An electrophysiological study (EP study) is a test used to evaluate your heart’s electrical system and to check for abnormal heart rhythms.

Natural electrical impulses coordinate contractions of the different parts of the heart. This helps keep blood flowing the way it should. This movement of the heart creates the heartbeat, or heart rhythm.

During an EP study, your doctor inserts small, thin wire electrodes into a vein in the groin (or neck, in some cases). He or she will then thread the wire electrodes through the vein and into the heart. To do this, he or she uses a special type of X-ray “movie,” called fluoroscopy. Once in the heart, the electrodes measures the heart’s electrical signals. Electrical signals are also sent through the electrodes to stimulate the heart tissue to try to cause the abnormal heart rhythm. This is done so that it can be evaluated and its cause can be found. It may also be done to help evaluate how well a medicine is working.