Role of inflammation in atrial fibrillation pathophysiology and management

Immune response caused by M1 macrophages elicits atrial fibrillation-like phenotypes in coculture model with isogenic hiPSC-derived cardiomyocytes

BACKGROUND

Atrial fibrillation has an estimated prevalence of 1.5-2%, making it the most common cardiac arrhythmia. The processes that cause and sustain the disease are still not completely understood. An association between atrial fibrillation and systemic, as well as local, inflammatory processes has been reported. However, the exact mechanisms underlying this association have not been established. While it is understood that inflammatory macrophages can influence cardiac electrophysiology, a direct, causative relationship to atrial fibrillation has not been described. This study investigated the pro-arrhythmic effects of activated M1 macrophages on human induced pluripotent stem cell (hiPSC)-derived atrial cardiomyocytes, to propose a mechanistic link between inflammation and atrial fibrillation.

METHODS

Two hiPSC lines from healthy individuals were differentiated to atrial cardiomyocytes and M1 macrophages and integrated in an isogenic, pacing-free, atrial fibrillation-like coculture model. Electrophysiology characteristics of cocultures were analysed for beat rate irregularity, electrogram amplitude and conduction velocity using multi electrode arrays. Cocultures were additionally treated using glucocorticoids to suppress M1 inflammation. Bulk RNA sequencing was performed on coculture-isolated atrial cardiomyocytes and compared to meta-analyses of atrial fibrillation patient transcriptomes.

RESULTS

Multi electrode array recordings revealed M1 to cause irregular beating and reduced electrogram amplitude. Conduction analysis further showed significantly lowered conduction homogeneity in M1 cocultures. Transcriptome sequencing revealed reduced expression of key cardiac genes such as SCN5A, KCNA5, ATP1A1, and GJA5 in the atrial cardiomyocytes. Meta-analysis of atrial fibrillation patient transcriptomes showed high correlation to the in vitro model. Treatment of the coculture with glucocorticoids showed reversal of phenotypes, including reduced beat irregularity, improved conduction, and reversed RNA expression profiles.

CONCLUSIONS

This study establishes a causal relationship between M1 activation and the development of subsequent atrial arrhythmia, documented as irregularity in spontaneous electrical activation in atrial cardiomyocytes cocultured with activated macrophages. Further, beat rate irregularity could be alleviated using glucocorticoids. Overall, these results point at macrophage-mediated inflammation as a potential AF induction mechanism and offer new targets for therapeutic development. The findings strongly support the relevance of the proposed hiPSC-derived coculture model and present it as a first of its kind disease model.

Could the periodontal therapy improve the cardiologic patient health? A narrative review

BACKGROUND

Cardiovascular diseases (CVD) is the major cause of mortality globally, with increasing evidence suggesting a link between periodontitis, and CVD. This study aims to explore the association between periodontitis and CVD, and the impact of periodontal therapy on cardiovascular health.

METHODS

This review synthesized findings from preclinical and clinical studies, without publication year restrictions, examining periodontitis and CVD through various lenses. Scientific databases were inspected with keywords related to periodontitis and CVD.

RESULTS

The review identifies a substantial association between periodontitis and an increased risk of several CVD, supported by both epidemiological and interventional studies. Results suggest the complexity of the relationship, influenced by factors like the severity of periodontitis and the presence of other systemic conditions. Clinical data indicates that periodontal therapy, particularly non-surgical periodontal therapy, may reduce systemic inflammatory markers and thus may play a role in the primary and secondary prevention of CVD events, highlighting the potential of periodontal therapy to not only maintain oral health but also to modulate cardiovascular risk factors.

CONCLUSIONS

Current evidence supports a significant association between periodontitis and increased cardiovascular risk, promoting integrated healthcare approaches that consider oral health as a key-component of cardiovascular care and wellbeing.

Exploring Diet-Based Treatments for Atrial Fibrillation: Patient Empowerment and Citizen Science as a Model for Quality-of-Life-Centered Solutions

Atrial fibrillation (AF) is the most common heart rhythm disorder in the Western world. Between the years 2010 and 2019, the global prevalence of AF rose from 33.5 million to 59 million, highlighting the importance of developing equitable treatments for patients. The disease is associated with symptoms such as palpitations, dizziness, fatigue, shortness of breath, and cognitive dysfunction. In addition, AF increases the risk of developing a stroke and heart failure. Despite new insights into risk factors that can lead to the development of AF, the success of current treatments is suboptimal. Numerous risk factors, such as hypertension, diabetes, and obesity, have been associated with the development and progression of AF. As these can be lifestyle-related risk factors, lifestyle modification may be a solution to reduce AF-related symptoms as well as episodes. Research results show that certain dietary changes can reduce AF and numerous risk factors for AF. Increasing attention is being given to Mediterranean and whole, plant-based eating patterns, which emphasize eating grains, legumes, vegetables, fruits, and nuts, while excluding most-or all-animal products. Hence, what are the beneficial aspects of a Mediterranean and plant-based diet which consists mainly of unprocessed foods? In the current review, we discuss the outcomes of diet-based treatments. Moreover, other diet-related treatments, brought up by patient initiatives, are highlighted. These patient-initiated studies include L-glutamine and electrolytes as options to manage AF. Also, we highlight the emerging importance of valuing patient needs and a quality-of-life-centered approach to medicine. As indicated by recent studies and patient experiences, citizen science can create inclusive solutions that lead to patient empowerment and a holistic approach for AF management.

Multidisciplinary Approach in Atrial Fibrillation: As Good as Gold

Atrial fibrillation (AF) represents the most common sustained arrhythmia necessitating dual focus: acute complication management and sustained longitudinal oversight to modulate disease progression and ensure comprehensive patient care over time. AF is a multifaceted disorder; due to such a great number of potential exacerbating conditions, a multidisciplinary team (MDT) should manage AF patients by cooperating with a cardiologist. Effective management of AF patients necessitates the implementation of a well-coordinated and tailored care pathway aimed at delivering optimized treatment through collaboration among various healthcare professionals. Management of AF should be carefully evaluated and mutually agreed upon in consultation with healthcare providers. It is crucial to recognize that treatment may evolve due to the emergence of new risk factors, symptoms, disease progression, and advancements in treatment modalities. In the context of multidisciplinary AF teams, a coordinated approach involves assembling a diverse team tailored to meet individual patients' unique needs based on local services' availability.

Obesity Arrhythmias: Role of IL-6 Trans-Signaling

Obesity is a chronic disease that is rapidly increasing in prevalence and affects more than 600 million adults worldwide, and this figure is estimated to increase by at least double by 2030. In the United States, more than one-third of the adult population is either overweight or obese. The global obesity epidemic is a major risk factor for the development of life-threatening arrhythmias occurring in patients with long QT, particularly in conditions where multiple heart-rate-corrected QT-interval-prolonging mechanisms are simultaneously present. In obesity, excess dietary fat in adipose tissue stimulates the release of immunomodulatory cytokines such as interleukin (IL)-6, leading to a state of chronic inflammation in patients. Over the last decade, increasing evidence has been found to support IL-6 signaling as a powerful predictor of the severity of heart diseases and increased risk for ventricular arrhythmias. IL-6's pro-inflammatory effects are mediated via trans-signaling and may represent a novel arrhythmogenic risk factor in obese hearts. The first selective inhibitor of IL-6 trans-signaling, olamkicept, has shown encouraging results in phase II clinical studies for inflammatory bowel disease. Nevertheless, the connection between IL-6 trans-signaling and obesity-linked ventricular arrhythmias remains unexplored. Therefore, understanding how IL-6 trans-signaling elicits a cellular pro-arrhythmic phenotype and its use as an anti-arrhythmic target in a model of obesity remain unmet clinical needs.

Association between inflammatory bowel disease and atrial fibrillation: A systematic review and meta-analysis

Background

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is a prevalent condition associated with chronic noninfectious inflammation of the gastrointestinal tract. It has been hypothesized that chronic inflammation can predispose patients to atrial fibrillation (AF), however, no clear evidence exists to support this.

Methods

A systematic literature search was conducted using major databases aimed at studies focusing on AF development in patients with IBD. Further subgroup analyses were performed for ulcerative colitis (UC) and crohn's disease (CD). Risk ratios (RR) with their corresponding 95 % confidence intervals (CI) were pooled using a random-effects model in the Review Manager Software. Statistical significance was set at p < 0.05.

Results

Seven studies with 88,893,407 patients were included (1,002,719 and 87, 890, 688 patients in the IBD and non-IBD groups, respectively). IBD patients were at an increased risk of developing AF [RR: 1.52; 95 % CI: 1.19-1.95; p = 0.0009] compared to the non-IBD group. In subgroup analyses, patients with UC were at an increased risk of developing AF [RR: 1.29; 95 % CI: 1.08-1.53; p = 0.004], as were CD patients [RR: 1.30; 95 % CI: 1.07-1.58; p = 0.008] compared to the non-UC and non-CD groups, respectively.

Conclusion

Patients with IBD are at nearly 1.5 times the risk of developing AF compared to the non-IBD population. Our meta-analysis was limited by heterogeneity among the studies, highlighting the importance of further large-scale prospective studies to establish more robust evidence.

Fibroblast growth factor 5 as a target for atrial fibrillation treatment: Evidence from mendelian randomization

BACKGROUND

Previous studies have found that inflammatory proteins are involved in the pathogenesis of atrial fibrillation (AF). We used mendelian randomization to explore the potential pathogenic inflammatory proteins of AF.

METHODS

This study adopts a Mendelian randomization design to primarily assess causal associations using the Wald ratio and the inverse variance weighting method. It leverages protein quantitative trait locus (pQTL) data encompassing 91 types of inflammatory proteins from 14,824 participants of European ancestry. The primary analysis phase utilizes AF GWAS data from 55,106 participants, with an additional 237,690 participants included in the validation stage. Sensitivity analyses, including reverse causality analysis, Bayesian colocalization analysis, and phenotype scanning, were conducted. Finally, the study explores potential targeted drugs.

RESULTS

The findings highlight a causal link between 7 inflammatory proteins and AF, with 2 showing positive correlations and 5 exhibiting negative correlations. Among these, fibroblast growth factor 5 (FGF5) emerges as particularly robust in sensitivity analysis. Colocalization analysis indicates a shared genetic variation between FGF5 and AF, supporting its potential as a targeted therapy for AF. Importantly, this causal relationship remains unaffected by reverse causality. Furthermore, significant pleiotropic effects were observed in phenotype scanning. Finally, the causal association between FGF5 and AF was successfully replicated during the validation phase.

CONCLUSION

FGF5 may become an intervention target for AF targeted therapy.

