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Why do I need EPS?

You may have an irregular rhythm or fast heart beats, palpitations, which are making you feel unwell or may have caused you to collapse.

To enable the successful elimination of an abnormal heart rhythm, we must be able to deduce where it comes from. To do this, we must bring on the palpitation or at least be able to map where the source is.

Therefore, in most cases, palpitations must fulfil two main criteria if they are to be treated. They must be sustained (however, in some cases one beat can be enough); and it must be tolerated by the patient for long enough to allow enough time for us to find the source

Pre-procedure assessment & care

If you are an outpatient, you will be invited to attend a pre-assessment appointment approximately 2-3 weeks prior to the test. You will be asked to have some blood tests prior to this appointment. This can be done at your GP surgery, outpatients at Frimley Park, Farnham Hospital or Aldershot Centre for Health. (The form will have been sent to you with your letter confirming your appointment).

The appointment will be with a Cardiac Nurse Specialist who will describe the test, discuss the risks involved and give guidance on preparing for the test, including any required changes to your medication, when to stop eating, and what to bring with you on the day. This clinic is very important for preparing you for the test, and the appointment lasts approximately 30 minutes. Please ensure you are on time for the appointment.

If you take Warfarin or any of the new anticoagulants, you will be given advice for managing your medication before, during, and after the test at your pre-assessment with the Cardiac Nurse Specialist.

If you are diabetic, you will be advised on your medication at this assessment.
Full individual instructions will be given by the nurse in your pre- assessment appointment.

The day before your procedure 

 You must avoid any alcohol for 24 hours before and after the procedure to avoid any bleeding complications.

On the day of your procedure

  • You can have a light meal (i.e. cereals or toast) 2 hours before your procedure time and may continue to have sips of water. You must not have any milky drinks as they are considered a food product and takes longer to digest.
  • UNLESS ADVISED OTHERWISE BY PRE ASSESSMENT NURSE you should take your usual medication (including blood pressure or water tablets) at 6.00am with a small amount of water.
  • Please bring all your medications with you on the day of the test.
  • Please bring your dressing gown and slippers with you, plus anything you may need for an overnight stay.
  • Please remember to bring your reading glasses with you.
  • Avoid bringing any valuables or cash with you, other than small change for a newspaper, as they may be left unattended while you are undergoing your test.

If it is only a day case, you must be collected from the Cardiac Interventional Suite and be driven home after the test as you must not drive yourself on the day of the procedure or the day after.

You may not be able to drive for a week post procedure.
A responsible adult should stay with you overnight.

Visitors

Relatives/ carers are asked to go home after dropping off the patient and come back once the patient is ready for discharge.

The EPS procedure and care

During your admission you will stay in the Cardiac Interventional Suite. You will be asked to put on a gown and paper pants, your details will be checked and a name band placed on both wrists.
The test is performed in a special x-ray room, which looks like a small operating theatre. You will be asked to walk to the x-ray room. If you are unable to walk a wheelchair will be provided. If you wear glasses and would like to watch the screens, please make sure you wear your glasses.

There will be several members of staff in the room during the procedure including a doctor, nurses, a cardiac technician, and a radiographer. You will lie on your back on a special x-ray table, and the radiographer will move the table and camera into different positions so that x-ray pictures can be taken if required.

The test will be undertaken through the groin veins (top of the right and left leg).
The skin around the groin is numbed with a local anaesthetic. Once numb, the doctor will insert a small tube, called a sheath, into the vein. Through this sheath, the wires (electrode catheters) will be inserted to record the electrical activity of the heart and stimulate the heart using very small electrical currents.

If the electrophysiologist can pinpoint exactly where the unwanted electrical impulses are coming from, they may do a catheter ablation treatment at the same time.

Please see page 34 of the British Heart Foundation (BHF) booklet on Heart rhythms, which describes this procedure.

After the procedure – what to expect

The test will take approximately 2 to 3 hours, and you will then be taken back to the Cardiac Interventional Suite. The nurse will remove the catheters from the groin and apply pressure to the area for approximately 10 minutes to stop any bleeding.

