and out to the rest of the body.

A large atrial septal defect can cause extra blood to overfill the lungs and overwork the right side of the heart. If not treated, the right side of the heart eventually grows larger and becomes weak. The blood pressure in the arteries in the lungs can also increase, leading to pulmonary hypertension.

Risk factors

Atrial septal defect (ASD) occurs as the baby's heart is developing during pregnancy. Certain health conditions or drug use during pregnancy may increase a baby's risk of atrial septal defect or other congenital heart defect. These things include:

German measles (rubella) infection during the first few months of pregnancy
Diabetes
Lupus
Alcohol or tobacco use
Illegal drug use, such as cocaine
Use of certain medications, including some anti-seizure medications and drugs to treat mood disorders

Some types of congenital heart defects occur in families (inherited). If you have or someone in your family has congenital heart disease, including ASD, screening by a genetic counselor can help determine the risk of certain heart defects in future children.

Complications

A small atrial septal defect might never cause any concern. Small atrial septal defects often close during infancy.

Larger atrial septal defects can cause serious complications, including:

Right-sided heart failure
Irregular heartbeats (arrhythmias)
Stroke
Early death
High blood pressure in the lung arteries (pulmonary hypertension)

Pulmonary hypertension can cause permanent lung damage. This complication, called Eisenmenger syndrome, usually develops over many years and occurs uncommonly in people with large atrial septal defects.

Treatment can prevent or help manage many of these complications.

Atrial septal defect and pregnancy

If you have an atrial septal defect and are pregnant or thinking about becoming pregnant, it's important to talk to your health care provider and to seek proper prenatal care. A health care provider may recommend ASD repair before conceiving. A large atrial septal defect or its complications can lead to a high-risk pregnancy.

Prevention

Because the cause of atrial septal defect (ASD) is unclear, prevention may not be possible. But getting good prenatal care is important. If you have an ASD and are planning to become pregnant, schedule a visit with your health care provider. This visit should include:

Discussing current health conditions and medications. You'll need to monitor certain health conditions, such as diabetes or lupus, during pregnancy. Your health care provider might also recommend adjusting or stopping certain medications before pregnancy.
Reviewing your family medical history. If you have a family history of congenital heart defects or other genetic conditions, consider talking with a genetic counselor to determine your specific risks.
Getting tested for immunity to German measles (rubella). Rubella in the mother has been linked to some types of congenital heart defects in the baby. If you're not immune, ask your health care provider about getting vaccinated.

Diagnosis

Some atrial septal defects are diagnosed before or soon after a child is born. However, smaller atrial septal defects may not be diagnosed until later in life.

If an atrial septal defect is present, the health care provider may hear a whooshing sound (heart murmur) when listening to the heart with a stethoscope.

Tests that are done to help diagnose an atrial septal defect include:

Echocardiogram. This is the most commonly used test to diagnose an atrial septal defect. Sound waves are used to create pictures of the heart in motion. An echocardiogram can show how well blood is moving through the heart and heart valves.
Chest X-ray. A chest X-ray shows the condition of the heart and lungs.
Electrocardiogram (ECG or EKG). This quick and painless test records the electrical activity of the heart. An ECG can help identify irregular heartbeats (arrhythmias).
Cardiac magnetic resonance imaging (MRI) scan. This imaging test uses magnetic fields and radio waves to create detailed images of the heart. A health care provider might request this type of MRI if echocardiography didn't provide a definitive diagnosis.
Computed tomography (CT) scan. This uses a series of X-rays to create detailed images of your heart. It can be used to diagnose an atrial septal defect and related congenital heart defects if echocardiography hasn't definitely diagnosed an atrial septal defect.

Treatment

Treatment for atrial septal defect depends on the size of the hole in the heart and whether you or your child has other congenital heart defects.

Many atrial septal defects close on their own during childhood. For those that don't close, some small atrial septal defects might not require treatment. A doctor specializing in heart diseases (cardiologist) might recommend monitoring it with regular health checkups to see if it closes on its own.

Your health care provider will discuss with you when you or your child needs treatment. Many persistent atrial septal defects eventually require surgery. However, closure isn't recommended if severe pulmonary hypertension is present.

Medications

Medications won't repair an atrial septal defect, but they can help reduce signs and symptoms. Medications for atrial septal defect might include drugs to control the heartbeat (beta blockers) or to reduce the risk of blood clots (anticoagulants).

Surgery or other procedures

Many cardiologists recommend surgery to repair a medium to large atrial septal defect that's diagnosed during childhood or adulthood to prevent future complications.

For adults and children, atrial septal defect repair surgery involves closing the hole in the heart. This can be done two ways:

Catheter-based repair. A thin, flexible tube (catheter) is inserted into a blood vessel, usually in the groin, and guided to the heart using imaging techniques. A mesh patch or plug is passed through the catheter and used to close the hole. Heart tissue grows around the seal, permanently closing the hole.

The catheter-based repair procedure is used only for the secundum type of atrial septal defects. Some large secundum atrial septal defects, however, might require open-heart surgery.
Open-heart surgery. This type of atrial septal defect repair surgery involves an incision through the chest wall to access the heart directly. The surgeons use patches to close the hole. This open-heart repair surgery is the only way to fix primum, sinus venosus and coronary sinus atrial defects.

Sometimes, atrial septal defect repair can be done using small incisions (minimally invasive surgery) and with a robot (robot-assisted heart surgery).

Anyone who has had surgery for atrial septal defect needs regular echocardiograms and health checkups to watch for possible complications, such as irregular heartbeats (arrhythmias), heart valve problems, high blood pressure in the lung arteries (pulmonary hypertension) and heart failure.

People with large atrial septal defects who do not have surgery to close the hole typically have worse long-term outcomes. They may have more difficulty performing everyday activities (reduced functional capacity) and are at greater risk for arrhythmias and pulmonary hypertension.

Lifestyle and home remedies

If you or your child has an atrial septal defect, the health care provider may recommend some lifestyle steps to keep the heart healthy and to prevent complications.

Exercise. Exercise is usually safe in patients with atrial septal defect. But if ASD repair is needed, a health care provider may recommend avoiding certain activities until the heart defect is fixed. A doctor trained in heart diseases (cardiologist) can help you learn what activity is safest for you or your child.
Extreme changes in altitude. Changes in altitude may cause concern if you have an unrepaired atrial septal defect. If you plan to scuba dive or hike in high altitudes, talk with your cardiologist to make sure the activities are safe.
Dental work. If you recently had ASD repair surgery and need dental work, your health care provider will likely recommend that you take preventive antibiotics for about six months after the hole in the heart is closed.

Preparing for an appointment

You or your child will likely be referred to a doctor trained in heart disorders (cardiologist). Here's some information to help you get ready for your appointment.

What you can do

Make a list of:

Your or your child's symptoms, and when you noticed them
Key personal information, including major stresses or recent life changes, and family history of heart defects
All medications, vitamins or other supplements you or your child takes, including doses
Questions to ask your health care provider

For atrial septal defect, questions to ask your health care provider include:

What's the most likely cause of these symptoms?
Are there other possible causes?
What tests are needed?
Is the atrial septal defect temporary or long lasting?
What are the treatment options?
What are the risks of repair surgery?
Are there any activity restrictions?
Are there brochures or other printed material I can have? What websites do you recommend?

Don't hesitate to ask other questions.

What to expect from your doctor

Your health care provider is likely to ask many questions, including:

Have the symptoms been continuous or occasional?
Do symptoms get worse with exercise?
Does anything else seem to make the symptoms worse?
Is there anything that seems to improve the symptoms?
Is there a family history of congenital heart defects?