Myeloperoxidase and its derivative hypochlorous acid combined clinical indicators predict new-onset atrial fibrillation in sepsis: a case-control study

BACKGROUD

New-onset atrial fibrillation (NOAF) is a common complication of sepsis and linked to higher death rates in affected patients. The lack of effective predictive tools hampers early risk assessment for the development of NOAF. This study aims to develop practical and effective predictive tools for identifying the risk of NOAF.

METHODS

This case-control study retrospectively analyzed patients with sepsis admitted to the emergency department of Xinhua Hospital, Shanghai Jiao Tong University School of Medicine from September 2017 to January 2023. Based on electrocardiographic reports and electrocardiogram monitoring records, patients were categorized into NOAF and non-NOAF groups. Laboratory tests, including myeloperoxidase (MPO) and hypochlorous acid (HOCl), were collected, along with demographic data and comorbidities. Least absolute shrinkage and selection operator regression and multivariate logistic regression analyses were employed to identify predictors. The area under the curve (AUC) was used to evaluate the predictive model's performance in identifying NOAF.

RESULTS

A total of 389 patients with sepsis were included in the study, of which 63 developed NOAF. MPO and HOCl levels were significantly higher in the NOAF group compared to the non-NOAF group. Multivariate logistic regression analysis identified MPO, HOCl, tumor necrosis factor-α (TNF-α), white blood cells (WBC), and the Acute Physiology and Chronic Health Evaluation II (APACHE II) score as independent risk factors for NOAF in sepsis. Additionally, a nomogram model developed using these independent risk factors achieved an AUC of 0.897.

CONCLUSION

The combination of MPO and its derivative HOCl with clinical indicators improves the prediction of NOAF in sepsis. The nomogram model can serve as a practical predictive tool for the early identification of NOAF in patients with sepsis.

Identification of atrial fibrillation-related genes through transcriptome data analysis and Mendelian randomization

Background

Atrial fibrillation (AF) is a common persistent arrhythmia characterized by rapid and chaotic atrial electrical activity, potentially leading to severe complications such as thromboembolism, heart failure, and stroke, significantly affecting patient quality of life and safety. As the global population ages, the prevalence of AF is on the rise, placing considerable strains on individuals and healthcare systems. This study utilizes bioinformatics and Mendelian Randomization (MR) to analyze transcriptome data and genome-wide association study (GWAS) summary statistics, aiming to identify biomarkers causally associated with AF and explore their potential pathogenic pathways.

Methods

We obtained AF microarray datasets GSE41177 and GSE79768 from the Gene Expression Omnibus (GEO) database, merged them, and corrected for batch effects to pinpoint differentially expressed genes (DEGs). We gathered exposure data from expression quantitative trait loci (eQTL) and outcome data from AF GWAS through the IEU Open GWAS database. We employed inverse variance weighting (IVW), MR-Egger, weighted median, and weighted model approaches for MR analysis to assess exposure-outcome causality. IVW was the primary method, supplemented by other techniques. The robustness of our results was evaluated using Cochran's Q test, MR-Egger intercept, MR-PRESSO, and leave-one-out sensitivity analysis. A "Veen" diagram visualized the overlap of DEGs with significant eQTL genes from MR analysis, referred to as common genes (CGs). Additional analyses, including Gene Ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, and immune cell infiltration studies, were conducted on these intersecting genes to reveal their roles in AF pathogenesis.

Results

The combined dataset revealed 355 differentially expressed genes (DEGs), with 228 showing significant upregulation and 127 downregulated. Mendelian randomization (MR) analysis identified that the autocrine motility factor receptor (AMFR) [IVW: OR = 0.977; 95% CI, 0.956-0.998; P = 0.030], leucine aminopeptidase 3 (LAP3) [IVW: OR = 0.967; 95% CI, 0.934-0.997; P = 0.048], Rab acceptor 1 (RABAC1) [IVW: OR = 0.928; 95% CI, 0.875-0.985; P = 0.015], and tryptase beta 2 (TPSB2) [IVW: OR = 0.971; 95% CI, 0.943-0.999; P = 0.049] are associated with a reduced risk of atrial fibrillation (AF). Conversely, GTPase-activating SH3 domain-binding protein 2 (G3BP2) [IVW: OR = 1.030; 95% CI, 1.004-1.056; P = 0.024], integrin subunit beta 2 (ITGB2) [IVW: OR = 1.050; 95% CI, 1.017-1.084; P = 0.003], glutaminyl-peptide cyclotransferase (QPCT) [IVW: OR = 1.080; 95% CI, 1.010-0.997; P = 1.154], and tripartite motif containing 22 (TRIM22) [IVW: OR = 1.048; 95% CI, 1.003-1.095; P = 0.035] are positively associated with AF risk. Sensitivity analyses indicated a lack of heterogeneity or horizontal pleiotropy (P > 0.05), and leave-one-out analysis did not reveal any single nucleotide polymorphisms (SNPs) impacting the MR results significantly. GO and KEGG analyses showed that CG is involved in processes such as protein polyubiquitination, neutrophil degranulation, specific and tertiary granule formation, protein-macromolecule adaptor activity, molecular adaptor activity, and the SREBP signaling pathway, all significantly enriched. The analysis of immune cell infiltration demonstrated associations of CG with various immune cells, including plasma cells, CD8T cells, resting memory CD4T cells, regulatory T cells (Tregs), gamma delta T cells, activated NK cells, activated mast cells, and neutrophils.

Conclusion

By integrating bioinformatics and MR approaches, genes such as AMFR, G3BP2, ITGB2, LAP3, QPCT, RABAC1, TPSB2, and TRIM22 are identified as causally linked to AF, enhancing our understanding of its molecular foundations. This strategy may facilitate the development of more precise biomarkers and therapeutic targets for AF diagnosis and treatment.

Risk Factors and Prognosis of Perioperative Atrial Fibrillation in Elderly Patients Undergoing VATS Lung Surgery: A Retrospective Cohort Study

Background

Atrial fibrillation (AF) has become the most common postoperative arrhythmia of thoracic surgery. This study aimed to investigate the risk factors and complications of perioperative atrial fibrillation (PoAF) in elderly patients who underwent video-assisted thoracoscopic surgery (VATS).

Methods

Data were collected from patients who underwent VATS between January 2013 and December 2022 at Peking Union Medical College Hospital (PUMCH). Univariable analyses and multivariable logistic regression analyses were used to determine the factors correlated with PoAF. Receiver operating characteristic (ROC) curve was used to evaluate the discrimination of the indicators to predict PoAF.

Results

The study enrolled 2920 patients, with a PoAF incidence of 5.2% (95% CI 4.4%-6.0%). In the logistic regression analyses, male sex (OR=1.496, 95% CI 1.056-2.129, P=0.024), left atrial anteroposterior dimension (LAD) ≥40 mm (OR=2.154, 95% CI 1.235-3.578, P=0.004), hypertension (HTN) without regular treatment (OR=2.044, 95% CI 0.961-3.921, P=0.044), a history of hyperthyroidism (OR=4.443, 95% CI 0.947-15.306, P=0.030), surgery of the left upper lobe (compared to other lung lobes) (OR=1.625, 95% CI 1.139-2.297, P=0.007), postoperative high blood glucose (BG) (OR=2.482, 95% CI 0.912-5.688, P=0.048), and the time of chest tube removal (per day postoperatively) (OR=1.116, 95% CI 1.038-1.195, P=0.002) were found to be significantly associated with PoAF. The area under the ROC curve was 0.707 (95% CI 0.519-0.799). 86.9% patients were successfully converted to sinus rhythm. Compared with the non-PoAF group, the PoAF group had significantly greater risks of prolonged air leakage, postoperative acute coronary syndrome, longer ICU stays, and longer hospital stays.

Conclusion

Male sex, LAD≥40 mm, HTN without regular treatment, a history of hyperthyroidism, surgery of the left upper lobe, postoperative BG, and the time of chest tube removal were associated with PoAF. These findings may help clinicians identify high-risk patients and take preventive measures to minimize the incidence and adverse prognosis of PoAF.

LNK/SH2B3 loss of function increases susceptibility to murine and human atrial fibrillation

AIMS

The lymphocyte adaptor protein (LNK) is a negative regulator of cytokine and growth factor signalling. The rs3184504 variant in SH2B3 reduces LNK function and is linked to cardiovascular, inflammatory, and haematologic disorders, including stroke. In mice, deletion of Lnk causes inflammation and oxidative stress. We hypothesized that Lnk-/- mice are susceptible to atrial fibrillation (AF) and that rs3184504 is associated with AF and AF-related stroke in humans. During inflammation, reactive lipid dicarbonyls are the major components of oxidative injury, and we further hypothesized that these mediators are critical drivers of the AF substrate in Lnk-/- mice.

METHODS AND RESULTS

Lnk-/- or wild-type (WT) mice were treated with vehicle or 2-hydroxybenzylamine (2-HOBA), a dicarbonyl scavenger, for 3 months. Compared with WT, Lnk-/- mice displayed increased AF duration that was prevented by 2-HOBA. In the Lnk-/- atria, action potentials were prolonged with reduced transient outward K+ current, increased late Na+ current, and reduced peak Na+ current, pro-arrhythmic effects that were inhibited by 2-HOBA. Mitochondrial dysfunction, especially for Complex I, was evident in Lnk-/- atria, while scavenging lipid dicarbonyls prevented this abnormality. Tumour necrosis factor-α (TNF-α) and interleukin-1 beta (IL-1β) were elevated in Lnk-/- plasma and atrial tissue, respectively, both of which caused electrical and bioenergetic remodelling in vitro. Inhibition of soluble TNF-α prevented electrical remodelling and AF susceptibility, while IL-1β inhibition improved mitochondrial respiration but had no effect on AF susceptibility. In a large database of genotyped patients, rs3184504 was associated with AF, as well as AF-related stroke.

