AF Ablation

In this procedure, heating energy (radiofrequency ablation) is used to get rid of the triggers that cause AF. In some cases freezing energy is delivered instead (cryoballoon). The triggers that cause AF usually come from the pulmonary veins (tubes that drain blood from the lungs to the heart). The aim of the procedure is to create an electrical barrier (like a road block) so that the electrical triggers can’t get out of the pulmonary veins to start up AF (see below). This procedure is called Pulmonary Vein Isolation (PVI). In some cases of AF ablation is performed in other areas of the heart.

No, it doesn’t. Current technology allows this treatment to be delivered simply via tubes placed into veins at the top of the leg. In some cases, the procedure is performed under local anaesthesia and sedation. In other cases a general anaesthetic is used. Patients are on their feet after a few hours, and go home the following day.

Success rates published in medical literature vary from 70-80% for a single procedure. Around 1 in 3 patients may need more than one ablation procedure. Success rates are lower in patients who are at a more advanced stage of the disease, i.e., persistent rather than paroxysmal AF.

During ablation strong blood-thinning drugs are used to prevent a clot from forming in the heart. This increases the risk of bleeding in the leg and around the heart. These are the commonest complications of the procedure, occurring in 1-2% of patients. These are seldom life threatening. Stroke can occur in between 0.5-1% of patients. Other rarer complications include damage to the nerve supplying the breathing muscle (phrenic nerve), blood clot in legs or lungs, heart attack, narrowing of the pulmonary veins, formation of a connection between the heart and the gullet, and the need for a permanent pacemaker. There is a procedural mortality of about 1 in 1000. Other unexpected complications can rarely occur.

AF ablation should only be performed when a patient understands the risks, benefits and alternatives to the procedure

Advances in treatment have allowed ablation therapy to be used for a wide range of AF patients. However, there are characteristics that markedly reduce the chance of success with ablation therapy. These include severe obesity (Body mass index >40), very long duration of persistent AF (longer than 2-3 years) or a very large size of the left atrium (>5.0-5.5 cm). If more than one of these adverse factors are present then the chance of success with ablation is much lower.

The duration of AF has very little bearing on the success of ablation for your atrial fibrillation if it is still in the intermittent/ paroxysmal stage, then. However, if your AF is already at the more advanced stage of continuous/persistent AF, the results of AF ablation will be poorer particularly if you’ve been in this stage for more than 2-3 years. There are other factors that determine the chances of success in these cases of ‘long standing persistent atrial fibrillation’ which are best assessed by a heart rhythm expert.

If you are on Warfarin, this is usually continued for the procedure. In many patients a CT scan or MRI will be arranged prior to ablation to evaluate the anatomy of the heart.  A TOE (Transesophageal Echocardiogram) is performed before the ablation to rule out a pre-existing heart clot in most patients. The ablation procedure usually takes 2 to 3 hours and can be performed under sedation but is often performed under general anaesthesia. Patients stay in hospital the night of the procedure and go home the following morning.

It is best to ‘take it easy’ for a week after the procedure. This involves not returning to active full time work. This is mainly to allow the groin site to heal properly.  It is not unusual for AF to occur during the first few weeks post-ablation and this does not necessarily indicate a procedure failure. Most patients find that these AF episodes subside with time as the positive effects of the ablation settle in. The full benefit of the ablation procedure may not be realised until up to 3 months following the procedure. Some patients become more aware of normal ectopic (missed or extra) beats following ablation. This increased awareness usually improves with the passage of time.