Sometimes, the human heartbeat needs to be “reset” to correct irregular or rapid heartbeat rhythms. Cardioversion is literally, a shock to the heart. During a cardioversion an electrical shock is sent through your chest wall to startle the heart out of its abnormal rhythm. The shock causes all the heart’s cells to contract simultaneously. Cardioversion does not “cure” heart rhythms, they may return. This split second interruption of the abnormal beat allows the heart’s electrical system to regain control and re-establish normal rhythm. Cardioversion is most often used when medications fail to control a persistent irregular heart rhythm to restore normal heart rhythms.
Patients in atrial fibrillation are at risk for stroke at the time when they come out of atrial fibrillation. For most patients the doctors will ask that the patient be anti-coagulated for 3-4 weeks on warfarin (Coumadin) or other prescription blood thinners prior to cardioversion. In some cases a moderately invasive imaging test called transesophageal echocardiogram (or TEE) may be performed prior to the cardioversion to make sure that the heart is free from blood clots. Blood thinners and/or a TEE are an important part of making sure that cardioversion can be performed safely. After the cardioversion, blood thinners will be continued for 4 weeks in most cases. In some patients anti-coagulation may be required for longer.
An electrical cardioversion is performed in a hospital setting and takes between 2-3 hours total (including the preparation and recovery time). The procedure is done after the patient has received heavy sedation.