Use of left atrial automated functional myocardial imaging to identify patients with paroxysmal atrial fibrillation at high risk of stroke

BACKGROUND: Left atrial automated functional myocardial imaging (AFILA) is a new software program for analyzing the structure and function of the left atrium (LA). The present study sought to analyze the correlation between the LA function parameters as measured by AFILA echocardiography and the risk of cerebral ischemic stroke (CIS) in patients with non-valvular paroxysmal atrial fibrillation (NVPAF) to explore the diagnostic value of LA strain in patients with congestive heart failure, hypertension, age of ≥75 years (doubled), diabetes mellitus, stroke or transient ischemic attack (TIA) (doubled), age of 65–74 years, and sex category (female) (CHA2DS2-VASc) scores of <2. METHODS: A total of 205 patients with NVPAF were included in the study and divided into the no-CIS group (154 patients) and the CIS group (51 patients). The baseline clinical data for the 2 groups were analyzed, and routine echocardiography examinations were performed. AFILA was used to evaluate the LA function of all the patients. RESULTS: Compared to the no-CIS group, the LA emptying fraction and the LA reservoir strain were decreased, the LA contractile strain (S_CT) was increased, and the S_CT value changed from negative to positive in the CIS group, and the difference between the 2 groups were statistically significant (P<0.001). However, there were no significant differences in the volume at the onset of LA contraction, LA evacuation volume, LA minimum volume, LA maximum volume, and LA conduit strain between the 2 groups. The multifactorial regression analysis showed that age, hypertension, and the S_CT were independently associated risk factors for patients with CIS. After correcting for the clinical factors included in the CHA2DS2-VASc score, the S_CT was shown to predict to NVPAF with stroke [odds ratio (OR): 1.234, 95% confidence interval (CI): 1.101–1.383, P=0.000]. In addition, we included the CHA2DS2-VASc score (instead of age, diabetes, coronary artery disease, and hypertension) in a multiple regression analysis, and found that the S_CT was still significant (OR: 1.252, 95% CI: 1.118–1.402, P=0.000). The difference between the 2 groups in the CHA2DS2-VASc score for the S_CT was statistically significant, especially when the CHA2DS2-VASc score was <2. The S_CT equaled −4.5% was the cut-off value for the presence or absence of CIS in the NVPAF patients, with an area under the curve (AUC) of 0.866, sensitivity of 0.80, and specificity of 0.75 (P<0.0001). CONCLUSIONS: Comparison with LA volume parameter, measuring LA strain by AFILA provides a better index for the dynamic assessment of impaired LA function in patients with NVPAF combined with CIS, especially in those with a CHA2DS2-VASc score of <2. In addition, a LA S_CT of >−4.5% is a valuable cut-off for patients with NVPAF. The results of the current study may form the basis for a large prospective multicenter interventional study in which patients with impaired LA S_CT are randomized to receive oral anti-coagulant (OAC) therapy or no OAC therapy for the primary prevention of stroke.