Background: Cardiovascular disease (CVD) is the leading cause of mortality and morbidity in the elderly and the ambient concentration of PM_2.5 has been associated with several cardiovascular diseases. Methods: We describe the present state of planetary air pollution, analyze epidemiological studies linking PM_2.5 and CVD, and discuss multiple pathophysiological mechanisms linking PM_2.5 and CVD. Results: A few epidemiological studies show that the elderly appear specifically susceptible to adverse cardiovascular effects triggered by PM_2.5 exposure. Plausible pathophysiological mechanisms include inflammatory dysfunction, oxidative stress, abnormal activation of the hemostatic system and disturbance of the autonomic nervous system. Conclusions: An in-depth knowledge of the chemical compounds, pathophysiological mechanisms, and epidemiological studies of PM_2.5 are recommended to understand this important and modifiable factor contributing to geriatric CVD burden. We offer public health recommendations to reduce this preventable cause of disease and death.

Background. Poge heart‐saving decoction (PHSD) has been used as a medicine treating heart failure in China for many years. The study aimed to explore the effect of PHSD on cardiac function in heart failure conditions and its underlying mechanism. Methods. Adriamycin was used to induce the model of heart failure (HF) in rats. Sixty rats were randomly divided into six groups: blank control group, sham group, 9.33 g/kg group (low‐PHSD, test group), 13.995 g/kg group (moderate‐PHSD, test group), 18.66 g/kg group (high‐PHSD, test group), and fosinopril group (4.67 mg/kg, comparison test group). Cardiac ultrasound was used to evaluate the cardiac function of the rats, and radioimmunoassay was used to measure aldosterone (ALD) and angiotensin II (AngII) levels in the serum. Results. Compared with the blank control group, the left ventricular end‐diastolic dimension (LVEDd) and left ventricular end‐systolic dimension (LVEDs) in the sham group were increased (1.04 ± 0.12 vs. 0.67 ± 0.13 cm; 0.75 ± 0.13 vs. 0.28 ± 0.10 cm; P < 0.05), and the left ventricular ejection fraction was decreased (36.65 ± 5.74 vs. 76.09 ± 4.23%; P < 0.05). The ejection fraction of HF rats was increased in 9.33 g/kg group, 13.995 g/kg group, and 18.66 g/kg group compared with those of the sham group (57.13 ± 1.63, 58.43 ± 1.98, and 59.21 ± 1.37 vs. 36.65 ± 5.74%; P < 0.05). PHSD also improved cardiac function by reducing the LVEDd and LVEDs (0.88 ± 0.11, 0.75 ± 0.13, and 0.72 ± 0.18 vs. 1.04 ± 0.12 cm; 0.62 ± 0.10, 0.63 ± 0.17, and 0.45 ± 0.11 vs. 0.75 ± 0.13 cm; P < 0.05). The levels of ALD and AngII in the serum of rats in the sham group were significantly higher than those in the blank control group (371.58 ± 39.25 vs. 237.12 ± 17.35 μg/L; 232.18 ± 16.33 vs. 159.44 ± 18.42 pg/L; P < 0.05). The ALD and AngII of the rats in all of the three PHSD groups and the fosinopril group were decreased (276.81 ± 25.63, 277.18 ± 21.35, 268.19 ± 19.28, and 271.47 ± 28.96 vs. 371.58 ± 39.25 μg/L; 169.41 ± 27.53, 168.81 ± 19.78, 164.23 ± 21.34, and 174.27 ± 22.84 vs. 232.18 ± 16.33 pg/L; P < 0.05). The histopathological changes of the myocardium in the sham group showed the disorganized fiber, shaded staining, fracture, and zonation. The fracture of the myocardium was relieved in all groups except the sham group and the blank control group. Conclusion. Therefore, PHSD could shorten LVEDd and LVEDs of rats and reverse ventricular remodeling. The mechanism might be related to the inhibition of the activation level of renin‐angiotensin‐aldosterone system (especially ALD and AngII) and decreasing the postload of the heart.

Background: Atrial fibrillation (AF) is the most common arrhythmia. Previous studies mainly focused on identifying potential diagnostic biomarkers and treatment strategies for AF, while few studies concentrated on post-operative AF (POAF), particularly using bioinformatics analysis and machine learning algorithms. Therefore, our study aimed to identify immune-associated genes and provide the competing endogenous RNA (ceRNA) network for POAF.Methods: Three GSE datasets were downloaded from the GEO database, and we used a variety of bioinformatics strategies and machine learning algorithms to discover candidate hub genes. These techniques included identifying differentially expressed genes (DEGs) and circRNAs (DECs), building protein-protein interaction networks, selecting common genes, and filtering candidate hub genes via three machine learning algorithms. To assess the diagnostic value, we then created the nomogram and receiver operating curve (ROC). MiRNAs targeting DEGs and DECs were predicted using five tools and the competing endogenous RNA (ceRNA) network was built. Moreover, we performed the immune cell infiltration analysis to better elucidate the regulation of immune cells in POAF.Results: We identified 234 DEGs (82 up-regulated and 152 down-regulated) of POAF via Limma, 75 node genes were visualized via PPI network, which were mainly enriched in immune regulation. 15 common genes were selected using three CytoHubba algorithms. Following machine learning selection, the nomogram was created based on the four candidate hub genes. The area under curve (AUC) of the nomogram and individual gene were all over 0.75, showing the ideal diagnostic value. The dysregulation of macrophages may be critical in POAF pathogenesis. A novel circ_0007738 was discovered in POAF and the ceRNA network was eventually built.Conclusion: We identified four immune-associated candidate hub genes (C1QA, C1R, MET, and SDC4) for POAF diagnosis through the creation of a nomogram and evaluation of its diagnostic value. The modulation of macrophages and the ceRNA network may represent further therapy methods.