Left atrial thrombus predicts transient ischemic attack in patients with atrial fibrillation

Abstract

Background Atrial fibrillation (AF) is widely accepted as a direct cause of cardioembolic stroke from left atrial (LA) thrombus formation. However, the relationship between LA thrombus and transient ischemic attack (TIA) in patients with AF is less well established. Methods Two hundred sixty-one adult patients (mean age 66 ± 11 years, 220 men and 41 women) with AF undergoing transesophageal echocardiography (TEE) were prospectively followed up for TIA (mean duration 30.3 ± 20.6 months). Results LA thrombus was present in 18% (n = 46) and LA spontaneous echocardiographic contrast in 50% (n = 131) of the group. Nineteen of 261 patients had TIA during follow-up. Multivariate logistic regression showed congestive heart failure (CHF) as the only predictor of TIA when a model of clinical variables was constructed (odds ratio [OR] 2.7, P = .04). Age, sex, hypertension, and use of warfarin or aspirin were not predictors. When TEE variables were added to the model, LA thrombus became the only predictor of TIA (OR 7.7, P = .0001). Survival free of TIA (Kaplan-Meier) was significantly less ( P = .0001) in patients with LA thrombus compared with those without, and the annual TIA event rate was 9.2% per year versus 1.9% per year ( P <.0001), respectively. Conclusions To our knowledge, this is the first prospective study documenting an association between LA thrombus and TIA in patients with AF. Other TEE variables, including aortic atheromata, and clinical parameters were not independently predictive. These data support a likely thromboembolic mechanism for TIA from LA thrombus in patients with AF.