THERAPEUTIC PROCEDURES << BACK Cardioversion Cardioversion uses a precisely timed electrical shock to disrupt abnormal electrical circuits in the heart and to restore a normal heartbeat. The procedure delivers the electric shock through the chest wall to the heart through special electrodes or paddles that are applied to the skin of the chest and back. The shock causes all the heart cells to contract simultaneously, interrupting the abnormal electrical rhythm without damaging the heart. The interruption allows the heart's electrical system to restore a normal heartbeat. Cardioversion requires sedation. During the procedure, a cardiologist, a nurse and/or an anesthesiologist are present to monitor the patient's breathing, blood pressure and heart rhythm. Special cardioversion pads are placed on the chest and back (sometimes both pads can be placed on the front of the chest). The pads are connected to an external defibrillator, by which the medical team can monitor the heart rhythm. The defibrillator is also used to deliver the electrical shock to restore the heart's normal rhythm. Because of the anesthesia, patients should not operate a motor vehicle for the rest of the day. Most patients may go home an hour or so after the procedure. There is a risk that blood clots may form, or that a blood clot could dislodge, potentially causing a heart attack or stroke. Often a blood thinner will be used before cardioversion to lower this risk.