Inflammatory pathways underlying atrial fibrillation

Atrial fibrillation incidence after coronary artery bypass graft surgery and percutaneous coronary intervention: the prospective AFAF cohort study

Objectives. Atrial fibrillation is a common arrhythmia in patients with ischemic heart disease. This study aimed to determine the cumulative incidence of new-onset atrial fibrillation after percutaneous coronary intervention or coronary artery bypass grafting surgery during 30 days of follow-up. Design. This was a prospective multi-center cohort study on atrial fibrillation incidence following percutaneous coronary intervention or coronary artery bypass grafting for stable angina or non-ST-elevation acute coronary syndrome. Heart rhythm was monitored for 30 days postoperatively by in-hospital telemetry and handheld thumb ECG recordings after discharge were performed. The primary endpoint was the cumulative incidence of atrial fibrillation 30 days after the index procedure. Results. In-hospital atrial fibrillation occurred in 60/123 (49%) coronary artery bypass graft and 0/123 percutaneous coronary intervention patients (p < .001). The cumulative incidence of atrial fibrillation after 30 days was 56% (69/123) of patients undergoing coronary artery bypass grafting and 2% (3/123) of patients undergoing percutaneous coronary intervention (p < .001). CABG was a strong predictor for atrial fibrillation compared to PCI (OR 80.2, 95% CI 18.1-354.9, p < .001). Thromboembolic stroke occurred in-hospital in one coronary artery bypass graft patient unrelated to atrial fibrillation, and at 30 days in two additional patients, one in each group. There was no mortality. Conclusion. New-onset atrial fibrillation during 30 days of follow-up was rare after percutaneous coronary intervention but common after coronary artery bypass grafting. A prolonged uninterrupted heart rhythm monitoring strategy identified additional patients in both groups with new-onset atrial fibrillation after discharge.

The association between systemic inflammation markers and paroxysmal atrial fibrillation

BACKGROUND

Systemic inflammation markers have recently been identified as being associated with cardiac disorders. However, limited research has been conducted to estimate the pre-diagnostic associations between these markers and paroxysmal atrial fibrillation (PAF). Our aim is to identify potential biomarkers for early detection of PAF.

METHODS

91 participants in the PAF group and 97 participants in the non-PAF group were included in this study. We investigated the correlations between three systemic inflammation markers, namely the systemic immune inflammation index (SII), system inflammation response index (SIRI), and aggregate index of systemic inflammation (AISI), and PAF.

RESULTS

The proportion of patients with PAF gradually increased with increasing logSII, logSIRI, and logAISI tertiles. Compared to those in the lowest tertiles, the PAF risks in the highest logSII and logSIRI tertiles were 3.2-fold and 2.9-fold, respectively. Conversely, there was no significant correlation observed between logAISI and PAF risk within the highest tertile of logAISI. The restricted cubic splines (RCS) analysis revealed a non-linear relationship between the elevation of systemic inflammation markers and PAF risk. Specifically, the incidence of PAF is respectively increased by 56%, 95%, and 150% for each standard deviation increase in these variables. The ROC curve analysis of logSII, logSIRI and logAISI showed that they had AUC of 0.6, 0.7 and 0.6, respectively. It also demonstrated favorable sensitivity and specificity of these systemic inflammation markers in detecting the presence of PAF.

CONCLUSIONS

In conclusion, our study reveals significant positive correlations between SII, SIRI, and AISI with the incidence of PAF.

Targeting Nrf2/HO-1 and NF-κB/TNF-α signaling pathways with empagliflozin protects against atrial fibrillation-induced acute kidney injury in rats

A bidirectional relationship exists between atrial fibrillation (AF) and kidney function. Uncontrolled AF may lead to kidney injury, whereas renal dysfunction may contribute to AF initiation and maintenance. This study aimed to investigate the protective effect of the sodium glucose cotransporter-2 inhibitor empagliflozin (EMPA) on acute kidney injury (AKI) associated with AF induced by acetylcholine and calcium chloride (ACh/CaCl2) in rats and elucidate the potential underlying mechanism. Rats were randomly divided as follows: control (CTRL) group: administered vehicles only; AF group: intravenously injected 1ml/kg of an ACh/CaCl2 mixture for seven days to induce AF; EMPA group: orally administered EMPA (30mg/kg) for seven days; AF+EMPA10 and AF+EMPA30 groups: co-administered the induction mixture and EMPA (10 and 30mg/kg, respectively) for seven days. Our results showed that EMPA (10 and 30mg/kg) effectively maintained kidney function and demonstrated a significant antioxidant potential. EMPA also suppressed AF-induced renal tubulointerstitial injury and fibrotic changes concurrently with reducing renal levels of the pro-inflammatory cytokines tumour necrosis factor-α (TNF-α) and interleukin-6, as well as the pro-fibrotic marker transforming growth factor beta-1 and collagen type I. Mechanistically, EMPA boosted nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) renal tissue expression while repressing nuclear factor kappa B (NF-κB) activation. In addition, these beneficial effects of EMPA on kidneys were concurrent with its ability to effectively inhibit AF-related electrocardiographic changes, reduce incidence and duration of AF episodes, and markedly suppress serum B-type natriuretic peptide and C-reactive protein levels. In conclusion, EMPA protected against AKI associated with AF induced by ACh/CaCl2 in rats through simultaneous modulation of the Nrf2/HO-1 and the NF-κB/TNF-α signaling pathways, exerting antioxidant, anti-inflammatory, and anti-fibrotic effects.

