The safety and efficacy of left atrial BOX ablation in persistent atrial fibrillation：A meta-analysis
Authors: Xi Yin , Li Yang , Zhang Wenyu , Hao Jie 
Published: June 2023

Background:Catheter ablation is an effective method to control
the rhythm of atrial fibrillation. Circumferential pulmonary vein
isolation (CPVI) is the cornerstone of catheter ablation of atrial
fibrillation.However, circumferential pulmonary vein isolation alone has
a higher recurrence rate in the treatment of persistent atrial
fibrillation.At present additional left atrial BOX ablation has been
shown to reduce the recurrence rate in patients with persistent atrial
fibrillation in some studies, but it remains controversial.
Objective: This meta-analysis aimed to investigate the safety
and efficacy of additional left atrial BOX ablation in the treatment of
persistent atrial fibrillation, furthermore,to provide evidence-based
medical evidence for catheter ablation in patients with persistent
atrial fibrillation. Methods: We searched the CNKI, PubMed, Web
of Science, and the Cochrane Library for randomised controlled trials
that undergoing circumferential pulmonary vein isolation alone or get
additional left atrial BOX ablation in patients with persistent atrial
fibrillation. The search period was from the establishment of the
database to January 2023. Baseline characteristics and clinical outcomes
were extracted from the included studies. The primary endpoint was the
recurrence rate of all atrial arrhythmias(AA) within one year
postoperatively, and the secondary endpoint was the incidence of
surgery-related adverse events. This meta-analysis was performed by R
version 4.1.2 Results: Six randomized controlled trials
involving 967 patients with persistent atrial fibrillation were
included.468 patients who underwent circumferential pulmonary vein
ablation + left atrial BOX ablation and 499 patients underwent
circumferential pulmonary vein ablation alone.The meta-analysis results
showed that circumferential pulmonary vein ablation + left atrial BOX
ablation did not significantly reduce the recurrence rate of all atrial
arrhythmias after catheter ablation in patients with persistent atrial
fibrillation compared with circumferential pulmonary vein isolation
alone (RR=0.86,95%CI=0.73-1.02,I =35%)。However,
subgroup analysis showed that circumferential pulmonary vein ablation +
left atrial BOX ablation significantly reduced the recurrence rate of
all atrial arrhythmias (RR=0.67, 95% CI=0.49-0.92, I
=15%). and the recurrence rate of atrial
fibrillation (RR=0.53, 95% CI=0.37-0.77, I =0%) in
patients with persistent atrial fibrillation when the left atrial
diameter was ≤44mm. There was no significantly increase in the incidence
of procedure-related adverse events (RR=1.04,95% CI=0.56-1.94, I
=0%), but the ablation time (MD=19.77, 95%
CI=15.84-23.70, I =0%) and procedure time
(MD=15.64,95% CI=6.99-24.29, I =0%) due to
additional ablation procedures were extended. Conclusion:
Additional left atrial BOX ablation does not significantly reduce the
recurrence rate of atrial arrhythmia after catheter ablation in patients
with persistent atrial fibrillation, but it can significantly reduce the
recurrence rate of atrial arrhythmia and atrial fibrillation in all
small left atrial diameter, without increasing the risks associated with
surgery.Additional left atrial BOX ablation is safe and effective.
However, further evidence from additional multicenter RCT studies is
needed. Keywords: Additional left atrial BOX ablation,
Persistent atrial fibrillation, Catheter ablation, Meta-analysis