1. Introduction
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia
affecting approximately 1-2% of the worldwide population [1].
Without appropriate treatment, AF can significantly impact quality of
life with risks of recurrences and/or arrhythmia progression reported to
be as high as 90% [2, 3]. Catheter ablation has shown to be an
effective treatment with superior efficacy compared to antiarrhythmic
drugs (AAD) alone for symptomatic AF [4, 5]. The principle aim of AF
ablation is to achieve durable circumferential pulmonary vein isolation
(PVI), which electrically separates the pulmonary vein (PV) from the
left atrium (LA) at the level of PV ostia/antrum. Although AF ablation
is considered relatively safe, the procedure is invasive and carries
risks of devastating complications such as esophageal-related injuries,
pericardial effusion with tamponade, pulmonary vein stenosis, and
cerebrovascular accident [6, 7]. Because of this, ablation is
typically utilized in patients who failed initial AAD therapy, and most
evidence supporting the use and the superiority of ablation was derived
from populations that had already received an AAD as the first-line
rhythm-based treatment [8, 9].
Similarly, previously published randomized controlled trials (RCTs)
suggest that pulmonary vein isolation is superior to AAD even as initial
therapy for paroxysmal atrial fibrillation (pAF). These include the
Radiofrequency Ablation vs Antiarrhythmic Drugs as First-Line Treatment
of Paroxysmal Atrial Fibrillation (RAAFT-2) trial, the Medical
Antiarrhythmic Treatment or Radiofrequency Ablation in Paroxysmal Atrial
Fibrillation (MANTRA-PAF) trial, and the Radiofrequency Ablation vs
Antiarrhythmic Drugs as First-line Treatment of Symptomatic Atrial
Fibrillation (RAAFT-1) trial [10-12]. A meta-analysis of the 3 RCTs
by Hakalathi et al. confirmed this finding but reported that ablation
was associated with more serious adverse events [13]. However, all 3
RCTs were done using only radiofrequency ablation without any trial
performing cryoablation. Moreover, the authors did not perform
time-to-event analysis for the main outcome of arrhythmic recurrence. In
this updated meta-analysis, we included 2 recently published RCTs that
use cryoballoon ablation, the Early Aggressive Invasive Intervention for
Atrial Fibrillation (EARLY-AF) trial and the Cryoballoon Catheter
Ablation in an Antiarrhythmic Drug Naive Paroxysmal Atrial Fibrillation
(STOP AF First) trial and perform a sensitivity-analysis to compare
arrhythmia-free survival and to evaluate adverse events between the two
strategies [14, 15].