Single-cell sequencing of immune cells from the coronary sinus reveals immune mechanisms of the progression of persistent atrial fibrillation

Identifying the atlas of immune cells from coronary sinus circulation (CSC) of patients with persistent atrial fibrillation (PerAF) may provide new insights into the role of immune cells in the progression of AF. Single-cell sequencing revealed substantial alterations in immune cells from CSCs of patients with PerAF, especially a markedly elevated abundance of T cells, after which we identified a T cell subset: FGFBP2(+)TRDC(-)CD4(-) T cells (Ftc-T cells), which can promote the proliferation of cardiac fibroblasts (CFs),and the proportion of Ftc-T had a positive linear with AF recurrence post catheter ablation (CA). Moreover, IFI27 was found to be highly enriched in Ftc-T cells and promoted CFs proliferation and collagen expression. Altogether, our findings represent a unique resource providing in-depth insights into the heterogeneity of the immune cell from CSC of patients with PerAF and highlight the potential role of Ftc-T cells and IFI27 for AF progression.

Association of red cell distribution width/albumin ratio and in hospital mortality in patients with atrial fibrillation base on medical information mart for intensive care IV database

BACKGROUND

Atrial fibrillation (AF) is a common cardiac arrhythmia. The ratio of red cell distribution width (RDW) to albumin has been recognized as a reliable prognostic marker for poor outcomes in a variety of diseases. However, the evidence regarding the association between RDW to albumin ratio (RAR) and in hospital mortality in patients with AF admitted to the Intensive Care Unit (ICU) currently was unclear. The purpose of this study was to explore the association between RAR and in hospital mortality in patients with AF in the ICU.

METHODS

This retrospective cohort study used data from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database for the identification of patients with atrial fibrillation (AF). The primary endpoint investigated was in-hospital mortality. Multivariable-adjusted Cox regression analysis and forest plots were utilized to evaluate the correlation between the RAR and in-hospital mortality among patients with AF admitted to ICU. Additionally, receiver operating characteristic (ROC) curves were conducted to assess and compare the predictive efficacy of RDW and the RAR.

RESULTS

Our study included 4,584 patients with AF with a mean age of 75.1 ± 12.3 years, 57% of whom were male. The in-hospital mortality was 20.3%. The relationship between RAR and in-hospital mortality was linear. The Cox proportional hazard model, adjusted for potential confounders, found a high RAR independently associated with in hospital mortality. For each increase of 1 unit in RAR, there is a 12% rise in the in-hospital mortality rate (95% CI 1.06-1.19). The ROC curves revealed that the discriminatory ability of the RAR was better than that of RDW. The area under the ROC curves (AUCs) for RAR and RDW were 0.651 (95%CI: 0.631-0.671) and 0.599 (95% CI: 0.579-0.620).

CONCLUSIONS

RAR is independently correlated with in hospital mortality and in AF. High level of RAR is associated with increased in-hospital mortality rates.

The relationship of atrial fibrillation with left atrial size in patients with essential hypertension

Atrial fibrillation (AF) is the most common sustained arrhythmia and it is a major public health problem worldwide. Hypertension is one of the major risk factors for the development of AF. This study is carried out to determine the prevalence and independent risk factors for atrial fibrillation (AF) in hypertensive patients and to evaluate the relationship of AF with left atrial size. This is a retrospective observational cross - sectional study that used a retrospective electronic chart review of all admitted patients to cardiology department at King Abdullah university hospital (KAUH) in Irbid, Jordan, with a diagnosis of hypertension along with various acute cardiac admissions, including AF during 1-year period (January 1st to December 31 of 2021). Risk factors for AF (age, sex, DM, coronary artery disease, valvular heart disease, Cor-pulmonale, obstructive sleep apnea, and congestive cardiac failure) were retrieved from electronic charts of the patients. A total of 958 patients were admitted to the coronary care unit (CCU) and intermediate care unit (IMCU) during a 1-year period. Among them, 276 had 2 or 3 admissions. The main reason of admission was acute coronary syndrome (n = 491), heart failure (n = 180), and AF (n = 144), indicating AF prevalence of 15%. However, there were 40 patients with combined causes. All patients in the study (n = 958) were diagnosed with hypertension, including patients with atrial fibrillation (n = 144). The mean age of patients was 61.4 (± 11.46) years, and approximately two thirds of them were males (65.4%). The binary logistic regression model demonstrated a significant statistical relationship of age, left atrial size, coronary artery disease, left ventricular ejection fraction, left ventricular dimensions in systole and diastole, and heart failure with the occurrence of AF after controlling for gender, smoking, and diabetes. Findings indicate that left atrial size plays a significant role in the development of AF in patients with hypertension. However, the prevalence of AF significantly increased with advancing age in both sexes because of increased left ventricular hypertrophy, which leads to increased left atrial size.

