To evaluate the function of the left atrium and left atrial appendage and identify the independent risk factors for left atrial and left atrial appendage thrombosis in non-valvular atrial fibrillation (NVAF) patients using transthoracic echocardiography (TTE), transesophageal echocardiography (TEE), and speckle tracking echocardiography (STE).

This study included 101 consecutive NVAF patients who underwent TEE at the People's Hospital of Liaoning Province. The patients were divided into two groups based on the presence of left atrium and left atrial appendage thrombosis or not: 47 patients (46.5%) with left atrium and left atrial appendage thrombosis and 54 patients (54.5%) without. TTE, TEE, and STE were performed to assess the function of the left atrium and left atrial appendage. The clinical characteristics, N-terminal proBNP (NT-proBNP), echocardiography parameters, and left atrial appendage morphology were compared between the two groups. Multivariate regression analysis was performed to to identify predictive factors for left atrial appendage thrombosis. ROC curve analysis was performed to calculate the diagnostic efficacy of the predictive factors for thrombosis.

The prevalence of persistent atrial fibrillation, NT-proBNP, left atrial anteroposterior diameter, left atrial maximum volume index, left atrial minimum volume index, and left atrial appendage maximal volume and minimal volume in the thrombosis group were significantly higher than those in the non-thrombosis group. Left atrial ejection fraction, left ventricle ejection fraction, left atrial appendage emptying velocity, left atrial appendage ejection fraction, left atrial peak longitudinal strain (LA PLS) and left atrial appendage peak longitudinal strain (LAA PLS) in the thrombosis group were lower than those of the non-thrombosis group. Multivariate logistic regression analysis revealed that NT-proBNP (odds ratio [OR]=1.003; 95% confidence interval [CI]: 1.000~1.007, P=0.045) and LA PLS (OR=0.668, 95%CI: 0.515~0.920, P=0.012) were the independent risk factor for left atrium and left atrial appendage thrombosis (P<0.05). The cut-off values for NT-proBNP and LA PLS for predicting the presence of left atrium and left atrial appendage thrombosis were 243.2 pg/ml (AUC=0.909, sensitivity 91.5%, specificity 77.8%, accuracy 84.2%) and 15.75% (AUC=0.960, sensitivity 88.9%, specificity 91.5%, accuracy 90.1%), respectively.

Echocardiography can effectively evaluate the structure and function of the left atrium and left atrial appendage in patients with NVAF. NT-proBNP and LA PLS are independently associated with the thrombosis of the left atrium and left atrial appendage in patients with NVAF, which can help clinicians to identify patients at a relatively high risk of thrombosis.