Atrial septal defect (ASD): symptoms, treatment and pregnancy

The heart has four chambers. The two upper chambers are the atria, and a wall called the atrial septum separates them. An atrial septal defect (ASD) is a hole in that wall. The British Heart Foundation (BHF) says it is a type of congenital heart disease, meaning it is something you are born with, and that it can occur on its own or with other types of congenital heart disease.

The NHS explains congenital heart disease more broadly as a problem with the structure of the heart that is present from birth. It says there are many different types, that some need surgery soon after birth, and that other types, such as a hole in the heart, can often be left untreated.

The BHF says some ASDs are very small and may never cause any problems or need treatment, but ASDs can be large and need treatment. How much it matters depends largely on size and position.

The BHF describes three main types of ASD. Which type you have affects how it is monitored and treated.

The BHF says there are usually no signs of an ASD at birth. Sometimes the only sign is a heart murmur, an extra, unusual sound that a doctor can hear through a stethoscope. The murmur is caused by blood flowing from the left to the right in the top chambers through the hole (shunting), which creates a swishing sound because of increased blood flow to the lungs.

In rare cases, the BHF says an ASD may cause symptoms in children, including shortness of breath (especially when exercising), being very tired, being underweight with slow growth, throat and lung infections and irregular heartbeats (arrhythmias).

An ASD can be found at any age. The BHF says it can be diagnosed in the womb, soon after birth or even later in adulthood. Adults with an ASD may notice shortness of breath, not being able to exercise for long, tiredness, irregular or extra heartbeats, fainting and lung infections. The BHF advises speaking to your doctor if you have any of these.

If an ASD is left untreated, the BHF says it can sometimes cause pulmonary hypertension (increased pressure in the lungs). The extra blood from the right atrium makes the lungs work harder, which can damage the lung arteries. Other problems an ASD can cause include heart failure, Eisenmenger syndrome, leaky heart valves and stroke.

The NHS says common symptoms of congenital heart disease in older children and adults include feeling tired all the time, shortness of breath, palpitations and, in some people, skin or lips turning blue or grey. A murmur is common. Symptoms sometimes do not appear until the teenage years or adulthood.

The BHF says the cause of an ASD is unknown, although some factors may increase the chance of a baby being born with one. The NHS explains that congenital heart disease is screened for during the 20-week pregnancy scan, but that this scan cannot find all conditions, so it is possible for congenital heart disease to be missed and sometimes not be diagnosed until adulthood.

A doctor might suspect a problem if they hear a murmur through a stethoscope, and may arrange tests to find the cause. The BHF lists the common tests that can diagnose an ASD.

• An electrocardiogram (ECG), which records the heart's electrical activity.

• An echocardiogram, an ultrasound scan of the heart.

• A chest X-ray.

• A cardiac CT scan or cardiac MRI.

• Exercise testing.

• In some cases a heart catheterisation to check how the heart is working in more detail.

The BHF says treatment depends on the size and position of the ASD. In most cases an ASD will close up by adulthood without treatment, and if you have a small ASD with no symptoms you might not need treatment to close it. If the ASD is large, or you have symptoms, your doctor will likely recommend closing it. There is currently no medicine that will make an ASD smaller or close faster, so it can only be fixed through a procedure on the heart. Most people feel better afterwards and can live a normal life.

The BHF describes two types of procedure, both usually done under general anaesthetic.

The BHF advises that if you have or have had an ASD you should speak to your doctor about your risk of heart problems in pregnancy. For most women with a small or repaired ASD, it says the risk of complications is low. In women with larger or unrepaired ASDs, there is an increased risk of stroke and of heart and lung problems during pregnancy.

If you have a child with an ASD, the BHF says there is around a 1 in 40 chance that another child will have a heart condition too, and suggests speaking to your doctor if you are planning a family. In the early months of pregnancy you can ask your midwife or doctor about a special scan to look at the baby's heart.

The BHF says that if you have a small or repaired ASD you should be able to live a normal, healthy life, and your doctor will say how often they need to see you. It stresses that follow-up appointments are important so that your doctor can make sure your heart stays healthy.

You should be able to exercise normally with a small or repaired ASD, though you should speak to your doctor before making big changes to your routine. With a bigger ASD or certain symptoms, your doctor can say what kind of exercise is safe for you.

People with congenital heart disease, including ASD, have an increased risk of endocarditis, a rare infection of the heart's valves and inner lining. The BHF says your doctor might recommend antibiotics after surgery, and in some cases before dental work, so check with your doctor and dentist. The NHS also recommends looking after your teeth and having regular dental check-ups for people with congenital heart disease.

The NHS says to call 999 if you or a child has lips, tongue, face or skin that suddenly turn blue or grey, difficulty breathing, chest pain, confusion, drowsiness or dizziness, or heart rhythm problems such as the heart beating too quickly or without a steady beat. It advises asking for an urgent GP appointment or NHS 111 help if you think you or a child may have symptoms of congenital heart disease.

The NHS says people diagnosed with congenital heart disease are referred to a specialist team at an NHS hospital, and may only need regular check-ups, with treatment if symptoms get worse. ASD closure is carried out by specialist cardiology or cardiac surgery teams. Some adults choose a private cardiology opinion for an echocardiogram or to discuss closure options sooner; the tests and procedures are the same, and ongoing follow-up with a congenital heart service is still advised.