A 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. It is most often performed to correct atrial fibrillation. If the abnormal rhythm has been present for more than 48 hours, the patient will usually be treated with 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.
The procedure is performed under a short general anaesthetic, and the patient must fast for 4 to 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). No medication is usually given on the morning of the procedure, unless directed by the cardiologist.
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 the patient. If the patient has been on warfarin, it is important to continue this, usually for at least 3 weeks after the cardioversion.