Atrial Septal Defect

An atrial septal defect (ASD) is a hole in the atrial septum, which is the wall that separates your heart’s two upper chambers (atria). An atrial septal defect is a common congenital heart defect (something you’re born with). It happens when the septum doesn’t form properly. It’s also called a “hole in the heart.”

An atrial septal defect creates an abnormal route for blood. Some blood from your left atrium flows in the wrong direction, into your right atrium. Your right atrium contains oxygen-poor blood that needs to cycle through your lungs. So, your right atrium gets extra blood (with oxygen) that ultimately goes back to your lungs again.

Normally, oxygen-rich blood flows from your left upper chamber (atrium) down to your left lower chamber (ventricle), and then out to supply oxygen to your body.

A wrong-way leak might be minor and not cause any problems. In those cases, the atrial septal defect can be left alone without treatment. Other times, it can lead to problems with your heart or lungs. The bigger the ASD, the more likely it is to cause symptoms and need treatment.

An atrial septal defect isn’t the same thing as a patent foramen ovale.

Types of this condition

There are four main types of atrial septal defects. Each has a different location in the atrial septum (wall).

• Secundum atrial septal defects are in the middle of your atrial septum. This is the most common type of atrial septal defect (eight out of 10 ASDs).
• Primum atrial septal defects are in the lower part of your atrial septum. Babies with this type may also have defects in their ventricular septum, tricuspid valve or mitral valve.
• Sinus venosus atrial septal defects are in the upper or lower back part of your atrial septum. This type is linked with defects in the right pulmonary vein or superior or inferior vena cava.
• Unroofed coronary sinus is the rarest type of ASD. It involves a missing or incomplete wall between your coronary sinus (a group of veins connected to your heart) and your left atrium. It’s more often linked with other complex congenital heart diseases.

Symptoms of atrial septal defect

Even though an atrial septal defect is present at birth, many people don’t have symptoms until far into adulthood. Small atrial septal defects (less than 5 millimeters) may not cause symptoms because they don’t strain your heart or lungs.

The most common (and often the only) sign of an atrial septal defect is a heart murmur. A healthcare provider will notice it when listening to your child’s heart with a stethoscope.

When children do have other atrial septal defect symptoms, they include a weight that’s less than what it should be, growth delays and recurrent respiratory infections. Rarely, children have fatigue when physically active, trouble breathing and abnormal heart rhythms (arrhythmias).

Tell your child’s provider about any symptoms you notice. Their provider may want to run some tests to check your child’s heart structure and function.

Adults with an atrial septal defect may feel symptoms by age 40. Symptoms depend on how much the issue has strained your heart and lungs. They include:

• Fatigue
• Shortness of breath with physical activity
• Heart palpitations
• Fast heartbeat (tachycardia)
• Swelling (edema) in your arms and legs
• Blue skin color (cyanosis)

If you have any of these symptoms, call your healthcare provider right away. These symptoms could mean you have an untreated atrial septal defect. Or they could mean you have another cardiovascular problem that needs treatment. If you have chest pain, you should call 911 or your local emergency number.

Atrial septal defect causes

The exact cause of atrial septal defects isn’t fully known. But genetic changes that happen before birth often cause congenital heart defects. Some genetic variations associated with atrial septal defect affect the NKX2.5/CSX, GATA4 and TBX5 genes.

Some babies born with an atrial septal defect also have other heart defects or genetic disorders. These include:

• Mitral or pulmonary valve disease
• Ventricular septal defect (VSD)
• Holt-Oram syndrome
• Down syndrome
• Williams syndrome

Risk factors

If you’re pregnant, some factors can raise your risk of having a baby with congenital heart disease. These risk factors include:

• Diabetes you already had before your pregnancy
• Flu
• Beverages containing alcohol
• Tobacco products
• Certain prescription medications
• Recreational drugs, especially cocaine

Complications of this condition

A small atrial septal defect doesn’t affect your body much. But a larger one can strain the right side of your heart. That’s because it has to pump extra blood out to your lungs. This extra blood flow can slowly damage the blood vessels in your lungs as well.

