Atrial Septal Defect

What is atrial septal defect?

An atrial septal defect (often shortened to ASD) is a hole in the wall of tissue that separates the two upper chambers of the heart. Doctors call this wall the atrial septum, and the two upper chambers are called the atria. In a heart without this defect, the septum keeps oxygen-rich blood returning from the lungs on the left side of the heart, separate from oxygen-poor blood returning from the body on the right side. When there is a hole in the septum, some blood can flow from one atrium to the other, most often from the left side to the right side. Over time, this extra blood flow can force the right side of the heart and the lungs to work harder than they should.

Atrial septal defect is a congenital heart condition, which means it is present at birth. It is one of the more common congenital heart defects. Understanding what is atrial septal defect begins with knowing that not every hole between the atria causes problems. Small defects may cause no symptoms at all and, in many infants, small openings close on their own during early childhood. Larger defects that stay open can lead to complications in adulthood, sometimes decades after birth.

The condition affects people of all backgrounds. It is often diagnosed in childhood, but because symptoms can be mild or absent for many years, some people first learn they have an atrial septal defect as adults, sometimes during testing for an unrelated issue.

There are several types of atrial septal defect, named for where the hole sits in the septum. The most common type is called a secundum defect, located near the middle of the septum. Other types include primum defects (lower in the septum, often linked with problems in the heart valves), sinus venosus defects (near the large veins that enter the right atrium), and rare coronary sinus defects. The type of defect can influence which treatments are possible.

Symptoms of atrial septal defect

Atrial septal defect symptoms vary widely. Many babies and children with this condition have no symptoms at all, and the defect may only be noticed when a doctor hears a heart murmur, which is an extra or unusual sound made by blood flowing through the heart. Symptoms are more likely with larger defects, and they often develop gradually rather than suddenly.

When symptoms do occur, they may include:

• Shortness of breath, especially during exercise or physical activity
• Tiring easily, or fatigue that seems out of proportion to activity
• Heart palpitations, a sensation of skipped, fluttering, or racing heartbeats
• Frequent respiratory infections in children, such as repeated chest colds or pneumonia
• Poor weight gain or slow growth in infants with larger defects
• Swelling in the legs, feet, or abdomen, usually a later sign in adults
• A heart murmur heard by a doctor during a physical examination

Symptoms often differ by age and by the size of the defect. Infants and young children with small or moderate defects frequently appear entirely healthy. Adults with an unrepaired atrial septal defect are more likely to develop symptoms over time, because years of extra blood flow can enlarge the right side of the heart, raise pressure in the lung arteries (a condition called pulmonary hypertension), and trigger abnormal heart rhythms (arrhythmias) such as atrial fibrillation. In many cases, adults first notice reduced stamina, breathlessness, or an irregular heartbeat in their thirties, forties, or later.

Rarely, an atrial septal defect can allow a blood clot to pass from the right side of the heart to the left side and travel to the brain, which can contribute to a stroke. This is uncommon, but it is one reason doctors take the condition seriously even when day-to-day symptoms are mild.

Causes and risk factors

Atrial septal defect causes are not fully understood. The defect forms during the early weeks of pregnancy, while the baby’s heart is developing. In most cases, no single cause can be identified, and having a child with this condition is not the result of anything a parent did or failed to do.

Researchers believe a combination of genetic and environmental factors plays a role. Recognized risk factors and associations include:

• Family history: congenital heart defects sometimes run in families, and having a parent or sibling with a heart defect may slightly increase the chance.
• Genetic conditions: some chromosomal and genetic syndromes, such as Down syndrome, are associated with heart defects, including certain types of atrial septal defect.
• Conditions during pregnancy: maternal diabetes that is not well controlled, certain infections during pregnancy such as rubella (German measles), and the use of some medications, alcohol, or tobacco during pregnancy have been linked to a higher chance of congenital heart defects in general.

It is important to understand that most children born with an atrial septal defect have no identifiable risk factor at all. If you have a family history of congenital heart disease and are planning a pregnancy, your doctor may suggest genetic counseling or additional screening during pregnancy, but this is a precaution rather than a prediction.

Diagnosis

Atrial septal defect diagnosis usually begins when a doctor hears a murmur or when a patient reports symptoms such as breathlessness or palpitations. Because the murmur of an atrial septal defect can be soft, the condition is sometimes missed in childhood and found later in life.

