Electrophysiological (EP) studies

Electrophysiological (EP) studies allow the heart's electrical activity to be analysed in great detail.

This test has revolutionised the way we understand and treat fast or abnormal heart rhythms.

However, at the moment it is only available at some hospitals in the UK.

How is an EP study done?

• The test usually takes about 2-3 hours, but can sometimes take longer.
• The hospital will ask you not to eat or drink anything for a few hours beforehand.
• Thin flexible tubes, called catheters, are placed into a vein, usually in the groin. You will have a local anaesthetic injection which numbs the area where the catheters are put in. You may also be given sedation to help relax you during the procedure.
• 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 position in 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. You should tell the staff if you experience any symptoms.
• 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 happens after the test?

When the test is over, the catheters are removed. Sometimes there may be a small amount of bleeding when they are taken out. A nurse or doctor will press on the area for a short while to stop any bleeding.

You will be asked to stay in bed for a while afterwards.

The test is sometimes done as a day case. However, most people will need to stay in hospital overnight.

You may feel tired afterwards, but you should feel back to normal within a few days.

What can the test show?

During the test, you are continuously monitored with an ECG. This can help to diagnose abnormal heart rhythms and to identify which areas of your heart are affected. 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.

Are there any risks?

An EP study does involve a very small amount of risk. Your doctor will explain this to you before you give your consent to have the test.

If there is bleeding from the area that the catheter was placed in, you might develop a collection of blood under the skin, which is called a haematoma. It can be uncomfortable and cause bruising, but this should go down after a few days. However, contact your doctor if you have any concerns.

There is a small risk of damage to the heart's normal electrical pathways. If this happens, you may need to be fitted with an artificial pacemaker.

Your doctor will not recommend that you have an EP study unless he or she thinks the benefits outweigh the risks.