Dr Simon Kennon MB ChB, FRCP, MD Consultant Cardiologist

EP Study

An electrophysiology (EP) study, is a test to see if there is a problem with your heart beat/rhythm.

In this test, the doctor inserts one or more flexible tubes (catheters)q, into veins in your groin, arm, or neck and feeds them into the heart. At the tip of the catheters are electrodes (small pieces of metal) that conduct electricity and collect information about your heart's electrical activity. This information can confirm heart rhythm problems and their location.

The procedure

The test usually takes about 2-3 hours and you will be asked to abstain from eating or drinking for a few hours beforehand. A local anaesthetic injection will numb the area where the catheters are inserted which is usually in the groin and you may also be given sedation to help you relax.

As the tubes are inserted, you may feel a sensation or discomfort in your chest, but this should not be painful. The catheters are gently moved into the heart, where the special electrode tip stimulates the heart and records the electrical activity. This may make you feel as if you are having palpitations and can make some people feel dizzy.

Abnormal heart rhythms often happen during the test. These can help with the results of the test but occasionally may need to be treated during the EP study.

What can the test show?

The electrodes send information to a computer which uses the information to draw pictures of your heart and its rhythm problems to show the doctor exactly where the problem areas are located.

If you have an abnormal heart rhythm, the test can also show if it is being controlled effectively with certain medicines. If the cause of your abnormal heart rhythm is found, the doctor may be able to treat the problem during the test by using radio frequency electrical energy to destroy the areas inside the heart which are causing the abnormal rhythm. This is called catheter ablation.


An EP study is considered safe. The more common complications are minor and include bleeding or bruising where the catheters were placed.

Serious complications are rare but include extra bleeding after the test, puncture of the heart, and damage to the electrical system of the heart that requires a pacemaker.