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Atrial Septal Defect

Atrial Septal Defect - What it is

What is an atrial septal defect?

Atrial septal defect (ASD) is a congenital defect between the two upper heart chambers (the atria). This defect allows mixing of oxygenated and deoxygenated blood, eventually causing right heart enlargement and high pressure in the lungs (pulmonary hypertension).

Moderate- to large-sized Atrial Septal Defect (ASD) causing right heart dilatation and raised pressure in the lungs should be closed. Closure can be performed either via percutaneous method using devices (through the femoral vein) or through open-heart surgery.

Small Atrial Septal Defect (ASD) with no chamber enlargement, raised lung pressure or other complications needs only to be followed up at the clinic.


Illustration of a heart with atrial septal defect | SingHealth

Atrial Septal Defect - Symptoms

What are the symptoms of an atrial septal defect?

Many babies born with atrial septal defects do not exhibit signs and symptoms. In adults, signs or symptoms usually begin by age 30, depending on the size of the defect and the flow across. However, in some cases, the signs and symptoms may not occur until years later.

Signs and symptoms of atrial septal defects (ASD) may include:

  • Heart palpitations or skipped beats
  • Frequent lung infections

  • Shortness of breath, especially when exercising
  • Fatigue
  • Swelling of legs, feet or abdomen
  • Stroke
  • Heart murmur, a whooshing sound that can be heard through a stethoscope

Atrial Septal Defect - How to prevent?

Atrial Septal Defect - Causes and Risk Factors

What causes atrial septal defects?

​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 may play a role.

Atrial Septal Defect - Diagnosis

How is an atrial septal defect diagnosed?

If your doctor suspects you have a heart defect, your doctor may request one or more of the following tests:

  • Echocardiogram (heart ultrasound) is the most commonly used test to diagnose an atrial septal defect.
  • Chest X-ray helps your doctor to see the condition of your heart and lungs and it may identify conditions other than a heart defect that may explain your signs or symptoms.
  • Electrocardiogram (ECG) is a test that records the electrical activity of your heart and helps identify heart rhythm problems.
  • Magnetic Resonance Imaging (MRI) is ordered to assess for right heart dilatation 

Atrial Septal Defect - Treatments

How is an atrial septal defect treated?

The defect can be closed percutaneously by inserting a device through the blood vessels in the groin (percutaneous transcatheter approach) or via surgical repair. The choice of treatment depends on the size of the defect and the presence of pulmonary hypertension. After the defect is closed, the patient will need regular follow up with a cardiologist.

Device closure for atrial septal defect 

This procedure is performed by inserting a device through the blood vessels in the groin (percutaneous transcatheter approach) which will close the ASD.

This minimally invasive procedure typically takes 1 to 2 hours, with a success rate of approximately 95%. However, it carries certain risks, including:

  • Device dislodgement (embolisation): 1%, may require emergency heart surgery
  • Device erosion: 0.3%, involves the device eroding through heart walls
  • Death: Less than 1%, usually due to perforation of a heart chamber
  • Stroke or organ damage: Less than 1%, caused by dislodged clots or air bubbles to the brain
  • Rhythm disturbance (arrhythmia): 1 to 2%, typically transient

Other potential risks include allergic reactions to dye or anaesthesia, bleeding or bruising at the groin site, injury to blood vessels or nerves in the groin, perforation of the oesophagus from the TEE probe, headache or migraine, infection or allergic reaction to the nickel component of the device.

Some complications, if they occur, may require further treatment such as surgery or prolonged hospitalisation. In the case of device dislodgement, surgery may be needed to remove the device and close the defect simultaneously.

Not all ASDs are suitable for device closure. Factors that may make a defect unsuitable include:

  • Insufficient rims for the device to sit securely
  • Proximity to heart structures such as veins or valves
  • Large defects (greater than 3.6 cm)

Detailed imaging, including transthoracic and transoesophageal echocardiograms, is necessary to determine if a defect is suitable for device closure.

In most cases, this procedure is performed under general anaesthetic (GA) which is given by a qualified anaesthetist. Once anaesthetised, an imaging probe (TEE) will be passed into your gullet (oesophagus) for accurate sizing of the ASD and to assist during deployment of the device. You will lie on an X-ray table and an X-ray camera will move over your chest during the procedure. A plastic catheter (a long tube) will be inserted via a vein in the groin and navigated until it reaches the heart.

Sometimes (depending on individual case), the catheter is positioned at different chambers of your heart to measure the pressure and oxygen content prior to device closure. In certain circumstances, balloon sizing of the ASD may be required. Once your doctor is satisfied with all the measurements, the appropriate size device is connected onto a cable, put into a special delivery tube, advanced through your ASD and carefully deployed. Your doctor will study the device's position and stability before releasing the device. The catheter and imaging probe are removed and the procedure is completed.

Surgical repair

For defects unsuitable for device closure, surgical repair is performed. This is often recommended for very large defects or those close to critical heart structures.

What are the potential complications of atrial septal defect and how are they managed?

Patients with small defects rarely experience complications. However, moderate to large defects may lead to:

  • Irregular heart rhythm
  • Heart pump failure
  • High lung pressure

Medications may be required to manage these issues.

Some of these complications, if they do occur, are of a serious nature and may require further treatment including surgery and prolonged hospitalisation. In the event of device dislodgement, you may require surgery for removal of the device and closure of the hole at the same time.

Atrial Septal Defect - Preparing for surgery

Atrial Septal Defect - Post-surgery care

What can you expect after an atrial septal defect procedure?

Activity restrictions are unnecessary unless there are associated problems that you and your cardiologist have discussed. However, after ASD device closure, patients will be advised to refrain from strenuous activity and heavy lifting for at least six months.

Atrial Septal Defect - Other Information

How can infective endocarditis (IE) be prevented in atrial septal defect patients?

The incident of IE in congenital patient is higher than general population. Therefore, it is important for congenital patient to maintain good oral, dental and skin hygiene as primary prevention. Cosmetic tattooing and piercing are discouraged due to the risk of IE. Antibiotic prophylaxis is considered for patient at highest risk for IE before surgery and dental procedures. Please discuss with your congenital team for the latest update on the antibiotic prophylaxis.


References

  1. Atrial septal defect (ASD). www.heart.org. (2024, October 31). https://www.heart.org/en/health-topics/congenital-heart-defects/about-congenital-heart-defects/atrial-septal-defect-asd
  2. Yale Medicine. (2024, October 17). Atrial septal defect (ASD). Yale Medicine. https://www.yalemedicine.org/conditions/atrial-septal-defect-asd
  3. Mhanna, C. (Ed.). (2021, November). Atrial septal defect (ASD) (for parents) | nemours kidshealth. KidsHealth. https://kidshealth.org/en/parents/asd.html
  4. Centers for Disease Control and Prevention. (n.d.). About atrial septal defect (ASD). Centers for Disease Control and Prevention. https://www.cdc.gov/heart-defects/about/atrial-septal-defect.html
The information provided is not intended as medical advice. Terms of use. Information provided by SingHealth

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