Computed Tomographic Analysis of Left Atrial Mass and Regional Variations of Posterior Wall in Patients with Atrial Fibrillation

Abstract

Background: Atrial fibrillation (AF) is associated with anatomical remodeling of the left atrium (LA). The study sought to explore the relationships between AF and the LA mass and regional difference of posterior wall. Methods: Forty-six patients with paroxysmal AF (PAF), 16 patients with Persistent (PeAF) and 28 controls without AF history were included. The LA wall mass, transmural thickness between the endocardial and epicardial surface and LA volume were evaluated with 64-slice multi-detector computed tomography. The entire LA body was divided into 18 segments for analysis of regional variability. Results: The LA wall mass was greater in AF patients (PeAF:PAF:control: 17.94±3.86 versus 13.19±358 versus 10.77±3.58 cm3, p<0.01). In addition, Patients with PeAF had larger LA volume than those with either PAF or control (p<0.01). The regional assessment showed the volume of posterior wall was less than that of anterior wall in AF patients (6.56±3.45 versus 7.86±2.91 cm3, p<0.01). Further analysis of posterior wall demonstrated that the middle segments were thickest and the inferior segments were thinner (p<0.01) than the other areas. Conclusions: The chronicity of AF is associated with the increased LA wall mass. The understanding of regional variations of LA segments could provide important information for catheter ablation.