Nonlinear Relationship Between Left Atrial Volume Measured by Computed Tomography and Recurrent Atrial Arrhythmias in Patients Undergoing Catheter Ablation for Atrial Fibrillation.

Background: Left atrial remodeling is commonly believed to contribute to the recurrence of atrial arrhythmias following catheter ablation for atrial fibrillation (AF). However, the relationship between left atrial volume (LAV) assessed via left atrial computed tomography (LACT) and AF recurrence remains insufficiently explored.

Aim: This study aimed to examine the association between LAV measured by LACT and the recurrence of AF.

Methods: In this cohort study, 532 consecutive AF patients undergoing their first catheter ablation at Fuwai Hospital were enrolled. The primary outcome was the recurrence of atrial arrhythmias after a 90-day blanking period following the ablation procedure. Semi-automated software (Materialize Mimics) was utilized to analyze LACT data and estimate left atrial size.

Results: After a median follow-up duration of 16.7 months, 189 patients experienced AF recurrence. Multivariate Cox regression revealed a significant positive association between LAV and recurrence risk (hazard ratio, 1.36; 95% confidence interval, 1.11-1.66, p = 0.003). Restrictive cubic spline analysis uncovered a U-shaped nonlinear association between LAV and AF recurrence, with an inflection point identified at 99.3 mL (P for nonlinear < 0.001, P for overall < 0.001). Kaplan-Meier survival analysis demonstrated significantly lower freedom from atrial arrhythmias in the 1st and 4th quartile compared to the 2nd quartile (Log-rank, p < 0.001).

Conclusion: In AF patients undergoing initial catheter ablation, LAV was found to have a positive relationship with the risk of recurrent atrial arrhythmias, exhibiting a U-shaped nonlinear pattern. Both excessively high and low LAV levels were associated with an elevated risk of AF recurrence.