Dr Simon Kennon MB ChB, FRCP, MD Consultant Cardiologist


If you have an irregular heart beat such as atrial fibrillation (when the heart beats too fast or irregularly), atrial flutter (when the heart may not always beat irregularly but beats too fast) or verntricular tachycardia (when the heart beats too fast) your doctor may want you to have a procedure called cardioversion.

Cardioversion aims to get your abnormal heart rhythm back to normal. This can be done either with anti-arrhythmic medicines or electrically. Electrical cardioversion is an electric shock used to help your heart beat at normal rhythm. It's usually given if your arrhythmia has lasted longer than 48 hours. It's less likely to work if the arrhythmia has been present for over a year and is unsuitable if the irregular rhythm comes and goes.

Electrical cardioversion surgery

Firstly, you will be given a short-acting general anaesthetic or heavy sedation so that you sleep 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.


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


Complications are not common and any side-effects are usually temporary. You may get headaches and dizziness, for example, which can result from a drop in your blood pressure. Feeling sick is also fairly common after an anaesthetic. You may also feel a small amount of discomfort in your chest, where the shock was given.