Limitations
The retrospective study design limits statistical power of our analysis and its multicenter nature introduces heterogeneity in both ablation performance and patient outcomes. Furthermore, our investigation explored a wide variety of ablation strategies in this patient population. Detailed information regarding the ablation procedures, including ablation settings and operator preferences, was not available. Therefore, we are likely be underpowered to detect true difference between AF ablation strategies and this analysis should be considered hypothesis-generating. Additionally, while the efficacy of ablation strategies was assessed, confirmation of lesion durability for each strategy (e.g., posterior wall isolation or mitral line block) was not systematically verified, which may have influenced the observed recurrence rates.
It should be emphasized that identification of these patients is only possible during repeat procedures, making the inclusion of large numbers of patients challenging. Nonetheless, despite the retrospective design, through the NHR we were still able to identify one of the largest series of patients with durably isolated PVs. Lastly, detection of AF recurrences was not standardized, possibly leading to under-detection of AF recurrence. Despite this, we still observed a high recurrence rate suggesting that AF recurrence is very common in this subset of patients.