Effects of different exercise methods and intensities on the incidence and prognosis of atrial fibrillation

Atrial fibrillation (AF), the most common sustained arrhythmia in clinical practice, exhibits a higher risk of cardiovascular adverse events. Exercise plays a crucial role in AF prevention, but the effects of different exercise types and doses are inconclusive. This review aims to comprehensively explore the most recent evidence and possible mechanisms of diverse exercise modalities concerning AF incidence and therapeutic outcomes. Multiple studies underscore the efficacy of moderate-intensity continuous training (MICT) in reducing AF incidence and symptom burden, rendering it the currently favored exercise therapy for AF patients. High-intensity interval training (HIIT) shows promise, potentially surpassing MICT, especially in reducing age-related AF susceptibility and improving symptoms and exercise capacity. Conversely, prolonged high-intensity endurance exercise exacerbates AF risk due to excessive exercise volume, with potential mechanisms encompassing irreversible atrial remodeling, heightened inflammation, and increased vagal tone. In summation, MICT is a secure strategy for populations in mitigating the risk associated with AF incidence and secondary cardiovascular events and should be encouraged. Also, it is recommended to initiate large-scale clinical intervention trials encompassing a variety of exercise types to delineate the optimal exercise prescription for cardiovascular patients, including those afflicted with AF.

Effects of the beta-blocker carvedilol on arrhythmia and long-term clinical outcomes in benign prostate hypertrophy patients

Benign prostatic hypertrophy (BPH) is associated with autonomic dysfunction and sympathetic nervous system mediated by the alpha receptor. However, limited data exist regarding the effects of the beta-blocker (BB) carvedilol on arrhythmia and urologic outcomes in BPH patients. Our database of patients diagnosed with BPH from 2015 to 2020 was used to obtain echocardiography and electrocardiogram data. Inclusion criteria were BPH patients taking BBs. International Prostate Symptom Score questionnaire were used to evaluate the urinary symptoms and quality of life. Among 448 patients with BPH (69.2 ± 10.9 years) taking BBs, 219 patients took carvedilol (48.9%) and 229 patients took a non-carvedilol BB (51.1%; bisoprolol, 184 patients, 80% or nebivolol, 45 patients, 20%). Difference in the baseline characteristics was not observed. During the median 36-month follow-up, a lower incidence of arrhythmic events (P = .029), total urologic events (P < .001), and less use of additive alpha-blocker was observed in the carvedilol group (P = .022). In multivariate analysis, less carvedilol use (P = .019), heart failure (P < .001), stroke (P < .001), and cardiomyopathy (P = .046) were independent risk factors for arrhythmic events. In addition, less carvedilol use (P = .009) and older age (P = .005) were independent risk factors for urologic events based on BB type at the median 36-month follow-up. The use of carvedilol was associated with less arrhythmic events in BPH patients with palpitation and decreased the incidence of urologic events in BPH compared with the use of non-carvedilol BBs in long-term follow-up.

Study protocol: A systematic review and meta-analysis regarding the influence of coagulopathy and immune activation on new onset atrial fibrillation in patients with sepsis

BACKGROUND

New onset atrial fibrillation (NOAF) is the most common arrhythmia affecting critically ill patients with sepsis. NOAF is associated with increased intensive care unit mortality, increased hospital mortality, development of heart failure and increased risk of permanent atrial fibrillation and thromboembolic events such as stroke. The pathophysiology of NOAF has been outlined, however, a knowledge gap exists regarding the association between abnormalities in coagulation and immune biomarkers, and the risk of developing NOAF in patients with sepsis.

METHODS AND ANALYSIS

This protocol describes a systematic review and meta-analysis following the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guideline (PRISMA-P) and the Meta-Analyses and Systematic Reviews of Observational Studies guideline (MOOSE). We will conduct the literature search in Medline, Scopus and Cochrane Library. We will include studies that report data in adult patients (>18 years) with sepsis that develop NOAF. We will extract data from studies that report at least one coagulation or immune biomarker. Risk of bias will be assessed by using the Newcastle Ottawa Scale (NOS) and Risk of Bias 2 tool (RoB2) for non-randomized and randomized trials respectively. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach will be utilized in assessing the quality of evidence.

DISCUSSION

This systematic review and meta-analysis will explore the scientific literature regarding the association between coagulation and immune activation in critically ill patients with sepsis, who develop NOAF. The findings will add to the existing knowledge base of NOAF in sepsis, highlight areas of uncertainty and identify future areas of interest to guide and improve management strategies for NOAF.

TRIAL REGISTRATION

Registration details. CRD42022385225 (PROSPERO).

Use of the CHA2DS2-VASc score to predict subsequent myocardial infarction in atrial fibrillation

BACKGROUND

The risk of subsequent myocardial infarction (MI) varies widely in patients with atrial fibrillation (AF). No convenient scoring system currently exists to identify MI in AF. While each element of the CHA2DS2-VASc (congestive heart failure; hypertension; age ≥75 years [doubled]; type 2 diabetes; previous stroke or thromboembolism [doubled]; vascular disease; age 65-75 years; and sex category) score can increase the likelihood of MI, this retrospective longitudinal study aimed to determine the accuracy of the CHA2DS2-VASc score in predicting subsequent MI risk in AF.

METHODS

A total of 29,341 patients with AF were enrolled and followed up from January 2010 until the first occurrence of MI or until December 2020. The primary endpoint was the occurrence of subsequent MI.

RESULTS

The average age of the study population was 71 years, and 43.2% were male. The mean CHA2DS2-VASc score was found to be higher in patients with AF who had experienced an MI than in those who had not (3.56 ± 1.92 vs. 3.32 ± 1.81, p < 0.001). During the long-term follow-up, the risk of subsequent MI increased by 22% with every one-point increase in the CHA2DS2-VASc score (hazard ratio 1.22, 95% confidence interval 1.19-1.25; p < 0.001). Kaplan-Meier analysis revealed that high CHA2DS2-VASc scores were more likely to experience an MI than those with low CHA2DS2-VASc scores (log-rank p < 0.001). Furthermore, the CHA2DS2-VASc score was a significant predictor of MI in multivariate regression analysis.

