Spontaneous echo contrast in the left atrial appendage is linked to a higher risk of thromboembolic events and mortality in patients with atrial fibrillation.

Background: Cardioversion, a rhythm control treatment for atrial fibrillation (AF), requires ruling out cardiac embolic sources, often originating from the left atrial appendage (LAA). Transesophageal echocardiography (TEE) is used for LAA evaluation, but it is invasive and not widely available. This study aimed to identify cardiovascular risk factors linked to LAA abnormalities and predictors of thromboembolic events and all-cause mortality. Methods: A single-center retrospective analysis included AF patients admitted to the University Hospital Würzburg between 2009 and 2018 undergoing TEE. Results: Among 2400 AF patients (median age 72; 36 % women), 469 (20 %) had LAA abnormalities: 282 (60 %) had spontaneous echo contrast (SEC), 72 (15 %) had thrombus formation (THR), and 115 (25 %) had both. Predictors of LAA abnormalities included age (OR 1.04; p = 0.002), congestive heart failure (OR 1.70; p = 0.009), diabetes (OR 1.74; p = 0.007), stroke history (OR 3.36; p = 0.001), vascular disease (OR 1.57; p = 0.026), elevated alkaline phosphatase (OR 1.15; p = 0.003), prior VKA intake (OR 1.53; p = 0.002), and DOAC intake (OR 0.57; p = 0.038). SEC with or without THR independently predicted thromboembolic events (HR 1.74, p = 0.031 and HR 1.53, p = 0.006) and all-cause mortality (HR 1.77, p = 0.011 and HR 1.57, p = 0.002), adjusted for cardiovascular risk factors, anticoagulation, and laboratory data. Conclusions: In AF patients undergoing TEE, SEC, often overlooked in cardioversion decisions, independently predicted thromboembolic events and mortality.