Study on the relationship between atrial high-rate episode and left atrial strain in patients with cardiac implantable electronic device.

Background: Although atrial high-rate episode (AHRE) and atrial fibrillation (AF) cannot entirely be identical, recent studies suggest AHRE is linked to AF development and shares some characteristics with AF regarding thromboembolism. At present, there is still lack of predictive indicators for AHRE and diagnostic methods and clinical indicators for AHRE in patients without cardiac implantable electronic device (CIED). The aim of this study was thus to explore the relationship between AHRE and left atrial (LA) strain parameters with the goal of identifying high-risk populations of AHRE by LA strain characteristics. Methods: From February 2022 to May 2023, a total of 105 CIED patients were enrolled and divided into two groups based on whether AHRE had occurred: AHRE (-) group (n=65) and AHRE (+) group (n=40). Real-time three-dimensional echocardiography (RT-3DE) technique was used to obtain the LA time-volume curve. The collected dynamic images were analyzed on the Echopac 204 workstation to obtain the parameters of LA. The four-dimensional automatic LA quantitative analysis (4D Auto LAQ) technology was used to analyze the LA strain parameters: LA reservoir longitudinal strain (LASr), LA conduit longitudinal strain (LAScd), LA contraction longitudinal strain (LASct), LA reservoir circumferential strain (LASr-c), LA conduit circumferential strain (LAScd-c), LA contraction circumferential strain (LASct-c). Correlation analysis was carried out using Binary logistic regression analysis. The area under the receiver operating characteristic (ROC) curve (AUC) was used to evaluate the diagnostic performance of LASct in AHRE. Results: Body surface area (BSA) [odds ratio (OR) =8.34, 95% confidence interval (CI): 1.32-72.30, P=0.037], LASct (OR =1.20, 95% CI: 1.05-1.39, P=0.013) and LA end-systolic volume (LAESV) (OR =1.02, 95% CI: 1.00-1.04, P=0.023) were the influencing factors of AHRE. Only LASct (OR =1.18, 95% CI: 1.01-1.38, P=0.041) was found to be an independent influencing factor of AHRE. This result remained significant after adjusting for age, sex, hypertension, diabetes, and stroke history. The ROC curve showed that the cut-off for predicting AHRE was LASct =-4.125% with sensitivity of 37.5% and specificity of 87.7%. Conclusions: This cross-sectional study found that decreased LASct (absolute value) is an independent risk factor for the AHRE and has diagnostic efficacy in certain degree for the occurrence of AHRE.

How the trabeculae protrude within the left atrial appendage is the key factor affecting thrombosis in patients with atrial fibrillation.

The left atrial appendage (LAA) is a major site of thrombosis in patients with non-valvular atrial fibrillation. The myocardial trabeculae within the LAA have a peculiar tendency to protrude but its relationship to thrombosis remains unknown. This study aimed to investigate the relationship between the condition of trabeculae protrusion and LAA thrombosis. This retrospective study consecutively selected patients diagnosed with non-valvular atrial fibrillation and prepared for radiofrequency ablation from January 2011 to May 2020. Patients were divided into the thrombus group (n = 43), the sludge group (n = 35), and the normal group (n = 407) according to whether the thrombus or sludge was present. The trabeculae protruding angle (TPA), which was measured by the CT scans, was used to quantify the trabeculae protrusion condition. Patients' clinical data, TPA, LAA emptying velocity, and other factors were collected and compared among the three groups. A total of 485 patients were enrolled. The range of TPA was between 0 and 158 degrees, with an average of 89.3 ± 35.6 degrees. The TPA was significantly greater in the thrombus (109.3 ± 14.8 degrees) and sludge groups (110.8 ± 12.8 degrees) than in the normal group (85.3 ± 37.1). The incidence of LAA thrombus and sludge increased with increasing TPA. Multivariate regression analysis showed that the TPA was an independent risk factor for LAA thrombus (OR = 1.046, 95%CI: 1.020-1.073, p < 0.001) and sludge (OR = 1.035, 95%CI: 1.017-1.053, p < 0.001). Further analysis revealed that the TPA was negatively correlated with LAA emptying velocity but its effect on promoting thrombosis was not only mediated by slowing down the flow velocity. The TPA can well reflect the condition of trabeculae protrusion. This study revealed that the TPA was an independent risk factor for LAA thrombus or sludge, providing a potential indicator for future thrombosis risk assessment.

Left atrial enlargement and high uric acid level are risk factors for left atrial thrombus or dense spontaneous echo contrast in atrial fibrillation patients with low to moderate embolic risk assessed by CHA2DS2-VASC score.

Aims: To investigate the correlation and predictive value of left atrial diameter and blood uric acid levels with the occurrence of left atrial thrombus or dense spontaneous echo contrast in atrial fibrillation patients with low to moderate CHA2DS2-VASc scores. Methods and results: A total of 849 inpatients diagnosed with atrial fibrillation who had low to moderate CHA2DS2-VASc scores and complete transesophageal echocardiography were included in this study. Among them, 66 patients had left atrial thrombus or dense spontaneous echo contrast. When different models were used to correct other known risk factors, acid levels and abnormal left atrial diameter were identified as additional risk factors for left atrial thrombus or dense spontaneous echo contrast. The incidence of left atrial thrombus or dense spontaneous echo contrast was higher in patients with abnormal serum uric acid levels than in the control group (12.4% vs. 5.6%, p < 0.05), and this difference persisted after correcting the baseline data with propensity score matching (10.6% vs. 4.1%, p < 0.05). Abnormal left atrial diameter was another risk factor suggested by regression analysis, with an increased incidence of left atrial thrombus or dense spontaneous echo contrast in the abnormal left atrial diameter group compared to the control group, both before (18.0% vs. 3.5%, p < 0.05) and after (15.5% vs. 5.2%, p < 0.05) propensity score matching. The best predictive value was obtained by adding both abnormal serum uric acid levels and abnormal left atrial diameter. Conclusion: Left atrial enlargement and high uric acid levels increase the risk of left atrial thrombus or dense spontaneous echo contrast in atrial fibrillation patients with low to moderate CHA2DS2-VASc scores.

Long noncoding RNA XIST promotes malignancies of esophageal squamous cell carcinoma via regulation of miR-101/EZH2.

The long non-coding RNA XIST is a long non-coding RNA that associates with polycomb repressive complex 2 to regulate X-chromosome inactivation in female mammals. The biological roles as well as the underlying mechanisms of XIST in esophageal squamous cell carcinoma remained yet to be solved. Our data indicated that XIST was significantly upregulated in esophageal squamous cancerous tissues and cancer cell lines, as compared with that in the corresponding non-cancerous tissues and immortalized normal squamous epithelial cells. High XIST expression predicted poor prognosis of esophageal squamous cancer patients. Lentivirus mediated knockdown of XIST inhibited proliferation, migration and invasion of esophageal squamous cancer cells in vitro and suppressed tumor growth in vivo. Knockdown of XIST resulted in elevated expression of miR-101 and decreased expression of EZH2. Further analysis showed that XIST functioned as the competitive endogenous RNA of miR-101 to regulate EZH2 expression. Moreover, enforced expression of EZH2 significantly attenuated the anti-proliferation activity upon XIST knockdown. Conclusively, XIST plays an important role in malignant progression of ESCC via modulation of miR-101/EZH2 axis.