Problems with large atrial septal defects include:

• Right heart enlargement. This can lead to heart failure if left uncorrected for a very long time.
• Abnormal heart rhythm (arrhythmia). At least half of adults over age 40 with an ASD heart have an arrhythmia like atrial fibrillation or atrial flutter.
• Stroke. This is a shortage of blood flow to your brain.
• Pulmonary hypertension. This is high blood pressure in the arteries that supply blood to your lungs.
• Eisenmenger syndrome. This condition can happen if you have an ASD heart along with severe pulmonary hypertension.

How doctors diagnose this condition

Healthcare providers diagnose atrial septal defects through a physical exam and tests that check your heart’s structure and function. Your provider will run one or more tests to learn how an atrial septal defect affects your heart. Possible tests include:

• Electrocardiogram (EKG). An EKG shows your heart’s electrical activity. It can reveal if you have an abnormal heart rhythm or other problems related to your heart’s electrical system.
• Chest X-ray. This test can show enlargement in the chambers on the right side of your heart. It’ll also show if an atrial septal defect affected the blood vessels in your lungs.
• Transthoracic echocardiogram (TTE). This test shows how the left-to-right shunting of blood affects your heart. It can also show details related to pulmonary hypertension.
• Transesophageal echocardiogram (TEE). This test shows the size, shape and location of an atrial septal defect. It can also check your heart valves.
• Intracardiac echocardiogram (ICE). For this test, a provider sends a tiny camera to your heart through a vein to see the size and shape of the ASD and the direction of blood flow across it.

In some cases, a provider may use a cardiac CT scan or heart MRI. They’re most helpful for people with associated defects or less common forms of atrial septal defect.

How is it treated?

Your healthcare provider may prescribe medications to treat some symptoms of atrial septal defect. But medications can’t close the hole. Providers can perform ASD closure through surgery or percutaneous (nonsurgical) repair.

It’s possible to live with an ASD in your heart if the hole is small. You usually don’t need a repair for a small atrial septal defect that doesn’t close by itself. Providers may recommend an ASD closure if an atrial septal defect is causing issues and hasn’t closed by age 2 or 3.

But you should get a repair for a larger ASD even if it isn’t causing symptoms. Treating it now prevents serious complications in the future, even for adults.

Once you have signs of heart or lung damage, atrial septal defect repair is essential. Your provider will recommend treatment if:

• The right side of your heart is bigger than normal
• There’s a significant flow of blood through the atrial septal defect

After a repair, you may need to take blood-thinning medication (anticoagulant or antiplatelet) for six to 12 months. These medicines keep blood clots from forming on the closure device (a rare complication).

You usually need to take antibiotics for at least six months following your repair. Antibiotics prevent an infection of your heart’s lining (endocarditis).

When should I see my healthcare provider?

If you have an atrial septal defect, it’s important to keep all your medical appointments and follow your provider’s guidance. Atrial septal defects often call for “watchful waiting.” This means your provider keeps an eye on the situation to see when you need treatment. They’ll tell you how often you need to come in for appointments.

If you’ve had ASD repair, follow your provider’s guidance for follow-ups. You’ll likely go back for follow-ups after one, three, six and 12 months. Then, you’ll have visits once a year.

If your child has an atrial septal defect, their provider will let you know the next steps and when they might need treatment. In general, providers use “watchful waiting” for smaller atrial septal defects. Larger ASDs usually require procedures at a younger age to prevent future problems.

You may want to ask your provider:

• Does my child need surgery?
• How often does my child need appointments for “watchful waiting?”
• Should my siblings get checked for an atrial septal defect?
• Should I have surgery as an adult?

What can I expect if my child has this condition?

After ASD repair, your child will likely have activity restrictions for a while as they recover. After that, they should be able to be physically active without limits.

The prognosis for a child with a repaired atrial septal defect is very good. Children usually don’t need any further treatment.

What is the life expectancy?

If you have an atrial septal defect, you may have a slightly shorter life expectancy. But life expectancy depends on many factors, including the size of the atrial septal defect and whether you have atrial septal defect repair.

The timing of repair also matters. Those who have atrial septal defect repair earlier in life have a better outlook. This is likely because early repair catches the problem before it can cause serious damage to your heart or lungs. The prognosis is worse in people who have complications.