Does Duration of Symptoms Reliably Predict Detection of Left Atrial Thrombus in Newly Diagnosed Atrial Fibrillation.

Background: Large prospective trials attribute minimal thromboembolic risk for cardioversion of atrial fibrillation (AF) when duration of symptoms is shorter than 48 hours. Our goal is to compare the prevalence of left atrial appendage (LAA) thrombus as demonstrated by a Trans esophageal echocardiography (TEE) exam between patients presenting with less or more than 48 hours of AF symptoms.

Methods: Observational cohort study including consecutive patients hospitalized with primary diagnosis of new onset AF, not previously treated with oral anticoagulation. All patients underwent TEE to exclude LAA thrombus, regardless of symptoms duration. Patients were divided into two groups based on AF duration: 1) early presenters: up to 48 hours, 2) later presenters: longer than 48 hours.

Results: The study included 122 patients mean age 65.8 years). The "early presenters" were younger, with less co-morbidities. LAA thrombus was detected in 13(21%) of 62 early presenters, compared to 20 (33%) of 60 patients of the second group (P=0.12). Significant predictors of LAA thrombus in the whole cohort by univariate analysis were ≥65 years of age (1.051, P=0.017), acute heart failure (2.394, P=0.038), and history of coronary artery/ peripheral vascular disease (2.7, P= 0.019). Notably neither duration of symptoms nor CHA2DS2-VASc score significantly predicted LAA thrombus. Inmultivariate analysis, only age ≥65 was found to be a significant predictor of LAA thrombus.

Conclusions: LAA thrombus in patients presenting within 48 hours of AF symptoms onset is not uncommon. Duration of symptoms is not reliable for excluding LAA thrombus.