Effect of Left Atrial Size and Volume Reduction on Pulmonary Vein Isolation Efficacy in Patients With Persistent and Longstanding Persistent Atrial Fibrillation: Subset Analysis From the aMAZE Trial.

BACKGROUND

Large left atrial volume (LAV) is a strong predictor of advanced left atrial substrate and is associated with less successful outcomes following pulmonary vein isolation (PVI) alone. Prespecified variables of the aMAZE trial (Left Atrial Appendage Ligation Adjunctive to PVI for Persistent or Longstanding Persistent Atrial Fibrillation) were evaluated to access for the impact of LAV and left atrial appendage ligation on atrial fibrillation (AF) outcomes.

METHODS

The aMAZE trial was a multicenter, randomized-controlled study evaluating the effects of LAV on freedom from atrial arrhythmias (AA) following PVI-only compared with LARIAT and PVI (LARIAT+PVI). In total, 610 drug-refractory patients with nonparoxysmal AF were randomized 2:1 to LARIAT versus PVI alone. Freedom from AA was assessed 12 months postprocedure. LAV was independently assessed by a core laboratory from cardiac computed tomography performed before ablation. (REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02513797).

RESULTS

There were 404 patients in the LARIAT+PVI group and 206 in the PVI-only group. Logistic regression performed within each subgroup for primary effectiveness with LAV demonstrated that the recurrence of AA after PVI was directly related to increasing LAV. Freedom from recurrence of AA in the LARIAT+PVI arm was independent and preserved irrespective of LAV. Similar results were seen with LAV index. A tercile analysis of early persistent AF (perAF) patients (AF >7 days and <6 months) and LARIAT+PVI in the highest (>148 cm3) LAV tercile showed statistically significant freedom from AA compared with PVI-only (69% versus 49%; P=0.02). Significant differences (P<0.04) between groups in the early perAF cohort began at an LAV of 130 cm3 and an LAV index of 65 cm3/m2.

CONCLUSIONS

The correlation of LAV with PVI effectiveness in this study demonstrates that AA recurrence after PVI alone is directly related to increasing LAV. Freedom from AA after left atrial appendage ligation in addition to PVI is independent of increasing LAV, and left atrial appendage ligation may therefore provide an adjunctive benefit in patients with nonparoxysmal AF and enlarged LAV.