Morphology and Function Assessment of Left Atrial Appendage in Patients With Atrial Fibrillation

Atrial fibrillation (AF) is among the most prevalent forms of clinically significant arrhythmia, and stroke incidence is among the most serious AF-related complications, causing high rates of morbidity and mortality among affected patients. The European Society of Cardiology guidelines recommend a thromboembolic event risk assessment based on the CHA₂DS₂-VAS_C score. However, stroke also occurs in some patients with a low CHA₂DS₂-VAS_C score. Therefore, it is necessary to improve thromboembolic risk stratification in AF patients. The left atrial appendage (LAA) is considered to be the most frequent site of thrombus formation. Approximately 47% of thrombi in valvular AF and 91% of thrombi in nonvalvular AF are localized in the LAA. Therefore, identification or exclusion of LAA thrombi is critical in many clinical situations. It is essential to assess LAA morphology and function using imaging modalities (particularly echocardiography) before, during, and after interventional procedures such as AF ablation and LAA occlusion. This review article describes the anatomical, physiological, and LAA assessment in daily practice.