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Cardioversion involves delivering an electrical shock to the heart in order to convert an irregular or fast heart rhythm (tachyarrhythmia) to a normal rhythm. A machine called a cardioverter is used to deliver a 'shock' of electrical energy to the heart.

The commonest types of arrhythmia that require cardioversion are atrial fibrillation and atrial flutter. Emergency cardioversion is used in more serious arrhythmias, such as ventricular tachycardia and ventricular fibrillation.

​The procedure

The anaesthetist will give you a light general anaesthetic which will only last a few minutes. Whilst you are asleep, the doctor will place some plastic pads over your chest, and sometimes the back. An electrical discharge will then be applied to the chest.


• Unless the cardioversion is performed as an emergency, you will need to take an anticoagulant (warfarin, synthrome or so called direct oral anticoagulants [DOACs], such rivaroxaban, apixaban, edoxaban or dabigatran) for 4-6 weeks prior to the procedure. This is to prevent formation of clots inside the heart. You should continue to take anticoagulants uninterrupted. Note that a successful cardioversion does not mean that you can stop taking anticoagulants. You should discuss this with the cardiologist.

• You may continue to take all medication as usual, unless otherwise instructed by the cardiologist.

• Take a bath or shower the night before your test and wash your chest.

• Do not to eat for 6 hours before the procedure.  You may drink water, but not milk, until one hour before.

• Please bring all your tablets in their original packets.

On arrival at hospital
A nurse will take your blood pressure, temperature and pulse. A doctor will take your medical history, examine you and take a blood sample. The procedure will be explained to you by a doctor and a nurse. This is an opportunity for you to ask questions and tell us any concerns you may have. The doctor will then ask you to sign a consent form showing that you understand what is involved and agree to the procedure.

After the cardioversion

On the ward, your blood pressure and pulse will be monitored by the nurse. Sometimes, the electrical discharge produces some soreness over the chest. If so, we shall give you a cream to alleviate it. You must not drive for 24 hours following the procedure, so please make arrangements to be collected from the hospital. You will be given a brief letter for your GP.  If you need a hospital outpatient appointment you will be sent one in the post.


What happens in a cardioversion

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