Electrophysiology Studies

Electrophysiology studies (EPS) use cardiac catheterization access techniques to study the electrical activity of the heart and to treat patients with irregular heartbeats (called arrhythmias). EPS allows doctors to see how the heart reacts to controlled electrical signals and to determine the cause, anatomic origin, and best treatment for a given arrhythmia. During the test, the doctor may safely reproduce the arrhythmia and then give the patient different medications to see which best control it.

How It Works

Doctors use EPS to fully diagnose and treat arrhythmias. Doctors perform EPS in the cardiac catheterization laboratory, and catheter access is used as the conduit to send electrical signals into the heart. Stimulating the heart through the catheter to cause an arrhythmia allows the doctor to discover its anatomic origin and location in the heart. In some cases, a patient might be given medicine to cause the arrhythmia. Treatment medicines are then given to determine which ones will stop the arrhythmia.

What To Expect Before the Test

Patients receive protocols from their doctors regarding eating and drinking prior to the test and regarding taking medication before the test, including insulin. As with most hospital procedures, patients should bring their list of medicines along. EPS patients may also have blood tests, an electrocardiogram, and a chest x-ray before the procedure.

What To Expect During the Test

In the catheterization laboratory (also called the cath lab), the patient sees television monitors, heart monitors, and blood pressure machines and lies on an examination table. Electrodes, leads, and various monitors are placed on the patient. The catheter insertion area on the patient’s leg is prepped. An intravenous line, or IV, is inserted in the patient’s arm into which a mild sedative is administered throughout the test.

Doctors place a catheter into the leg artery and gently thread up and into the heart. After the catheter is in place, the EPS begin. The doctor uses a pacemaker to give the patient’s heart small electrical impulses to make it beat at different speeds. The patient is able to feel the heartbeat changing speeds, and this may cause some mild discomfort. The patient should tell the doctors and nurses about any such symptoms. If the arrhythmia occurs, the doctor may administer medications through the IV to test their effectiveness in treating it. If necessary, a small amount of energy may be delivered to the chest patches to restore a normal heart rhythm. EPS last two to four hours.

What To Expect After the Test

The patient is moved to a recovery room and may feel drowsy until the sedative wears off. The patient will follow the doctor’s rest and recovery protocol. Those who are able to go home afterwards should have a companion to drive them.


Texas Heart Institute www.texasheartinstitute.com/HIC/Topics/Diag/dieps.cfm
The Cleveland Clinic www.clevelandclinic.org/heartcenter/pub/guide/tests/invasive/ep.htm