Objective To investigate the useful parameters of transthoracic echocardiography (TTE) for the diagnosis of stroke subtypes in patients with acute cerebral infarction.Methods One hundred and one acute ischemic stroke patients met all of the following criteria including ≥50 years of age,normal sinus rhythm on admission,and transesophageal echocardiography (TEE) within 7 days from the onset.The clinical significance of the TEE parameters on admission was examined for identifying intracardiac thrombus formation as follows; left atrial dimension,left ventricular end-diastolic dimension,percentage fractional shortening,left ventricular mass index,ratio of the transmitral inflow velocities (E/A),and the deceleration time of the E wave.Results There were 28 patients with E/A ≥ 1.0 (70 ± 12) years old and 73 with E/A ＜ 1.0 (73 ± 10) years old.No patients showed pulmonary congestion on chest radiography.There were no significant differences in age,TTE parameters,and plasma levels of brain natriuretic peptide between the two groups.Patients with E/A≥ 1.0 had higher incidence of left atrial appendage (LAA)thrombus formation and/or spontaneous echograhic contrast than those with ＜ 1.0 (25.0％ vs 5.5％,x2 =7.95,P ＜0.01).A significant relationship was found between E/A and emptying flow velocity of the LAA (r =-0.569,P ＜0.01).Multivariate logistic regression analysis showed E/A was an independent predictor for LAA thrombus (risk ratio 1.531 per0.1 increase,95％ confidence interval 1.129-2.076,P =0.0002).Conclusions Increased level of E/A on admission was associated with the occurrence of left atrial appendage thrombus formation in patients with acute ischemic stroke.