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Dr Mark Kennedy - Private Internal Medicine Specialist

Private Service

Electrical Cardioversion

Patient information:

Electrical cardioversion is a procedure used to correct rhythm abnormalities of the heart, in which a small electric shock is used to "jolt" the heart back into a normal rhythm.  The procedure is usually undertaken for the common rhythm disturbances, atrial fibrillation and atrial flutter.   If the abnormal rhythm has been present for more than 48 hours, the patient will usually be treated with Dabigatran or Warfarin (an anticoagulant, or "blood thinner") for at least 3 weeks prior to a cardioversion. This is to ensure that there is no blood clot in the heart, which could be released into the circulation by the cardioversion causing a significant problem, such as a stroke. Sometimes a transoesophageal echo may be performed immediately before a cardioversion to exclude the presence of any blood clot inside the heart.  

Medicines are often given to hold the rhythm stable when there is a successful cardioversion. Blood thinning with Dabigatran or Warfarin is required to reduce the risk of clotting and stroke for an interval both before and following the procedure.  Electrical cardioversion has a high immediate success rate, and is a low risk procedure.

The procedure is performed under a short general anaesthetic, and the patient must fast for 4 - 6 hours before the procedure. The shock is delivered through electrode pads placed on the chest and back.  Up to 3 shocks may be given in an attempt to restore the heart's natural rhythm (sinus rhythm).

After the procedure:

Following cardioversion the patient is monitored for approximately one hour, and should not drive for 24 hours. A report will be sent to the referring doctor or GP, and the cardiologist performing the procedure will explain ongoing treatment and medication to you. If you have been on Dabigatran or Warfarin, it is important to continue this, usually for at least 4 weeks after the cardioversion.  This will be discussed at your follow-up visit in 4 weeks' time.

On occasions cardioversion can be repeated if the rhythm disturbance recurs. 

This page was last updated at 2:04PM on October 8, 2019.