Returning your heart back to normal rhythm.

Sometimes your heart is in an abnormal rhythm such as atrial fibrillation or atrial flutter. This can lead to symptoms of chest pain, shortness of breath, dizziness or blackouts. To return the heart back to normal rhythm, a cardioversion using an electric shock may be recommended by your cardiologist.


You will be asked to fast for at least 6 hours prior to the cardioversion. You will need to continue your usual medications especially any blood thinners. These can be taken first thing in the morning with a sip of water.

Your cardioversion will only be performed if you have had a minimum of 4 weeks on adequate blood thinners. It is vital that you inform your cardiologist that you have missed any doses or if you are on warfarin your INR level has been below 2 in the last 4 weeks.

If your blood has not been adequately thinned, your risk of stroke during the cardioversion may be too high. This may cause your cardiologist to cancel the Cardioversion or arrange a trans-eosophageal echocardiogram (TOE) to be performed prior to Cardioversion to rule our any clotting inside the heart.

How is it done?

The electrical cardioversion is performed in the angiography suite, coronary care unit or recovery room.

Pads attached to the chest and you will be connected to an external defibrillator to allow monitoring of your heart rhythm and to allow the application of the necessary energy to restore your heart’s rhythm back to normal. The pads minimise any skin burning or irritation from the electrical shock. You will be given a sedation type anesthesia prior to the electrical shock and should wake up quickly after the procedure with no recollection of the electrical shock.

Once you are anesthetized if necessary the transoesophageal echocardiogram is performed and then then shock is delivered. Additional shocks at higher energy levels can be delivered if the first shock does not restore your rhythm back to normal. There is an approximately 90% chance that your normal rhythm (sinus rhythm) will be returned but this depends on multiple factors.

There is a very small risk of stroke immediately after the cardioversion procedure as a result of stunning of the top chamber of the heart or atrium. This risk is greatest in the first few weeks after the cardioversion procedure. This is why it is crucial that you continue your blood thinners for at least a month after the procedure, your cardiologist will direct you if and when to stop them.

In some people the abnormal rhythm returns and repeated cardioversion may be required.

You will need to get someone else to drive you home after the procedure and you will need a responsible adult to stay with you overnight after the procedure. As with all types of anesthesia you should not make any important decisions for 24 hours after the procedure.


30 minutes.