CONCLUSION

These findings identify a novel role for LNK in the pathophysiology of AF in both experimental mice and humans. Moreover, reactive lipid dicarbonyls are critical to the inflammatory AF substrate in Lnk-/- mice and mediate the pro-arrhythmic effects of pro-inflammatory cytokines, primarily through electrical remodelling.

miR-338-5p regulated the NF-κB/MAPK pathway to alleviate inflammation and oxidative stress by targeting IL-6 in rats with atrial fibrillation

The aim of this study was to investigate the functional effect of miR-338-5p targeting IL-6 on NF-κB/MAPK pathway-mediated inflammation and oxidative stress in atrial fibrillation (AF) rats. AF model rats were generated by tail vein injection of 0.1 mL Ach-CaCl2 mixture. The overexpression and suppression of miR-338-5p were established by injecting a miR-338-5p-agomir and a miR-338-5p-antagomir, respectively, into AF rats. Cardiac morphological changes were detected by H&E and Masson staining. The levels of ROS, SOD, T-AOC, IL-6, IL-1β, and TNF-α were detected via ELISA. Dual luciferase assays, qRT‒PCR, and western blotting were used to verify that miR-338-5p targets IL-6. The expression of NF-κB/MAPK pathway proteins was detected by western blot. Overexpression of miR-338-5p ameliorated heart damage in AF rats. Increased miR-338-5p reduced the levels of CK, CK-MB, and cTnT to alleviate myocardial injury. Furthermore, overexpression of miR-338-5p relieved inflammation and oxidative stress by downregulating SOD and T-AOC and upregulating IL-6, IL-1β, TNF-α, and ROS. Further research revealed that upregulation of miR-338-5p reduced the protein levels of p-p38, p-p65 and p-ERK1/2. The opposite results were obtained following miR-338-5p-antagomir treatment. Taken together, these findings indicate that the upregulation of miR-338-5p alleviated inflammation and oxidative stress by targeting IL-6 to inhibit the NF-κB/MAPK pathway, thus providing a new therapeutic target for AF.

Epicardial placement of human placental membrane allografts in coronary artery bypass graft surgery is associated with reduced postoperative atrial fibrillation: a pilot study for a future multi-center randomized controlled trial

BACKGROUND

Post-operative atrial fibrillation (POAF) occurs in up to 40% of patients following coronary artery bypass grafting (CABG) and is associated with a higher risk of stroke and mortality. This study investigates how POAF may be mitigated by epicardial placement of aseptically processed human placental membrane allografts (HPMAs) before pericardial closure in CABG surgery. This study was conducted as a pilot feasibility study to collect preliminary for a forthcoming multi-center randomized controlled trial.

METHODS

This retrospective observational study of patients undergoing CABG surgery excluded patients with pre-operative heart failure, chronic kidney disease, or a history of atrial fibrillation. The "treatment" group (n = 24) had three HPMAs placed epicardially following cardiopulmonary bypass decannulation but before partial pericardial approximation and chest closure. The only difference in clinical protocol for the control group (n = 54) was that they did not receive HPMA.

RESULTS

HPMA-treated patients saw a significant, greater than four-fold reduction in POAF incidence compared to controls (35.2-8.3%, p = 0.0136). Univariate analysis demonstrated that HPMA treatment was associated with an 83% reduction in POAF (OR = 0.17, p = 0.0248). Multivariable analysis yielded similar results (OR = 0.07, p = 0.0156) after controlling for other covariates. Overall length of stay (LOS) between groups was similar, but ICU LOS trended lower with HPMA treatment (p = 0.0677). Post-operative inotrope and vasopressor requirements were similar among groups. There was no new-onset post-operative heart failure, stroke, or death reported up to thirty days in either group.

CONCLUSIONS

Epicardial HPMA placement can be a simple intervention at the end of CABG surgery that may provide a new approach to reduce post-operative atrial fibrillation by modulating local inflammation, possibly reducing ICU and hospital stay, and ultimately improving patient outcomes.

Metabolic remodelling in atrial fibrillation: manifestations, mechanisms and clinical implications

Atrial fibrillation (AF) is a continually growing health-care burden that often presents together with metabolic disorders, including diabetes mellitus and obesity. Current treatments often fall short of preventing AF and its adverse outcomes. Accumulating evidence suggests that metabolic disturbances can promote the development of AF through structural and electrophysiological remodelling, but the underlying mechanisms that predispose an individual to AF are aetiology-dependent, thus emphasizing the need for tailored therapeutic strategies to treat AF that target an individual's metabolic profile. AF itself can induce changes in glucose, lipid and ketone metabolism, mitochondrial function and myofibrillar energetics (as part of a process referred to as 'metabolic remodelling'), which can all contribute to atrial dysfunction. In this Review, we discuss our current understanding of AF in the setting of metabolic disorders, as well as changes in atrial metabolism that are relevant to the development of AF. We also describe the potential of available and emerging treatment strategies to target metabolic remodelling in the setting of AF and highlight key questions and challenges that need to be addressed to improve outcomes in these patients.

A microfluidic model to study the effects of arrhythmic flows on endothelial cells

Atrial fibrillation (AF) is the most common type of cardiac arrhythmia and an important contributor to morbidity and mortality. Endothelial dysfunction has been postulated to be an important contributing factor in cardiovascular events in patients with AF. However, how vascular endothelial cells respond to arrhythmic flow is not fully understood, mainly due to the limitation of current in vitro systems to mimic arrhythmic flow conditions. To address this limitation, we developed a microfluidic system to study the effect of arrhythmic flow on the mechanobiology of human aortic endothelial cells (HAECs). The system utilises a computer-controlled piezoelectric pump for generating arrhythmic flow with a unique ability to control the variability in both the frequency and amplitude of pulse waves. The flow rate is modulated to reflect physiological or pathophysiological shear stress levels on endothelial cells. This enabled us to systematically dissect the importance of variability in the frequency and amplitude of pulses and shear stress level on endothelial cell mechanobiology. Our results indicated that arrhythmic flow at physiological shear stress level promotes endothelial cell spreading and reduces the plasma membrane-to-cytoplasmic distribution of β-catenin. In contrast, arrhythmic flow at low and atherogenic shear stress levels does not promote endothelial cell spreading or redistribution of β-catenin. Interestingly, under both shear stress levels, arrhythmic flow induces inflammation by promoting monocyte adhesion via an increase in ICAM-1 expression. Collectively, our microfluidic system provides opportunities to study the effect of arrhythmic flows on vascular endothelial mechanobiology in a systematic and reproducible manner.

The Role of Ferroptosis in Atrial Fibrillation: A Promising Future

Atrial fibrillation (AF) is one of the most common cardiac arrhythmias, with its diagnosis being closely tied to higher rates of cardiovascular morbidity and mortality. AF is associated with a range of dangerous complications including stroke and heart failure, making it a key driver of healthcare spending and a major threat to global public health. The precise mechanisms that govern AF incidence and the onset of related complications, however, remain uncertain. Ferroptotic cell death has been the focus of rising interest in the cardiac arrhythmias, and there is recent evidence supporting a role for atrial ferroptosis as a mediator of AF development. Interventional strategies focused on ferroptotic activity, such as novel ferroptosis inhibitors, have also shown promise as a means of protecting against AF through their ability to reduce iron overload. In this review, we provide a summary of the proposed mechanisms whereby ferroptosis contributes to the pathophysiology of AF and their therapeutic implications.

The relationship between atrial cardiopathy biomarkers and prognosis of patients with acute ischemic stroke after endovascular treatment

Thromboembolism is a possible consequence of underlying atrial cardiopathy, which can occur even before the onset of atrial fibrillation. Our objective was to examine the association between biomarkers of atrial cardiopathy and outcomes of acute ischemic stroke (AIS) following endovascular treatment (EVT). We conducted a retrospective study that collected data from patients with AIS who underwent EVT and compared the outcomes between those with and without atrial cardiopathy. Neurological function was assessed using the modified Rankin Scale (mRS), with an mRS score >2 indicating poor function at day 90. Additionally, we evaluated secondary consequences, including symptomatic intracerebral hemorrhage (sICH), early neurological deterioration (END), and malignant cerebral edema (MCE). Our study included 87 patients (77.6 ​% male; mean age 60.93 ​± ​12.47 years). Among these patients, 29 (33.3 ​%) had atrial cardiopathy, while the remaining 58 (66.7 ​%) did not. In the atrial cardiopathy group, 12 patients (41.4 ​%) had poor functional outcomes (mRS>2), compared to 19 (32.8 ​%) in the non-atrial cardiopathy group. We observed sICH in 22 (25.3 ​%) patients, END in 14 (16.1 ​%) patients, MCE in 11 (12.6 ​%) patients, and two (2.3 ​%) patients who died in the hospital. We found that patients with PTFV1>5000 ​μV/ms (OR: 8.39, 95 ​% CI: 1.43-105.95, P ​= ​0.02) and NT-proBNP>250 ​pg/mL (OR: 5.09, 95 ​% CI: 1.20-27.63, P ​= ​0.03) had significantly higher risk of END. After adjusting for covariates in the Firth logistic regression, we further found that atrial cardiopathy was significantly associated with END, as revealed by both univariate (OR: 6.31, 95 ​% CI: 1.42-59.87, P ​= ​0.01) and multivariable firth regression models (Modle 1, OR: 7.10, 95 ​% CI: 1.57-67.38, P ​< ​0.01; Modle 2, OR: 7.82, 95 ​% CI: 1.69, 76.36, P ​< ​0.01; Modle 3, OR: 8.59, 95 ​% CI: 1.72-91.70, P ​< ​0.01). Moreover, we observed that atrial cardiopathy was associated with an increased risk of END in AIS patients with large artery atherosclerosis (LAA) receiving EVT. Therefore, clinicians should consider atrial cardiopathy as a possible underlying cause of AIS in their patients. Further investigation is warranted to elucidate the relationship between atrial cardiopathy and AIS's occurrence, progression, and prognosis.

CT-Assessment of Epicardial Fat Identifies Increased Inflammation at the Level of the Left Coronary Circulation in Patients with Atrial Fibrillation

Background: Atrial fibrillation (AF) can often be triggered by an inflammatory substrate. Perivascular inflammation may be assessed nowadays using coronary computed tomography angiography (CCTA) imaging. The new pericoronary fat attenuation index (FAI HU) and the FAI Score have prognostic value for predicting future cardiovascular events. Our purpose was to investigate the correlation between pericoronary fat inflammation and the presence of AF among patients with coronary artery disease. Patients and methods: Eighty-one patients (mean age 64.75 ± 7.84 years) who underwent 128-slice CCTA were included in this study and divided into two groups: group 1 comprised thirty-six patients with documented AF and group 2 comprised forty-five patients without a known history of AF. Results: There were no significant differences in the absolute value of fat attenuation between the study groups (p > 0.05). However, the mean FAI Score was significantly higher in patients with AF (15.53 ± 10.29 vs. 11.09 ± 6.70, p < 0.05). Regional analysis of coronary inflammation indicated a higher level of this process, especially at the level of the left anterior descending artery (13.17 ± 7.91 in group 1 vs. 8.80 ± 4.75 in group 2, p = 0.008). Conclusions: Patients with AF present a higher level of perivascular inflammation, especially in the region of the left coronary circulation, and this seems to be associated with a higher risk of AF development.

