Cardioversion is a procedure carried out in the hospital to restore a normal heart beat if you are experiencing certain abnormally fast or irregular heart rhythms (arrhythmia). When we talk about cardioversion we usually mean electrical cardioversion which is a controlled process where an electrical current is delivered to your heart through paddles or patches placed on your chest.

Occasionally your doctor may use medication only to ‘chemically’ convert your heart rhythm back to normal.


Why is it done

Cardioversion is done to correct abnormally fast or irregular heart rhythms (arrhythmias), most commonly atrial fibrillation and atrial flutter. These conditions can cause your heart to beat inefficiently, so cardioversion can help restore a normal controlled rhythm.

Although atrial fibrillation and atrial flutter are not generally life-threatening, the irregularity of the heart beat can cause blood clots to form in your heart. Occasionally you may need a trans-oesophageal echo performed prior to cardioversion to check there are no blood clots in your heart’s chambers.


What are the risks

Complications of cardioversion are uncommon and usually temporary. Your doctor will take measures to reduce your risk with additional investigations if necessary.

Cardioversion can cause blood clots in your heart to become dislodged which could travel in the blood circulation and cause life-threatening complications, such as a stroke. This is why your doctor may check for blood clots before the procedure. Taking blood thinning medication (anticoagulants)  before and after the procedure can reduce this risk.

Occasionally after cardioversion, you may feel lightheaded or dizzy due to your blood pressure being a little low. This generally resolves itself and doesn’t need treatment. Sometimes you can feel a discomfort on your chest where the shock was given or rarely some people have minor burns on their skin.

For some people, cardioversion does not restore a normal heart beat or the abnormal rhythm can recur.

How it is done

You will be asleep throughout the procedure so an intravenous (IV) line will be inserted in your arm before it begins. This is used to give a short acting anaesthetic medicine or sedation to make you sleep.

Large patches called electrodes will be stuck to your chest and sometimes your back. These are connected to the defibrillator machine which is used to deliver the controlled shocks. It also monitors your heart rhythm throughout the procedure, so it can be seen straight away if the cardioversion is successful and normal heart rhythm is restored.

Once you are asleep the procedure only takes a few minutes.


Usually, cardioversion is done as a day-case procedure, meaning you go to the hospital for part of a day and can go home after the procedure is complete. You will remain in bed and be monitored closely afterwards until you are awake and alert.

You should not drive or operate machinery for the rest of the day and may need someone to accompany you home until the effects of the medication (anaesthetic and sedation) wear off.

You will most likely continue to take blood thinning medication for several weeks to prevent blood clots forming in your heart chambers.  Medication to prevent heart rhythm problems may be prescribed or continued also.



For most people, cardioversion is successful in quickly restoring normal heart rhythm. For some though it may only be successful for a few minutes, days or weeks and the abnormal heart rhythm may return. If this happens you may need to have the procedure again or your doctor will discuss other options.

To improve the overall health of your heart you may need to make some lifestyle changes. You can do this by not smoking, controlling your blood pressure, monitoring your cholesterol level, taking regular exercise, keeping your weight down and reducing your stress.


Heart & Stroke Conditions A-Z – see our range of guides.

AF and You – our information booklet for people living with Atrial Fibrillation

Your Heart Health – view our articles on ways to manage and reduce your risk factors, from being active to stress, cholesterol, losing weight, blood pressure and more.


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