ATRIAL FIBRILLATION ABLATION

This is an invasive procedure performed on patients with atrial fibrillation if the attending cardiologist, taking into account the particular characteristics of each patient, decides to follow a rhythm control strategy.

Atrial fibrillation ablation is often referred to as pulmonary vein isolation (PVI). To perform this, a peripheral vein stem (femoral vein) is punctured. The invasive electrophysiologist subsequently advances special catheters into the right atrium of the heart (where the venous network ends), performs a trans-septal puncture (that is, creates a small hole in the inter-atrial septum) and thus gains access to the left atrium. Pulmonary veins drain into the left atrium (they return oxygenated blood from the lungs to the heart – most people have 4 pulmonary veins). Cardiologists advances the special catheters into the antrum of the pulmonary veins and applies the treatment. These treatments aim to destroy the points of contact between the tissue of the atrial myocardium and that of the pulmonary veins.

Today we have at our disposal a series of different techniques for the isolation of the pulmonary veins (pulmonary vein isolation – PVI). The first method used was the use of catheters that apply radiofrequency (RF) at their tip. In addition to radiofrequency ablation, balloon cryoablation may alternatively be utilized. These techniques are generally equivalent. The experience of the operator and the particularities of each patient lead to the final choice of method. In addition, other techniques are being developed, such as laser ablation – retain, indeed, the same therapeutic approach.

The effectiveness of atrial fibrillation ablation in maintaining sinus rhythm (which is strictly defined as the absence of any episode of atrial fibrillation) after the first 2-3 months after the intervention is approximately 60-70%. In some cases, a re-do procedure may be required. The benefits of ablation in terms of the possibility of maintaining sinus rhythm are greater the earlier in the natural course of the disease the procedure is performed. This is because a higher and prolonged burden of atrial fibrillation leads to electro-anatomical alterations of the myocardium. However, available data imply that patients whose ablation procedure failed in the sense of full absence of atrial fibrillation may also benefit from this intervention. However, the benefits arise from a reduction in symptoms, a reduction in the overall burden of atrial fibrillation (ie the percentage of time at which the heart rhythm is atrial fibrillation versus normal sinus rhythm) and a reduction in heart rate.

Of note, today the strict indication of this intervention refers to patients with paroxysmal atrial fibrillation after failure to maintain normal sinus rhythm under medication. However, its employment as a first line treatment after the patient’s preference is also foreseen. In any case, therapeutic decisions are made after an individual assessment of symptoms, anatomical substrate and medical history.

Atrial fibrillation ablation is a generally safe intervention, however as with any invasive procedure there is a risk of death (<0,2%), stroke (<1%) and other minor complications at corresponding frequencies (~1-2%). The potential benefits of the intervention and its risks are always taken into account before final decisions are made.