11622 Atrial Septal Defect Asd
Informed by recognized medical guidance
Overview
An atrial septal defect, or ASD, is a small opening in the wall between the two upper chambers of the heart. This wall is called the atrial septum. The hole lets some oxygen-rich blood mix with oxygen-poor blood and sends extra blood to the lungs. Many ASDs are small and cause no problems. Larger holes can make the heart work harder over time.
Key facts
- An ASD is a heart condition a person is born with, not an illness caught later in life.
- Small ASDs sometimes close on their own during childhood; larger ones often need treatment.
- With good medical care, most people with ASD live full, active lives.
An ASD is one of the most common heart problems present at birth. It is found in people around the world, though many do not know they have it because symptoms can be very mild or absent.
ASD affects babies, children, and adults. It can be found in a newborn baby or not discovered until later, sometimes in adulthood. It is slightly more common in girls and women, but it can affect anyone.
Symptoms
- Sudden, severe difficulty breathing while at rest — call your local emergency number immediately.
- Chest pain or pressure that does not go away — call emergency services right away.
- Fainting or collapse — call your local emergency number.
- Sudden weakness on one side of the body, drooping face, or trouble speaking — these can be signs of a stroke and need immediate emergency care.
- ⚠A fast or irregular heartbeat that is new or does not settle
- ⚠New or worsening swelling in the legs, feet, or stomach
- ⚠In a child: blue or grey lips, very fast breathing, or extreme tiredness — seek same-day medical care
- ⚠Fever along with a known heart condition — contact your healthcare team the same day
Common symptoms
- No symptoms at all, especially with small holes
- Feeling short of breath during exercise or everyday activity
- Tiring easily
- Palpitations, which feel like a fast, fluttering or pounding heartbeat
- Swelling in the legs, feet, or belly
Symptoms in children
- Tiring quickly during play or feeding
- Poor weight gain or slow growth
- Fast breathing or breathing harder than usual
- Frequent chest infections
Symptoms in older adults
- Increasing breathlessness with activity
- An irregular heartbeat, sometimes called atrial fibrillation
- Feeling dizzy or fainting
- Fear of exercise due to tiredness
- Swelling in the legs or stomach
Causes
Main causes
- An ASD forms during the first weeks of pregnancy when the heart is still developing.
- The exact cause is usually not known, and it is not something the parents did or did not do.
- In rare cases, ASD is linked to a genetic condition or to an infection during pregnancy.
Risk factors
- Having a parent or sibling with a congenital heart condition
- Certain infections during pregnancy, such as rubella, if not protected by vaccination
- Being exposed to some medicines, alcohol, or harmful substances during early pregnancy
When to see a doctor
See a doctor urgently if:
- Your child is breathing very fast, has blue lips, is not feeding, or is unusually sleepy
- You have sudden chest pain, fainting, or severe breathlessness at rest
Book a routine appointment if:
- Your child tires easily, breathes faster than other children, or is not gaining weight well
- You feel short of breath more than expected, have heart palpitations, or have new swelling in your feet or legs
- You have been told you have a heart murmur and no one has explained what it means
Diagnosis
A doctor will ask about symptoms, check for a heart murmur, and refer you or your child for heart tests. The most reliable way to diagnose an ASD is with an ultrasound scan of the heart.
Tests that may be done
- Echocardiogram: an ultrasound test that shows the heart’s structure and the hole
- Electrocardiogram (ECG): records the heart’s rhythm and can show extra strain
- Chest X-ray: can reveal an enlarged heart or extra blood flow to the lungs
- Cardiac catheterisation: a thin tube is passed through a blood vessel to measure pressures inside the heart; this is not always needed
What to expect at your appointment
The tests are usually painless and many are done as an outpatient, meaning you can go home the same day. After the tests, the cardiologist will explain whether the ASD needs monitoring or treatment.
