Atrial Fibrillation Ablation

Procedure

What Happens During The Ablation Procedure?

You will usually be admitted to hospital on the day of your procedure. You will be required to fast for at least six hours before the procedure. Prior to the procedure you will be required to have an ECG. Once in the Electrophysiology Laboratory (EP lab) you will be given a light sedative and your groin will be shaved. The EP lab has a patient table, X-Ray tube, ECG monitors and various equipment. The staff in the lab will all be dressed in hospital theatre clothes. Many ECG monitoring electrodes will be attached to your chest area and patches to your chest and back. These patches may momentarily feel cool on your skin.

A nurse or doctor will insert an intravenous line usually into the back of your hand. This is needed as a reliable way to give you medications during the procedure without further injections. You will also be given further sedation if and as required. You will also have a blood-pressure cuff attached to your arm that will automatically inflate at various times throughout the procedure. The oxygen level of your blood will also be measured during the EP study and a small plastic device will be fitted on your finger for this purpose. Your groin area and possibly your neck will be washed with an antiseptic cleansing liquid and you will be covered with sterile sheets leaving these areas exposed.

In general, the ablation procedure is performed under conscious sedation. There are many advantages to this as it allows evaluation for the presence of rare complications such as stroke (which is crucial to detect as early as possible). However, it means that we must adjust the degree of pain relief and sedation based on how you are feeling. A nurse will be checking with you on the degree of discomfort that you may be experiencing. It is important that you mention any discomfort to them. Occasionally, for medical reasons or at your preference, the procedure is performed under general anaesthesia. This will be discussed with you before the procedure.

If the procedure is performed under local anaesthetic, the doctor will inject the anaesthetic to the area in the groin where the catheters are to be placed. After that, you may feel pressure as the doctor inserts the catheters but you should not feel pain. If there is any discomfort you should tell the nursing staff so that more local anaesthetic and sedative medication can be given. Occasionally it is also necessary to place a catheter in a vein in the side of the neck.

The catheters are positioned in your heart using X-Ray guidance. Once the catheters are in place you may feel your heart being stimulated and usually your abnormal heart rhythm will be induced. Radiofrequency ablation will be applied to the regions discussed above.

The duration of the procedure is quite variable. In general, pulmonary vein isolation takes between 1 and 3 hours while additional ablation will prolong the procedure further. In cases of permanent AF this may be considerably longer.

What Is The Success Rate of The Procedure?

The success rates of ablation are variably described around the world. In general, the success rate of the procedure at present is approximately 70% having no arrhythmia and without using antiarrhythmic drugs at 12 months after the procedure. These figures are much better in patients with short episodes of atrial fibrillation and normal hearts where it is between 85% and 90% and slightly worse in patients with permanent atrial fibrillation. It should be noted that approximately 1/3 of patients will require more than 1 ablation session and this improves the success further. This is either because there is recovery of previously ablated regions or that a crucial region was not ablated during the previous session. We will not know for certain whether the procedure has been successful until several months afterwards.

Sometimes it is necessary to perform a second or more procedures in order to cure the problem. This will obviously be decided later on after further discussion with you.

Ablation of paroxysmal atrial fibrillation has been undertaken in its current form since 2000. The group that pioneered the techniques has only presented long-term data out to 5 years. This data suggests that if you remain without any arrhythmia over the first 12 months you had a good chance of remaining in normal rhythm at 5 years.

To date there have been two studies that have suggested that this procedure improves survival compared to using medications. These studies need to be interpreted with caution in that they were both single centre experiences and were not randomised study designs. Similarly, there has been no data on stroke risk reduction after an ablation procedure. The cessation of warfarin will be discussed on an individual basis with you after the procedure. With this in mind, the decision to undertake atrial fibrillation ablation is primarily for symptom control.


  • Professor Sanders says...

     
    Atrial fibrillation is a consequence of several reversible risk factors - high blood pressure, diabetes, obesity, sleep apnoea, and excessive alcohol. Your management of atrial fibrillation must include strict control of these risk factors.