Outcomes for Atrial Fibrillation Patients with Silent Left Atrial Thrombi Detected by Transesophageal Echocardiography

Although we have occasionally experienced silent thrombi in the left atrium (LA), defined as thrombi free from embolic events, by screening transesophageal echocardiography (TEE) for atrial fibrillation (AF), few data are available on predictors and outcomes of silent LA thrombi in patients with AF. We retrospectively reviewed clinical records and identified 83 patients (2.6%) with silent LA thrombi, out of 4,214 TEE procedures in 3,139 patients with AF at 6 hospitals from January 2010 to December 2012. The median [interquartile range] CHA2DS2-VASc score was 3 [2, 5]. Most patients (n = 71, 86%) were taking oral anticoagulants before the TEE, and 59 patients (71%) had heart failure (HF). During follow-up periods of 905 [620, 1301] days, ischemic stroke and systemic embolism, and hemorrhagic stroke occurred only in 3 (3.6%) and 2 patients (2.4%), respectively. All-cause death developed in 14 patients (17%), and cardiac death was the primary cause of death (n = 9, 11%). Multivariate Cox regression analysis showed the composite end point of death, stroke, systemic embolism, and major bleeding was significantly associated with age (hazard ratio; 1.06, 95% confidence interval; 1.01 to 1.11, p = 0.019) and HF (3.18, 1.27 to 7.99, p = 0.014). In conclusion, the incidence of ischemic stroke after detecting silent LA thrombi was relatively low in patients with AF under oral anticoagulation. Advanced age and HF were predictors for worse outcomes in AF patients with silent LA thrombi.