Importance of left atrial appendage flow as a predictor of thromboembolic events in patients with atrial fibrillation

Aim The purpose of this study was to investigate the role of transoesophage al echocardiography in predicting subsequent thromboembolic events in patie nts with atrial fibrillation. Methods and patients Transoesophageal echocardiography was performed in 88 patients with documented paroxysmal (n=53) or chronic atrial fibrillation ( n=35) to assess morphological and functional predictors of thromboembolic e vents. Prospective selection was from patients with non-valvular atrial fib rillation who had undergone transoesophageal echocardiography because of pr evious thromboembolism (n=30); prior to electrical cardioversion (n=31); or for other reasons (n=27). All patients were followed up for 1 year. Results During the period of follow-up new thromboembolic events occurred i n 18 of 88 patients (20(n)/o/year); 16 of these patients had a stroke and t wo a peripheral embolism. Univariate analysis revealed that previous thromb oembolism (P<0.005; odds ratio 5.3 [CI 1.9, 12.1]), history of hypertension (P<0.01; odds ratio 4.0 [CI 1.4, 10.4]), presence of left atrial spontaneo us echo contrast (P<0.025; odds ratio 3.5 [CI 1.2, 10.0]), and presence of left atrial appendage peak velocity less than or equal to 0.20m.s(-1) (P<0. 01; odds ratio 4.1 [CI 1.4, 11.6]) were significantly related to subsequent thromboembolic events. Stepwise logistic regression showed that independen t predictors of thromboembolic events were: history of thromboembolism (P<0 .005), history of hypertension (P<0.05) and low left atrial appendage peak velocity less than or equal to 0.20 m.s(-1) (P<0.01). Conclusions In patients with atrial fibrillation, the presence of spontaneo us echo contrast in the left atrium, and in particular a low left atrial ap pendage peak flow velocity, can be used to identify a subgroup of atrial fi brillation patients at either increased or decreased risk of subsequent thr omboembolism, which might have important implications for anticoagulation t herapy.