Risk factors for left atrial thrombus in younger patients (aged < 65 years) with atrial fibrillation or atrial flutter: Data from the multicenter left atrial thrombus on transesophageal echocardiography (LATTEE) registry.

Background: Our aim was to assess the characteristics and to identify predictors of left atrial thrombus (LAT) in patients under age 65 with atrial fibrillation (AF) or atrial flutter (AFl).

Methods: We conducted a subanalysis of a multicenter, prospective, observational study [the LATTEE registry]. Consecutive AF/AFl patients referred for cardioversion or ablation were enrolled.

Results: Of the 3,109 patients included in the study, 1,276 were under age 65 (41%). Compared to non-LAT patients, those with LAT ( = 76) had higher CHADS-VASc score ( < 0.001), more frequently had non-paroxysmal AF/AFl ( < 0.001), heart failure ( < 0.001), history of diabetes mellitus ( = 0.001), transient ischemic attack ( = 0.04), coronary artery disease ( = 0.02), and chronic kidney disease ( < 0.001). The LAT patients were also more often smokers ( = 0.004) and were more frequently treated with vitamin K antagonists (VKAs) ( < 0.001). Transthoracic echocardiography revealed a higher left atrial area ( < 0.001), lower left ventricular ejection fraction (LVEF) ( < 0.001), and lower value of LA appendage emptying volume in LAT than in non-LAT patients ( < 0.001). LVEF (OR 2.95; 95% CI: 1.32-6.59, = 0.008), non-paroxysmal AF/AFl (OR 7.1; 95% CI: 2.05-24.63, = 0.002) and treatment with VKAs (OR 4.92; 95% CI: 2.48-9.75, < 0.001) were identified as independent predictors of LAT in younger patients.

Conclusions: Our study, which focused on younger patients with AF/AFl, indicated substantial clinical and echocardiographic differences between participants with and without LAT. In the AF/AFl patients younger than age 65, the independent predictors of LAT included non-paroxysmal AF/AFl, lower LVEF, and treatment with VKAs.