CONCLUSION

The CHA2DS2-VASc score is a valuable predictor of subsequent MI risk in patients with AF.

Hydrogenated silicene nanosheet functionalized scaffold enables immuno-bone remodeling

An ideal implant needs to have the ability to coordinate the foreign body response and tissue regeneration. Here, Hydrogenated-silicon nanosheets (H-Si NSs) with favorable biodegradability are integrated and functionalized into a β-tricalcium phosphate scaffold (H-Si TCP) for bone defect healing. H-Si TCP can greatly improve bone regeneration through osteoimmunomodulation-guided biodegradation in vivo. The spatiotemporal regulation of degradation products replenishes sufficient nutrients step by step for the entire process of bone repair. Extracellular and intracellular reactive oxygen species (ROS) are first downregulated by reaction with H-Si NSs, followed by marked M2 polarization, remodeling the micro-environment timely for immune-bone regeneration. The release of primary reaction products awakened bone marrow mesenchymal stem cells (BMSCs), which are converted into osteoblasts anchored on scaffolds. Subsequently, biomineralization is promoted by the final degradation products. The intrinsic ROS-responsive, immunoregulatory, and osteo-promotive capability of 2D H-Si NSs makes such composite H-Si TCP scaffold a highly potential alternative for the treatment of critical bone defect.

Triggers of Atrial Fibrillation in the Geriatric Medical Intensive Care Unit: An Observational Study

Background

Atrial fibrillation (AF) is a common arrhythmia in the non-cardiac intensive care unit (ICU). However, data concerning AF incidence and predictors in such populations are scarce and controversial. The study aimed to investigate the contributing factors of new-onset AF in elderly patients within the medical intensive care setting.

Methods

Patients admitted to ICU during a 6-month period were prospectively studied. Patients admitted for short period postoperative monitoring and patients with chronic or paroxysmal AF were excluded. The conditions involved as AF risk factors or "triggers" from demographic data, history, and echocardiography were recorded. Acute Physiology and Chronic Health Evaluation II score was calculated. Electrolytes including some trace elements (zinc, copper, and magnesium) were analyzed.

Results

The study included 142 patients (49% females). Mean age was 69.5 ± 7.3 years. AF was observed in 12%. Diagnosis of pneumonia (P < 0.001), low copper (P < 0.0001) and low zinc levels (P < 0.0001) was significantly associated with the occurrence of AF. By multivariate analysis, they remained statistically significant (odds ratio, 7.0; 95% confidence interval, 2.0 - 24.6; P < 0.01).

Conclusions

A significant fraction of ICU elderly patients manifests AF. The relevant factors contributing to AF incidence in the elderly are pneumonia and low zinc and low copper.

Experimental study on the effect of chlorhexidine gluconate (CG)-induced atrial fibrillation on renal water and sodium metabolism

To construct an animal model of atrial fibrillation and observe the effect of acute atrial fibrillation on renal water and sodium metabolism in mice. A total of 20 C57 mice were randomly assigned to 2 groups (n = 10/group): control group (CON) and atrial fibrillation group (AF). The mice model of atrial fibrillation was induced by chlorhexidine gluconate (CG) in combination with transesophageal atrial spacing. The urine of the two groups of mice was collected, and then we calculate the urine volume and urine sodium content. The expression of TGF-β and type III collagen in the atrial myocardium of the two groups was detected by immunohistochemistry and Western Blot. The levels of CRP and IL-6 in blood were observed by ELISA, and the NF-κB, TGF-β, collagen type III, AQP2, AQP3, AQP4, ENaC-β, ENaC-γ, SGK1 and NKCC proteins in the kidneys of the two groups of mice was observed by Western Blot. Compared with CON, the expression of TGF-β and type III collagen in the atrial myocardium of the mice in AF were increased, the levels of CRP and IL-6 in the blood in AF were increased, and the renal NF-κB, TGF-β, type III collagen AQP2, AQP3, ENaC-β, ENaC-γ, SGK1 and NKCC protein expression in AF were up-regulated. The level of urine volume and urine sodium content in AF were significantly reduced. In the acute attack of atrial fibrillation, the formation of renal inflammatory response and fibrosis is activated, and the renal water and sodium metabolism is hindered, which is related to the up-regulated of the expressions of renal NKCC, ENaC and AQPs.

Gut Microbiota Dysbiosis Induced by a High-Fat Diet Increases Susceptibility to Atrial Fibrillation

BACKGROUND

Obesity is a significant risk factor for atrial fibrillation (AF), and the gut microbiota is closely related to obesity-induced diseases. However, whether the gut microbiota is involved in regulating obesity-induced AF has not been studied. This study investigated whether gut microbiota dysbiosis affects obesity-related AF.

METHODS

Fecal microbes derived from normal diet (ND)-fed and high-fat diet (HD)-fed mice were transplanted into those fed normally. Morphologic, biochemical, functional, histologic, electrophysiological studies, molecular analysis, 16S rRNA gene amplicon sequencing, and RNA-sequencing were performed.