You will then rest in bed for approximately 3 hours. You must not bend your leg during this time to avoid bleeding from the groin site. Your foot pulses will be checked to detect any restriction in blood flow to the lower limbs.

Once you are sitting up in bed, you will be provided with a hot drink, a sandwich, and water. If a contrast dye has been used, you will be encouraged to drink plenty of fluids.

You may need to stay overnight.

Results

A doctor will discuss the results of the procedure with you, and you will have the opportunity to ask any questions. The doctor will discuss any changes to your medication or further treatment that may be required. The results of the test will be sent to you in a written report, with a copy going to your GP.

Wound area and care

The site will be covered with a clear dressing, which must be removed after 24 hours. You may have a shower after 24 hours, and it may be easiest to soak the dressing off in the shower. You do not need to replace the dressing. Do not have a bath or use talcum powder for 48 hours.

At first, the groin may feel tender or bruised. A painkiller such as paracetamol may be useful, but do not take aspirin as a painkiller. You may develop a small pea-sized lump. This is normal and should flatten within the next 2-4 weeks. If the lump feels larger than this, it appears to be increasing in size, with the bruising getting darker, harder and painful, or you notice a discharge, you must see your GP urgently. If out of hours, you should contact your local Emergency Department.

If the wound begins to bleed, lie down; then you or the responsible adult should press firmly over the wound area for 10 minutes. It is important to contact your GP or the Cardiac Interventional Suite for further advice or dial 999.

General Information

It is important to avoid constipation, particularly in the first week, as straining can increase pressure around the groin area.
During the first week after your procedure, your activities should be restricted.

You should not do any heavy lifting for the first week to ensure groin vessel recovery. When moving in and out of the car, going up and down stairs, or sneezing, coughing, or laughing, apply gentle pressure to the groin area to help support it and prevent pain.

You may need to take up to a week off work. The cardiac specialist nurse will discuss this with you at your pre-assessment appointment.

Driving

You must not drive on the day of the procedure or for 48 hours afterwards.

Please arrange for a responsible adult to collect you from the Cardiac Interventional Suite, drive you home and stay with you for 24 hours.

On some occasions the Consultant may not wish you to drive for ONE WEEK post procedure.

Flying

The British Cardiovascular Society guidelines state that you can fly after 2 days. However, if you plan to fly within 1 week of the procedure, you should consider yourself at high risk of forming blood clots and talk to your doctor.

Risks of EP Studies/Ablation

To consent to the procedure, you should understand that possible adverse effects and risks are involved. Such as:

  • Bleeding or bruising around the area where the catheter was inserted
  • In 1 in 500 cases the catheter may cause damage to the groin vein, requiring surgical repair
  • Cardiac perforation: In about 1 in 1000 cases a leak of blood occurs into the sac surrounding the heart; this is treated by inserting a small tube next to the breastbone to drain the blood, in 1 in 100 cases.
  • In approximately one percent of cases, ablation damages the normal electrical wiring of the heart, causing a slow heart rate. This would be treated by inserting a Pacemaker.
  • There is a very small risk of stroke with a complex procedure, approximately 1 in a 1000.
  • In a small number of cases patients may find the procedure uncomfortable despite the use of strong painkillers. In these cases, the use of a different form of energy may be used, i.e., cryoablation.

On the day of the procedure your doctor will discuss the procedure, including any other risks, prior to taking your consent.

Alternatives to this procedure/treatment

Other tests such as ECG, Echocardiogram, heart monitors, Reveal Linq Insertable Cardiac Monitor or treadmill ECG are available, but these will not always provide all the information required.

More information can be found at the following websites:

If any problems arise after you have gone home, please contact:

Contact us

If you have any queries relating to this information, please contact the Cardiology service.

About this information

Service:
Cardiology

Reference:
C/021

Approval date:
7 August 2025

Review date:
1 August 2028

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Important note 

This page provides general information only. It is developed by clinical staff and is reviewed regularly every 3 years for accuracy. For personal advice about your health, or if you have any concerns, please speak to your doctor.