Post Cardiovascular Surgery Atrial Fibrillation. Biomarkers Determining Prognosis

Notoginsenoside R1 treatment facilitated Nrf2 nuclear translocation to suppress ferroptosis via Keap1/Nrf2 signaling pathway to alleviated high-altitude myocardial injury

High-altitude myocardial injury (HAMI) represents a critical form of altitude illness for which effective drug therapies are generally lacking. Notoginsenoside R1, a prominent constituent derived from Panax notoginseng, has demonstrated various cardioprotective properties in models of myocardial ischemia/reperfusion injury, sepsis-induced cardiomyopathy, cardiac fibrosis, and myocardial injury. The potential utility of notoginsenoside R1 in the management of HAMI warrants prompt investigation. Following the successful construction of a HAMI model, a series of experimental analyses were conducted to assess the effects of notoginsenoside R1 at dosages of 50 mg/Kg and 100 mg/Kg. The results indicated that notoginsenoside R1 exhibited protective effects against hypoxic injury by reducing levels of CK, CK-MB, LDH, and BNP, leading to improved cardiac function and decreased incidence of arrhythmias. Furthermore, notoginsenoside R1 was found to enhance Nrf2 nuclear translocation, subsequently regulating the SLC7A11/GPX4/HO-1 pathway and iron metabolism to mitigate ferroptosis, thereby mitigating cardiac inflammation and oxidative stress induced by high-altitude conditions. In addition, the application of ML385 has confirmed the involvement of Nrf2 nuclear translocation in the therapeutic approach to HAMI. Collectively, the advantageous impacts of notoginsenoside R1 on HAMI have been linked to the suppression of ferroptosis via Nrf2 nuclear translocation signaling.

Metabolic signatures in pericardial fluid and serum are associated with new-onset atrial fibrillation after isolated coronary artery bypass grafting

Postoperative atrial fibrillation (POAF) is a common complication of coronary artery bypass grafting (CABG) procedures. However, the molecular mechanism of POAF remains poorly understood, hence the absence of effective prevention strategies. Here we used targeted metabolomics on pericardial fluid and serum samples from CABG patients to investigate POAF-associated metabolic alterations and related risk prediction of new-onset AF. Nine differential metabolites in various metabolic pathways were found in both pericardial fluid and serum samples from patients with POAF and without POAF. By using machine learning algorithms and regression models, a 4-metabolite (aceglutamide, ornithine, methionine, and arginine) risk prediction model was constructed and showed accurate performance in predicting POAF in both discovery and validation sets. This work extends the metabolic insights of the cardiac microenvironment and blood in patients with POAF and paves the way for the use of targeted metabolomics for predicting POAF in patients with CABG surgery.

Correlation between Serum Myosin Light Chain 4 Levels and Recurrence after Radiofrequency Ablation in Patients with Atrial Fibrillation

Atrial fibrillation (AF) is the most common arrhythmia that is harmful to human health. This study aims to explore the relationship between myosin light chain 4 (MYL4) and AF recurrence after radiofrequency ablation (RFA). Patients with AF (n = 85) were enrolled, and healthy subjects (n = 90) with normal sinus rhythm and no previous history of AF were selected as controls. The serum levels of MYL4, transforming growth factor (TGF) -β1, and procollagen type-I C-terminal propeptide (PICP) were determined. The correlation between MYL4 and atrial fibrosis remodeling indicators (TGF-β1/PICP) and left atrial diameter (LAD) was analyzed. The influence of MYL4 on AF recurrence after RFA was evaluated, and the independent correlation between them was assessed. Patients with AF and the controls showed no significant differences in age, gender, body mass index, systolic blood pressure, diastolic blood pressure, left ventricular ejection fraction, triglycerides, total cholesterol, high-density lipoprotein, low-density lipoprotein, white blood cell count, neutrophil/lymphocyte ratio, brain natriuretic peptide, and history of smoking, drinking, hypertension, and diabetes (P > 0.05), but with increased LAD in patients with AF (P < 0.01). Serum MYL4 level was reduced in patients with AF (0.6 ± 0.2) compared with that of controls (0.1 ± 0.6) (P < 0.01), and it was negatively correlated with TGF-β1, PICP, and LAD (r = -0.2389, P < 0.05; r = -0.5174, P < 0.01; r = -0.3191; P < 0.01). Low levels of MYL4 increased the risk of AF recurrence after RFA (χ² = 16.64; P < 0.0001). A low MYL4 level in patients with AF showed a poorer prognosis. Serum MYL4 level and AF type were independent risk factors affecting AF recurrence after RFA.

