Diagnostics

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Cardioversion

  • Purpose of Test:

    Cardioversion is a brief procedure where an electrical shock is delivered to the heart to convert an abnormal heart rhythm back to a normal rhythm. Most elective or "non-emergency" cardioversions are performed to treat atrial fibrillation or atrial flutter, benign heart rhythm disturbances originating in the upper chambers (atria) of the heart. Cardioversion is used in emergency situations to correct a rapid abnormal rhythm associated with faintness, low blood pressure, chest pain, difficulty breathing, or loss of consciousness.

  • What to Expext During Procedure:

    An electrical cardioversion is performed in a hospital setting such as an emergency room, intensive care unit, recovery room, special procedure room or Electrophysiology Laboratory. A cardiologist, a nurse and/or an anesthesiologist are present to monitor your breathing, blood pressure and heart rhythm. Special cardioversion pads are placed on your chest and back (or alternatively, both pads can be placed on the front of the chest). The pads are connected to an external defibrillator by a cable. The defibrillator allows the medical team to continuously monitor your heart rhythm and to deliver the electrical shock to restore your heart's rhythm back to normal.

    Since the shock can be painful, an anesthesiologist or specially trained nurse administers intravenous sedation. Once you are asleep (but still breathing on your own), the physician charges the defibrillator to a specified energy level and then delivers the shock by pressing a button on the defibrillator. The shock is transmitted along the cable to the pads on the chest where the energy is delivered across the chest wall to the heart muscle. Additional shocks at higher energy levels can be delivered if the first shock does not restore the rhythm back to normal. Rarely, minor skin redness can occur at the site of the cardioversion pads where the electrical energy was delivered. Patients typically awake quickly without any recollection of the shocks, due to the amnesic effects of the sedatives. Because of residual effects of the anesthetic medications used, patients 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. The anesthetic agents typically used for the procedure are short acting; therefore most patients are able to go home an hour or so after the procedure. A normal heart rhythm can be restored more than 90% of the time, although abnormal rhythms may recur in about half the patients within 1 year. The success of electrical cardioversion often depends on the duration of atrial fibrillation and the underlying cause (heart disease). Cardioversion is not appropriate for every patient with atrial fibrillation.

  • How to Prepare:

    You should have nothing to eat or drink for at least eight hours prior to the procedure. Take your regularly scheduled medications the morning of the procedure unless your medical practitioner has told you otherwise. Your medications should only be taken with enough water to get the tablets down. If you are diabetic, you should discuss your insulin or other diabetes medication dosing with your medical practitioner. Bring a list of all your medications with you. Do not apply any lotions or ointments to your chest or back as this may interfere with the adhesiveness of the shocking pads.

    Most medical centers will not let you drive yourself home after receiving sedation/anesthesia; therefore you should arrange a ride home that day. For the remainder of the day, you should not operate a car, heavy machinery, or make any important decisions. You may experience some minor chest discomfort and/or skin irritation following the procedure. An ointment can be applied to the area to reduce the discomfort.