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.

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 abdomen
• Heart palpitations or skipped beats
• Stroke
• Heart murmur, a whooshing sound that can be heard through a stethoscope

When to see a doctor

Contact your doctor if you or your child has:

• Shortness of breath
• Easy tiring, especially after activity
• Swelling of legs, feet or abdomen
• Heart palpitations or skipped beats

How the heart normally works

The heart is divided into four chambers, two on the right and two on the left. To pump blood throughout the body, the heart uses its left and right sides for different tasks.

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

Why do heart defects develop?

Doctors know that heart defects present at birth (congenital) arise from errors early in the heart's development, but there's often no clear cause. Genetics and environmental factors might play a role.

How the heart works with an atrial septal defect

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 enlarges and weakens. The blood pressure in your lungs can also increase, leading to pulmonary hypertension.

There are several types of atrial septal defects, including:

• Secundum. This is the most common type of ASD and occurs in the middle of the wall between the atria (atrial septum).
• Primum. This defect occurs in the lower part of the atrial septum and might occur with other congenital heart problems.
• Sinus venosus. This rare defect usually occurs in the upper part of the atrial septum and is often associated with other congenital heart problems.
• Coronary sinus. In this rare defect, part of the wall between the coronary sinus — which is part of the vein system of the heart — and the left atrium is missing.

It's not known why atrial septal defects occur, but some congenital heart defects appear to run in families and sometimes occur with other genetic problems, such as Down syndrome. If you have a heart defect, or you have a child with a heart defect, a genetic counselor can estimate the odds that future children will have one.

Some conditions that you have during pregnancy can increase your risk of having a baby with a heart defect, including:

• Rubella infection. Becoming infected with rubella (German measles) during the first few months of your pregnancy can increase the risk of fetal heart defects.
• Drug, tobacco or alcohol use, or exposure to certain substances. Use of certain medications, tobacco, alcohol or drugs, such as cocaine, during pregnancy can harm the developing fetus.
• Diabetes or lupus. Having diabetes or lupus might increase your risk of having a baby with a heart defect.

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

Larger defects can cause serious problems, including:

• Right-sided heart failure
• Heart rhythm abnormalities (arrhythmias)
• Increased risk of a stroke
• Shortened life span

Less common serious complications may include:

• Pulmonary hypertension. If a large atrial septal defect goes untreated, increased blood flow to your lungs increases the blood pressure in the lung arteries (pulmonary hypertension).
• Eisenmenger syndrome. 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

Most women with an atrial septal defect can go through pregnancy without problems related to the defect. However, having a larger defect or having complications such as heart failure, arrhythmias or pulmonary hypertension can increase the risk of complications during pregnancy.

Doctors strongly advise women with Eisenmenger syndrome not to become pregnant because it can endanger their lives.

The risk of congenital heart disease is higher for children of parents with congenital heart disease. Anyone with a congenital heart defect, repaired or not, who is considering starting a family should talk to a doctor. The doctor might recommend repair before pregnancy.

In most cases, atrial septal defects can't be prevented. If you're planning to become pregnant, schedule a visit with your health care provider. This visit should include:

• Getting tested for immunity to rubella. If you're not immune, ask your doctor about getting vaccinated.
• Going over your current health conditions and medications. You'll need to monitor certain health problems during pregnancy. Your doctor might also recommend adjusting or stopping certain medications before you become pregnant.
• Reviewing your family medical history. If you have a family history of heart defects or other genetic disorders, consider talking with a genetic counselor to determine what the risk might be.

Hearing a heart murmur during a checkup might cause your or your child's doctor to suspect an atrial septal defect or other heart defect. For a suspected heart defect, your doctor might request one or more of the following tests:

• Echocardiogram. This is the most commonly used test to diagnose an atrial septal defect. Sound waves are used to produce a video image of the heart. It allows your doctor to see your heart's chambers and measure their pumping strength.

  This test also checks heart valves and looks for signs of heart defects. Doctors can also use this test to evaluate your condition and determine your treatment plan.

