An electrophysiology study (EPS) tests your heart’s electrical activity to help your doctor learn more about an arrhythmia. During this test, you’ll be given a mild sedative to help you relax and a local anesthetic to numb the part of the body being worked on. Your doctor will insert a sheath into an artery or vein and use it to guide several specialized catheters (long, thin, flexible tubes) to your heart. Small electrical pulses will be sent through the catheter to make your heart beat at different speeds, which will help your doctor locate where arrhythmias are starting in your heart. An EPS can take 1 to 4 hours to complete.