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Atrial Septal Defect

Atrial Septal Defect: Symptoms, Causes and Risk Factors, Diagnosis, Treatments  | National Heart Centre Singapore

Atrial Septal Defect - What it is

Atrial septal defect (ASD) is a 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 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 ASD with no chamber enlargement, raised lung pressure or other complications needs only to be followed up at the clinic.

Percutaneous Closure of Atrial Septal Defect (ASD)

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

Atrial Septal Defect - Symptoms

Many babies born with atrial septal defects do not exhibit signs and symptoms. In adults, signs or symptoms usually begin by age 30. However, for some cases, the signs and symptoms may not occur until years later.

Signs and symptoms 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

​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

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

  • Echocardiogram 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

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 (ASD) 

The procedure usually takes between 1 and 2 hours and the success rate is about 95%. However, there are known risks involved. The risks and their estimated incidence of occurrence are:

  • Device dislodgement (embolisation) and the need for emergency heart surgery: 1%
  • Device erosion (device eroding through the heart walls): 0.3%
  • Death: less than 1% (usually from perforation of the heart chamber)
  • Dislodgement of clot or air bubbles to the brain (causing stroke) and other organs:  less than 1%
  • Rhythm disturbance (arrhythmia) (usually transient): 1 to 2%
  • Other potential risks: Allergic dye reaction, anaesthetic reaction, bleeding and bruising around the sheaths in the groin, injury to the artery/vein/nerves in the groin, perforation of the oesophagus (from the TEE probe), headache or migraine, infection, allergic reaction to the nickel component of the device

Patients with small ASD seldom develop any complications. However patients with moderate- to large-sized defects may develop irregular heart rhythm, heart pump failure and high pressure in the lung. These patients may need additional medications to treat these complications.

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. 

Not all types of ASD are suitable for device closure. You will need to have a detailed echocardiogram scan including both transthoracic echocardiogram as well as a transoesophageal echocardiogram to assess if your defect is suitable for closure. Defects which do not have sufficient rims for the device to sit safely, are too near to other heart structures such as veins, valves and very large (more than 3.6cm) may not be suitable for device closure and may be better treated with surgery.

Atrial Septal Defect - Preparing for surgery

This procedure for device closure for ASD is performed in the cardiac catheterisation lab. You will be given an anaesthetic which may be general (GA) or local (LA) depending on the technique used. 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.

Atrial Septal Defect - Post-surgery care

Post-surgery Activities 

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 6 months.

Prevention of endocarditis

Antibiotic prophylaxis prior to dental or other surgical procedures is no longer recommended for patients with unrepaired ASD unless there are other associated heart defects. After ASD device closure or surgical repair, antibiotic prophylaxis is still required up to 6 to 12 months depending on whether the defect has completely closed.  

Atrial Septal Defect - Other Information

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