Left atrial appendage orifice morphology in sickness and in health.

Background: The left atrial appendage (LAA) is the primary site of embolism in individuals with atrial fibrillation (AF). We aimed to evaluate the morphological features of the LAA orifice in patients with sinus rhythm, paroxysmal AF, and persistent AF using three-dimensional (3D) transesophageal echocardiography (TOE). We also intended to identify morphometric parameters of the LAA orifice that may be potentially associated with an increased risk of ischemic stroke.

Methods: We prospectively enrolled 106 patients undergoing TOE. Patients were divided into three groups: group 1 (sinus rhythm), group 2 (persistent AF), and group 3 (paroxysmal AF). All patients underwent a comprehensive evaluation through transthoracic echocardiography (TTE) and TOE. Off-line analyses were performed of the recorded images.

Results: The LAA minor orifice area and minimal orifice diameter were greater in patients with persistent AF compared with individuals in sinus rhythm. Patients with persistent AF also had deeper LAAs compared with those in sinus rhythm. None of the LAA orifice morphometric measures were related to ischemic stroke risk. The only independent predictors of ischemic stroke were heart rhythm and the CHA₂DS₂VASc score.

Conclusion: Persistent AF is associated with LAA dilation, increased depth, and larger orifice size. To our knowledge, this is the first study to demonstrate LAA orifice structural remodeling in patients with AF using 3D TOE.