RESULTS

Transplantation of the HD gut microbes in ND-maintained (THD) mice led to a significant increase in the susceptibility to AF. Gut microbiota analysis showed a significant increase in Desulfovibrionaceae, which generated metabolic endotoxemia in THD mice. Transplantation with HD microbes also resulted in significantly increased levels of circulating lipopolysaccharide (LPS), significant disruption in the histologic architecture of the intestinal tissue, and significantly increased proinflammatory cytokines in the left atrium, indicating that atrial inflammation likely contributed to AF susceptibility. RNA-sequencing showed that the THD group had enhanced activation of ferroptosis and TLR4/NF-κB/NLRP3 inflammasome signalling pathway. Inhibiting the ferroptosis or NLRP3 inflammasome signalling pathway significantly improved atrial fibrosis and reduced susceptibility to obesity-related gut dysbiosis-induced AF.

CONCLUSIONS

This study provides evidence showing an original causal role of gut microbiota dysbiosis in the pathogenesis of obesity-related AF, which showed elevated LPS and dysregulation of atrial pathologic remodelling by activating ferroptosis and the TLR4/NF-κB/NLRP3 inflammasome signalling pathway.

Risk factors for new-onset atrial fibrillation during critical illness: A Delphi study

Background

New-onset atrial fibrillation (NOAF) is common during critical illness and is associated with poor outcomes. Many risk factors for NOAF during critical illness have been identified, overlapping with risk factors for atrial fibrillation in patients in community settings. To develop interventions to prevent NOAF during critical illness, modifiable risk factors must be identified. These have not been studied in detail and it is not clear which variables warrant further study.

Methods

We undertook an international three-round Delphi process using an expert panel to identify important predictors of NOAF risk during critical illness.

Results

Of 22 experts invited, 12 agreed to participate. Participants were located in Europe, North America and South America and shared 110 publications on the subject of atrial fibrillation. All 12 completed the three Delphi rounds. Potentially modifiable risk factors identified include 15 intervention-related variables.

Conclusions

We present the results of the first Delphi process to identify important predictors of NOAF risk during critical illness. These results support further research into modifiable risk factors including optimal plasma electrolyte concentrations, rates of change of these electrolytes, fluid balance, choice of vasoactive medications and the use of preventative medications in high-risk patients. We also hope our findings will aid the development of predictive models for NOAF.

Association of atopic diseases with atrial fibrillation risk: A systematic review and meta-analysis

Background

Atopic diseases and atrial fibrillation (AF) seem to share an underlying inflammatory pathology. To date, some population-based studies have explored the relationship between the two. We aimed to conduct a meta-analysis to examine the role of atopic condition in AF risk.

Methods

All relevant observational studies in PubMed and EMBASE databases up to November 2021 were searched. In RevMan 5.3, we used random-effects or fixed-effects models to pool the effect sizes of hazard ratio (HR), odds ratio (OR) and their corresponding 95% confidence intervals (95% CI). In addition, I² and Cochran Q test were used to evaluate the heterogeneity.

Results

A total of 2488 records were retrieved. After screening according to the predetermined criteria, 6 cohort studies and 2 case-control studies were included in this meta-analysis. Herein, the meta-analysis of 6 cohort studies suggested that atopic diseases potentially increased the AF risk with the pooled HR of 1.26 (95%CI,1.14–1.39), while the pooled effect size (OR, 1.04; 95%CI,0.74–1.46) of 2 case-control studies was not statistically significant. Based on the types of atopic diseases, further subgroup analyses of 6 cohort studies revealed that asthma, allergic rhinitis, and atopic dermatitis all potentially increased the risk of subsequent AF with the pooled HR of 1.41 (n = 4; 95%CI, 1.25–1.58), 1.12 (n = 1; 95%CI,1.10–1.14) and 1.06 (n = 3; 95%CI, 1.01–1.12), respectively.

Conclusion

This meta-analysis demonstrated that patients with atopic diseases have a higher risk of developing AF, particularly those with asthma.

Association between atrial fibrillation and risk of end-stage renal disease among adults with diabetes mellitus

Diabetes mellitus (DM) is an important risk factor in patients with end-stage renal disease (ESRD). DM is associated with the development of cardiovascular diseases, such as atrial fibrillation (AF), due to poor glycemic control. However, few studies have focused on the risk of developing ESRD among DM patients with and without AF. This study evaluated ESRD risk among DM patients with and without AF in Taiwan. Data were retrieved from one million patients randomly sampled from Taiwan’s National Health Insurance Research Database, including 6,105 DM patients with AF propensity score–matched with 6,105 DM patients without AF. Both groups were followed until death, any dialysis treatment, or December 31, 2013, whichever occurred first. AF was diagnosed by a qualified physician according to the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM), using the diagnostic code 427.31. Patients aged <20 years or diagnosed with ESRD before the index date were excluded. A Cox proportional hazard regression model was used to calculate the relative ESRD risk. Among DM patients, those with AF have more comorbidities than those without AF. We also found a 1.18-fold (95% confidence interval [CI]: 1.01–1.46) increase in ESRD risk among patients with AF compared with those without AF. In addition, DM patients with hypertension, chronic kidney disease (CKD), or higher Charlson Comorbidity Index scores also have significantly increased ESRD risks than those without these complications. A 1.39-fold (95% CI: 1.04–1.86) increase in risk was observed for patients with AF among the non-CKD group. Our findings suggest that patients with DM should be closely monitored for irregular or rapid heart rates.

Left atrial epicardial adipose tissue is associated with low voltage zones in the left atrium in patients with non-valvular atrial fibrillation

Objective

Epicardial adipose tissue (EAT) is related to atrial fibrillation (AF), but the specific mechanism is still unclear. Left atrial (LA) low voltage zones (LVZ) can well reflect atrial fibrosis. This study investigated the relationship between EAT and LVZ in non-valvular AF (NVAF) patients.

