Factors Associated with Documented Arrhythmia Recurrence After Cryoballoon Ablation in a Low-Risk Atrial Fibrillation Population Without Major Comorbidities

Background: Arrhythmia recurrence after cryoballoon ablation remains a clinically relevant problem in atrial fibrillation (AF). However, factors associated with documented recurrence in low-risk patients without major comorbidities are not well defined. This study aimed to evaluate factors associated with documented arrhythmia recurrence after cryoballoon ablation in a highly selected low-risk AF population. Methods: This retrospective, single-center study included 153 eligible patients selected from an institutional cryoablation database after application of predefined exclusion criteria. Only patients with a CHA2DS2-VA (congestive heart failure, hypertension, age ≥ 75 years, diabetes mellitus, stroke/transient ischemic attack/thromboembolism, vascular disease, and age 65–74 years) score ≤ 1 and without major comorbidities, including diabetes mellitus, hypertension, coronary artery disease, chronic kidney disease, cerebrovascular disease, and heart failure, were included. Recurrence was defined as electrocardiographically documented AF or atrial tachyarrhythmia after the 3-month blanking period over 1 year of follow-up; Holter-detected episodes were required to last ≥30 s. The primary multivariable model included sex, age, AF type, and absolute left atrial diameter; a sensitivity model replaced absolute left atrial diameter with left atrial diameter indexed to body surface area (BSA). Results: The study population included 70 women (45.8%) and 83 men (54.2%). Paroxysmal AF was present in 125 patients (81.7%), whereas 28 patients (18.3%) had persistent AF. Documented arrhythmia recurrence occurred in 40 patients (26.1%). Female sex was more frequent in the recurrence group than in the no-recurrence group (62.5% vs. 39.8%, p = 0.013). The complete-case primary multivariable model included 126 patients with 36 recurrence events. Female sex was associated with documented arrhythmia recurrence (odds ratio [OR] 2.69, 95% confidence interval [CI] 1.14–6.37; p = 0.024). The estimate for left atrial diameter was directionally positive but statistically uncertain (OR 1.086 per mm, 95% CI 0.989–1.192; p = 0.085). In the BSA-indexed sensitivity model (n = 123), the female-sex estimate was attenuated and statistically uncertain (OR 2.16, 95% CI 0.90–5.18; p = 0.084), while left atrial diameter/BSA was also statistically uncertain (OR 1.145 per mm/m2, 95% CI 0.977–1.343; p = 0.095). Conclusions: In this selected low-risk cohort undergoing second-generation cryoballoon ablation, female sex was associated with clinically detected, electrocardiographically documented arrhythmia recurrence in the primary model under an intermittent rhythm-surveillance strategy based on scheduled 12-lead electrocardiograms (ECGs) and symptom-driven evaluations. However, the estimate was attenuated and statistically uncertain after indexing left atrial diameter to BSA. Given the retrospective, single-center design, non-systematic rhythm monitoring, and sensitivity of the sex estimate to body-size adjustment, these findings should be interpreted as hypothesis-generating.