Radiofrequency catheter versus cryoballoon ablation for left atrial box isolation in patients with atrial fibrillation: a propensity score-matched analysis

Abstract Background Box isolation (Boxi), achieving posterior wall isolation (PWI) of the left atrium (LA) adjunct to pulmonary vein isolation (PVI), either using contact force sensing radiofrequency catheter ablation (RF) or the second-generation cryoballoon ablation (CB) has shown favorable outcomes in patients with atrial fibrillation (AF). Purpose We sought to compare the efficacy and safety of Boxi using RF vs. CB in patients with AF. Methods A total of 131 patients with AF 80 (61.1%) paroxysmal, mean age: 71±9 years who underwent de novo Boxi RF: 68 (51.9%), CB: 63 (48.1%) were enrolled. Of them, 54 patients followed by RF were compared to propensity score-matched patients (1:1) followed by CB. Both cohorts were followed for any documented atrial tachyarrhythmia (ATA) lasting longer than 30 s after a 3-month blanking period. Results Procedure time was significantly shorter, whereas fluoroscopy time was significantly longer in patients who underwent CB as compared with those who underwent RF CB vs. RF: 237±42 vs. 280±68 min.(P=0.012), and 72±25 vs. 49±17 min.(P=0.034). The proportion of first-pass Boxi were 37% of overall patients with RF, and 77.8% with CB (P0.001). Overall complication rates were 5.6% with RF and 9.3% with CB (P=0.46). The 2-year Kaplan-Meier estimated free-survival rate of ATA were comparable between the patients who underwent RF and CB (RF vs. CB: 77.8% vs. 88.9%; Log-rank P=0.42). Conclusion Boxi completion with RF and CB were feasible and safe, with similar arrhythmia freedom at 2-year follow-up.