Unbiased characterization of atrial fibrillation phenotypic architecture provides insight to genetic liability and clinically relevant outcomes

Background

Atrial Fibrillation (AF) is a common and clinically heterogeneous arrythmia. Machine learning (ML) algorithms can define data-driven disease subtypes in an unbiased fashion, but whether the AF subgroups defined in this way align with underlying mechanisms, such as high polygenic liability to AF or inflammation, and associate with clinical outcomes is unclear.

Methods

We identified individuals with AF in a large biobank linked to electronic health records (EHR) and genome-wide genotyping. The phenotypic architecture in the AF cohort was defined using principal component analysis of 35 expertly curated and uncorrelated clinical features. We applied an unsupervised co-clustering machine learning algorithm to the 35 features to identify distinct phenotypic AF clusters. The clinical inflammatory status of the clusters was defined using measured biomarkers (CRP, ESR, WBC, Neutrophil %, Platelet count, RDW) within 6 months of first AF mention in the EHR. Polygenic risk scores (PRS) for AF and cytokine levels were used to assess genetic liability of clusters to AF and inflammation, respectively. Clinical outcomes were collected from EHR up to the last medical contact.

Results

The analysis included 23,271 subjects with AF, of which 6,023 had available genome-wide genotyping. The machine learning algorithm identified 3 phenotypic clusters that were distinguished by increasing prevalence of comorbidities, particularly renal dysfunction, and coronary artery disease. Polygenic liability to AF across clusters was highest in the low comorbidity cluster. Clinically measured inflammatory biomarkers were highest in the high comorbid cluster, while there was no difference between groups in genetically predicted levels of inflammatory biomarkers. Subgroup assignment was associated with multiple clinical outcomes including mortality, stroke, bleeding, and use of cardiac implantable electronic devices after AF diagnosis.

Conclusion

Patient subgroups identified by unsupervised clustering were distinguished by comorbidity burden and associated with risk of clinically important outcomes. Polygenic liability to AF across clusters was greatest in the low comorbidity subgroup. Clinical inflammation, as reflected by measured biomarkers, was lowest in the subgroup with lowest comorbidities. However, there were no differences in genetically predicted levels of inflammatory biomarkers, suggesting associations between AF and inflammation is driven by acquired comorbidities rather than genetic predisposition.

The relationship between right atrial wall inflammation and poor prognosis of atrial fibrillation based on 18F-FDG positron emission tomography/computed tomography

Background

Atrial fibrillation (AF) has been identified to increase stroke risk, even after oral anticoagulants (OACs), and the recurrence rate is high after radiofrequency catheter ablation (RFCA). Inflammation is an essential factor in the occurrence and persistence of AF. 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) is an established molecular imaging modality to detect local inflammation. We aimed to investigate the relationship between atrial inflammatory activity and poor prognosis of AF based on 18F-FDG PET/CT.

Methods

A total of 204 AF patients including 75 with paroxysmal AF (ParAF) and 129 with persistent AF (PerAF) who underwent PET/CT before treatment were enrolled in this prospective cohort study. Clinical data, electrocardiograph (ECG), echocardiography, and cardiac 18F-FDG uptake were collected. Follow-up information was obtained from patient clinical case notes or telephone reviews, with the starting point being the time of PET/CT scan. The follow-up deadline was either the date of AF recurrence after RFCA, new-onset stroke, or May 2023. Cox proportional hazards regression models were used to identify predictors of poor prognosis and hazard ratios (HRs) with 95% confidence intervals (CIs) was calculated.

Results

Median follow-up time was 29 months [interquartile range (IQR), 22-36 months]. Poor prognosis occurred in 52 patients (25.5%), including 34 new-onset stroke patients and 18 recrudescence after RFCA. The poor prognosis group had higher congestive heart failure, hypertension, age ≥75 years (doubled), diabetes mellitus, prior stroke or transient ischemic attack (TIA) or thromboembolism (doubled), vascular disease, age 65-74 years, sex category (female) (CHA2DS2-VASc) score [3.0 (IQR, 1.0-3.75) vs. 2.0 (IQR, 1.0-3.0), P=0.01], right atrial (RA) wall maximum standardized uptake value (SUVmax) (4.13±1.82 vs. 3.74±1.58, P=0.04), higher percentage of PerAF [39 (75.0%) vs. 90 (59.2%), P=0.04], left atrial (LA) enlargement [45 (86.5%) vs. 104 (68.4%), P=0.01], and RA wall positive FDG uptake [40 (76.9%) vs. 79 (52.0%), P=0.002] compared with the non-poor prognosis group. Univariate and multivariate Cox proportional hazard regression analysis concluded that only CHA2DS2-VASc score (HR, 1.29; 95% CI: 1.06-1.57; P=0.01) and RA wall positive FDG uptake (HR, 2.68; 95% CI: 1.10-6.50; P=0.03) were significantly associated with poor prognosis.

Conclusions

RA wall FDG positive uptake based on PET/CT is tightly related to AF recurrence after RFCA or new-onset stroke after antiarrhythmic and anticoagulation treatment.

Bioinformatics analysis reveals the potential common genes and immune characteristics between atrial fibrillation and periodontitis

BACKGROUND AND OBJECTIVE

Atrial fibrillation (AF) and periodontitis, both classified under chronic inflammatory diseases, share common etiologies, including genetic factors and immune pathways. However, the exact mechanisms are still poorly understood. This study aimed to explore the potential common genes and immune characteristics between AF and periodontitis.

METHODS

Gene expression datasets for AF and periodontitis were downloaded from the Gene Expression Omnibus (GEO) database. Differential expression analysis was used to identify common genes in the training set. Functional analyses, including Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, were conducted to elucidate the underlying mechanisms. Hub genes were further screened based on expression levels, receiver operating characteristic (ROC) curves, and least absolute shrinkage and selection operator (LASSO) regression. Then, based on the expression levels and ROC values of the hub genes in the validation set, the target genes were identified. Finally, immune cell infiltration analysis was performed on the AF and periodontitis datasets in the training set using the "CIBERSORT" R package. The relationships between target genes, infiltrating immune cells, and inflammatory factors were also investigated. In addition, AF susceptibility, atrial fibrosis, inflammatory infiltration, and RGS1 protein expression in rat models of periodontitis were assessed through in vivo electrophysiology experiments, Masson's trichrome staining, hematoxylin-eosin staining, immunohistochemistry, and western blotting, respectively.

RESULTS

A total of 21 common genes were identified between AF and periodontitis among the differentially expressed genes. After evaluating gene expression levels, ROC curves, and LASSO analysis, four significant genes between AF and periodontitis were identified, namely regulator of G-protein signaling 1 (RGS1), annexin A6 (ANXA6), solute carrier family 27 member 6 (SLC27A6), and ficolin 1 (FCN1). Further validation confirmed that RGS1 was the optimal shared target gene for AF and periodontitis. Immune cell infiltration analysis revealed that neutrophils and T cells play an important role in the pathogenesis of both diseases. RGS1 showed a significant positive correlation with activated memory CD4 T cells and gamma-delta T cells and a negative correlation with CD8 T cells and regulatory T cells in both training sets. Moreover, RGS1 was positively correlated with classical pro-inflammatory cytokines IL1β and IL6. In periodontitis rat models, AF susceptibility, atrial fibrosis, and inflammatory infiltration were significantly increased, and RGS1 expression in the atrial tissue was upregulated.

CONCLUSION

A common gene between AF and periodontitis, RGS1 appears central in linking the two conditions. Immune and inflammatory responses may underlie the interaction between AF and periodontitis.

Impaired Well-Being and Insomnia as Residuals of Resolved Medical Conditions: Survey in the Italian Population

BACKGROUND

Well-being encompasses physical, mental, social, and cultural aspects. Sleep quality and pathologies are among the objective conditions jeopardising it. Chronic insomnia, inflammatory-based diseases, and mood disorders often occur in a single cluster, and inflammation can negatively impact sleep, potentially harming well-being. Some evidence from specific clinical populations suggests that also some resolved past diseases could still have an impact on present sleep quality and well-being. The aim of the present study is to investigate, in the general population, whether and to what degree well-being and insomnia are associated with resolved pathologies.

METHODS

A cross-sectional survey (IPSAD®) was carried out using anonymous postal questionnaires that investigated past and present general health, well-being, and insomnia. A total of 10,467 subjects answered the questionnaire.

RESULTS

Several classes of both current and resolved pathologies resulted in increased odds ratios for current insomnia (odds ratios = 1.90; 1.43, respectively) and impaired well-being (odds ratios = 1.75; 1.33, respectively), proportional to the number of the displayed pathologies. Notably, both current and resolved past psychiatric disorders were strongly associated with both current impaired well-being (odds ratios = 5.38; 1.70, respectively) and insomnia (odds ratios = 4.99; 2.15, respectively).

CONCLUSIONS

To explain these associations, we suggest that systemic inflammation conveyed by several medical conditions disrupts homeostatic processes, with final effects on sleep quality and behaviour.

Oral anticoagulants increased 30-day survival in sepsis patients complicated with atrial fibrillation: a retrospective analysis from MIMIC-IV database

Background

The severity of sepsis is associated with systemic clotting activation. Atrial fibrillation (AF) is the most commonly observed arrhythmia in patients with sepsis and can lead to a poor prognosis. The aim of this study is to elucidate the association between oral anticoagulants and survival from septic patients complicated with AF.

Methods

The data of 8,828 septic patients, including 2,955 AF and 5,873 without AF, were all originated from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Patients with sepsis and AF are divided into OAC- group (n = 1,774) and OAC+ group (n = 1,181) based on OAC therapy. Septic patients with no AF were considered as the control group (n = 5,873, sepsis and no AF group). The main outcome endpoint was the survival rate of 30 day. The secondary outcome endpoint was the length of stay (LOS) from intensive care unit and hospital. Propensity score matching (PSM) was used to adjust the influence of superfluous factors, and a restricted mean survival time (RMST) analysis was used for calculating the benefit of survival time and survival rate. Analysis including univariate and multivariate logistic regression analysis was conducted to find prognosis-related predictors.

Results

After PSM, the OAC+group had a higher 30-day survival rate compared to the OAC- group (81.59% vs. 58.10%; P < 0.001) in the ICU. Despite the higher survival, the hospital LOS (14.65 days vs. 16.66 days; P = 0.15) and ICU LOS (6.93 days vs. 5.92 days; P = 0.02) were prolonged at OAC+ group than OAC- group. No difference was found in survival rate of 30 day between the sepsis patients using warfarin and patients using NOAC (85.60% vs. 79.84%, P = 0.12). The sepsis patients using warfarin had a prolonged LOS in ICU and hospital compared with the sepsis patients using NOAC. In the vasopressor subgroup, patients who received NOAC therapy were associated with a reduced 30-day survival rate (73.57% vs. 84.03%; P = 0.04) and reduced LOS in ICU and hospital than those on warfarin therapy.