Methods

This observational study including patients with NVAF (n = 214) undergoing radiofrequency ablation (RFCA) for the first time in our hospital and 62 matched controls. The EAT volume and attenuation were measured by contrast-enhanced computed tomography. A three-dimensional mapping system was used to map the left atrial endocardium and evaluate LA-LVZ. Patients were divided into LVZ and non-LVZ groups according to the presence or absence of LVZ.

Results

Patients with AF showed higher LA-EAT volume and lower attenuation value than controls (29.7 ± 11.2 cm³ vs. 20.9 ± 8.6 cm³, P = 0.021; −91.2 ± 5.6 HU vs. −88.7 ± 5.9 HU, P < 0.001). Compared with the group without LVZ, there were significant differences in age [65 (59–71) vs. 60 (52–69), P = 0.006], LAVI [75.1 ± 20.7 ml/m² vs. 67.2 ± 20.9 ml/m², P = 0.018], LA-EAT volume (34.8 ± 11.5 cm³ vs. 28.1 ± 10.6 cm³, P < 0.001) and LA-EAT attenuation (−93.9 ± 5.3 HU vs. −90.4 ± 5.5 HU, P < 0.001). Multivariate regression analysis showed that age (OR = 1.040; 95%CI: 1.001–1.078, P = 0.042), LAVI (OR = 1.019; 95%CI: 1.002–1.037, P = 0.032), LA-EAT volume (OR = 1.193; 95%CI: 1.015–1.402, P = 0.034) and attenuation value (OR = 0.801; 95%CI: 0.701–0.916 P = 0.001) were independent predictors of LVZ. After LA-EAT attenuation was incorporated into the clinical model, the comprehensive discrimination and net reclassification tended to improve (IDI and NRI > 0, P < 0.05).

Conclusion

LA-EAT volume and attenuation values can independently predict the presence of LVZ, and LA-EAT attenuation has a better predictive value than LA-EAT volume.

A case-control study to investigate association between serum uric acid levels and paroxysmal atrial fibrillation

The relationship between serum uric acid (SUA) levels and paroxysmal atrial fibrillation (AF) remains controversial. The objective of this case–control study was to investigate the association between serum SUA levels and paroxysmal AF by gender in 328 patients. This study included 328 hospitalized patients with newly diagnosed paroxysmal AF in China between January 2019 and September 2021. Controls with sinus rhythm were matched (2:1) to cases by age and gender. Baseline data were analyzed using ANOVA, T-test, and Chi-square test. Pearson correlation analyses were used to confirm the correlation between variables, and multivariate regression analyses were used to adjust for covariates. Elevated SUA levels in female patients were significantly associated with paroxysmal AF after adjusting for confounding factors (OR = 1.229, 95% CI 1.058–1.427, P = 0.007). Further results showed SUA levels were negatively correlated with high-density lipoprotein cholesterol (HDL-C) (r = − 0.182, p = 0.001) and apolipoprotein A1 (APOA1) (r = − 0.109, p = 0.049), were positively correlated with low-density lipoprotein cholesterol (LDL-C) (r = 0.169, p = 0.002) and prealbumin (PAB) (r = 0.161, p = 0.004) . Nevertheless, there was no significant complication difference between SUA levels and paroxysmal AF (P > 0.05). Increased SUA in female patients was significantly associated with paroxysmal AF in a Chinese population. This finding implies that it would be interesting to monitor and interfere with hyperuricemia in paroxysmal AF patients.

Hyperuricemia Is Associated With the Risk of Atrial Fibrillation Independent of Sex: A Dose-Response Meta-Analysis

Background:

Conflicting findings of the association between serum uric acid (SUA) and atrial fibrillation (AF) have been reported in both men and women. The sex-specific associations between SUA and the risk of AF are unclear, although hyperuricemia is independently associated with the risk of AF. We performed this meta-analysis to assess the sex-specific effect of SUA on the risk of AF.

Methods

The PubMed, EMBASE, and Cochrane Library databases were searched up to October 3, 2021, for studies that reported sex-specific associations of SUA levels with AF. Linear relationships were assessed by the generalized least squares trend estimation. This study was registered with PROSPERO (42020193013).

Results

Ten eligible studies with 814,804 participants (415,779 men and 399,025 women) were identified. In the category analysis, high SUA was associated with an increased risk of AF in both men (OR: 1.42; 95% CI, 1.18–1.71, I² = 34%) and women (OR: 2.02; 95% CI, 1.29–3.16, I² = 70%). In the dose-response analysis, for each 60 μmol/L (1 mg/dL) increase in the SUA level, the risk of AF increased by 15% (OR: 1.15; 95% CI, 1.07–1.25, I² = 74%) in men and 35% (OR: 1.35; 95% CI, 1.18–1.53, I² = 73%) in women. There was a borderline difference in the impact of SUA on the risk of AF between men and women (P for interaction = 0.05). A significant linear relationship between SUA and the risk of AF was observed in men (P for non-linearity = 0.91) and women (P for non-linearity = 0.92).

Conclusions

This study suggested that there was a significant linear relationship between SUA and the risk of AF among men and women, with a higher risk estimate for women. Additional trials are required to assess the effect of reduced SUA therapy on AF incidence.

Systematic Review Registration

https:www.crd.york.ac.uk/PROSPERO/, identifier: CRD 42020193013.

