The “Floating Lotus” Sign on Intracardiac Echocardiography: Characterization and Predictors of a Novel Left Atrial Appendage Pseudo-Thrombus

Background: Intracardiac echocardiography (ICE) is increasingly used for left atrial appendage (LAA) assessment during atrial fibrillation (AF) procedures. We describe a novel, thrombus-mimicking artifact on ICE, termed the “Floating Lotus” sign. Methods: In this retrospective multicenter study, we analyzed data from 172 patients undergoing ICE-guided AF ablation and/or LAA occlusion. The incidence, imaging features, and clinical correlates of the “Floating Lotus” sign were assessed. Results: The “Floating Lotus” sign was observed in 48 patients (27.9%). It manifested as a mobile, echogenic mass within an anechoic space, revealing an underlying pericardial effusion. Patients exhibiting the sign had a higher prevalence of recent stroke (35.4% vs. 15.3%, p = 0.004), heart failure (64.6% vs. 8.1%, p < 0.001), and larger left atrial diameter (44.3 ± 6.8 vs. 39.7 ± 5.4 mm, p < 0.001). In multivariable analysis, only heart failure (left ventricular ejection fraction (LVEF) <55%) remained an independent predictor (odds ratio [OR] 14.39, 95% confidence interval [CI] 5.51–37.58, p < 0.001). Lower LAA emptying velocity was independently associated with persistent AF, higher CHA2DS2-VASc score, and recent stroke (all p < 0.05). Conclusion: The “Floating Lotus” sign is a common ICE pseudo-thrombus, often associated with heart failure. Accurate recognition of this sign, based on its dynamic imaging features, is therefore critical to prevent misdiagnosis and avoid unnecessary procedural cancellation or anticoagulation changes.