AF termination and rhythm outcome
The importance of AF termination as a procedural endpoint that
correlates positively with rhythm outcome is still in debate. AF termed
in 51% of catheter ablation using a sequential biatrial linear
defragmentation approach. Miyazaki et al. reported that AF termination
was the sole factor predicting freedom from both arrhythmia recurrence
and crossover to rate control strategies during long-term
follow-up.2 While, in
the subgroup analysis of STAR AF II, AF termed in 8% of the PVI, 45%
in the PVI plus CFAE ablation and 22% of the PVI plus linear ablation
and the AF termination could not predict the better rhythm
outcome.4 This
discrepancy might be caused by 1) multiple procedure or single
procedure, 2) follow-up period (60 months vs. 18 months). CFAE ablation
was associated with a high likelihood of AT as the mode of arrhythmia
recurrence. Actually, linear ablation was mainly performed for
macro-reentrant ATs in the 2nd procedure. Of note, the
AF recurrence was significantly less after eliminating AT after index
procedure when 2nd or 3rd session
was mainly performed from 4 to 28 months after the initial procedure. In
our study, the mode of the arrhythmia recurrence was perimitral AT in
one patient with a favorable response. Thus, no AF recurrence was found
in patients with a favorable response. We speculated that AF termination
during RF application could reduce the AF recurrence, however,
additional RF application could have a potential risk of increasing the
AT substrate. The PLS ablation provide the relatively high AF
termination and the excellent outcome, however, the ablation target area
should have been more specifically focused and we should have used the
time for creating a durable PVI and linear lesion. Recently, Ashihara et
al. had developed a novel online real-time phase mapping system: ExTRa
Mapping.13 By using
this novel system, we reported the case in which RF application at the
AF rotor area overlapped with the PLS could convert AF to common atrial
flutter.21 We would
like to hope that this real-time mapping system and LGE-MRI assessment
could make it possible to intervention on the specific AF substrate.