Conclusion

This study demonstrated that oral anticoagulants may increase the 30-day survival rate of patients with sepsis and AF.

The Role of Pro-Inflammatory Cytokines in the Pathogenesis of Cardiovascular Disease

With cardiovascular disease (CVD) being a primary source of global morbidity and mortality, it is crucial that we understand the molecular pathophysiological mechanisms at play. Recently, numerous pro-inflammatory cytokines have been linked to several different CVDs, which are now often considered an adversely pro-inflammatory state. These cytokines most notably include interleukin-6 (IL-6),tumor necrosis factor (TNF)α, and the interleukin-1 (IL-1) family, amongst others. Not only does inflammation have intricate and complex interactions with pathophysiological processes such as oxidative stress and calcium mishandling, but it also plays a role in the balance between tissue repair and destruction. In this regard, pre-clinical and clinical evidence has clearly demonstrated the involvement and dynamic nature of pro-inflammatory cytokines in many heart conditions; however, the clinical utility of the findings so far remains unclear. Whether these cytokines can serve as markers or risk predictors of disease states or act as potential therapeutic targets, further extensive research is needed to fully understand the complex network of interactions that these molecules encompass in the context of heart disease. This review will highlight the significant advances in our understanding of the contributions of pro-inflammatory cytokines in CVDs, including ischemic heart disease (atherosclerosis, thrombosis, acute myocardial infarction, and ischemia-reperfusion injury), cardiac remodeling (hypertension, cardiac hypertrophy, cardiac fibrosis, cardiac apoptosis, and heart failure), different cardiomyopathies as well as ventricular arrhythmias and atrial fibrillation. In addition, this article is focused on discussing the shortcomings in both pathological and therapeutic aspects of pro-inflammatory cytokines in CVD that still need to be addressed by future studies.

Trends and sex differences in atrial fibrillation among patients hospitalized due to asthma: Insights from a nationwide population-based discharge database in Spain, 2016-2021

AIMS

To analyze changes in the prevalence of atrial fibrillation (AF) in patients hospitalized due to asthma; to compare hospital outcomes in asthma patients with and without AF, assessing sex differences; to identify variables associated with the presence of AF; and to analyze the factors associated with in-hospital mortality (IHM) among asthma patients with AF.

METHODS

We used data from the Registry of Specialized Care Activity-Basic Minimum Data Set to select all patients aged ≥40 years with an asthma diagnosis in Spain, from 2016 to 2021. We stratified the study population according to the presence of AF and sex.

RESULTS

We identified 65,233 hospitalizations that met the inclusion criteria (14.85 % with AF). The prevalence of AF significantly increased over time, with the male sex being a protective factor for its presentation. IHM were significantly higher in patients with AF. Older age, being a woman, congestive heart failure, renal disease, obstructive sleep apnea, hypertension, and hyperthyroidism were associated with the presence of AF. Advanced age and the presence of cancer and COVID-19 were factors associated with a higher IHM, as well as admission to an intensive care unit and the use of invasive mechanical ventilation. There were no association of sex with the IHM.

CONCLUSIONS

AF is highly prevalent among subjects hospitalized due to asthma, with this prevalence having increased significantly in Spain over time. The presence of AF in patients with asthma was associated significantly with a higher LOHS and IHM. Sex was not associated with IHM in these patients.

The Significance of Inflammation in Atrial Fibrillation

AIM

The aim of the study was to assess the inflammatory status in individuals diagnosed with atrial fibrillation (Afi) and establish an association between this status and the clinicopathological features.

MATERIAL AND METHODS

Our study was conducted retrospectively and initially involved 278 patients. However, after excluding 27 patients, we ultimately ended up with 167 patients who had an inflammatory status and 84 patients who did not have an inflammatory status. These patients were then analyzed.

RESULTS

Patients who had inflammation showed higher values for the CHA2DS2-VASc and HAS-BLED scores (P= 0.0132 for CHA2DS2-VASc and P= 0.0024 for HAS-BLED). Also, it was observed that patients with associated inflammation exhibited an increase in both the volume and the area of the left atrium. Patients with hypertension had a higher prevalence of inflammation, with heart failure and with ischemic heart disease. It is worth noting that patients with atrial fibrillation and increased inflammatory status exhibited higher rates of stroke (22.75% vs 10.71% in patients without inflammation, odds ratio = 2.455, 95% confidence interval 1.161 to 5.425, p = 0.0253).

CONCLUSIONS

Our research has demonstrated that patients diagnosed with atrial fibrillation and exhibiting a heightened inflammatory status also present association with other comorbidities, including hypertension, heart failure, ischemic heart disease, and stroke.

Developing Pharmacological Therapies for Atrial Fibrillation Targeting Mitochondrial Dysfunction and Oxidative Stress: A Scoping Review

Atrial fibrillation (AF) is a cardiac arrhythmia caused by electrophysiological anomalies in the atrial tissue, tissue degradation, structural abnormalities, and comorbidities. A direct relationship exists between AF and altered mitochondrial activity resulting from membrane potential loss, contractile dysfunction, or decreased ATP levels. This review aimed to elucidate the role of mitochondrial oxidative mechanisms in AF pathophysiology, the impact of mitochondrial oxidative stress on AF initiation and perpetuation, and current therapies. This review followed the Preferred Reporting Items for Systematic Reviews and the Meta-Analysis Extension for Scoping Reviews. PubMed, Excerpta Medica Database, and Scopus were explored until June 2023 using "MESH terms". Bibliographic references to relevant papers were also included. Oxidative stress is an imbalance that causes cellular damage from excessive oxidation, resulting in conditions such as AF. An imbalance in reactive oxygen species production and elimination can cause mitochondrial damage, cellular apoptosis, and cardiovascular diseases. Oxidative stress and inflammation are intrinsically linked, and inflammatory pathways are highly correlated with the occurrence of AF. AF is an intricate cardiac condition that requires innovative therapeutic approaches. The involvement of mitochondrial oxidative stress in the pathophysiology of AF introduces novel strategies for clinical treatment.

Detection and modification of biomarkers of inflammation determining successful rhythm control in patients with atrial fibrillation

INTRODUCTION

Multiple pathophysiological mechanisms are involved in the pathogenesis of atrial fibrillation (AF). Growing evidence suggests that both local and systemic inflammation plays a key role even in early stages and its progression towards persisting and permanent AF. Rhythm control therapy via pulmonary vein isolation or cardioversion is the cornerstone of AF therapy for most symptomatic patients, yet arrhythmia recurrence after treatment is still common, especially in patients with persistent AF.

MATERIAL AND METHODS

In this review, we summarize the current state of knowledge of biomarkers of inflammation with prognostic value in patients with atrial fibrillation as well as anti-inflammatory medication with potential benefits after rhythm control therapy.

RESULTS AND DISCUSSION

Both onset of AF, progression and arrhythmia recurrence after rhythm control therapy can be caused by local and systemic inflammation. Various inflammatory biomarkers have been established to predict treatment success. Furthermore, additional anti-inflammatory therapy may significantly improve success rates.

Variability of baroreceptor reflex assessed by tilt table test in a patient undergoing pulmonary vein isolation

BACKGROUND

The autonomic nervous system (ANS) plays a significant role in atrial fibrillation (AF). Catheter ablation (CA) affects the ANS balance. The assessment of baroreceptor (BR) function is an established method to measure parasympathetic activity; however, it has been rarely used in patients undergoing CA of AF.

AIMS

This study is to assess changes in BR function caused by CA and to compare these changes between two different types of CA: point-by-point radiofrequency (RF) versus cryoballoon (CB).

METHODS

In this observational, prospective, single center study, 78 patients (25 females, mean age 58 ± 9) with paroxysmal AF and first CA were included: 39 patients (RF group) and 39 (CB group). The BR function was assessed non-invasively using tilt testing and three parameters: event count (BREC) depicting overall BR activity, slope mean depicting BR sensitivity (BRS), and BR effectiveness index (BEI).

RESULTS

The groups did not differ in clinical or demographic data. Before CA, tilting caused a marked decrease in BR function parameters in the whole study group (BREC (29 ± 14.0-50.0 vs 28 ± 9.0-44.0, p < 0.068), BRS (10.2 ± 7.1-13.2 vs 5.8 ± 4.9-8.5; p < 0.001), and BEI (52.9 ± 39.9-65.5 vs 39.6 ± 23.6-52.1; p < 0.001), supine vs tilting, respectively). These changes were similar in the both groups. After CA, BR function decreased in the whole group (BREC 12.0 ± 3.0-22.0 vs 6.0 ± 3.0-18.0, p = 0.004; BRS 4.8 ± 3.6-6.8 vs 4.0 ± 3.0-5.8, p = 0.014; BEI 18.7 ± 8.3-27.4 vs 12.0 ± 5.1-21.0, p = 0.009). BREC was significantly more decreased in the CB vs RF. Similar trend was noted for BRS and BEI.

CONCLUSIONS

CA significantly affects BR function. These changes were more pronounced following CB rather than RF CA.

Identification of functional lncRNAs in atrial fibrillation based on RNA sequencing

BACKGROUND

Atrial fibrillation (AF) is one of the most common arrhythmia contributing to serious conditions such as stroke and heart failure. Recent studies demonstrated that long noncoding RNAs (lncRNAs) were related to cardiovascular disease. However, the molecular mechanisms of AF are not fully clear. This study intended to discover lncRNAs that are differentially expressed in AF compared with controls and evaluate the potential functions of these lncRNAs.

METHODS

Ninety-seven patients (49 patients with AF and 48 patients without AF) were included in this study. Among these patients, leucocyte suspensions of 3 AF patients and 3 controls were sent for RNA-seq analysis to select differentially expressed lncRNA and mRNA. Different lncRNA expressions were validated in another samples (46 AF patients and 45 controls). Gene ontology (GO) enrichment analysis was conducted to annotate the function of selected mRNAs. Alternative splicing (AS) analysis was performed and a lncRNA-mRNA network was also constructed. The receiver operating characteristics (ROC) curve was used to evaluate diagnostic values. Logistic regression analysis was utilized to assess the risk or protective factor of AF.

