Aging-associated atrial fibrillation: A comprehensive review focusing on the potential mechanisms.

Atrial fibrillation (AF) has been receiving a lot of attention from scientists and clinicians because it is an extremely common clinical condition. Due to its special hemodynamic changes, AF has a high rate of disability and mortality. So far, although AF has some therapeutic means, it is still an incurable disease because of its complex risk factors and pathophysiologic mechanisms, which is a difficult problem for global public health. Age is an important independent risk factor for AF, and the incidence of AF increases with age. To date, there is no comprehensive review on aging-associated AF. In this review, we systematically discuss the pathophysiologic evidence for aging-associated AF, and in particular explore the pathophysiologic mechanisms of mitochondrial dysfunction, telomere attrition, cellular senescence, disabled macroautophagy, and gut dysbiosis involved in recent studies with aging-associated AF. We hope that by exploring the various dimensions of aging-associated AF, we can better understand the specific relationship between age and AF, which may be crucial for innovative treatments of aging-associated AF.

Hydrochemical interpretation of groundwater in Yinchuan basin using self-organizing maps and hierarchical clustering.

Self-organizing maps (SOM) is emerging as an alternative to traditional clustering methods for the hydrochemical analysis of groundwater due to the visualization of high-dimensional data. In this study, a combined method of the SOM and hierarchical clustering was applied to analyze the hydrochemical characteristics of groundwater in phreatic aquifer in the Yinchuan basin, China. 154 groundwater samples classified by SOM were projected on 65 neurons and grouped into 6 clusters with hierarchical clustering. The results showed that there exist three principal types of groundwater in the study area, namely high HCO3- type (Cluster-1, 2, and 6), high SO42- type (Cluster-3, and 4), and high Na+ type (Cluster-5). Chadha diagram indicated that the phreatic water in Yinchuan basin mainly belongs to the group of alkaline earths that exceed alkali metals (n = 107, 69%). Rock weathering and evaporation-crystallization are the predominant mechanism in the hydrogeochemical evolution of phreatic groundwater. The present study suggested that the combined method of the SOM and hierarchical clustering provides a reliable approach for interpreting the hydrochemical characteristics of groundwater with high-dimensional data.

Fuzzy comprehensive evaluation with AHP and entropy methods and health risk assessment of groundwater in Yinchuan Basin, northwest China.

Water quality evaluation and health risk assessment are not only the basis of environmental protection work, but also of great significance to water environment supervision and management. In this paper, the fuzzy comprehensive evaluation for water quality was improved by using the analytic hierarchy process (AHP) and Entropy, and a health risk assessment model based on triangular fuzzy theory was developed. The evaluation results show 5 water categories: Class-1 (n = 1, 2%), Class-2 (n = 14, 32%), Class-3 (n = 15, 34%), Class-4 (n = 8, 18%) and Class-5 (n = 6, 14%), manifesting about 67% of the phreatic water can be used for drinking purposes in the research area. The Chadha diagram provides hydrochemical facies of the phreatic water are mainly NaCl type (n = 16, 36%) and Ca-Mg-Na type (n = 15, 34%). Fluorine as non-carcinogenic factor in health risk assessment, showing moderate correlation with SO42- (r = 0.54) and low correlation with Na+ (r = 0.38) in Pearson correlation analysis. The order of non-carcinogenic risk per year is as follow: Class-2, Class-3, All, Class-4 and Class-5 with the mean of 0.29, 0.51, 0.67, 0.86 and 1.55 × 10-8 for adults, 0.54, 0.95, 1.27, 1.58 and 2.89 × 10-8 for children. Compare with adults, children undertake higher health risk, in research area. Particularly, the region accepting Class-5 water supplement encounter high non-carcinogenic risk, where risk level is 2.24 and 2.28 times to the average risk level for adults and children, respectively. This paper provides insights into solving uncertainties in groundwater management and environmental protection, as well as into fuzzy logic techniques addressing pollution.

Left bundle branch pacing for cardiac resynchronization therapy: A systematic literature review and meta-analysis.

BACKGROUND: Left bundle branch pacing (LBBP) recently has been suggested as an alternative modality to deliver cardiac resynchronization therapy (CRT). Data on LBBP for CRT are limited to small sample reports, and clinical benefits and risks have not been systematically assessed. We sought to systematically examine published studies of LBBP for CRT and quantify the feasibility and efficacy of the therapy. METHODS: Cochrane Library, PubMed, Web of Science, and Embase databases were searched from inception to September 30, 2020 to identify relevant studies evaluating LBBP in patients for CRT. Clinical outcomes of interest included implant success rate, QRS duration (QRSd), pacing threshold, left ventricular (LV) function at baseline and follow-up, heart failure-related hospitalization, and mortality. Data were extracted and summarized. RESULTS: A total of six studies (two single-arm studies and four comparative studies) involving 174 patients were included. The results showed that the average age of patients was 64.9 years and all were implanted for CRT. The procedural success rate was only reported in two studies (97% and 81.1%, respectively). LBBP resulted in a narrow of mean QRSd from 172.7 ± 4.8 to 115.1 ± 7.6 ms. LV function, including LV ejection fraction and LV end-diastolic dimension improved at follow-up. During a mean follow-up of 8.1 months, 1.3% of patients experienced heart failure-related hospitalization and no patients died. CONCLUSION: LBBP is a feasible strategy with significant efficacy and safety for CRT candidates.

Reversion of cardiac memory during left bundle branch pacing.

Cardiac memory (CM) is identified as an altered T wave when normal ventricular activation resumes after an abnormal myocardial activation period. We present a case who initially underwent temporary right ventricular apex (RVA) pacing for one week which induced typical pseudo-primary T wave changes. The T wave inversion was observed after the end of RVA pacing when left bundle branch pacing (LBBP) was initiated, and the abnormal T waves gradually return to almost normal repolarization during LBBP 40 days later.