Background-The mainstay of treatment for atrial fibrillation (AF) remains pharmacological; however, catheter ablation has increasingly been used over the last decade. The relative merits of each strategy have not been extensively studied. Methods and Results-We conducted a randomized multicenter comparison of these 2 treatment strategies in patients with paroxysmal AF resistant to at least 1 antiarrhythmic drug. The primary end point was absence of recurrent AF between months 3 and 12, absence of recurrent AF after up to 3 ablation procedures, or changes in antiarrhythmic drugs during the first 3 months. Ablation consisted of pulmonary vein isolation in all cases, whereas additional extrapulmonary vein lesions were at the discretion of the physician. Crossover was permitted at 3 months in case of failure. Echocardiographic data, symptom score, exercise capacity, quality of life, and AF burden were evaluated at 3, 6, and 12 months by the supervising committee. Of 149 eligible patients, 112 (18 women [16%]; age, 51.1Ϯ11.1 years) were enrolled and randomized to ablation (nϭ53) or "new" antiarrhythmic drugs alone or in combination (nϭ59). Crossover from the antiarrhythmic drugs and ablation groups occurred in 37 (63%) and 5 patients (9%), respectively (Pϭ0.0001). At the 1-year follow-up, 13 of 55 patients (23%) and 46 of 52 patients (89%) had no recurrence of AF in the antiarrhythmic drug and ablation groups, respectively (PϽ0.0001). Symptom score, exercise capacity, and quality of life were significantly higher in the ablation group. Conclusion-This randomized multicenter study demonstrates the superiority of catheter ablation over antiarrhythmic drugs in patients with AF with regard to maintenance of sinus rhythm and improvement in symptoms, exercise capacity, and quality of life. (Circulation. 2008;118:2498-2505.)

Triggers from the Purkinje arborization or the right ventricular outflow tract have a crucial role in initiating ventricular fibrillation associated with the long-QT and Brugada syndromes. These can be eliminated by focal radiofrequency ablation.

The present study provides evidence that the mechanism of successful AFI ablation targeting the IVC-TA isthmus is local bidirectional conduction block. This change can be used as a new and complementary electrophysiological end point for the procedure. AFI recurrences are associated with failure to achieve a permanent block.