Intracardiac Electrophysiology Studies (EPS)


Electrophysiology studies, or EPS, use cardiac catheterization techniques to study patients who have irregular heartbeats (called arrhythmias).  EPS shows how the heart reacts to controlled electrical signals.  These signals can help doctors find out where in the heart the arrhythmia starts and what medicines will work to stop it.  EPS can also help doctors know what other catheter techniques can be used to stop the arrhythmia, for example, ablation procedures.


EPS use electrical signals to help doctors find out what kind of arrhythmia you have and what can be done to prevent or control it.  Doctors will perform a cardiac catheterization procedure in which a long, thin tube (called a catheter) will be put into a vein in your leg and threaded into your heart.  This catheter can be used to send the electrical signals into your heart.

Stimulating the heart will cause an arrhythmia, and doctors can record where in the heart it started.  In some cases, you might be given a medicine to cause an arrhythmia.  Certain medicines can also be given through the catheter to see which ones will stop the arrhythmia.


You will most likely have blood tests and an electrocardiogram taken before the procedure. These are performed in a hospital outpatient setting 

Once you are in the catheterization laboratory (also called the cath lab), you will see television monitors, heart monitors, and blood pressure machines.  You will be asked to lie down on a table.  Electrodes will be placed on your chest.  These electrodes have wires called leads, which hook up to an electrocardiogram machine.  This machine will monitor your heart rhythm during the test.

To prevent infection, you will be shaved and cleansed around the area of your leg where the catheter will be inserted.  A needle with a tube connected to it will be put in your arm.  This is called an intravenous line or IV.  A mild sedative will inject through the IV to relax you throughout the test.

You will be given an anesthetic medicine with a needle to numb the area around where the catheter will be inserted and may feel mild discomfort. Once doctors access the vein catheter is inserted into the vein in your leg.  You should not feel pain during this part of the test.

The catheter is gently threaded through the vein and into your heart.  Once the catheter is in place, doctors will give your heart small electrical impulses to make it beat at different speeds.  You will be able to feel your heartbeat changing speeds, and this may cause mild discomfort.  After the doctors have the information they need, the catheter and IV will be removed.  Firm pressure will be applied to the site where the catheter was inserted to stop any bleeding and you will also be bandaged.

After the procedure, staff will move you to another room where you will need to rest for a few hours.  You may feel a little sleepy until the sedative has worn off.  You should try to lie still and not bend your knee too much.  Nurses will watch you to see that your heart rate and blood pressure are normal.

After this time of rest, you will be able to go home.