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An electrophysiology study is a procedure to diagnose and treat an arrhythmia or irregular heartbeat.

What is a cardiac electrophysiology study and catheter ablation?

A cardiac electrophysiology study is used to investigate what is causing an abnormal heart rhythm. In some people the abnormal heart rhythm may be amenable to treatment, which this is known as catheter ablation.

In many cases, depending on the rhythm problem, these can be performed at the same time. Doctors who specialise in treating people with abnormal heart rhythms (known as Cardiac Electrophysiologists) will be able to advise people whether or not this is something that is suitable for them and worth considering in terms of benefit from the procedure and potential risks.

Is a cardiac electrophysiology study and catheter ablation right for me?

If you are experiencing abnormal heart rhythm (‘arrhythmia’) there may benefit in working out in more detail exactly what the abnormal heart rhythm is and treating it where possible.

What happens during a cardiac electrophysiology study and catheter ablation?

Before the procedure

You will be advised by the team about preparation for the procedure. This may include having blood tests done before the day of the procedure itself. There may be medication that needs to be adjusted or stopped before the procedure. Fasting instructions (when to stop eating food and/or drink) will also be given.

There is nothing else generally that you will need to do in preparation for the procedure but if you have got any questions then please ask the team when they do their pre-assessment checks and interview with you.

During the procedure

A cardiac electrophysiology study, often referred to as an EP study, is normally carried out as a day case procedure, meaning you are usually discharged home later the same day.

It is performed with some sedation to keep the person relaxed but generally does not usually require a general anaesthetic. Local anaesthetic is injected into the groin to numb the skin (top of the leg, sometimes just one side and sometimes both). A small incision made less than a half a centimetre in length, and small tubes inserted mostly into the vein and very occasionally into the artery at the top of the leg(s), a bit like a bigger version of the ones that are in inserted into the hand or arm to give medication or fluid directly into the vein. Through these tubes fine, floppy wires referred to as ‘catheters’ are fed through the tubes, through the veins that run directly to the heart, and into the heart using a small amount of x-ray to guide their path. Once these catheters are in the heart and come into contact with the heart tissue they will record the electrical signals and the team doing the procedure can interpret and work out where the normal rhythm is, and also potentially where any abnormal rhythm is.

Various techniques may be used to try and set off the abnormal rhythm, including pacing the heart and using medications given through the cannula (needle) in your arm. You may experience palpitations and feel much the same as if you were having an arrhythmia episode. These techniques help us to determine any abnormalities in the electrical system within the heart that could be responsible for your symptoms and we are able to control these very precisely during the procedure so you do not need to worry that you will be left feeling very uncomfortable with the arrhythmia whilst this is being done.

If we are able to determine abnormalities, we can then proceed to ablation therapy and use radiofrequency to burn/destroy the abnormal pathway(s) or mechanism(s) that could previously sustain the arrhythmia. In some cases, cryotherapy, or freezing, may be more appropriate in which case that will be used.

The heart is then tested again to check that the arrhythmia can no longer be started.

For some types of heart rhythm abnormality the procedure may be performed preferentially under general anaesthetic and it may not be necessary to actually set off the abnormal rhythm as the area that needs to be ablated is already known. This may be true for atrial fibrillation in many people.

Once finished, the catheters are removed from the groin, manual pressure applied, and you are taken back to the recovery area and then the ward. 

An average EP study and simple ablation takes between 90 and 120 minutes. Some forms of ablation may take longer.

After the procedure

After the procedure you may go to a recovery area for a period of time before returning to your room.

You will be able to eat and drink quite soon after the procedure. After an ablation procedure patients are normally asked to remain lying down for some hours (anywhere between 2 and 4 is quite common) to allow the top of the leg(s) to heal and minimise the risk of bleeding. The team looking after you on the ward will monitor your ECG and the incision sites at the top of the leg(s). When they are happy they will gradually start to sit you up and eventually let you start to walk around. 

It is quite common to experience some discomfort at the top of the leg(s) where the tubes inserted. It is also quite common to experience some chest discomfort after some of the ablations. Neither of these are anything to worry about.

Depending on the type of ablation and type of anaesthetic used you may go home the same day or sometimes the following day. When you are discharged you will be given advice about medication, washing, exercise, and driving.

Recovery from cardiac electrophysiology and ablation

Recovery time depends on what type of ablation has been performed.

The DVLA state that it is illegal to drive for a minimum of 48 hours after an ablation procedure. We will often recommend people do not drive for 1 week.

You can shower the day after the procedure but is recommended not to sit immersed in water for at least 1 to 2 weeks whilst the small incisions in the skin at the top of the leg(s) heal.

Whilst many people will walk out of hospital the same day, we generally recommend that exercise is limited to walking around the house for at least the first 2 or 3 days. After that people can gradually walk slightly longer distances. For most ablation procedures, after a week people can be walking fairly decent distances, but still avoiding very strenuous exercise. Between 1 and 2 weeks after the ablation procedure people can gradually increase the level of exercise such that after 2 weeks people should be able to do any form of exercise or exertion they like.

For some people the problem they had prior to the ablation is effectively cured straight away after the ablation is done. In some there can be a period of time where the heart rhythm can still behave abnormally for up to a few months and then settle. This will again depend on the exact type of ablation procedures performed and will be managed by the team looking after you.

Some medication may be discontinued after the ablation procedure, some will be continued for a period of time, and some may be continued long-term. This will again depend on the individual and the type of ablation performed.


There are some risks and complications that are common to any cardiac electrophysiology study and ablation procedure. These relate to the insertion of the small tubes and catheters into the veins (and possibly arteries) in the legs and include:

  • Bruising
  • Pain - this can normally be managed with some simple pain relief tablets such as paracetamol. Occasionally the pain may be more severe and might need treatment with something stronger
  • Swelling around the puncture site under the skin
  • Damage to the blood vessels at the top of the leg, or bleeding around the heart (known as a pericardial effusion) which may need specific treatment - this occurs in less than 1% of patients
  • Damage to the normal heart rhythm can occur - this may require a pacemaker. In general the risk of this is very low for all ablation treatments. However in some the risk may be slightly higher. Sometimes this risk cannot be very accurately determined until the procedure is performed and the initial electrophysiological testing is done. This aspect will be discussed prior to any procedure and an estimate of risk given.

The risk of serious complications from most ablation procedures such as heart attacks, stroke, or a fatal problem are very low. For many of them the risk is quoted as less than 1 in 2000. For some ablation procedures such as AF ablation the risk of a stroke is slightly higher than that because of the specific nature of how that the ablation is performed, reported as being somewhere between 1 in 500 to 1 in 1000. However multiple precautions are taken to keep that risk and all other risks as low as possible.

Alternative treatment options

There are no specific alternative procedures although the type of procedure may vary from individual to individual. For example there are different ways of performing AF ablation using either heating energy (radiofrequency) or freezing energy (cryoablation). The optimal type of procedure will be determined by the team looking after you.

In many cases the treatment is not being performed because the heart rhythm problem is life-threatening, but mainly for quality of life purposes. It is therefore entirely up to the individual to decide if they want to take the small risks of the procedure to try and improve their quality of life. Some people will opt to use medication alone and not have a procedure done.

It is often performed with ablation to correct an arrhythmia that has not responded to conservative treatment.

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