Background
Cardioversion is a procedure in which an electrical shock is applied to the heart in order to convert an abnormal heart rhythm to a normal rhythm. Most cardioversions are performed in individuals with symptomatic atrial fibrillation or atrial flutter.

Preparation
Please do not eat or drink after midnight before the procedure.  It is important that you are taking coumadin (warfarin) in order to minimize your risk of clot formation around the time of the test.  In addition, in most cases it is preferable for your blood to have been thinned with coumadin for at least several weeks prior to the cardioversion procedure.  If this is not the case, your physician may want for you to undergo a special ultrasound of the heart called a trans-esophageal echocardiogram prior to the cardioversion, in order to verify that no clots exist in the heart before the shock is applied.

During the procedure
Please come to the EP Lab on the day of your procedure.  You will be interviewed about your medical history, and you will have an intravenous line placed.  Special pads are placed on your chest and back, and these are connected to a defibrillator.  Your vital signs and heart rhythm will be monitored. 

An anesthesiologist will administer medication for you to fall asleep for several minutes.  Once you are asleep, the physician charges the defibrillator and then delivers a shock through the pads on your torso.  The vast majority of the time, only one shock is needed to restore normal rhythm.  However, in rare cases more than one shock is required.  There are also very rare cases where it is not possible to restore normal rhythm despite several shocks. 

You will be monitored as you wake up from the anesthesia.  Rarely, you may experience minor skin redness at the site of the pads where the electrical energy was delivered.

You are advised not to drive or make any important decisions for the rest of the day.  A responsible adult should be available to provide transportation home. Most patients are able to go home within an hour after the procedure.