If you have an abnormal heart rhythm such as atrial fibrillation your doctor may want you to have a treatment called cardioversion.

This treatment aims to get your abnormal heart rhythm back to normal.

What happens during a cardioversion?

You will be given a short-acting general anaesthetic or heavy sedation so you will be asleep throughout the procedure.

A doctor or nurse will put electrodes, stuck to large sticky pads, on your chest. The electrodes are connected to a defibrillator machine and will give you one or more controlled electric shocks to your chest wall. The whole procedure usually lasts about 10 minutes.

The defibrillator monitors your heart rhythm throughout the procedure so the medical staff can see straight away if the cardioversion was successful.

How long will I be in hospital for?

You will usually only need to go to hospital for part of the day, although some people need to stay overnight. 

Are there complications or side effects I should be aware of?

Complications are not common and if you experience any side effects after the cardioversion, they will usually be temporary. 

After your cardioversion, you may get headaches and dizziness from a drop in your blood pressure. You may also feel a small amount of discomfort in your chest where the shock was given. Feeling sick is also a common side effect of an anaesthetic.

How successful are cardioversions?

Cardioversion doesn’t always restore normal heart rhythm. Sometimes it’s successful to start with, but then your abnormal heart rhythm comes back several days, weeks or even months later. If this happens, your doctor may want to repeat the cardioversion or they may consider another treatment for you.

If you have any questions, talk to your doctor or call our Heart Helpline on 0300 330 3311.

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Heart rhythms