The right atrial diameter as a risk factor predicting recurrence of atrial fibrillation after catheter ablation at mid-term follow-up

Abstract Background Left atrial diameter (LAD) has been confirmed to predict recurrence of atrial fibrillation (AF) after catheter ablation (CA). The influence of right atrium (RA) size on the prognosis after CA was relatively unclear and lack of research. The objective of the present study was to investigate the relationship between right atrial diameter (RAD) and the mid-term outcome of AF after CA. Methods This study retrospectively examined 121 patients who underwent initial CA for symptomatic AF. Cox regression model was used to find risk factors of recurrence. Receiver operating characteristic (ROC) curve was used to evaluate predictive power and determine clinic cutoff value. Kaplan-Meier survival curve and log-rank test were used to analyze success rate. Results There were 94 (77.7%) patients of freedom from AF after 24.2 ± 4.5 months’ follow-up. Multivariate Cox regression analysis showed both hypertension and RAD were independent risk factors of arrhythmia recurrence after ablation regardless of AF type (HR: 4.915; 95% CI: 1.370-17.635; P = 0.015 and HR: 1.059; 95% CI: 1.001–1.120; P = 0.045, respectively). However, in patients with paroxysmal AF (par-AF), Multivariate analysis showed RAD become the only independent risk factor (HR: 1.031; 95% CI: 1.016–1.340; P = 0.029). ROC curve demonstrated the cutoff value of RAD was 35.5 mm with an area under the curve (AUC) of 0.715 (95% CI: 0.586–0.843, P = 0.009), sensitivity of 81.3% and specificity of 54.2%. Kaplan-Meier survival curve showed significant difference of freedom from par-AF (67.5 vs. 91.4%, log-rank, P = 0.015) between patients with RAD ≥ 35.5 mm and < 35.5 mm in this subgroup. Nevertheless, in patients with persistent AF (per-AF), no risk factor of arrhythmia recurrence was found. In addition, Kaplan-Meier survival curve showed no significant difference of freedom from per-AF (69.7 vs. 87.5%, log-rank, P = 0.31) between patients with RAD ≥ 35.5 mm and < 35.5 mm. Conclusions RAD was the independent risk factor predicting recurrence of AF after CA only in patients with par-AF. In patients with RAD < 35.5 mm, there was a significantly higher freedom from par-AF recurrence compared with RAD ≥ 35.5 mm after a mid-term follow-up.