Anatomical analysis of the left atrial appendage using segmented, three-dimensional cardiac CT: a comparison of patients with paroxysmal and persistent forms of atrial fibrillation

Abstract

Successful implantation of percutaneous left atrial appendage (LAA) occlusion devices requires an accurate understanding of LAA anatomy and orifice dimensions. We sought to quantitatively compare LAA anatomy in patients with paroxysmal and persistent patterns of atrial fibrillation (AF). Fifty-nine consecutive patients undergoing catheter ablation for AF underwent pre-procedural multislice cardiac computed tomography (CT) scans. Maximal LAA orifice dimensions and left atrial and LAA volumes were measured from three-dimensional segmented CT reconstructions. Thirty-six patients with paroxysmal and 23 with persistent AF were analysed. The mean maximal LAA orifice dimension was larger in persistent (27.2 ± 4 mm) than paroxysmal AF (22.9 ± 3 mm, p < 0.001). A strong correlation was found between both increasing LAA volume (r = 0.76), maximal LAA orifice dimension (r = 0.63) and left atrial volume. Increased LAA orifice dimension is associated with left atrial enlargement in AF. This finding may impact LAA occlusion device sizing.