To confirm the diagnosis and assess how the defect is affecting the heart, doctors typically use one or more of the following tests:

• Echocardiogram (heart ultrasound): this is the main test for diagnosing an atrial septal defect. It uses sound waves to create moving pictures of the heart, showing the hole, the direction of blood flow across it, the size of the heart chambers, and how the valves are working. A standard echocardiogram is done through the chest wall and is painless.
• Transesophageal echocardiogram (TEE): in this test, a thin ultrasound probe is passed down the esophagus (the food pipe) under sedation. Because the esophagus lies close to the heart, this gives very detailed images. Doctors often use it to measure the defect precisely and to plan treatment, especially before a catheter-based closure.
• Electrocardiogram (ECG): a recording of the heart’s electrical activity through stickers placed on the skin. It can show strain on the right side of the heart or abnormal heart rhythms.
• Chest X-ray: this may show an enlarged heart or extra blood flow in the lungs, although it cannot show the defect itself.
• Cardiac MRI or CT scan: these detailed imaging tests are sometimes used when the echocardiogram does not give a complete picture, particularly for less common defect types such as sinus venosus defects, or to look at nearby veins.
• Cardiac catheterization: a thin, flexible tube (catheter) is guided through a blood vessel into the heart. This is not needed for most diagnoses, but it can directly measure pressures inside the heart and lungs when doctors need to assess pulmonary hypertension before deciding on treatment.

When deciding whether treatment is needed, doctors consider more than the size of the hole. They look at whether the right side of the heart has become enlarged, whether there is significant extra blood flow across the defect, whether lung pressures are raised, and whether the patient has symptoms. Evaluation and long-term follow-up are usually coordinated by a cardiologist, a doctor who specializes in the heart; at institutions such as Acibadem, this care is managed within the Cardiology Department, with pediatric cardiologists involved for children.

Treatment options

Atrial septal defect treatment depends on the size and type of the defect, the patient’s age, the presence of symptoms, and whether the heart or lungs show signs of strain. Not every defect needs to be closed, and the right approach is a decision made together with your cardiology team.

Watchful waiting

Small defects that cause no symptoms and no enlargement of the heart often need no immediate treatment. In infants and young children, many small secundum defects close on their own within the first years of life. In these cases, doctors usually recommend regular check-ups with echocardiograms to monitor the defect over time. Adults with very small defects and no heart strain may also simply be followed with periodic reviews.

Medication

No medication can close an atrial septal defect. However, medicines may be used to manage related problems. For example, your doctor may prescribe drugs to control an irregular heart rhythm, blood thinners (anticoagulants) to reduce the risk of blood clots in certain situations, or medicines to relieve symptoms of heart strain. Medication is a supportive measure, not a repair.

Catheter-based (transcatheter) closure

Many secundum atrial septal defects can be closed without open surgery. In this procedure, a doctor guides a thin tube through a vein, usually in the groin, up into the heart. A small closure device, often shaped like two connected discs, is positioned across the hole and released, sealing the defect. Over the following months, the heart’s own tissue grows over the device. This approach generally involves a shorter hospital stay and faster recovery than surgery, but it is only suitable when the defect has enough surrounding tissue rim to anchor the device and when the defect is of the secundum type. After device closure, patients typically take antiplatelet medication (medicine that reduces clotting) for a period of time and attend follow-up visits with imaging.

Surgical repair

Defects that are large, that lack adequate tissue rims, or that are of types not suited to a device — such as primum, sinus venosus, and coronary sinus defects — are usually repaired with heart surgery. The surgeon closes the hole with stitches or with a patch of the patient’s own tissue or synthetic material. Surgical repair of atrial septal defects is a well-established operation with a long track record, and in children it is performed by specialists in pediatric cardiac surgery. Some centers can perform the repair through smaller, minimally invasive incisions in selected patients. Recovery from surgery takes longer than recovery from a catheter procedure, typically involving several days in the hospital and a period of weeks before returning to full activity, depending on age and overall health.

When closure may not be advised

In a small number of adults with long-standing, unrepaired defects, the pressure in the lung arteries becomes severely elevated. In advanced cases, closing the defect may no longer help and can even be harmful, so treatment focuses instead on medicines for pulmonary hypertension and careful specialist follow-up. This is one reason timely evaluation matters.

Living with atrial septal defect and outlook

The outlook for people with an atrial septal defect is generally favorable, especially when the defect is small or is repaired before lasting damage develops. Children who undergo successful closure often go on to live active lives with few or no restrictions, although your care team will advise on activity levels during recovery and on how often follow-up visits are needed.

