What is atrial fibrillation?
Atrial fibrillation (AF) is the most frequent form of sustained arrhythmia, found in 1-2% of the population. It is the most frequent cause of access to the emergency room in Italy and its incidence increases with increasing age. It is estimated that in 2050 the number of patients with FA will be at least double that of today.
How is atrial fibrillation treated?
The atrial fibrillation is treated with an antiarrhythmic drug therapy, but when this is not effective, it is necessary to resort to ablation of arrhythmogenic substrate.
Ablation is generally performed by the catheter route and, only in selected cases, by the surgical route. In both cases the goal of ablation is to electrically isolate the pulmonary veins from the rest of the left atrium. It is from these veins, in fact, that the (irregular) ectopic beats that characterize AF originate. In some patients, especially those with persistent atrial fibrillation, additional lesions must be performed in the right and left atrium.
The intervention of the catheter ablation consists in the insertion, through the femoral vein, of some leads which are then advanced inside the heart. Once positioned, the electrodes release a radio frequency electric current that destroys the tissue that causes the arrhythmia.
The ablation takes advantage of modern three-dimensional mapping systems of the heart, which allow you to virtually navigate the real anatomy of the atrium, through computerized axial tomography (CT) or nuclear magnetic resonance.
Cryablation
Cryoablation is a transcatheter ablation technique that has become increasingly popular over the years in the treatment of atrial fibrillation.
The cryoablation uses an ablation catheter equipped with an electrode to be introduced into the duct of the pulmonary vein. Through a console, coolant (NO2) is released under pressure inside the lumen of the catheter: when the temperature reaches -40 ° C, a layer of ice is created that wraps around the tip of the catheter and which determines perfect adhesion and stability of the catheter to the myocardial tissue. Thanks to the adhesion of the catheters inside the pulmonary vein, the electrical circuits responsible for atrial fibrillation are interrupted.
Is ablation recommended for all patients with atrial fibrillation?
Ablation is recommended for patients suffering from paroxysmal (occasional) AF; on the other hand, the risk-benefit ratio is less defined for those who suffer from resistant AF, which may require more ablation sessions. For this reason, it is indicated only for those who are strongly symptomatic, refractory to antirhythmic therapy or when structural heart disease is present.
Other factors to consider are the patient’s age, the type and severity of any associated heart disease, the diameter of the left atrium and any comorbidities.
In any case, ablation for AF cannot be considered a definitive intervention: unfortunately, it is still burdened by a high percentage (about 40%) of relapses even in those patients who initially no longer had arrhythmic phenomena. However, it remains the most effective therapy in maintaining sinus rhythm.
