Electrophysiologic Study (EPS)
The information on this page is for patients who are having an electrophysiologic study for the heart known as an EPS. It explains what the examination is for, what is involved and any significant risks that there may be.

What is an Electrophysiologic Study for?
It is an examination to identify the causes of abnormal heart rhythms in patients who have palpitations, blackouts or dizzy spells. It is often used for patients who have abnormally fast heart rhythms. An EPS may be followed by treatment of the problem, using 'catheter ablation'; see Catheter Ablation.

What preparation do I need?
Your specialist doctor may want you to stop taking certain drugs that regulate the heart beat, sometime before your examination.
If you take warfarin tablets they must be stopped some days (usually 2-3) days before the test.
If you have diabetes do not take your insulin or diabetic tablets on the morning of the test. Please check with you GP if you are worried.
If there is any possibility of you being pregnant x-ray examination is not advised.
You may be asked to shave both groins before the test. You will be given instructions to stop eating and drinking a number of hours before the examination.

On the day of the EPS
Usually you will come into hospital the day of the procedure. But if catheter ablation is needed, this may mean a stay overnight so is best to come prepared with an overnight bag.
A specialist doctor will explain the examination and ask you to sign a consent form that you understand the procedure and agree to go ahead with it. (This may be done earlier at a pre-asssessment clinic).
You will be given a hospital gown to change into. A nurse will take you to the cardiac suite where you will have the procedure.

What does it involve?
It involves identifying the short circuit within the heart that is interfering with the control of the normal heart beat. You will be lying on a table, mounted above is an x-ray machine. Fine wires (catheters) are passed into a blood vessel in your groin. This will not be painful (you will have a local anaesthetic first to numb the area) although you may be aware of the pressure in the groin. The doctor guides the catheters into your heart using the x-ray screen monitor, and positions them to make electrical recordings. Mild electrical stimuli are given to the heart to find out where the short curcuit is occuring. This involves starting off your palpitations. These palpitations can almost always be started and stopped by your doctor and will not be allowed to continue for long periods. Very occasionally it may be necessary to stop the palpitations with an electric shock; in this case you may have sedation or a brief general anaesthetic so that you are unaware of the shock. Once the area of the short-circuit has been indentified the doctor will explain the results of the EPS, and the decision can then be made whether to go ahead and treat the condition with a catheter ablation or to stop the examination at this point and remove the catheters.

After the examination
When the catheters are removed, the doctor or nurse will stop any bleeding from the grion by pressing on the site for a few minutes, a bandage will be applied. You will then go back to the ward and stay in bed for a few hours to make sure that the bleeding stops. You will then be given pain killers if you need them, please ask. After more time out of bed and moving around, you should be able to go home.

Going Home
Please ask a friend or relative to collect you and accompany home. You should take it easy for the first 24 hours. You can take your normal pain killers if you experience any pain from the bruising around the groin site. You will be advised about taking any other medication. You can bathe after 24 hours. You can go back to work 1 - 2 days after the procedure.

What are the risks?
Generally this is a very safe examination. The chance of staying in hospital longer than expected due to complications is less than 1%. How ever, the risk of complications may vary a little for different cardiac hospitals.
With an EPS, there is some risk off bleeding or brusing around the groin site where the catheters were inserted. This can be made worse if you are on anti-clotting drugs. The is a tiny risk of a small tear of the heart or lungs.
For some patients the risks may be higher, please speek to your consultant before youyr operation if you have any worries.