RESULTS

A total of 223 mRNAs and 105 lncRNAs were detected in AF patients compared with controls. Total 4 lncRNAs (LINC01781, AC009509.2, AL662844.3, AL662844.4) associated with AF were picked out for validation in another samples by quantitative real-time PCR (qRT-PCR), detecting that upregulated AC009509.2 and downregulated LINC01781 in AF patients. Multivariate logistic regression analysis illustrated that left atrial diameter (OR 1.201; 95% CI 1.093-1.320; P=0.000) and AC009509.2 (OR 1.732; 95% CI 1.092-2.747; P=0.020) were related to AF respectively. ROC curve showed that AC009509.2, LINC01781 and left atrial diameter (LAD) were predictors of AF. For LINC01781, the area under the curve (AUC) was 0.654 (95% CI 0.541-0.767, P=0.0113). For AC009509.2, the AUC was 0.710 (95% CI 0.599-0.822, P=0.0005). Bioinformatic methods (GO enrichment, AS analysis and lncRNA-mRNA network construction) were performed to reveal the role of lncRNAs.

CONCLUSIONS

This study discussed differentially expressed lncRNA and their potential interaction with mRNA in AF. LncRNA AC009509.2 could be a new potential biomarker for AF prediction.

Inflammation and Coagulation are Two Interconnected Pathophysiological Pathways in Atrial Fibrillation Pathogenesis

Introduction

Atrial fibrillation (AF) is associated with elevated levels of clotting factors such as tissue factor (TF) and factor XII (FXII). Various inflammation markers, such as interleukin-6 (IL-6), tumor necrosis factor-α (TNF- α), and high-sensitive C-reactive protein (hs-CRP), have also been associated with AF. This study explores the relationship between inflammation markers and coagulation activity, including their impact on heart structural changes in these patients.

Methods

We observed 283 patients with nonvalvular AF who underwent a complete examination at admission, but only 183 patients have successful cardioversion. As a control group, similar patients without AF were examined. The markers of the coagulation and inflammation were studied by ELISA on the analyzer "Stat Fax 303 Plus". Studies were conducted using l statistical package SPSS 13.0.

Results

It was revealed that patients with AF had significantly higher levels of hs-CRP, IL-6, and TNF-α and had elevated levels of TF and FXII compared with control group. The moderate correlations were observed between IL-6 and left atrial diameter (LAD), IL-6 and LA stiffness, hs-CRP and left atrial volume (LAV), TF and LAV.

Conclusion

We have demonstrated that patients with AF have the relationship between elevated levels of inflammatory markers and coagulation activity, which contributes to structural atrial remodeling.

The Role of Extracellular Matrix and Inflammation in the Stratification of Bleeding and Thrombotic Risk of Atrial Fibrillation on Oral Anticoagulant Therapy: Insights from Strat-Af Study

In anticoagulated atrial fibrillation (AF) patients, the validity of models recommended for the stratification of the risk ratio between benefits and hemorrhage risk is limited. We hypothesize that both circulating and neuroimaging-based markers might improve the prediction of bleeding and thrombotic risk in anticoagulated AF patients. The Strat-AF study is an observational, prospective, single-center study enrolling 170 patients with AF; recruited patients are evaluated by means of a comprehensive protocol, with clinical, cerebral magnetic resonance imaging and circulating biomarkers assessment. The main outcome is the evaluation of cerebral microangiopathy related to the levels of circulating biomarkers of inflammation and extracellular matrix (ECM) remodeling. At multivariate logistic regression analysis adjusted for age, sex, CHA2DS2-VASc, HAS-BLED and type of anticoagulant, matrix metalloproteinases (MMP)-2 levels were significantly and positively associated with the presence of cerebral microbleeds (CMBs). A significant association between MMP-2, tissue inhibitor of metalloproteinases (TIMP)-1,-2,-4 levels and white matter hyperintensity was also found. Concerning the small vessel disease (SVD) score, MMP-2 and TIMP-1,-2 levels were associated with the presence of two and three or more signs of SVD, whereas TIMP-4 levels were associated with the presence of three signs of SVD with respect to patients with no instrumental signs of SVD. As regarding the presence of enlarged perivascular spaces (EPVS), a significant association was found for high levels of interleukin (IL)-8 and TIMP 1-2-3. These results demonstrate that patients with AF have evidence of impaired ECM degradation, which is an independent risk factor for thrombotic complications of AF patients on oral anticoagulant therapy. The incorporation of these markers in the prognostic schemes might improve their clinical capability in predicting stroke risk and thrombotic complications.

Atrial fibrillation is not an independent determinant of 28-day mortality among critically III sepsis patients

This study was conducted to investigate the relationship between atrial fibrillation and the clinical prognosis of patients with sepsis in intensive care unit. A total of 21,538 sepsis patients were enrolled in the study based on the Medical Information Mart for Intensive Care IV database, of whom 6,759 had AF. Propensity score matching was used to compare the clinical characteristics and outcomes of patients with and without AF. Besides, the inverse probability of treatment weighting, univariate and multivariate Cox regression analyzes were performed. Of the 21,538 patients, 31.4% had AF. The prevalence of AF increased in a step-by-step manner with growing age. Patients with AF were older than those without AF. After PSM, 11,180 patients remained, comprising 5,790 matched pairs in both groups. In IPTW, AF was not associated with 28-day mortality [hazard ratio (HR), 1.07; 95% confidence interval (CI), 0.99-1.15]. In Kaplan-Meier analysis, it was not observed difference of 28-day mortality between patients with and without AF. AF could be associated with increased ICU LOS, hospital LOS and need for mechanical ventilation; however, it does not remain an independent short-term predictor of 28-day mortality among patients with sepsis after PSM with IPTW and multivariate analysis.

Platelet Receptor Glycoprotein VI-Dimer Is Overexpressed in Patients with Atrial Fibrillation at High Risk of Ischemic Stroke

Introduction  Atrial fibrillation (AF) increases the risk of ischemic stroke (IS). We hypothesized that the functional form of platelet receptor glycoprotein (GP) VI, GPVI-dimer, which binds to collagen and fibrin causing platelet activation, is overexpressed in patients with AF who have not had a stroke. Methods  A total of 75 inpatients with AF were recruited. None were admitted with or had previously had thrombotic events, including IS or myocardial infarction. Platelet surface expression of total GPVI, GPVI-dimer, and the platelet activation marker P-selectin were quantitated by whole blood flow cytometry. Serum biomarkers were collected in AF patients. Results were compared against patients contemporaneously admitted to hospital with similar age and vascular risk-factor profiles without AF (noAF, n  = 30). Results  Patients with AF have similar total GPVI surface expression ( p  = 0.58) and P-selectin exposure ( p  = 0.73) on their platelets compared with noAF patients but demonstrate significantly higher GPVI-dimer expression ( p  = 0.02 ). Patients with paroxysmal AF express similar GPVI-dimer levels compared with permanent AF and GPVI-dimer levels were not different between anticoagulated groups. Serum N-terminal pro b-type natriuretic peptide ( p  < 0.0001 ) and high sensitivity C-reactive protein ( p  < 0.0001 ) were significantly correlated with GPVI-dimer expression in AF platelets. AF was the only vascular risk factor that was independently associated with higher GPVI-dimer expression in the whole population ( p  = 0.02 ) . Conclusion  GPVI inhibition is being explored in clinical trials as a novel target for IS treatment. As GPVI-dimer is elevated in AF patients' platelets, the exploration of targeted GPVI-dimer inhibition for stroke prevention in patients at high risk of IS due to AF is supported.

The role of IL-6, IL-10, TNF-α and PD-1 expression on CD4 T cells in atrial fibrillation

Backgrounds

While not completely understood, the electrical, structural, and communication pathways that play a role in the onset and progression of atrial fibrillation (AF) seem to be connected to the intricate interplay between neurohormones and cellular mediators. Our study's objective was to examine how the expression profiles of the inflammatory cytokines interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor (TNF), and programmed death 1 (PD-1) changed in Cluster of Differentiation 4 (CD4) T cells depending on whether atrial fibrillation was paroxysmal or permanent. This analysis would provide new diagnostic markers for the detection and management of atrial fibrillation.

Methods

In a cross-sectional study, 60 healthy controls, 49 patients with persistent atrial fibrillation, and 50 patients with paroxysmal atrial fibrillation were compared. Serum biomarker levels are found using the ELISA method, which uses enzyme-linked immunosorbent assay. Echocardiography was used to assess heart function.

Results

Patients with atrial fibrillation had serum concentrations of IL-6, TNF-a, and IL-10 that were considerably higher than but PD-1 was lower those in the non-AF control group and those in patients with persistent atrial fibrillation. According to the diameter of LA and the serum level of NT-proB-type natriuretic peptide (NT-proBNP) is greater than that of patients with paroxysmal atrial fibrillation than control group. Patients with persistent atrial fibrillation had increased serum levels of low-density lipoprotein cholesterol (LDL-C) compared with those without atrial fibrillation. While PD-1 in patients with paroxysmal atrial fibrillation is closely related to C-reactive protein (CRP), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), and very low density lipoprotein cholesterol. In addition, PD-1 in patients with persistent atrial fibrillation is closely related to IL-6, TNF-a, and IL-10.

Conclusion

Higher blood concentrations of NT-proBNP, IL-6, IL-10, TNF-, and LDL-C but low level of PD-1 are associated with progression from paroxysmal or chronic AF.

Cfa-circ002203 was upregulated in rapidly paced atria of dogs and involved in the mechanisms of atrial fibrosis

Background and aims

The role of circular RNAs (circRNAs) in the pathophysiology of cardiovascular disease is gradually being elucidated; however, their roles in atrial fibrillation (AF)-related fibrosis are largely unknown. This study aimed to characterize the different circRNA profiles in the rapid-pacing atria of dogs and explore the mechanisms involved in atrial fibrosis.

Methods

A rapid right atrial-pacing model was established using electrical stimulation from a pacemaker. After 14 days, atrial tissue was collected for circRNA sequencing analysis. In vitro fibrosis was established by stimulating canine atrial fibroblasts with angiotensin II (Ang II). The fibroblasts were transfected with siRNA and overexpressing plasmids to explore the effects of cfa-circ002203 on fibroblast proliferation, migration, differentiation, and the expression of fibrosis-related proteins.

Results

In total, 146 differentially expressed circRNAs were screened, of which 106 were upregulated and 40 were downregulated. qRT-PCR analysis showed that cfa-circ002203 was upregulated in both in vivo and in vitro fibroblast fibrosis models. The upregulation of cfa-circ002203 enhanced proliferation and migration while weakening the apoptosis of fibroblasts. Western blotting showed that cfa-circ002203 overexpression increased the protein expression levels of fibrosis-related indicators (Col I, Col III, MMP2, MMP9, and α-SMA) and decreased the protein expression levels of pro-apoptotic factors (Bax and Caspase 3) in Ang II-induced fibroblast fibrosis.

Conclusion

Cfa-circ002203 might serve as an active promoter of the proliferation, migration, and fibrosis of atrial fibroblasts and is involved in AF-induced fibroblast fibrosis.