Prednisone Ameliorates Atrial Inflammation and Fibrosis in Atrial Tachypacing Dogs

Atrial inflammation and fibrosis have long been considered culprits in the development of atrial fibrillation (AF). Prior clinical studies showed that corticosteroid therapy is beneficial in patients with AF. Here we sought to determine whether prednisone treatment prevents atrial tachypacing (ATP) induced atrial fibrosis.Dogs were randomized into the sham, ATP, ATP + low-dose prednisone (ALP), and ATP + high-dose prednisone (AHP) groups. After 6 days of recovery from surgery, dogs were subjected to ATP at 400 beats per minute for 4 weeks while being treated with prednisone (15 or 40 mg/day) or a placebo. Pacemakers were not activated in the sham group.Compared with the ATP group, the expression of collagen I, collagen III, α-smooth muscle actin, transforming growth factor-β1 and connective tissue growth factor were significantly reduced in the ALP and AHP groups. Fluorescence assays showed that reactive oxygen species formation in the right atrium was suppressed in the ALP and AHP groups compared with the ATP group. The protein level of NADPH oxidase 2 was reduced in the ALP and AHP groups' versus ATP group, while NOX4 and NOX5 were unchanged. ATP-induced downregulation of BH4 and eNOS uncoupling in the atria was partially restored in the prednisone-treated groups.Our study demonstrated that atrial fibrosis induced by ATP were suppressed by prednisone. Low-dose prednisone was also effective in suppressing the development of atrial fibrosis.

The presence of cardiotropic viral genomes is not increased in atrial tissue of atrial fibrillation patients

Background

Infections with potentially cardiotropic viruses are associated with the development of atrial fibrillation (AF). However, whether direct viral infection of the atria is involved in the pathogenesis of AF is unclear. We have therefore analysed the presence of cardiotropic viral genomes in AF patients.

Methods

Samples of left atrial tissue were obtained from 50 AF patients (paroxysmal, n = 20; long-standing persistent/permanent, n = 30) during cardiac surgery and from autopsied control patients (n = 14). Herein, the presence of PVB19, EBV, CMV, HHV‑6, adenovirus and enterovirus genomes was determined by polymerase chain reaction. The densities of CD45+ and CD3+ cells and fibrosis in the atria were quantified by (immuno)histochemistry.

Results

Of the tested viruses only the PVB19 genome was detected in the atria of 10% of patients, paroxysmal AF (2 of 20) and long-standing persistent/permanent AF (3 of 30). Conversely, in 50% of controls (7 of 14) PVB19 genome was found. No significant association was found between PVB19 and CD45+ and CD3+ cells, or between the presence of PVB19 and fibrosis, in either control or AF patients.

Conclusion

The presence of viral genomes is not increased in the atria of AF patients. These results do not support an important role for viral infection of the atria in the pathogenesis of AF.

Supplementary Information

The online version of this article (10.1007/s12471-022-01660-4) contains supplementary material, which is available to authorized users.

Circulating Soluble Suppression of Tumorigenicity 2 Predicts Recurrence After Radiofrequency Ablation of Persistent Atrial Fibrillation

Objective: A more extensively fibrotic left atrium contributes to atrial fibrillation (AF) occurrence, persistence, and recurrence. The soluble suppression of tumorigenicity 2 (sST2) has emerged as a ventricular fibrotic biomarker for patients with heart failure. The present study is to investigate associations between circulating sST2 and risk of recurrence after ablation in AF patients.

Methods: We measured the baseline plasma level of sST2 from patients with persistent AF (n = 117) and paroxysmal AF (n = 93) patients. Patients were followed up for 15 months after ablation. The relationship between circulating sST2 and recurrence was assessed by multivariable Cox regression. The cutoff value of sST2 was determined by receiver operating characteristic curve. The relationship between baseline sST2 level and left atrial volume index (LAVI) was assessed by multivariate linear regression analysis. Serial sST2 measurements were also conducted after 24 h, 6 months, and 15 months of ablation. ST2 localization was examined in left atrial appendages of persistent AF patients by immunohistochemistry and Western blot.

Results: Baseline sST2 positively associated with LAVI in the persistent AF group, and elevated sST2 (≥39.25 ng/ml) independently increased the risk of recurrence after ablation (area under the curve = 0.748), with hazard ratio of 1.038 (95% confidence interval 1.017–1.060, P < 0.001) when adjusted for co-variables. In contrast, elevated sST2 cannot predict recurrence in paroxysmal AF.

Conclusions: In persistent AF patients, increased sST2 serves as a marker of recurrence after radiofrequency ablation. Patients with sST2 ≥ 39.25 ng/ml are more likely to develop recurrence within a year.

Left Atrial Myopathy in Atrial Fibrillation and Heart Failure: Clinical Implications, Mechanisms, and Therapeutic Targets

PURPOSE OF REVIEW

This review discusses the mechanisms, clinical implications, and treatments of left atrial (LA) myopathy in comorbid atrial fibrillation (AF) and heart failure (HF) across the spectrum of ejection fraction.

RECENT FINDINGS

AF and HF are highly comorbid conditions. Left atrial (LA) myopathy, characterized by impairments in LA structure, function, or electrical conduction, plays a fundamental role in the development of both AF and HF with preserved ejection fraction (AF-HFpEF) along with AF and HF with reduced ejection fraction (AF-HFrEF). While the nature of LA myopathy in AF-HFpEF is unique from that of AF-HFrEF, LA myopathy also leads to progression of both of these conditions. There may be a vulnerable cohort of AF-HF patients who have a disproportionate degree of LA myopathy compared with left ventricular (LV) dysfunction. Further investigations are required to identify therapies to improve LA function in this cohort.

