The prevalence of left atrial (LA)/atrial appendage (LAA) thrombus in patients with atrial fibrillation/atrial flutter on anticoagulation and the echocardiographic parameters to delineate risk is unknown. The aim of this study was to assess the thrombus prevalence in patients on anticoagulation and their echocardiographic parameters. We retrospectively assessed patients who presented for transoesopheageal echocardiogram guided direct cardioversion at a single centre from 2016 to 2022. 500 patients were included in the analysis. The prevalence of LAA thrombus was 4.8%. The patient characteristics and echocardiographic parameters are listed in the Table. LA thrombus rate was higher in patients with systolic dysfunction, large LA size, spontaneous echo contrast (SEC) and low LAA velocity. There was no significant difference in prevalence of thrombus based on type of anticoagulation, ie, NOAC or warfarin. Despite oral anticoagulation, LAA thrombus is prevalent in patients with AF. Routine usage of TOE is vital especially in high-risk patient groups.Tabled 1Pts with LA/LAA thrombus (n=24)Pts without LA/LAA thrombus (n=476)Age68.2 ± 8.270.4 ± 10.6M:F17:7335:144AF/A. Flutter24/0408/65Mean LAA velocity (m/sec)0.260.33Mean LA size (mL/m2)42.534.9Mean LVEF42% ± 11.5%48% ± 12%SEC10 (42%)60 (13%)Anticoagulant:Apixaban11 (46%)202 (42%)Rivaroxaban7 (29%)205 (43%)Dabigatran016 (3.4%)Warfarin2 (8.3%)41 (8.6%)CHADSVASC 0-17 (29%)99 (21%)CHADSVASC ≥216 (67%)367 (56%) Open table in a new tab