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Tests & procedures


What is a Cardioversion?

Cardioversion is a procedure used to convert an abnormal (irregular) heart rhythm to a normal rhythm by using small amount of electrical current. When the heart beats abnormally the blood doesn’t get pumped around your body effectively. You may have been experiencing dizziness, shortness of breath, palpitations or feeling tired. If medications alone are not successful, then a cardioversion may be required.

How is it done? 

Cardioversion is done whilst you are asleep. Patches will be placed on your chest and your heart rhythm will be monitored. A small amount of electrical energy will be delivered to your heart muscle.

The purpose of the cardioversion is to interrupt the abnormal electrical circuit in the heart and restore a normal heartbeat. The delivered shock causes all the heart cells to contract simultaneously, thereby interrupting and terminating the abnormal electrical rhythm without damaging the heart. The heart’s electrical system then restores a normal heartbeat.

Before the Cardioversion

A blood thinning medication is recommended prior and after having a cardioversion. You may also need to have a Trans Oesophageal Echo (TOE) prior to your cardioversion. You will be asked to either fast from MIDNIGHT or AFTER BREAKFAST. You can generally take your usual medications with a small amount of water; your nurse will let you know.

You can have a shower as normal prior to coming in for the procedure. Do not apply lotions or powders to your skin and remove all your jewellery. When you arrive for your procedure the nursing staff will confirm that you have done all of this and that you have signed a consent form.

A small needle with a tube connected to it (cannula) will be put into a vein in your arm. You will be given some medication through this cannula to sedate you.

During the Cardioversion

You will be attached to a heart monitor and given an anaesthetic to make you sleepy. (You will generally wake with no recollection of the procedure due to the effects of the sedation.) Once you are asleep the staff will deliver a small electrical current to your chest via a defibrillator machine. This electrical current cause all the heart muscles to contract simultaneously, stopping all fibrillating contractions and allowing the heart’s natural pacemaker (the sinoatrial node) to take over and restore a normal heart beat. When you wake up you will have to stay and be observed. When you are stable you will be allowed to go home BUT you will need to be picked up by someone. (we strongly advise against catching a bus or taxi).

How long will it take?

The procedure itself is relatively quick and is completed within a matter of minutes; however, more than one attempt may be needed.

You may be required to wait a while (before the procedure) as the anaesthetist that puts you to sleep will come down from theatres at a time that fits in to their operating schedule.

After the Cardioversion

You will not be able to drive for 24 hours following the procedure. (You should have a friend or family member to take you home.) You will be unable to drink alcohol, operate machinery or sign important documents for a minimum of 24 hours after the procedure.

You may experience some mild skin irritation/ redness from the adhesive pads, please observe this and see your GP if ongoing concerns. You should make an appointment for GP follow-up a week after the procedure.

Are there any risks?

As with any medical tests there are risks, but serious problems are rare. Your doctor will discuss any risks with you at the time of signing the consent form.

A cardioversion may not be successful. It may work initially, but then your symptoms and heart arrhythmia can return. Keep in contact with your own GP for ongoing heart checks.

Going back to work:

Depending on the type of work that you do, you may require a day or two off work. Please discuss with your doctor and request a medical certificate on discharge if required.