Adults whose defects are repaired later in life usually feel better afterward, but some effects of long-term strain — such as an enlarged right heart, atrial fibrillation, or raised lung pressures — may persist to some degree and require ongoing management. This is why doctors often recommend lifelong follow-up with a cardiologist after repair, even when you feel well. Follow-up typically includes periodic examinations, echocardiograms, and rhythm checks.

Practical points for daily life often include:

• Keeping regular follow-up appointments, even in the absence of symptoms.
• Discussing exercise with your doctor; most people with small or repaired defects can be physically active, but individual advice varies.
• Planning pregnancy with your care team if you are a woman with a known or repaired defect, since pregnancy places extra demands on the heart and may need closer monitoring.
• Telling dentists and other doctors about your heart history; antibiotic protection before dental work is only recommended in specific situations, such as for a limited period after device or patch closure, and your cardiologist can advise you.

No doctor can promise a specific outcome, and each person’s situation is different. What can be said honestly is that atrial septal defect is a well-understood condition with effective treatments, and that most people who receive appropriate care do well over the long term.

Frequently asked questions

What is atrial septal defect in simple terms?

It is a hole in the wall between the two upper chambers of the heart that is present from birth. The hole lets some blood flow from the left side of the heart to the right side, which can make the right side of the heart and the lungs work harder than normal. Small holes often cause no problems, while larger ones may need to be closed.

Can an atrial septal defect heal on its own?

In many infants and young children, small defects — particularly small secundum defects — close on their own during the first years of life. Larger defects, and defects of other types, are much less likely to close by themselves. Defects that are still open in later childhood or adulthood generally do not close on their own, which is why doctors monitor them and consider closure when appropriate.

How serious is an atrial septal defect?

Seriousness depends on the size of the defect and how long it has been present. Many small defects cause no symptoms and require only observation. Larger untreated defects can, over years, lead to enlargement of the right heart, abnormal heart rhythms, raised pressure in the lung arteries, and reduced exercise capacity. With timely diagnosis and treatment, most of these complications can be prevented or managed.

What are the first symptoms of an atrial septal defect in adults?

Adults often notice gradually worsening shortness of breath during activity, unusual fatigue, or palpitations from an irregular heartbeat. Some adults have no symptoms and learn of the defect only when a murmur is heard or when a scan is done for another reason. Because atrial septal defect symptoms can be subtle, unexplained breathlessness or reduced stamina deserves medical evaluation.

What is the best treatment for an atrial septal defect?

There is no single best treatment for everyone. Options range from watchful waiting for small, harmless defects, to catheter-based device closure for suitable secundum defects, to surgical repair for larger or more complex defects. The right choice depends on the defect’s type and size, the condition of the heart and lungs, and the patient’s age and overall health, so it is decided individually with a cardiology team.

How long is recovery after atrial septal defect closure?

Recovery after catheter-based closure is usually short; many patients go home within a day or so and return to normal routines within days to a couple of weeks, following their doctor’s advice on activity. Recovery after open surgical repair takes longer, often involving several days in the hospital and a number of weeks before full activity, depending on age and overall health. Your care team will give you a personal recovery plan.

Can you live a normal life with an atrial septal defect?

Many people can. Those with small defects that never cause heart strain, and most people whose defects are repaired in a timely way, often live full, active lives. Ongoing follow-up with a cardiologist is generally recommended so that any late issues, such as rhythm problems, are caught early. Individual outcomes vary, and no outcome can be guaranteed, but the overall outlook for treated atrial septal defect is generally good.

When to see a doctor

If you or your child has been told there may be a heart murmur, or if you notice unexplained breathlessness, unusual fatigue, or palpitations, arrange a medical evaluation. If an atrial septal defect has already been diagnosed, keep the follow-up schedule your care team recommends, even when you feel well.

Seek urgent medical attention if you or your child experiences any of the following red-flag warning signs:

• Severe or sudden shortness of breath, or breathlessness at rest
• Chest pain or chest pressure, especially with exertion
• Fainting or near-fainting (losing consciousness or feeling about to)
• A fast, pounding, or very irregular heartbeat that does not settle
• Bluish color of the lips, tongue, or skin (a sign of low oxygen)
• Sudden weakness, numbness, difficulty speaking, or facial drooping — possible signs of a stroke, which is a medical emergency
• In infants: difficulty feeding, rapid or labored breathing, sweating during feeds, or poor weight gain
• New or worsening swelling of the legs, ankles, or abdomen

These symptoms do not necessarily mean an atrial septal defect is the cause, but they should always be assessed promptly by a medical professional. Early evaluation gives doctors the best chance to identify the problem and, where needed, treat it before complications develop.