The Electrophysiology (EP) Study Procedure

Electrophysiology ProgramTo begin your electrophysiology (EP) study at University of Wisconsin Hospital and Clinics, you will be asked to lie down on an examination table and electrodes will be placed on your chest. These electrodes have wires that are connected to an electrocardiogram machine, which monitors your heart rhythm during the test.


As an infection precaution, you will be shaved and cleansed around the area where the thin catheter tubes will be inserted, usually at the groin or neck area. You will receive a mild sedative through an intravenous line (IV) in your arm, which will help you relax during the test.


To get inside the heart, EP catheters will be gently threaded into and through large veins accessible at the groin or neck. First, a small puncture is made in order to access the vein and a guide wire is inserted into the vein. A catheter sheath, essentially a hollow tube, is then guided over the wire. Thin catheters can then be inserted into the hollow sheath. Once in the vein, the catheters can be steered into the heart with the help of x-rays displayed on a monitor.


Observing Your Arrhythmia


Each catheter includes multiple electrodes, which send electrical signals to your heart to make it beat at different speeds. This is called pacing, which can be used by doctors to induce an arrhythmia in the heart. Watching and recording an arrhythmia can help doctors find areas that contribute to the problem and to address those areas if necessary. When the observation is finished, another pacing signal will be sent to the heart so that it resumes its normal rhythm.




If a patient undergoing an EP test is awake, the person may be asked to report any symptoms or sensations they feel during the arrhythmia. However, most of the time, patients are heavily sedated and asleep during the procedure.