title: 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: longer atrial fibrillation-free survival time but similar survival time free of any atrial arrhythmia.
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.
  
  
  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.
authors.affiliation: Department of Cardiology, Westmead Hospital, Sydney, Australia.
authors.forename: Toon Wei
authors.initials: TW
authors.lastname: Lim
authors.forename: Choon Hiang
authors.initials: CH
authors.lastname: Koay
authors.forename: Valerie A
authors.initials: VA
authors.lastname: See
authors.forename: Rebecca
authors.initials: R
authors.lastname: McCall
authors.forename: William
authors.initials: W
authors.lastname: Chik
authors.forename: Robert
authors.initials: R
authors.lastname: Zecchin
authors.forename: Karen
authors.initials: K
authors.lastname: Byth
authors.forename: Swee-Chong
authors.initials: SC
authors.lastname: Seow
authors.forename: Liza
authors.initials: L
authors.lastname: Thomas
authors.forename: David L
authors.initials: DL
authors.lastname: Ross
authors.forename: Stuart P
authors.initials: SP
authors.lastname: Thomas
mesh_terms: D001281:Atrial Fibrillation / Q000503:physiopathology / Q000601:surgery*; D015716:Electrocardiography, Ambulatory; D005260:Female; D005500:Follow-Up Studies; D006325:Heart Atria / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011667:Pulmonary Veins / Q000601:surgery*; D012008:Recurrence; D015996:Survival Rate; D016896:Treatment Outcome