Heart Disease Health Center

An electrophysiology study, or EP study, is a test to see if there is a problem with your heartbeat (heart rhythm) and to find out how to fix it.

In this test, the doctor inserts one or more flexible tubes, called catheters, into veins in your groin, arm, or neck. Then he or she threads these catheters into the heart. At the tip of these catheters are electrodes, which are small pieces of metal that conduct electricity. The electrodes collect information about your heart's electrical activity. Your doctor can tell what kind of heart rhythm problems you have and where those problems are.

Sometimes the problem can be fixed at the same time. A procedure called catheter ablation uses the catheters to destroy (ablate) small areas of your heart that are causing the problem.

Heart Problems: Should I Have Catheter Ablation?

Health Tools

Health Tools help you make wise health decisions or take action to improve your health.

Decision Points focus on key medical care decisions that are important to many health problems.

Why It Is Done

An electrophysiology study is used to:

• Identify heart rhythm problems.
• See how well heart rhythm medicines work for you.
• Check your heart before you have a pacemaker or an ICD (implantable cardioverter-defibrillator) implanted.
• Treat certain problems with catheter ablation.

How To Prepare

Tell your doctor if you:

• Are allergic to any medicines, including iodine, or to latex.
• Have any bleeding problems or take blood-thinning medicine (anticoagulants), including any nonsteroidal anti-inflammatory drugs (NSAIDs) like aspirin or ibuprofen.
• Are or might be pregnant.
• Have diabetes.
• Have ever had clots in your legs, groin, or pelvis.
• Have a filter in a large vein to prevent clots from traveling to the heart.

Talk to your doctor about any concerns you have about the need for the test, its risks, how it will be done, or what the results will show. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).

Tell your doctors all the medicines, vitamins, supplements, and herbal remedies you take. Some of these can increase the risk of bleeding or interact with anesthesia. Your doctor will tell you which medicines to take or stop before your procedure.

If you take blood-thinning medicine, be sure to talk to your doctor. He or she will tell you if you should stop taking this medicine before your procedure. Make sure that you understand exactly what your doctor wants you to do.

Arrange for someone to take you home after the test. You may not have to stay in the hospital overnight.

Do not eat or drink (except for a small amount of water) for a few hours before the test. If you are taking any medicines, ask your doctor if you should take them on the day of the test.

Take off any nail polish. That will make it easier for doctors and nurses to check the circulation in your fingers and toes.

Be sure to empty your bladder completely just before the test.