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.