The Relationship between Hyperuricemia and Echocardiographic Parameters in Patients with Chronic Atrial Fibrillation

Purpose Uric acid serves as a marker for cardiovascular risk and is often linked to inflammation and oxidative stress. There is evidence suggesting an association between uric acid and atrial fibrillation (AF), including its severity and occurrence of crises, as well as its involvement in cardiovascular mechanisms. The objective of this study was to assess the correlation between hyperuricemia and echocardiographic features in patients with chronic AF lasting for more than 5 years. Methods This case-control study involved 107 patients diagnosed with chronic non-valvular AF. Uric acid levels were measured in all patients, and they were divided into two groups: the first group consisted of 66 patients with hyperuricemia (>7.2 mg/dL), while the second group included 41 patients with normal uric acid levels. Echocardiography (TTE) was performed to evaluate each patient. Various clinical and echocardiographic parameters, such as left ventricle telediastolic (LVTDD) and telesystolic (LVTSD) diameters, left atrial diameter (LAD), aortic diameter (AoD), ejection fraction (EF), and pulmonary artery pressure (PAP), were analyzed. Results Binary logistic regression analysis revealed a statistically significant relationship between uric acid levels (>7.2 mg/dL) and LAD. For each unit increase in LAD, the probability of having hyperuricemia increased by 9% [odds ratio (OD): 0.91, 95% confidence interval (CI): 0.84-0.99]. A significant relationship was found between uric acid levels (>8 mg/dL) and LVESD (p = 0.045) as well as PAP (p = 0.006). For every unit increase in LVESD, the likelihood of having uric acid levels greater than 8 mg/dL increased by 22% [OD: 0.82, 95% CI: 0.67-0.99, b = -0.2]. Likewise, for each unit increase in PAP, the probability of having uric acid levels greater than 8 mg/dL was 9.4% [OD: 0.91, 95% CI: 0.86-0.97, b = -0.09]. Conclusions This study demonstrates that hyperuricemia has a significant relationship with the development of atrial remodeling, with an important association observed between hyperuricemia and an increase in left atrial diameter. Hyperuricemia is also correlated with an enlargement of the left ventricle end-systolic diameter and pulmonary artery pressure, showing a possible influence that hyperuricemia might have also left ventricle morphology and right ventricle function.

The effect of icosapent ethyl on left atrial and left ventricular morphology

Atrial fibrillation (AF) is a common arrhythmia associated with poor outcomes. N-3 fatty acids have been shown to provide significant cardiovascular risk reduction, but they may exacerbate the risk of AF. The pathway by which N-3 fatty acids may be arrhythmogenic is unknown. One possible mechanism involves cardiac chamber morphology alteration. The purpose of this study was to investigate the effect of icosapent ethyl (IPE) on left atrial (LA) size and left ventricular (LV) mass. This study used coronary computed tomographic angiography images gathered from the Effect of Icosapent Ethyl on Progression of Coronary Atherosclerosis (EVAPORATE) trial. EVAPORATE was a randomised, double-blind, placebo-controlled study finding a significant reduction in coronary atherosclerosis progression in patients with residually elevated triglycerides despite statin therapy on 4 g IPE daily versus 4 g placebo daily. Computed tomography images were used to measure LA size and LV mass at 0 and 18 months. Of 80 enrolled patients, 68 were included in the final analysis. Baseline demographics and risk factors were similar between IPE and placebo cohorts. LA anterior- posterior diameter measured on axial (p=0.51) and sagittal (p=0.52) orientations were not different over time. Also, there was no difference between groups in the change in LA volume (p=0.84). Change in LV mass was similar between groups (p=0.13). In conclusion, this study did not detect differences in LA size or LV mass over 18 months between patients on 4 g daily IPE versus placebo.

A systematic review and meta-analysis of cohort studies on the potential association between NAFLD/MAFLD and risk of incident atrial fibrillation

Background and objective

The association between atrial fibrillation (AF) and non-alcoholic fatty liver disease (NAFLD) or metabolic-associated fatty liver disease (MAFLD) has been explored in recent cohort studies, however, the results have been controversial and inconclusive. This meta-analysis aimed to explore this potential association.

Methods

We systematically searched PubMed, Embase, and Web of Science databases to identify all relevant cohort studies investigating the association between NAFLD/MAFLD and AF published from database inception to October 30, 2022. Random-effects models were utilized to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for summary purposes. Additionally, subgroup and sensitivity analyses were performed.

Results

A total of 13 cohort studies with 14 272 735 participants were included. Among these, 12 cohort studies with 14 213 289 participants (median follow-up of 7.8 years) showed a significant association between NAFLD and an increased risk of incident AF (HR = 1.18, 95% CI: 1.12-1.23, P < 0.00001). Our subgroup analyses mostly yielded similar results, and the results of sensitivity analyses remained unchanged. However, meta-analysis of data from 2 cohort studies with 59 896 participants (median follow-up of 2.15 years) showed that MAFLD was not linked to incident AF (HR = 1.36, 95% CI: 0.63-2.92, P = 0.44).

Conclusion

Current evidence shows that NAFLD may be linked to a slightly higher risk of developing AF, particularly among Asian populations and those diagnosed with NAFLD using FLI criteria. Nevertheless, there is not enough evidence to support the proposed association between MAFLD and an increased risk of AF. To better understand this relationship, future studies should consider factors such as specific population, the severity of NAFLD/MAFLD, diagnostic methods of NAFLD and AF, and cardiometabolic risk factors.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero, identifier CRD42022371503.

Disordered gut microbiota promotes atrial fibrillation by aggravated conduction disturbance and unbalanced linoleic acid/SIRT1 signaling

Emerging evidence suggests an association of dysbiotic gut microbiota (GM) with atrial fibrillation (AF). The current study aimed to determine whether aberrant GM promotes AF development. A fecal microbiota transplantation (FMT) mouse model demonstrated that dysbiotic GM is sufficient to enhance AF susceptibility assessed by transesophageal burst pacing. Compared with recipients transplanted with GM obtained from healthy subjects (FMT-CH), the prolonged P wave duration and an enlarging tendency for the left atrium were detected in recipients transplanted with AF GM (FMT-AF). Meanwhile, the disrupted localizations of connexin 43 and N-cadherin and increased expression levels of phospho-CaMKII and phospho-RyR2, were observed in the atrium of FMT-AF, which indicated aggravated electrical remodeling caused by the altered gut flora. Specifically, exacerbated fibrosis disarray, collagen deposition, α-SMA expression, and inflammation in the atrium were also confirmed to be transmissible by the GM. Furthermore, deteriorated intestinal epithelial barrier and intestinal permeability, accompanied by disturbing metabolomic features in both feces and plasma, especially decreased linoleic acid (LA), were identified in FMT-AF mice. Subsequently, the anti-inflammatory role of LA among the imbalanced SIRT1 signaling discovered in the atrium of FMT-AF was confirmed in mouse HL-1 cells treated with LPS/nigericin, LA, and SIRT1 knockdown. This study provides preliminary insights into the causal role of aberrant GM in the pathophysiology of AF, suggesting the GM-intestinal barrier-atrium axis might participate in the vulnerable substrates for AF development, and the GM could be utilized as an environmental target in AF management.

Should atrial fibrillation be considered a vascular disease? The need for a comprehensive vascular approach

INTRODUCTION

Atrial fibrillation (AF) cannot be considered an isolated disease. Patients with AF should be managed using a comprehensive approach that is not limited to stroke prevention.

AREAS COVERED

In this manuscript, the potential role of AF as a vascular disease that is managed as part of a holistic approach was reviewed.

EXPERT OPINION

The residual risk of stroke in patients with AF reaches 1-2% annually, despite appropriate anticoagulation therapy. Additionally, patients with AF may develop cognitive impairment through stroke-independent pathways. Furthermore, patients with AF may have a higher risk of developing atherosclerotic vascular disease in various vascular beds and chronic kidney disease; conversely, patients with atherosclerotic disease may have an increased risk of developing AF. AF should be considered a truly systemic vascular disease, since it brings together several hemodynamic and systemic changes, including inflammation, oxidative stress, activation of the renin-angiotensin-aldosterone and sympathetic systems, as well as a prothrombotic state and endothelial dysfunction. In this regard, patients with AF should be treated based on a holistic approach that is not limited to oral anticoagulation but includes complete vascular protection.

Analyses of m6A regulatory genes and subtype classification in atrial fibrillation

Objective

To explore the role of m6A regulatory genes in atrial fibrillation (AF), we classified atrial fibrillation patients into subtypes by two genotyping methods associated with m6A regulatory genes and explored their clinical significance.

Methods

We downloaded datasets from the Gene Expression Omnibus (GEO) database. The m6A regulatory gene expression levels were extracted. We constructed and compared random forest (RF) and support vector machine (SVM) models. Feature genes were selected to develop a nomogram model with the superior model. We identified m6A subtypes based on significantly differentially expressed m6A regulatory genes and identified m6A gene subtypes based on m6A-related differentially expressed genes (DEGs). Comprehensive evaluation of the two m6A modification patterns was performed.

Results

The data of 107 samples from three datasets, GSE115574, GSE14975 and GSE41177, were acquired from the GEO database for training models, comprising 65 AF samples and 42 sinus rhythm (SR) samples. The data of 26 samples from dataset GSE79768 comprising 14 AF samples and 12 SR samples were acquired from the GEO database for external validation. The expression levels of 23 regulatory genes of m6A were extracted. There were correlations among the m6A readers, erasers, and writers. Five feature m6A regulatory genes, ZC3H13, YTHDF1, HNRNPA2B1, IGFBP2, and IGFBP3, were determined (p < 0.05) to establish a nomogram model that can predict the incidence of atrial fibrillation with the RF model. We identified two m6A subtypes based on the five significant m6A regulatory genes (p < 0.05). Cluster B had a lower immune infiltration of immature dendritic cells than cluster A (p < 0.05). On the basis of six m6A-related DEGs between m6A subtypes (p < 0.05), two m6A gene subtypes were identified. Both cluster A and gene cluster A scored higher than the other clusters in terms of m6A score computed by principal component analysis (PCA) algorithms (p < 0.05). The m6A subtypes and m6A gene subtypes were highly consistent.

Conclusion

The m6A regulatory genes play non-negligible roles in atrial fibrillation. A nomogram model developed by five feature m6A regulatory genes could be used to predict the incidence of atrial fibrillation. Two m6A modification patterns were identified and evaluated comprehensively, which may provide insights into the classification of atrial fibrillation patients and guide treatment.

