Single-Ring Posterior Left Atrial (Box) Isolation Results in a Different Mode of Recurrence Compared With Wide Antral Pulmonary Vein Isolation on Long-Term Follow-Up

Abstract

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%–82%]) than WAI (61% [51%–70%]; P =0.031). Organized atrial tachyarrhythmia–free survival was similar after SRI and WAI (67% [57%–75%] ersus 64% [54%–72%], respectively, at 2 years; P =0.988). MIL ablation resulted in better 2-year organized atrial tachyarrhythmia–free survival (71% [62%–79%] versus 60% [50%–69%]; P =0.07), which approached statistical significance. Survival free of any atrial arrhythmia after one procedure was not significantly affected by isolation technique or MIL ablation. Conclusions—: SRI resulted in fewer AF recurrences compared with WAI on long-term follow-up but did not reduce the recurrence of all atrial arrhythmias. MIL ablation may reduce organized atrial tachyarrhythmia recurrences. Clinical Trial Registration—: http://www.anzctr.org.au ; ACTRN12606000467538.