An intravenous line (IV) will be started for fluids and medications. Electrodes (adhesive stickers) will be placed on your chest to monitor your EKG (heart rate and rhythm) throughout the procedure. You will be given a medication through your IV that will make you drowsy but will not put you to sleep. A local anesthetic will be injected into the groin to numb the area where the doctor will insert catheters (a narrow, flexible tube) into the vein. Once the catheters reach the heart, they can sense the electrical activity and be used to evaluate your heart’s conduction system.