An atrial septal defect is a hole between the two chambers at the top of the heart (left atrium and right atrium). It is a congenital problem (present since birth) but may not cause symptoms until adulthood. The hole permits the mixing of blood with oxygen in on one side of the heart with blood without oxygen in on the other – this is known as shunting.
The size of the hole determines what if anything needs to be done about it. It is important to know whether an ASD is present because if large and left without treatment, the blood shunting from left to right can cause the right heart to fail and the blood vessels in the lungs to become damaged. This can be irreversible even if the ASD is subsequently treated.
Sometimes an ASD causes no symptoms, particularly if it is small. Sometimes however it can cause breathlessness or palpitations, or occasionally migraines or be a risk factor for stroke.
The most important investigation is a transthoracic echocardiogram which is safe and painless and uses ultrasound to search for a hole in the septum between the left and right atrium. If the pictures are not clear or you are found to have a hole, you will be offered some other tests to investigate further.
These may include a transoesophageal echocardiogram, in which an ultrasound probe is inserted into your gullet and stomach (which is close to your heart on the inside). You are given some medication to make you sleepy and some local anaesthetic spray beforehand. This gives clear pictures of the septum between the atria and helps decide whether the ASD is a single hole or is a more complex problem involving the valves of the heart.
You may also need a CT or MRI scan of the heart. These give additional information about where in the the location, size and relationship of the ASD to other structures. In some patients with an ASD there may also be an additional congenital problem in which one of the veins returning blood from the lungs to the heart (pulmonary veins) is connected to the right atrium rather than the left atrium. This is important to know about because these patients need surgery because closing the ASD through a keyhole approach will not sort this out.
Your expert cardiologist will help decide whether treatment is required. If the ASD is small then nothing may be required. However, if it is larger or the right side of the heart is showing strain, then treatment will be required. The procedure can be a keyhole approach in which a small device is inserted from the top of the leg under general anaesthetic. Under imaging guidance the device is placed across the hole to close it. The device requires a clear path to the ASD with no obstructions and the shape of the ASD must leave remaining around the edges of the septum for the device to fix in place. If the shape of the ASD or the rest of the heart is not suitable for a device then open heart surgery will be needed.
An atrial septal defect requires careful assessment to decide if and how treatment is required. Our experienced cardiologists work in a team to deliver the best care for patients with these problems and are available for consultation on any day of the week and weekends as well.
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