Atrial septal defect

What is an atrial septal defect?

An atrial septal defect (ASD) is a hole in the atrial septum, the wall between the two upper chambers of the heart (atria). It’s a type of congenital heart disease, which means it is something you are born with.
 
An ASD can happen on its own or with other types of congenital heart disease.

Some ASDs are very small and may never cause any problems or need treatment. ASDs can be large and need treatment.

Types of atrial septal defects

There are three main types of ASD.

• Secundum ASD. The hole is in the middle of the atrial septum. It is the most common type of ASD.

• Primum ASD (also called ostium primum defect or partial atrioventricular septal defect). This hole is in the lower part of the atrial septum, near the ventricles (the lower chambers of the heart). It can create other heart conditions or problems.

• Sinus venosus ASD. This is is another type of ASD. It is found in an area close to the major blood vessels which bring oxygen poor blood back to the heart. There are two types. One is found nearer the top of this area, and another closer to the bottom.

Signs and symptoms of atrial septal defect

There are usually no signs of ASD at birth. Sometimes, the only sign is an extra, unusual sound in the heartbeat called a murmur. Your doctor can hear this through a stethoscope.

The murmur is caused by shunting, a condition where blood flows from the left to the right in the top chambers (atria) of the heart through the ASD. This creates a swishing sound as there is increased blood flow to the lungs.

In rare cases, ASD may cause signs and symptoms in children such as;

• shortness of breath, especially when exercising

• being very tired

• being underweight and slow growth

• respiratory infections such as throat and lung infections

• arrhythmias (irregular heartbeats).

Symptoms of atrial septal defect in adults

Adults with ASD may also have signs and symptoms such as;

• shortness of breath
• you may not be able to exercise for long
• feeling tired
• irregular or extra heart beats
• fainting
• lung infections.

If you have any of these symptoms, speak to your doctor.

If left untreated, an ASD can sometimes cause pulmonary hypertension (increased pressure in the lungs). This is because the extra blood from the right atrium makes the lungs work harder resulting in damage to the lung arteries. Other heart and lungs problems that ASDs can cause include;

• heart failure
• Eisenmenger syndrome
• leaky heart valves
• stroke.

Diagnosing atrial septal defects 

An ASD can be diagnosed in the womb, soon after birth, or even later during adulthood. A doctor might suspect a problem with your heart if they hear a swishing sound (also known as a murmur) through a stethoscope. They may send you for other tests to find out the cause of the murmur. Some of the common tests that can diagnose an ASD are;

• electrocardiogram (ECG)
• echocardiogram
• chest x-ray
• cardiac CT scan
• cardiac MRI
• exercise testing.

Your doctor may also ask you to have a certain type of heart catheterisation to check the working of your heart in more detail. 

If you have any questions or worries about any of these tests, speak to your doctor.

Causes of atrial septal defects

The cause of ASD is unknown. However, it is possible that certain factors can increase the chances of a baby being born with ASD.

• Read more information on congenital heart disease and causes.

Treating atrial septal defects

The treatment for an ASD depends on the size of the ASD and where it is. In most cases, ASDs will close up by adulthood without treatment. If you have a small ASD and show no symptoms, you might not need treatment to close it.

However, if you have a large ASD or experiencing or showing symptoms, your doctor will likely recommend that the hole be closed.

There is currently no medication that will make the ASD get smaller or close any faster than it naturally can. ASDs can only be fixed through procedures on your heart. Most people feel better afterwards and can live a normal life.

There are two types of procedures used to repair ASDs. They are both usually done under general anaesthetic so you're asleep and looked after by healthcare professionals throughout.

Endovascular ASD Closure

This is a keyhole surgery also known as heart percutaneous ASD Closure. It is a way of closing an ASD without having to make a large cut into the skin.

A long thin tube called a catheter is put into a large vein at the top of the leg and guided to the heart. A patch made of special material is put over the ASD to close the hole. The patch will stay inside your heart and become covered over by your own tissue over time.

You may need to take some medicines to help reduce the risk of blood clots (gel like clumps of blood) forming on the patch for some time after your procedure. Your medical team will talk to you about this.

Open heart surgery

During open heart surgery, the surgeon will close the ASD by working directly on your heart. You’ll be completely asleep so you shouldn’t feel a thing. The surgeon will cut your breastbone to access your heart through your rib cage.

You will be put on a bypass machine, also known as a heart and lung machine. It will help pump oxygenated blood around the body during the procedure. The surgeon will close the ASD and take you off the heart lung machine.

If you have any questions about the procedure, speak to your doctor.

It's normal to be worried about having a scar after surgery. Speak to your doctor about any concerns you might have about scarring. They will be able to tell you how your scar is going to look.

Living with an atrial septal defect

If you have a small or repaired ASD, you should be able to live a normal healthy life. Your doctor will let you know how often they need to see you to make sure your heart is healthy. It's really important to go to your follow-up appointments so your doctor can make sure you keep well.

Exercise

You should be able to exercise normally if you have a small or repaired ASD. However, you should still speak with your doctor when considering making big changes to your exercise routine.

If you have a bigger ASD or showing certain signs and symptoms, your doctor will be able to tell you what kind of exercise is safe for you.

Family planning

If you have or had an ASD, speak to your doctor about your risk for heart problems during pregnancy. For most women with a small or repaired ASD, the risk of complications is low. In women with larger or unrepaired ASDs, there is an increased risk of stroke and heart and lung problems during pregnancy.

If you have a child with ASD, there is around a 1 in 40 chance that if you have another child, they will have a heart condition too. Speak to your doctor if you are planning a family.

In the early months of pregnancy, ask your midwife or doctor about a special scan to look at the baby’s heart.

Endocarditis

This is a rare infection that causes inflammation of the valves and inner lining of the heart. People with congenital heart diseases, including ASD, have an increased risk of endocarditis. To reduce the risk of developing endocarditis, your doctor might recommend antibiotics after surgery. 

In some cases, you may need to take antibiotics before you have dental work to reduce your risk of endocarditis. Check with your doctor and dentist to see if this applies to you.

More information and support

Your healthcare team are here to support you. You can ask them anything. It might feel uncomfortable or embarrassing to ask questions but most people feel much better once they do.

Here are some other ways you can get support.

• Read about the most commonly asked questions about congenital heart diseases. We talk about things like alcohol, mental health, preparing for surgery, and more.

• If you still have more questions, speak to our cardiac nurses on our Heart Helpline by phone, callback, email or online chat (Monday to Friday, 9am to 5pm).

• You can also speak to others with heart conditions by joining a support group or online community.