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    Intracardiac electrophysiology study (EPS)

    Electrophysiology study - intracardiac; EPS - intracardiac

    Intracardiac electrophysiology study (EPS) is a test to look at how well the heart’s electrical signals are working. It is used to check for abnormal heartbeats or heart rhythms.

    How the Test is Performed

    Wire electrodes are placed in the heart to do this test. These electrodes measure electrical activity in the heart.

    The procedure is done in a hospital laboratory. The staff will includea cardiologist, technicians, and nurses.

    To have this study:

    • Your groin or neck area will becleanedand numbing medicine (anesthetic) will be applied to the skin.
    • The cardiologist will then place several IVs (called sheaths) into the groin or neck area. Once these IVs are in place, wires or electrodes can be passed through thesheaths into your body.
    • The doctor uses moving x-ray images to guide the catheter into the heart and place the electrodes in the right places.
    • The electrodes pick up the heart's electrical signals.
    • Electrical signals from the electrodes may be used to make the heart skip beats or produce an abnormal heart rhythm. This can help the doctor understand more about what is causing the abnormal heart rhythm or where in the heart it is starting.
    • You may also begivenmedicines may also be used for the same purpose.

    Other procedures that may also be done during the test:

    • Placement of a heart pacemaker
    • Procedure to destroy small areas in your heart that may be causing your heart rhythm problems (called catheter ablation)

    How to Prepare for the Test

    You will be told not toeat or drink for 6 - 8 hours before the test.

    You will wear a hospital gown. You must sign a consent form for the procedure.

    Your health care provider will tell you ahead of time if you need to make changes to the medicines you regularly take. Do not stop taking or change any medicines without first talking to your health care provider.

    In most cases, you will be given medicine to help you feel calm before the procedure. The study can last from 1 hour up to several hours. You may not be able to drive home afterward so you should plan for someone to drive you.

    How the Test Will Feel

    You will be awake during the test. You may feel some discomfort when the IV is placed into your arm. You may also feel some pressure at the site when the catheter is inserted. You may feel your heart skipping beats or racing at times.

    Why the Test is Performed

    Your doctor may order this test if you have signs of an abnormal heart rhythm (arrhythmia).

    You may need to have other tests before this study is done.

    An EPS may be done to:

    • Test the function of your heart's electrical system
    • Pinpoint a known abnormal heart rhythm (arrhythmia) that is starting in the heart, and help decide the best therapy for it
    • Determine whether you are at risk for future heart events, especially sudden cardiac death
    • See if medicine is controlling an abnormal heart rhythm
    • See whether you need a pacemaker or implantable cardioverter-defibrillator (ICD)

    What Abnormal Results Mean

    Abnormal results may be due to abnormal heart rhythms that are too slow or too fast. These may include:

    • Atrial fibrillation or flutter
    • Heart block
    • Sick sinus syndrome
    • Supraventricular tachycardia (a collection of abnormal heart rhythms that start in the upper chambers of the heart)
    • Ventricular fibrillation and ventricular tachycardia
    • Wolff-Parkinson-White syndrome

    There may also be causes that are not on this list.

    The health care provider must find the location and type of heart rhythm problem in order to determine the proper treatment.


    The procedure is very safe in most cases. Possible risks include:

    • Arrhythmias
    • Bleeding
    • Blood clots that lead to embolism
    • Cardiac tamponade
    • Heart attack
    • Infection
    • Injury to the vein
    • Low blood pressure
    • Stroke


    Miller JM, Zipes DP. Diagnosis of cardiac arrhythmias. In: Bonow RO, Mann DL, Zipes DP, Libby P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 36.

    Olgin JE. Approach to the patient with suspected arrhythmia. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 62.


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    Tests for Intracardiac electrophysiology study (EPS)

    Review Date: 5/3/2013

    Reviewed By: Michael A. Chen, MD, PhD, Assistant Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, Washington Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, Bethanne Black, Stephanie Slon, and Nissi Wang.

    The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

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