Impact of Left Atrial Dilatation on Catheter Ablation Outcomes for Persistent Atrial Fibrillation: Does Size Matter?

Left atrial (LA) enlargement is commonly used in patient selection for catheter ablation. However, its role in predicting postablation outcomes in persistent atrial fibrillation (AF) remains uncertain.

The study goal was to evaluate the relationship between baseline LA volume index (LAVI) and arrhythmia outcomes after ablation for persistent AF.

A total of 338 patients with persistent AF enrolled in the CAPLA (Catheter Ablation for Persistent Atrial Fibrillation: Pulmonary Vein Isolation vs. PVI plus Posterior Wall Isolation) trial were screened for pre-ablation LAVI evaluation on echocardiography. Atrial arrhythmia recurrence and burden were assessed at 1 year and 3 years' postablation using intensive rhythm monitoring (implantable devices, twice-daily mobile electrocardiograms, or serial Holter monitors). The association between LAVI and arrhythmia recurrence, burden, and recurrence phenotype were analyzed by using both survival and logistic regression models.

A total of 281 (83.1%) of 338 patients had baseline LAVI data available. At 1 year, arrhythmia recurrence occurred in 130 (46.3%) patients, increasing to 173 (61.6%) at 3 years. LAVI was not associated with arrhythmia recurrence in a multivariable analysis (OR: 1.01; 95% CI: 0.99-1.02; P = 0.55) nor when stratified according to LAVI category (log-rank test, P = 0.19). However, among patients with arrhythmia recurrence, increased LAVI was associated with greater arrhythmia burden (R² = 0.12; P < 0.001) and persistent (vs paroxysmal) recurrence (OR: 1.78 per 10 mL/m²; 95% CI: 1.33-2.47; P < 0.001) at 12 months.

In persistent AF, baseline LAVI did not predict arrhythmia recurrence after first-time ablation but was associated with higher AF burden and persistent recurrence phenotype at 1 year postablation. These findings suggest that LA size may influence recurrence burden and phenotype rather than overall ablation success.