Radiofrequency Ablation in Atrial Fibrillation: From Palliative Therapy to Cure

pp 525-532

Abstract

Less than a decade has passed since the early studies on radiofrequency ablation for cardiac arrhythmias and this technique has already become a first line therapy to cure of diverse disorders of the cardiac rhythm. Suppression of the mechanisms underlying the genesis and perpetuation of atrial fibrillation is one of the most confronting challenges faced by interventional arrhythmology. In this review we analyze the pathophysiologic and electrophysiologic basis of atrial fibrillation and describe the ablation strategies designed for the treatment of this arrhythmia. Atrial fibrillation may be paroxysmal or occur as a long-lasting permanent arrhythmias. It has been shown that atrial fibrillation maybe caused by either multiple reentrant wavelets or a single ectopic atrial focus giving rise to high-frequency repetitive impulses. The radiofrequency ablation techniques applied to these two varieties of atrial fibrillation are different. The rationale for RF ablation of "focal" atrial fibrillation lies upon eradication of atrial tachycardias or non-sustained salvos of atrial extrasystoles, which are the source of high frequency atrial impulses triggering atrial fibrillation. These foci have been ablated in both atria, mainly at the pulmonary vein ostiums in the atrium. The success rate of radiofrequency ablation of "focal' atrial fibrillation has proved to be highly encouraging. The radiofrequency ablation strategy for chronic atrial fibrillation is based on the "maze" surgical procedure. It consists of linear endocardial lesions produced by radiofrequency energy in both atria.Thus, the atria are split into several sections, reducing atrial critical mass and creating barriers to propagation of the reentrant atrial wavelets. As of today, the efficacy of this technique is limited and better technologic tools are necessary to shorten along-lasting intervention as well as to attain a greater success rate.