Atrial Fibrillation Ablation: First-Line Therapy?

Abstract

Background: Ablation for atrial fibrillation (AF) is a widely-accepted treatment for this arrhythmia. Ablation is traditionally reserved for second-line therapy in patients who have failed drug therapy, but it may be ready for first-line treatment. Objective: This article outlines the rationale for using ablation as first-line therapy for AF. Findings: AF increases both morbidity and mortality. Unfortunately, drug-based therapy for AF is very ineffective and may contribute adversely to both patient morbidity and mortality. Ablation addresses the root causes of AF and thus may be curative. The technique for ablation has become quite consistent and the outcomes better than those with drug therapy. The complication risk is also acceptably low. There is even preliminary evidence to suggest that AF ablation is superior as first-line treatment compared to drugs. Conclusion: AF ablation is rapidly evolving towards becoming first-line therapy for some patients with this debilitating arrhythmia.

Keywords: Atrial fibrillation; Catheter Ablation; Pulmonary Veins; Review.

Figure 1.. Panels depicting the similarity in location of the radiofrequency lesions produced by various groups’ approaches to atrial fibrillation ablation. The upper left panel shows an outer view of a patient’s left atrium as seen from the posterior aspect using three-dimensional, multislice computed tomography. Seen clearly are the tubular portions of each of the four pulmonary veins (individually labeled). The borders between the antra of the pulmonary veins and the posterior wall of the left atrium are indicated by the small white arrows. The upper right panel shows a three-dimensional electroanatomical map (CARTO, Biosense Webster Inc.) of the left atrium (same patient as panel above) acquired during atrial fibrillation ablation guided by intracardiac echocardiography (ICE). Using ICE, the borders of the pulmonary venous antra can be accurately defined and lesions can be placed to completely surround and electrically isolate the antra. The red dots represent the anatomical locations of these lesions produced by ICE-guided ablation. The lower panel shows the location of lesions produced using a CARTO-guided approach described by Morady and colleagues. In both cases, the location of the lesion sets is similar, encompassing the anterior and posterior borders of all four pulmonary venous antra. LSPV=left superior pulmonary vein, LIPV=left inferior pulmonary vein, RSPV=right superior pulmonary vein, RIPV=right inferior pulmonary vein. (Reproduced from Verma et al, Circulation 2005, 112:1214-22 with permission from publisher Lippincott Williams & Wilkins)

Figure 2.. Kaplan-Meier curves depicting freedom from atrial fibrillation (AF) in patients undergoing AF ablation by pulmonary vein antrum isolation (PVI) compared to being treated with an antiarrhythmic drug (AAD) from the pilot study of the Radiofrequency Ablation for Atrial Fibrillation Trial (RAAFT). Seventy patients with symptomatic, mostly paroxysmal AF, were randomized to PVI (n=33) or AAD (n=37). Overall recurrence of symptomatic AF was 13% in the PVI group compared to 63% in the AAD group treated with their first drug (p<0.05, mean follow-up time 8.5±3.2 months). Even after patients were switched from a first AAD to a second AAD, recurrence still remained significantly higher compared to the PVI arm (p<0.05). (Reproduced from Verma et al, Circulation 2005, 112:1214-22 with permission from publisher Lippincott Williams & Wilkins)