• Chest X-ray. This helps your doctor see the condition of your heart and lungs. An X-ray can identify conditions other than a heart defect that might explain your signs or symptoms.
• Electrocardiogram (ECG). This test records the electrical activity of your heart and helps identify heart rhythm problems.

• Cardiac catheterization. A thin, flexible tube (catheter) is inserted into a blood vessel at your groin or arm and guided to your heart. Through catheterization, doctors can diagnose congenital heart defects, test how well your heart is pumping, check heart valve function and measure the blood pressure in your lungs.

  However, this test usually isn't needed to diagnose an atrial septal defect. Doctors might also use catheterization techniques to repair heart defects.

• MRI. This uses a magnetic field and radio waves to create 3D images of your heart and other organs and bodily tissues. Your doctor might request an MRI if echocardiography can't definitively diagnose an atrial septal defect or related conditions.
• 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.

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. But many persistent atrial septal defects eventually require surgery.

Medical monitoring

If you or your child has an atrial septal defect, your cardiologist might recommend monitoring it for a time to see if it closes on its own. Your doctor will decide when you or your child needs treatment, depending on your condition and whether you or your child has other congenital heart defects.

Medications

Medications won't repair the hole, but they may be used to reduce some of the signs and symptoms that can accompany an atrial septal defect. Drugs may also be used to reduce the risk of complications after surgery. Medications may include those to keep the heartbeat regular (beta blockers) or to reduce the risk of blood clots (anticoagulants).

Surgery

Many doctors recommend repairing a medium to large atrial septal defect diagnosed during childhood or adulthood to prevent future complications. However, surgery isn't recommended if you have severe pulmonary hypertension because it might make the condition worse.

For adults and children, surgery involves sewing closed or patching the abnormal opening between the atria. Doctors will evaluate your condition and determine which of two procedures to use:

• Cardiac catheterization. Doctors insert a thin, flexible tube (catheter) into a blood vessel in the groin and guide it to the heart using imaging techniques. Through the catheter, doctors place a mesh patch or plug to close the hole. The heart tissue grows around the mesh, permanently sealing the hole.

  This type of procedure is used to repair only 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 surgery is done under general anesthesia and requires the use of a heart-lung machine. Through an incision in the chest, surgeons use patches to close the hole. This procedure is the only way to repair primum, sinus venosus and coronary sinus atrial defects.

  This procedure can be done using small incisions (minimally invasive surgery) and with a robot for some types of atrial septal defects.

Follow-up care

Follow-up care depends on the type of defect, the treatment suggested and whether other defects are present. Repeated echocardiograms are done after hospital discharge, one year later and then as requested by your or your child's doctor. For simple atrial septal defects closed during childhood, only occasional follow-up care generally is needed.

Adults who've had atrial septal defect repair need to be monitored throughout life to check for complications, such as pulmonary hypertension, arrhythmias, heart failure or valve problems. Follow-up exams are typically done yearly.

If you have a congenital heart defect or you've had surgery to correct one, you might wonder about limitations on activities and other issues.

• Exercise. Having an atrial septal defect usually doesn't restrict you from activities or exercise. If you have complications, such as arrhythmias, heart failure or pulmonary hypertension, you might be counseled to avoid some activities or exercises. Your cardiologist can help you learn what is safe.

  If you have an unrepaired defect, your doctor will likely advise you to avoid scuba diving and high-altitude climbing.

• Preventing infection. Some heart defects and the repair of defects create changes to the surface of the heart that make it more prone to infection (infective endocarditis). Atrial septal defects generally aren't associated with infective endocarditis, though your doctor will likely recommend preventive antibiotics for about six months after closure whenever you have dental work done.

  But if you have other heart defects besides an atrial septal defect, or if you've had atrial septal defect repair within the last six months, you might need to take antibiotics before certain dental or surgical procedures.

If your doctor suspects an atrial septal defect, 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 doctor

For atrial septal defect, questions to ask your doctor include:

• What's the most likely cause of these symptoms?
• Are there other possible causes?
• What tests are needed?
• Is this condition temporary or long lasting?
• What are the treatment options?
• What are the risks of cardiac catheterization or surgery?
• Are there activity restrictions you recommend?
• 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 doctor is likely to ask you 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 birth defects?