Treatment
Treatment depends on the size of the hole, whether symptoms are present, and the person’s age and general health. Small ASDs may need no treatment at all. Larger ASDs can be closed by a special device placed through a thin tube, or by surgery.
Self-care at home
- Keep up with regular medical follow-up, even if you feel well
- Take care of your teeth and gums to reduce the risk of infection
- Tell your doctor, dentist, or surgeon about your ASD before any procedures
- Ask your healthcare team whether you need to restrict any types of exercise
Medical treatments
Medicines do not close the hole, but they can be used to manage symptoms such as fluid build-up or an irregular heart rhythm. Closing a larger ASD is usually done with a catheter procedure or open-heart surgery, not with tablets alone.
When is surgery considered?
Surgery may be recommended if the hole is large, if the heart is becoming enlarged or strained, or if symptoms such as breathlessness and palpitations develop. The best timing varies from person to person, and the heart team will discuss the options with you.
Living with this condition
Most people with a repaired ASD live a normal daily routine. Some people with an unrepaired small ASD only need a check-up every few years. Follow the plan your cardiac team gives you, and report any new symptoms.
Lifestyle tips
- Stay physically active, but check with your heart team about what level of activity is right for you
- Do not smoke, and avoid second-hand smoke
- Limit alcohol and avoid street drugs, as they can put extra strain on the heart
- Get enough sleep and manage stress in healthy ways, such as walking, talking, or relaxation exercises
Diet and exercise
Eat a heart-friendly diet with plenty of vegetables, fruit, whole grains, lean protein, and less salt. For exercise, low-impact activities such as walking, cycling, or swimming are often good choices, but always follow the personalised advice of your healthcare team.
Mental health and emotional wellbeing
Living with a heart diagnosis can feel worrying, and it is normal to feel anxious or low sometimes. Talk about how you feel with someone you trust, and ask your healthcare team for support if you need it. If you are in crisis or have thoughts of harming yourself, reach out to a crisis support line right away or go to your nearest emergency department.
Prevention
Most ASDs cannot be prevented because they begin very early in pregnancy. The best way to support a baby’s heart development is to attend antenatal care, have recommended vaccinations before pregnancy, avoid alcohol and harmful substances, and manage health conditions with a doctor.
Vaccines
There is no vaccine that prevents ASD, but being up to date on vaccinations, especially for rubella, before pregnancy helps reduce the risk of infections that can affect a baby’s developing heart.
Screening programmes
Some ASDs can be seen on a pregnancy ultrasound scan, while others are found during a newborn check or later in life. There is no single worldwide screening programme, so it is important to have regular health checks and report any worrying symptoms.
Complications
If left untreated
- The right side of the heart can become enlarged from pumping extra blood to the lungs
- High blood pressure in the lungs, called pulmonary hypertension
- Irregular heart rhythms, such as atrial fibrillation
- A higher risk of stroke
- Heart failure in severe or long-standing cases
Long-term outlook
With monitoring, catheter closure, or surgery, the outlook for ASD is very good. Many people who have treatment live healthy, normal lives. Even when ASD is found in adulthood, treatment can still reduce strain on the heart and prevent symptoms from getting worse.
Find support
External links open third-party websites. Ruqelo Health is not responsible for external content. Listing an organisation does not imply endorsement.
Always verify with your doctor
Health guidelines vary by country and region. The information in this article is based on international clinical guidelines but may not reflect the specific guidelines, medications, or practices in your country. Always discuss your health concerns with your own doctor or healthcare provider, and refer to your local national health guidelines where available.
Important notice This information is for educational purposes only. It does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your specific situation. If you are experiencing a medical emergency, call your local emergency services immediately.
Related conditions
Sources and guidance
This article is educational and is prepared with reference to recognized health information and clinical guidance sources where available. Specific source links may vary by topic.
Last updated: July 31, 2026
Educational note: This information is for education only and is not a diagnosis.
Use it to support, not replace, advice from a licensed clinician.
If symptoms are severe, worsening, or urgent, call your local emergency number or seek emergency care.