Treatments - Cardioversion

This treatment is most commonly recommended to certain patients who have a disturbance of heart rhythm called atrial fibrillation, less commonly atrial flutter. See diagnosis section, arrhythmias. The procedure involves passing an electric shock across the heart to restore a normal heart rhythm.

Cardioversion is usually carried out as a daycase procedure under a brief general anaesthetic. In preparation it is important to receive treatment with warfarin, as a blood thinner, for a minimum of four to six weeks. Blood tests are needed to ensure that a satisfactory level of blood thinning has been achieved before the cardioversion is performed.

On the day of the procedure you must not eat or drink for six hours before the cardioversion. An ECG (heart recording) will be made when you are admitted to confirm you are still out of rhythm and need the procedure. Due to the general anaesthetic you will not feel the electric shock, but on waking up may be aware of mild discomfort or warmth across the chest. This rapidly settles down.

There are very small risks associated with the procedure. By far the commonest complication is failure for the electric shock to convert the heart rhythm back to normal. If this is the case your doctor will discuss the other treatment options with you. The procedure carries an exceedingly small risk of stroke which is minimised by effective blood thinning. It is important to continue warfarin for a period of time after the procedure. Your doctor will discuss with you what medications you need to take following discharge, and for how long.

There are other types of cardioversion that are less commonly recommended. These include using drugs, or an electric shock delivered inside the heart (‘internal cardioversion’). Your doctor will discuss these in detail if he feels either is best for you.