Association of Mitral Regurgitation with Postoperative Atrial Fibrillation in Critically Ill Noncardiac Surgery Patients: A Prospective Cohort Study

Purpose

Atrial fibrillation (AF) is common in critically ill patients and can have serious consequences. Postoperative AF (POAF) in critically ill patients following noncardiac surgery has been understudied, contrary to cardiac procedures. Mitral regurgitation (MR) is associated with left ventricular dysfunction, which might contribute to the occurrence of AF in postoperative critically ill patients. This study aimed to investigate the association between MR and POAF in critically ill noncardiac surgery patients and establish a new nomogram for the prediction of POAF in critically ill noncardiac surgery patients.

Patients and Methods

A prospective cohort of 2474 patients who underwent thoracic and general surgery was enrolled in this study. Data on preoperative transthoracic echocardiography (TTE), electrocardiogram (ECG), and several commonly utilized scoring systems (CHA2DS2-VASc, HATCH, COM-AF, HART, and C2HEST) and baseline clinical data were collected. Independent predictors were selected by univariate and multivariable logistic regression analysis, and a nomogram was constructed for POAF within 7 days after postoperative intensive care unit (ICU) admission. The ability of the MR-nomogram and other scoring systems to predict POAF was compared by receiver operator characteristic (ROC) curve analysis and decision curve analysis (DCA). Additional contributions were evaluated by integrated discrimination improvement (IDI) and net reclassification improvement (NRI) analysis.

Results

A total of 213 (8.6%) patients developed POAF within 7 days after ICU admission. Compared to CHA2DS2-VASc, HATCH, COM-AF, HART, and C2HEST scoring systems, MR-nomogram showed better predictive ability for POAF with an area under the ROC curve of 0.824 (95% confidence interval: 0.805-0.842, p < 0.001). The improvement of the MR-nomogram in predictive value was supported by NRI and IDI analysis. The net benefit of the MR nomogram was maximal in DCA.

Conclusion

MR is an independent risk factor of POAF in critically ill noncardiac surgery patients. The nomogram predicted POAF better than other scoring systems.

Changes in Intestinal Flora Structure and Metabolites Are Associated With Myocardial Fibrosis in Patients With Persistent Atrial Fibrillation

Background: The occurrence of atrial fibrillation is often accompanied by myocardial fibrosis. An increasing number of studies have shown that intestinal flora is involved in the occurrence and development of a variety of cardiovascular diseases. This study explores the relationship between changes in the structure and function of intestinal flora and the progression of myocardial fibrosis in patients with persistent atrial fibrillation.

Methods: Serum and stool samples were collected from 10 healthy people and 10 patients with persistent atrial fibrillation (PeAF), and statistical analyses were performed on the subjects' clinical baseline conditions. ELISA was used to measure the levels of carboxy-terminal telopeptide of type I collagen (CTX-I), propeptide of type I procollagen (PICP), procollagen III N-terminal propeptide (PIIINP), fibroblast growth factor-23 (FGF-23), and transforming growth factor-beta 1 (TGF-β1) in serum. Through 16S rRNA sequencing technology, the structural composition of the intestinal flora was detected and analyzed. In addition, metabolomics data were analyzed to determine the differences in the metabolites produced by the intestinal flora of the subjects.

Results: By comparing the baseline data of the subjects, it was found that compared with those of the control group, the levels of creatinine (CRE) and serum uric acid (SUA) in the serum of PeAF patients were significantly increased. In addition, we found that the levels of CTX-I, PICP, PIIINP, and TGF-β1 in the serum of PeAF patients were significantly higher than those of the control group subjects. Although the control and PeAF groups exhibited no significant differences in the α diversity index, there were significant differences in the β diversity indexes (Bray-Curtis, weighted UniFrac and Anosim). At the phylum, family and species levels, the community structure and composition of the intestinal flora of the control group and those of the PeAF group showed significant differences. In addition, the compositions of the intestinal metabolites in the two different groups of people were significantly different. They were correlated considerably with PIIINP and specific communities in the intestinal flora.

Conclusion: Pathologically, PeAF patients may have a higher risk of myocardial fibrosis. Systematically, abnormal changes in the structure and composition of the intestinal flora in PeAF patients may lead to differences in intestinal metabolites, which are involved in the process of myocardial fibrosis through metabolite pathways.

Mechanism of IL-6-related spontaneous atrial fibrillation after coronary artery grafting surgery: IL-6 knockout mouse study and human observation

Clinical observation and ex vivo studies have established a strong association between inflammation and postoperative atrial fibrillation (POAF). However, it is unclear whether the inflammatory phenotype is causally linked to this event or is an epiphenomenon, and it is not known which inflammatory meditators may increase susceptibility to POAF. The limitations of available animal models of spontaneous POAF (sPOAF) makes it difficult to select an experimental system. Here, we provide experimental and clinical evidence for mechanistic involvement of interleukin-6 (IL-6) in sPOAF.

