Early arrhythmia recurrence after cryoballoon ablation in atrial fibrillation: A systematic review and meta-analysis

INTRODUCTION: Early arrhythmia recurrence within the 3-month blanking period is a common event that historically has been attributed to reversible phenomena. While its mechanistic links remain obscure, accumulating evidence support the argument of shortening the blanking period. We aimed to elucidate the association between early and late arrhythmia recurrence after atrial fibrillation cryoablation. METHODS: The MEDLINE database, ClinicalTrials. gov, medRxiv, and Cochrane Library were searched for studies evaluating early and late arrhythmia recurrence rates in patients undergoing cryoablation for atrial fibrillation. Data were pooled by meta-analysis using a random-effects model. The primary endpoint was late arrhythmia recurrence. RESULTS: Early arrhythmia recurrence was found predictive of decreased arrhythmia-free survival after evaluating 3975 patients with paroxysmal or persistent atrial fibrillation who underwent cryoablation (odds ratio [OR]: 5.31; 95% confidence interval [CI]: 3.75-7.51). This pattern remained unchanged after subanalyzing atrial fibrillation type (paroxysmal; OR: 7.16; 95% CI: 4.40-11.65 and persistent; OR: 7.63; 95% CI: 3.62-16.07) as well as cryoablation catheter generation (first generation; OR: 5.15, 95% CI: 2.39-11.11 and advanced generation; OR: 5.83, 95% CI: 3.68-9.23). Studies permitting antiarrhythmic drug utilization during the blanking period or examining early recurrence as a secondary outcome were found to be a significant source of statistical heterogeneity. CONCLUSION: Our findings suggest that early arrhythmia recurrence is predictive of late outcomes after cryoablation for atrial fibrillation. Identifying which patients deserve earlier reintervention is an open research avenue.