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 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.
Preparation for cardioversion
• Unless the cardioversion is performed as an emergency, you will need to take an anticoagulant (warfarin, synthrome) for 4-6 weeks prior to the procedure. This is to prevent formation of clots inside the heart. We will need to monitor your 'INR' through the Anticoagulant Clinic prior to the procedure. The 'INR' (a measure of how thin the blood is) will have to be above 2 for at least 6 weeks. This is to ensure that your blood is “thin” enough before we proceed with cardioversion.
• 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 until one hour before.
• Please bring all your tablets in their original packets.
On arrival at hospital for your cardioversion
A nurse will take your blood pressure, temperature and pulse. A doctor will take your medical history, examine you and take a blood sample. If you are taking warfarin, we may need to wait for the results of the “INR”, which will tell us how thin the blood is. The procedure for cardioversion 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 about the procedure. 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