Limitations:
The current sub-analysis has several limitations. First, this is a
sub-analysis of the DECAAF II trial, evaluating patients in the control
arm who received PVI alone. More patients in the control arm received RF
ablation (n = 345) compared to Cryo (n = 58), resulting in selection
bias. While the baseline characteristics were well matched, more
patients in the RF arm received antiarrhythmic therapy and
anticoagulation prior to ablation, which could affect the rate of AAR
and bleeding post ablation. Additionally, RF patients had more days of
transmitted ECGs, which may have resulted in less atrial arrhythmia
detection in Cryo patients. Being an international study, there were
operators of varying skill levels and expertise, which may have affected
the efficacy of RF ablation more than Cryo given the former’s inherent
complexity. Also, while the CMR protocol was standardized, the CMR
machines varied between study sites, influencing the reproducibility of
the images. Lastly, the follow-up period was relatively short (12-18
months) which may have been insufficient time to see a difference in the
primary outcome.
Conclusion:
In patients with persistent AF, routine PVI with Cryo was non-inferior
to RF in terms of atrial arrhythmia recurrence. Patients with ≥ 6.5%
total LA scar on post ablation CMR had less AAR. Cryo ablation formed a
greater percentage of PV scar compared to RF, suggesting more effective
scar localization that may have important prognostic implications.