High-power, short-duration atrial ablation was as safe and effective as the conventional ablation. Compared with the conventional 40 W/30 s setting, 50 and 60 W ablation for 5 s achieved transmurality and had fewer complications.

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Additional linear ablations have been added to WAI in an attempt to improve efficacy, in particular at the left mitral isthmus and left atrial roof. [7][8][9] However, linear ablation can be technically demanding, and conduction recovery across these additional ablation lines is common and associated with recurrences, especially of macroreentrant atrial tachyarrhythmias. 10 Wider isolation techniques are associated with a high incidence of organized atrial © 2012 American Heart Association, Inc. Background-Electric isolation of the pulmonary veins and posterior left atrium with a single ring of radiofrequency lesions (single-ring isolation [SRI]) may result in fewer atrial fibrillation (AF) recurrences than wide antral pulmonary vein isolation (wide antral isolation [WAI]) by abolishing extravenous AF triggers. The effect of mitral isthmus line (MIL) ablation on outcomes after SRI has not previously been assessed. Methods and Results-We randomly assigned 220 consecutive patients (58±10 years old; 82% men) with highly symptomatic AF (61% paroxysmal, 39% persistent/longstanding persistent) to undergo either SRI or WAI. Half of each cohort was also randomly allocated to have left lateral MIL ablation (2×2 factorial study design). Patients were followed clinically and with 7-day Holter studies for arrhythmia recurrences. The primary end points were recurrence of AF and organized atrial tachyarrhythmias. AF-free survival at 2 years was better after SRI (74% [95% CI, 65% 10-12 Therefore, an MIL may be effective in reducing OAT recurrences when used with SRI or WAI. However, the efficacy of additional MIL ablation in SRI is unknown. Our second hypothesis was that additional MIL ablation would result in fewer AF and all arrhythmia recurrences compared with no MIL. Circ Arrhythm ElectrophysiolTo address these hypotheses, a randomized trial was conducted to compare the efficacy and safety of WAI of the pulmonary veins with SRI of the pulmonary veins and the posterior left atrium, with or without additional MIL ablation. MethodsThe study cohort consisted of 220 consecutive patients who were referred for catheter ablation for drug-refractory and highly symptomatic AF. They were block-randomized (1:1) to have either WAI of the pulmonary veins as ipsilateral pairs ( Figure 1A and 1B) or SRI of the posterior left atrium and pulmonary veins ( Figure 1C and 1D). These 2 pulmonary vein isolation techniques have been previously described and are detailed in the online-only Data Supplement.3,10 Within each group, half of the patients were also randomly assigned to have empirical MIL ablation or no MIL ablation unless they had mitral isthmus-dependent flutter during the procedure, resulting in a 2×2 factorial study design.Patients were excluded if they were <18 years of age, had previous left atrial ablation procedures, or were unable to give informed consent. ProcedureWAI was performed by isolating ipsilateral vein pairs with a ring of ablation lesions ≈5 to 10 mm from the vein ostia ( Figure 1A and 1B). A roofline was also include...