Electrophysiology (EP) study: An EP study is a way to evaluate your heart’s conduction system. This is done by watching the heart rate and rhythm for any abnormalities. EP studies reproduce your symptoms or rhythm disturbances under controlled circumstances. This allows your physician to analyze your heart’s conduction system further and to decide the best way to treat your problem. The care before and after an EP study is similar to that of the cardiac catheterization; both are invasive procedures, and performed under mild sedation. Once a catheter is accurately positioned in each area being tested, the procedure will begin. During the procedure, tiny electrodes at the tip of the catheters will record the electrical impulses within your heart. The physician will be pacing your heart at different rates and rhythms making recordings called intracardiac electrograms.