Lower heart rates and beta-blockers are associated with new-onset atrial fibrillation

Background

Lower heart rates (HRs) prolong diastole, which increases filling pressures and wall stress. As a result, lower HRs may be associated with higher brain natriuretic peptide (BNP) levels and incident atrial fibrillation (AF). Beta-blockers may increase the risk for AF due to suppression of resting HRs.

Objective

Examine the relationships of HR, BNP, beta-blockers and new-onset AF in the REVEAL-AF and SPRINT cohort of subjects at risk for developing AF.

Methods

In REVEAL-AF, 383 subjects without a history of AF and a mean CHA₂DS₂VASC score of 4.4 ± 1.3 received an insertable cardiac monitor and were followed up to 30 months. In SPRINT, 7595 patients without prior history of AF and a mean CHA₂DS₂VASC score of 2.3 ± 1.2 were followed up to 60 months.

Results

The median daytime HR in the REVEAL-AF cohort was 75bpm [IQR 68-83]. Subjects with below-median HRs had 2.4-fold higher BNP levels compared to subjects with above-median HRs (median BNP [IQR]: 62 pg/dl [37-112] vs. 26 pg/dl [13-53], p < 0.001). HRs <75bpm were associated with a higher incidence of AF: 37% vs. 27%, p < 0.05. This was validated in the SPRINT cohort after adjusting for AF risk factors. Both a HR < 75bpm and beta-blocker use were associated with a higher rate of AF: 1.9 vs 0.7% (p < 0.001) and 2.5% vs. 0.6% (p < 0.001), respectively. The hazard ratio for patients on beta-blockers to develop AF was 3.72 [CI 2.32, 5.96], p < 0.001.

Conclusions

Lower HRs are associated with higher BNP levels and incident AF, mimicking the hemodynamic effects of diastolic dysfunction. Suppression of resting HR by beta-blockers could explain their association with incident AF.

Molecular mechanisms of postoperative atrial fibrillation in patients with obstructive sleep apnea

Obstructive sleep apnea (OSA) promotes atrial remodeling and fibrosis, providing a substrate for atrial fibrillation (AF). Herein, we investigate the pathophysiological mechanisms of AF in association with OSA in a cohort of cardiac surgery patients. A prospective study including patients undergoing cardiac surgery. Biomarkers reflective of AF pathophysiology (interleukin [IL-6], C-reactive protein [CRP], von Willebrand factor [vWF], N-terminal pro-brain natriuretic peptide [NT-proBNP], high-sensitivity Troponin T [hs-TnT], and Galectin-3 [Gal-3]) was assessed by functional or immunological assays. miRNAs involved in AF were analyzed by reverse transcription-polymerase chain reaction (RT-PCR). Using atrial tissue samples, fibrosis was assessed by Masson's trichrome. Connexin 40 and 43 (Cx40; Cx43) were evaluated by immunolabeling. Fifty-six patients (15 with OSA and 41 non-OSA) were included in this hypothesis-generating pilot study. OSA group had a higher incidence of postoperative AF (POAF) (46.7% vs. 19.5%; p = .042), presented an increased risk of POAF (OR 3.61, 95% CI 1.01-12.92), and had significantly higher baseline levels of NT-proBNP (p = .044), vWF (p = .049), Gal-3 (p = .009), IL-6 (p = .002), and CRP (p = .003). This group presented lower levels of miR-21 and miR-208 (both p < .05). Also, lower Cx40 levels in POAF and/or OSA patients (50.0% vs. 81.8%, p = .033) were found. The presence of interstitial fibrosis (according to myocardial collagen by Masson's trichrome) was raised in OSA patients (86.7% vs. 53.7%, p = .024). Several biomarkers and miRNAs involved in inflammation and fibrosis were dysregulated in OSA patients, which together with a higher degree of interstitial fibrosis, altered miRNA, and Cxs expression predisposes to the development of a substrate that increases the AF risk.

Mechanisms of Atrial Fibrillation: How Our Knowledge Affects Clinical Practice

Atrial fibrillation (AF) is a very common arrhythmia that mainly affects older individuals. The mechanism of atrial fibrillation is complex and is related to the pathogenesis of trigger activation and the perpetuation of arrhythmia. The pulmonary veins in the left atrium arei confirm that onfirm the most common triggers due to their distinct anatomical and electrophysiological properties. As a result, their electrical isolation by ablation is the cornerstone of invasive AF treatment. Multiple factors and comorbidities affect the atrial tissue and lead to myocardial stretch. Several neurohormonal and structural changes occur, leading to inflammation and oxidative stress and, consequently, a fibrotic substrate created by myofibroblasts, which encourages AF perpetuation. Several mechanisms are implemented into daily clinical practice in both interventions in and the medical treatment of atrial fibrillation.

Association between serum apolipoprotein A1 and atrial fibrillation in the Chinese population: a case-control study

BACKGROUND

The relationship between serum apolipoprotein A1 (APOA1) and atrial fibrillation (AF) is not known. Therefore, we sought to investigate the associations between APOA1 and AF in the Chinese population.

METHODS

This case-control study included 950 patients with AF (29-83 years old, 50.42% male) who were hospitalized consecutively in China between January 2019 and September 2021. Controls with sinus rhythm and without AF were matched (1:1) to cases by sex and age. Pearson correlation analysis was performed to investigate the correlation between APOA1 and blood lipid profiles. Multivariate regression models were used to explore the association between APOA1 and AF. The receiver operator characteristic (ROC) curve was constructed to examine the performance of APOA1.

RESULTS

Multivariate regression analysis showed that low serum APOA1 in men and women with AF was significantly associated with AF (OR = 0.261, 95% CI: 0.162-0.422, P < 0.001). Pearson correlation analysis indicated that serum APOA1 was positively correlated with total cholesterol (TC) (r = 0.456, p < 0.001), low-density lipoprotein cholesterol (LDL-C) (r = 0.825, p < 0.001), high-density lipoprotein cholesterol (HDL-C) (r = 0.238, p < 0.001), and apolipoprotein B (APOB) (r = 0.083, p = 0.011). ROC curve analysis showed that APOA1 levels of 1.105 g/L and 1.205 g/L were the optimal cut-off values for predicting AF in males and females, respectively.

CONCLUSION

Low APOA1 in male and female patients is significantly associated with AF in the Chinese population of non-statin users. APOA1 may be a potential biomarker for AF and contribute to the pathological progression of AF along with low blood lipid profiles. Potential mechanisms remain to be further explored.

The Association Between Rheumatoid Arthritis and Atrial Fibrillation: Epidemiology, Pathophysiology and Management

Atrial fibrillation (AF) is the most common cardiac arrhythmia with a significant increase in morbidity and mortality worldwide. Rheumatoid arthritis (RA), as a systemic inflammatory disease, affecting 0.5-1.0% of the adult population, is associated with increased incidence of cardiac arrhythmias such as AF. Several epidemiologic studies find that the risk of AF is increased in RA when compared with the general population. Other studies are inconsistent. Considering that inflammation plays an important role in AF, RA may be involved in the occurrence and development of AF. This review summarizes the epidemiology, pathophysiology, and management of AF in patients with RA.

Associations between neutrophil-lymphocyte ratio and monocyte to high-density lipoprotein ratio with left atrial spontaneous echo contrast or thrombus in patients with non-valvular atrial fibrillation

BACKGROUND

The importance of inflammation in thrombosis is increasingly appreciated. Neutrophil-lymphocyte ratio (NLR) and monocyte to high-density lipoprotein ratio (MHR) are important indicators of systemic inflammation. This study aimed to investigate the associations between NLR and MHR with left atrial appendage thrombus (LAAT) and spontaneous echo contrast (SEC) in patients with non-valvular atrial fibrillation.

METHODS

This retrospective, cross-sectional study enrolled 569 consecutive patients with non-valvular atrial fibrillation. Multivariable logistic regression analysis was used to investigate independent risk factors of LAAT/SEC. Receiver operating characteristic (ROC) curves were used to evaluate the specificity and sensitivity of NLR and MHR in predicting LAAT/SEC. Subgroup and Pearson correlation analyses were used to assess the correlations between NLR and MHR with the CHA₂DS₂-VASc score.

RESULTS

Multivariate logistic regression analysis showed that NLR (OR: 1.49; 95%CI: 1.173-1.892) and MHR (OR: 2.951; 95%CI: 1.045-8.336) were independent risk factors for LAAT/SEC. The area under the ROC curve of NLR (0.639) and MHR (0.626) was similar to that of the CHADS₂ score (0.660) and CHA₂DS₂-VASc score (0.637). Subgroup and Pearson correlation analyses showed significant but very weak associations between NLR (r = 0.139, P < 0.05) and MHR (r = 0.095, P < 0.05) with the CHA₂DS₂-VASc score.

CONCLUSION

Generally, NLR and MHR are independent risk factors for predicting LAAT/SEC in patients with non-valvular atrial fibrillation.

Comparison of the Efficacy of Atorvastatin and Rosuvastatin in Preventing Atrial Fibrillation after Coronary Artery Bypass Grafting: A Double-Blind Randomized Comparative Trial

Background

Atrial fibrillation (AF) is a supraventricular tachyarrhythmia characterized by disorganized atrial activity and subsequent mechanical atrial failure. Postoperative AF is a frequent complication of coronary artery bypass grafting (CABG). Although there is evidence of decreased AF after CABG with statin usage, information is scarce regarding a direct comparison between atorvastatin and rosuvastatin. The present study was conducted to compare the efficacy of rosuvastatin and atorvastatin in preventing post-CABG AF.

Methods

The present double-blind randomized comparative clinical trial selected CABG candidates with stable ischemic heart disease or acute coronary syndromes. Atorvastatin (40 mg per day) or rosuvastatin (20 mg per day) was prescribed 1 week before surgery, and the outcomes were compared.

Results

Two-hundred patients, 100 cases in each group, completed the study. Twenty-five patients in each group were female, and the mean age was 59.30±8.42 years in the rosuvastatin group and 60.13±9.40 years in the atorvastatin group (P=0.513). The frequency of AF was 31% in the atorvastatin group and 27% in the rosuvastatin group (P=0.534). No significant differences existed between the groups concerning the length of hospital and ICU stay (P=0.333 and P=0.161) and in-hospital and 3-month mortality (P=0.315 and P=0.648). A subgroup analysis of only patients with stable ischemic heart disease could not detect a significant difference between the study groups in any of the investigated outcomes. Our logistic regression analysis showed an association only between age and the incidence of AF after CABG (OR, 1.12; 95% CI, 1.05 to 1.20; P<0.01).

Conclusion

Rosuvastatin and atorvastatin are similar concerning the prevention of post-CABG AF, but there is a need for future well-designed multicenter studies on this topic.