The Risk of Left Atrial Appendage Thrombus in Patients With Atrial Flutter Versus Atrial Fibrillation

Objective: Patients with atrial fibrillation (AF) are at increased risk of thromboembolic events originating mainly from left atrial appendage thrombus (LAAT). Patients with atrial flutter (AFL) are treated with anticoagulation based on the same criteria as patients with AF. However, whether patients with AFL have similar thromboembolic risk as AF is unclear. In the current study we aimed to estimate the prevalence of LAAT in patients with AFL undergoing trans-esophageal echocardiography (TEE). Methods/results: We included 438 patients (404 with AF and 34 with AFL) scheduled for TEE to rule out LAAT before cardioversion (patients who reported no or inadequate anticoagulation before cardioversion). Demographic and echocardiographic data were compared between patients with and without LAAT. Despite a similar CHA 2 DS 2 -VASC score (3.8 ± 1.3 vs 3.4 ± 1.5 in the AF and AFL groups, respectively, P = .09), LAAT was documented in 12 (2.8%) in the AF group and in no patient in the AFL group ( P