BACKGROUND: Treatment of PAF with PVI is the gold standard approach. Recently, esophageal cooling has been shown to significantly reduce the risk of esophageal injury during thermal ablation. This study investigated outcomes of HPSD before and after instituting esophageal cooling. METHODS: In this natural experiment, we enrolled 346 consecutive patients with PAF undergoing initial ablation using HPSD, 143 patients immediately prior to and 203 patients immediately after switching from luminal esophageal monitoring (LET arm) to esophageal cooling with ensoETM (ensoETM arm). The primary endpoint was time-to-atrial arrhythmia recurrence. RESULTS: The procedure times were significantly faster with ensoETM (82.9 ± 27 vs 112 ± 49 min, p <
0.0001). At a median follow-up of 10.3 ± 3.4 months, the atrial arrhythmia recurrence rate did not significantly differ between LET and ensoETM arms (25.2% vs 30.0%, p = 0.3202). Kaplan-Meier analysis showed no significant difference in the overall atrial arrhythmia recurrence (log-rank, p = 0.3780). Statistical analysis of all notable comorbidities revealed no significant association with procedural outcomes. CONCLUSION: In patients with PAF undergoing an initial ablation procedure with HPSD, esophageal cooling led to significantly faster procedures, with no decrease in efficacy.