Comparison of left atrial dimensions in CT and echocardiography as predictors of long-term success after catheter ablation of atrial fibrillation

Abstract

Left atrium (LA) size is a common predictor of ablation outcomes in atrial fibrillation (AF), but different LA diameters have not been adequately studied yet. We aimed to find the best predictor of ablation outcomes using single-linear LA dimensions by computed tomography (CT) or echocardiography. Patients (n = 103, 72 males, 59 ± 9 years) undergoing AF ablation were analyzed. LA diameter (LA-D) was measured by transthoracic echocardiography (parasternal long axis). After 3D reconstruction of CT data (EnSite Verismo, SJM, MN), maximal LA dimensions were measured on a coronal plane (superior-inferior, SI, and transversal, TV) and a sagittal plane (anterior-posterior, AP). Volume (LAV) was rendered after LA appendage and pulmonary vein exclusion. Patients with persistent AF (n = 40) had significantly larger LA size than those with paroxysmal AF (n = 63). After 26 ± 14 months, 31 (30 %) patients had AF recurrence. Univariate Cox regression analysis revealed that LA-D, LA-SI, LA-TV, LAV, and LAV-index (LAV/body surface area) were associated with AF recurrence. Multivariate Cox regression analysis revealed that LAV was the strongest independent predictor of AF recurrence (HR = 1.011 per ml, 95 % CI 1.003-1.020, p = 0.002). LA-TV had the best correlation with LAV (r = 0.69, p < 0.01) and was the strongest single-linear predictor (HR = 1.07 per mm, 95 % CI 1.022-1.121, p = 0.004). Independent of LA-D, an LA-TV>74.5 mm predicted AF recurrence similarly to LAV>126 ml. LA dilatation, especially on the coronal plane, is associated with reduced long-term success after catheter ablation. LA-TV is the best linear predictor of AF recurrence, stronger than the commonly used LA-D.