Electrophysiology Study/Ablation

An Electrophysiology Study (EP Study) is an invasive test to evaluate the electrical functioning of your heart.

At the Mater Private we treat more Electrophysiology and Arrhythmia patients than any other centre in Ireland. Patients are cared for in a dedicated Electrophysiology treatment suite equipped for state-of-the-art diagnostic, ablation and device implantation procedures - available 24 hours a day.

Electrophysiology Study/Ablation

An Electrophysiology Study (EPS) is an invasive test used to evaluate the electrical functioning of your heart.


The procedure involves wires (catheter electrodes) which are passed through a vein in your groin and are carefully placed at specific positions within your heart to record the electrical activity. You will be sedated for this procedure to make you more comfortable. 


This test shows how your heart reacts to extra electrical signals delivered to different areas of your heart.  It gives your Consultant detailed information about the cause of your heart arrhythmia and helps identify the most appropriate treatment for you.  


Once an abnormal pathway is identified, the Doctor will block this pathway by using energy delivered through the wires to create scar tissue.


The creation of scar tissue to block this abnormal pathway is called ablation.

  • An EPS is a catheter technique where flexible wires (catheter electrodes) are passed through a vein in your groin (usually right side) and carefully placed at specific positions with your heart to record the electrical activity. An EPS records how your heart reacts to extra electrical signals (paced beats) delivered within the different areas of the heart. During the study, you might also receive intravenous medication to further stimulate the heart to be able to trigger your abnormal heart rhythm. This allows your consultant to collect detailed information about the cause of your arrhythmia and choose the most appropriate treatment for you. An EPS may be followed by a procedure called catheter ablation to treat the cause of the abnormal rhythm. Catheter ablation might happen at a different procedure later, if the source and complexity of the arrhythmia requires extra preparation before proceeding with ablation. Alternatively, the information gathered during an EPS will allow your consultant to determine which antiarrhythmic drug is the most appropriate to treat your specific condition. During an EPS only a light sedation is applied to make the procedure more comfortable, as too deep sedation might spoil the results. If your consultant decides to perform an ablation at the same stage after discussing this with you, a deeper sedation or general anaesthesia will be given to prevent any discomfort during the procedure.

  • The results of your EPS may show that you have an area within the heart capable of generating/conducting abnormal electrical beats. In such cases it is possible with a procedure known as a Catheter Ablation to permanently interrupt this abnormal rhythm and to provide a potentially permanent cure for your arrhythmia. This is achieved by delivering energy through a catheter positioned in the area of the abnormal signal to cauterise the cardiac tissue there. Depending on your specific arrhythmia, your Consultant might need to enter the left side of your heart either by puncturing your artery or the septum of the upper chambers of the heart. Your consultant will use the ablation catheter to deliver a small amount of energy (hot or cold) onto the area of extra electrical activity to create a scar.

    In many cases it is possible to proceed to the ablation procedure immediately following the EPS. The doctor will discuss the results of the EPS with you and the possibility of proceeding if appropriate.  Patients undergoing ablation stay in hospital overnight after the procedure during which time your heart rhythm will be monitored.

    • You will be required to fast for 6 hours prior to your procedure, unless you are told otherwise.
    • If you are female you must inform the staff if there is any chance you may be pregnant.
    • You must arrange to be collected on discharge, as you are not allowed to drive or travel home unaccompanied.
    • If a catheter ablation needs to be performed you will require an overnight stay. Your doctor will discuss this at the time with you
    • When arranging your appointment, please tell us about any medication you are taking and discuss any instructions with your doctor.
    • If you are on heart rhythm medications you may be told to stop them for 3–4 days before. Your doctor will discuss this with you.
    • Unless your doctor tells you differently, medications should be taken as usual.
    • If you are taking a blood thinner, you should skip taking this on the morning of the procedure.  If you are taking Warfarin you should ask your doctor about stopping it.
    • Please inform the staff if you are aware of any allergies, as you might receive medication during the procedure
    • In general you do not need to be put asleep for this procedure.
    • You will receive some sedation, which will be given through a drip in your arm to help you relax.
    • A local anaesthetic is applied to the top of the leg/groin area – both sides may be used.
    • Once the area is numb, a puncture is made through which a needle is inserted into a blood vessel.
    • A catheter is passed through a sheath and gently advanced through the blood vessel to the heart. These special wires will record the electrical signals from inside your heart
    • Once the catheters are in place your consultant will attempt to start your arrhythmia by giving your heart small electrical impulses to make it beat at different speeds.
    • During the test you may be aware of your heart rate speeding up, slowing down and missing a beat.
    • This allows the doctor to collect detailed information about the cause of your arrhythmia and pinpoint where the area of extra electrical activity responsible for your arrhythmia is within your heart.
    • If the test initiates the abnormal heart rhythm, you may feel the symptoms that you have been complaining of.
    • During the procedure you may be given a special drug through a drip which also helps to stimulate your abnormal fast heart rhythm. The doctor can terminate the tachycardia by using pacing.
    • In the very unlikely event of a dangerous, life-threatening heart rhythm occurring, it may be necessary to give you an external defibrillation shock. If you need this treatment your consultant will give you more sedation.

    If you do have any uncomfortable symptoms during the procedure, for example chest pain, dizziness or shortness of breath, please inform the nurse. It is important for your consultant to know how you feel when you have your arrhythmia

    • Strict bed rest is required for 4–6 hours after the completion of the study.
    • You will be asked to limit leg movement on the puncture site(s) to reduce the risk of bleeding.
    • The nurse will inspect the puncture site to ensure there is no bleeding.
    • You may go home after 4 to 6 hours or as directed by the Consultant.
    • The Catheter Ablation will add an additional time to your procedure and you will be advised to stay in the Hospital for the night
    • If you had a Catheter Ablation, you are restricted from driving for 2 days following your procedure as per the Medical Fitness to Drive Guidelines by the Road Safety Authority.
  • Risks may vary according to the need of ablation therapy and to the actual type of arrhythmia. A diagnostic EP study itself carries a very low risk.

    The procedure is a simple and safe procedure and is usually relatively painless though minor discomfort such as the following may occur:

    • Possible discomfort when injecting local anaesthetic.
    • Bruising, mild soreness or mild oozing from the puncture site(s).
    • Usually there is some bruising around the puncture site following the procedure.
    • If bleeding, a pressure dressing may be placed on the wound to stop it. Very rarely the wound may need to be reopened to remove collected blood and treat the source of bleeding.
    • Possible reaction to medications administered.

    Very rare complications occur in less than 1-in-500 cases:

    • Infection of blood, heart valve or puncture site.
    • Pseudo aneurysm or arterio-venous fistula
    • Phrenic nerve injury
    • Damage to the blood vessels that might need surgical correction.
    • Aortic Dissection
    • Deep venous thrombosis
    • Bleeding around the heart (Cardiac Tamponade) requiring emergency corrective surgery.
    • Damage to the normal electrical pathway may occur requiring placement of a permanent pacemaker

    Extremely rare complications occurring in less than 1-in-1,000 cases:

    • Heart attack
    • Pulmonary Embolus
    • Stroke
    • Death