Objective: This study sought to investigate the impact of left atrium size on left atrial (LA) thrombus in patients with non-valvular persistent atrial fibrillation (AF).
Methods: In a prospectively established database, patients with AF underwent transesophageal echocardiography prior to AF ablation were screened from January 2007 to June 2010. Exclusive criteria included paroxysmal AF, vavular AF, deep vein thrombus, pulmonary embolism, on warfarin, redo procedure. Of 1 524 patients, 367 patients (male 267, female 100) with age 26-89 (mean 56±11) were enrolled. The patients were divided into LA thrombus group and non-thrombus group. Receptor-operating curves were used to test the value of CHA2DS2Vasc score and LA diameter predicting LA thrombus. Logistic analysis were used to find the independent predictor of LA thrombus.
Results: Thirty-two (8.7%) patients had LA thrombus. The LA diameter, left ventricular end diastolic diameter, left ventricular end systolic diameter were significantly larger in thrombus group than non-thrombus group. Left ventricular ejection fraction was significantly lower in thrombus group than non-thrombus group. CHA2DS2Vasc score did not differ between the two groups. The area under the receptor-operating curve for LA diameter predicting LA thrombus was 0.656 (0.563-0.750), the best cut-off point was 42.5 mm. The incidence of LA thrombus was significantly higher in patients with LA diameter≥42.5 mm than those with LA<42.5 mm (14.0% vs. 5.1%, χ2=8.888, P=0.003). In univariate analysis, LA diameter≥42.5 mm increased the risk of LA thrombus with odds ratio 3.05 (95% confidence interval 1.42-6.53, P=0.004. The sensitivity and specificity of LA diameter≥42.5 mm in predicting LA thrombus were 67.7% and 61.5%, respectively. In multivariate analysis, after adjustment of CHA2DS2Vasc score, left ventricular end diastolic diameter, left ventricular end systolic diameter, left ventricular ejection fraction, LA diameter≥42.5 mm was an independent risk factor of LA thrombus (odds ratio 2.77, 95% confidence interval 1.17-6.57, P=0.021).
Conclusion: LA enlargement is an independent risk factor of LA thrombus in patients with non-vavular persistent AF.