The purpose of the electrical system of the heart is to coordinate the pumping of the four chambers of the heart and to control the heart rate so that the heart speeds up and slows down as the demands of the body change. The Sinoatrial (SA) node starts the electrical signal. The electrical signal then travels through the atria (or upper chambers of the heart) causing them to contract. Then the electrical signal passes through the AV node, the bundle of His, and bundle branches and then out to the muscle fibers of the ventricles. As the impulse spreads, the muscles contract and the ventricles pump out blood to the rest of the body.

To perform an electrophysiology study, three to five electrically sensitive catheters or tubes are temporarily placed in through the veins in the groin into the heart to record the electrical activity of the heart. These recordings locate abnormal tissue that causes irregularities in the heartbeat (arrhythmias).