Direct comparison of clinical outcome between linear and EGM
(CFAE)-guided ablation
Although previous meta-analyses comparing different strategies for PsAF
ablation in the different cohorts reported non-superiority of additional
substrate modification beyond PVI, the studies were associated with
heterogenous patient populations and follow-up
periods.9,21 Only two previous studies have
prospectively compared linear ablation and CFAE ablation in PsAF
patients. In contrast to our results, both studies reported no
significant differences in arrhythmia-free survival between the two
groups during medium-term follow-up.11,12 While Estner
et al. reported similar outcomes between linear ablation and CFAE
ablation at 1 year, the success rates were lower than those in the
present study (linear vs. CFAE: 37% vs. 39%) despite high success
rates of linear block (100%) and AF termination (82%) during CFAE
ablation. Of note, their ablation strategy in the linear ablation group
included roof and anterior lines in only two thirds of patients, and
mean LA size was larger (47-49 mm).12 These results
may suggest that the effect of linear ablation, especially anterior line
ablation, is limited in advanced PsAF. In the STAR-AFII trial, there was
no difference in AF/AT-free survival between linear ablation (roof and
MI lines) and CFAE ablation during 1.5 years of follow-up (41% vs.
37%). Regarding procedural results, AF terminated in 45% by CFAE
ablation, and successful linear ablation was achieved in 93% and 75%
of roof and MI lines, respectively.11 There are a
number of potential explanations for the inconsistent results between
our study and STAR AF II. Firstly, the acute success rate of MI line
block was relatively lower than our study (81%). Secondly, our ablation
protocol included ablation for non-PV foci. Thirdly, we confirmed
elimination of dormant conduction post-PVI with isoproterenol and
adenosine after 30 minutes waiting in all patients. Fourthly, a
steerable sheath was used for linear ablation, which may have
contributed to the higher successful rate in the linear ablation
group.33 Overall, our study showed consistent efficacy
of linear ablation in PsAF patients during very long-term follow-up
(>8 years) after the initial and multiple catheter ablation
procedures with fewer procedures compared to the EGM-guided ablation
cohort. Multiple ATs was more frequently induced at the re-do procedure
in the EGM-guided ablation group. These findings may suggest that some
of the critical CFAE areas were not targeted during the index
ablation,15,32 and potential incompletely ablated
areas may create a substrate for iatrogenic
arrhythmias.34