Abstract Body (Do not enter title and authors here): Background: Cavotricuspid isthmus (CTI) ablation is a highly effective intervention for the treatment of typical atrial flutter (AFL). The emergence of new-onset atrial fibrillation (AF) following CTI ablation is clinically relevant but limited data exist regarding predictors of post-CTI AF in these patients. The goal of this study is therefore to investigate predictors of new-onset AF following CTI ablation.
Methods: Patients who underwent CTI ablation between April 2016 and November 2022 were included in this analysis. Baseline variables including age, sex, body mass index (BMI), left atrial volume index (LAVI), cardiac comorbidities, left ventricular ejection fraction (LVEF), CHA₂DS₂-VASc score, and medication use were collected. The primary outcome was the occurrence and timing of new-onset AF after the index CTI ablation.
Results: New AF occurred in 44 (29%) of 153 patients at a median of 264 days. Patients who developed AF were more likely men (p=0.046), had hypertension (p=0.014), and higher LAVI (40.6 ± 12.2 vs. 34.2 ± 9.5 mL/m², p<0.001). After adjusting for unbalanced covariates in a Cox multivariable model, protective predictors against developing new AF included female sex (HR 0.31, 95% CI 0.12–0.76, p=0.011) and prior cardiac surgery (HR 0.22, 95% CI 0.07–0.72, p=0.013) while increased LAVI (HR 1.02, 95% CI 1.00–1.05, p=0.08) showed a trend towards higher risk of new AF.
Conclusion: In this cohort of AF-naive patients undergoing CTI ablation for typical AFL, nearly one-third developed new-onset AF. Independent predictors of developing AF include male sex, no-prior cardiac surgery, and larger LA volume index. These findings have clinical implications to the management of AFL patients, including the decision to perform concomitant AF ablation in patients with higher risk features.