Wires are placed in the epicardium and brought out onto the patient’s chest wall with atrial wires on the right and ventricular wires on the left. Pacing can comprise two right atrial wires (AOO or AAI), two right ventricular wires (VVI) or four atrioventricular wires (DDD or DVI) depending on the underlying rhythm. Mal-functioning pacing wires can trigger ventricular tachycardia (VT) or ventricular fibrillation (VF) and should always be set in the demand mode to avoid pacing on a T wave. If full recovery of conduction does not occur then a permanent pacemaker will be needed.