PHASE I

We established a mouse model of cardiac surgery with nonpaced sPOAF. IL-6 knockout mice were protected from sPOAF compared with wild-type mice.

PHASE II

At 48 hours after surgery, the heart was separated into 6 regions and cultured. IL-6 was expressed in all regions, with highest abundance in the left atrium (LA). In PHASE III, we demonstrated that IL-6 in the LA elicited early profibrotic properties in atria via the pSTAT3/STAT3 signaling pathway and contributed to sPOAF.

PHASE IV

In a translational prospective clinical study, we demonstrated that humans with POAF had a higher IL-6 concentration in pericardial drainage (PD). This study provides preliminary evidence of a causal relationship between IL-6 and POAF in a novel nonpaced sPOAF mouse model. IL-6 is a crucial prerequisite for eliciting profibrotic properties in cardiac myocytes via the pSTAT3 pathway during the early postoperative period, leading to an increased susceptibility to POAF. Measuring IL-6 in PD could be a new noninvasive biomarker for the clinical prediction of POAF.

The C-reactive protein/albumin ratio as a new predictor for postoperative atrial fibrillation after coronary artery bypass graft surgery

BACKGROUND

This study aimed to investigate the predictive significance of C-reactive protein/albumin ratio for postoperative atrial fibrillation occurrence in patients who were underwent coronary artery bypass graft surgery.

METHODS

Among 830 patients who underwent coronary artery bypass grafting with cardiopulmonary bypass between January 2016 and February 2020, 137 patients with no prior arrhythmia history were included in this cross sectional study.

RESULTS

One hundred and thirty-seven (16.5%) patients developed atrial fibrillation in postoperative period. Patients who experienced postoperative atrial fibrillation were more likely to be older but displayed similar rates of diabetes mellitus, hypertension, hypercholesterolemia, cerebrovascular disease, peripheral vascular disease and chronic obstructive pulmonary disease. For prediction of postoperative atrial fibrillation development, diagnostic odds ratio (OR) and positive likelihood ratio of C-reactive protein/albumin ratio value (OR: 1.854; confidence interval [CI]: 1.598-2.142; P < .001) was higher than serum C-reactive protein and albumin levels. (OR: 1.159; CI: 1.115-1.201; P < .001; OR: 0.438; CI: 0.258-0.865; P < .001, respectively). Which means that C-reactive protein/albumin ratio may detect postoperative atrial fibrillation development better C-reactive protein itself.

CONCLUSION

Based on our results, patients who developed postoperative atrial fibrillation after coronary artery bypass grafting had significantly higher preoperative C-reactive protein/albumin ratio levels than patients who remained in normal sinus rhythm in the postoperative period. Also, higher C-reactive protein/albumin ratio value was one of the independent predictive factors for postoperative atrial fibrillation. Therefore, we concluded that evaluating preoperative C-reactive protein/albumin ratio value might provide early identification of patients with high risk for postoperative atrial fibrillation.

Atrial fibrillation following heart transplantation: A systematic review and meta-analysis of observational studies

OBJECTIVE

Previous studies have suggested a high incidence of atrial fibrillation (AF) in heart transplant recipients. However, incidence trends of AF in heart transplant recipients remain unclear. The study's aims were (1) to investigate the pooled incidence/incidence trends of AF following heart transplantation and (2) to assess the mortality risk of heart transplant recipients with AF.

METHODS

A literature search for studies that reported the incidence of AF following heart transplantation was conducted using MEDLINE, EMBASE, and The Cochrane Database from inception through March 2018. Pooled incidence and odds ratios (OR) with 95%CI were calculated using a random-effects model.

RESULTS

Eighteen studies (2 cohorts from clinical trials and 16 cohort studies) with 5393 heart transplant recipients were enrolled. The pooled estimated incidence of AF in heart transplant was 10.1% (95%CI: 7.6%-13.2%). Meta-analysis based on the type of anastomotic technique demonstrated a pooled estimated incidence of AF following heart transplantation of 18.7% (95%CI: 10.3%-31.5%) and 11.1% (95%CI: 6.5%-18.4%) by biatrial and bicaval techniques, respectively. There was a significant association between AF following a heart transplant and increased mortality risk with a pooled OR of 2.86 (95%CI: 2.08-3.93). Meta-regression analyses showed no significant correlations between the year of study and incidence of AF (P = 0.47) or mortality risk of AF after heart transplantation (P = 0.99).

CONCLUSIONS

The overall estimated incidence of AF following heart transplantation is 10.1%. There is a significant association between AF and increased mortality after transplantation. Furthermore, incidence and mortality risk of AF following heart transplant does not seem to decrease over time.