Atrial fibrosis underlying atrial fibrillation (Review)

Atrial fibrillation (AF) is one of the most common tachyarrhythmias observed in the clinic and is characterized by structural and electrical remodelling. Atrial fibrosis, an emblem of atrial structural remodelling, is a complex multifactorial and patient-specific process involved in the occurrence and maintenance of AF. Whilst there is already considerable knowledge regarding the association between AF and fibrosis, this process is extremely complex, involving intricate neurohumoral and cellular and molecular interactions, and it is not limited to the atrium. Current technological advances have made the non-invasive evaluation of fibrosis in the atria and ventricles possible, facilitating the selection of patient-specific ablation strategies and upstream treatment regimens. An improved understanding of the mechanisms and roles of fibrosis in the context of AF is of great clinical significance for the development of treatment strategies targeting the fibrous region. In the present review, a focus was placed on the atrial fibrosis underlying AF, outlining its role in the occurrence and perpetuation of AF, by reviewing recent evaluations and potential treatment strategies targeting areas of fibrosis, with the aim of providing a novel perspective on the management and prevention of AF.

Atrial fibrillation in patients with heart failure with preserved ejection fraction

PURPOSE OF REVIEW

To review the shared pathology of atrial fibrillation and heart failure with preserved ejection fraction (HFpEF) and the prognostic, diagnostic, and treatment challenges incurred by the co-occurrence of these increasingly prevalent diseases.

RECENT FINDINGS

Multiple risk factors and mechanisms have been proposed as potentially linking atrial fibrillation and HFpEF, with systemic inflammation more recently being invoked. Nonvitamin K oral anticoagulants, left atrial appendage occlusion devices, and catheter ablation have emerged as alternative treatment options. Other novel pharmacological agents, such as neprilysin inhibitors, need to be studied further in this patient population.

SUMMARY

Atrial fibrillation and HFpEF commonly co-occur because of their shared risk factors and pathophysiology and incur increased morbidity and mortality relative to either condition alone. Although the presence of both diseases can often make each diagnosis difficult, it is important to do so early in the disease course as there are now a variety of treatment options aimed at improving symptoms and quality of life, slowing disease progression, and improving prognosis. However, more research needs to be performed on the role of catheter ablation in this population. Novel pharmacologic and procedural treatment options appear promising and may further improve the treatment options available to this growing population.

Inflammatory Cytokines During Cardiac Rehabilitation After Heart Surgery and Their Association to Postoperative Atrial Fibrillation

Inflammation is associated with atrial fibrillation (AF), but little is known about the association of AF with the inflammatory serum cytokines after the acute postoperative phase. Thus, we aimed to explore how plasma cytokines concentrations modify during a 3-week cardiac rehabilitation after heart surgery, comparing patients who developed postoperative AF (POAF) and those with permanent AF with patients free from AF (NoAF group). We enrolled 100 consecutive patients and 40 healthy volunteers as a control group. At the beginning of cardiac rehabilitation, 11 days after surgery, serum levels of MPO, PTX3, ADAM17, sST2, IL-25, and IL-33 were dramatically higher, whereas TNFα and IL-37 levels were much lower in NoAF, POAF, and permanent AF patients than in the healthy volunteers. After rehabilitation, most of the cytokines changed tending towards normalization. POAF patients (35% of the total) had higher body mass index and abdominal adiposity than NoAF patients, but similar general characteristics and risk factors for POAF. However, ADAM-17 and IL-25 were always lower in POAF than in NoAF patients, suggesting a protective role of IL-25 and ADAM 17 against POAF occurrence. This finding could impact on therapeutic strategies focusing on the postoperative prophylactic antiarrhythmic interventions.

Does Atrial Fibrillation Increase the Risk of Developing End-stage Renal Disease in Patients with Chronic Kidney Disease?

Patients with atrial fibrillation (AF) have elevated risks of developing stroke, heart failure, and myocardial infarction. However, the impact of AF on the progression of chronic kidney disease (CKD) is uncertain. Our review objective is to investigate whether AF increases the risk of developing end-stage renal disease (ESRD) in patients with CKD. On 31 January 2019, a systemic search was performed on the MEDLINE database using the predefined search criteria. Limits included human participants and English-language publications. Studies that evaluated an association of AF and the risk of CKD progression to ESRD were selected. A total of 751 articles were identified. One prospective cohort study was included after screening abstracts from overall retrieved studies based on our inclusion/exclusion criteria, with a total of 3,091 CKD patients and a mean follow-up of 5.9 years. A total of 172 CKD patients developed AF, of which 43 patients later developed ESRD. Of 2,919 CKD patients with no incident AF, 581 patients progressed to ESRD. The rate of ESRD after the development of AF was 11.8/100 person-years compared with 3.4/100 person-years in CKD patients without AF. In conclusion, AF is an independent risk factor for developing ESRD in CKD patients, but more evidence is needed to support this result.

Distinct origins and functions of cardiac orthotopic macrophages

Macrophages are one cell type in the innate immune system. Recent studies involving macrophages have overturned the conventional concept that circulating bone marrow-derived blood mononuclear cells in the adult body continuously replace macrophages residing in the tissues. Investigations using refined technologies have suggested that embryonic hematopoiesis can result in the differentiation into macrophage subgroups in some tissues. In adulthood, these macrophages are self-sustaining via in situ proliferation, with little contribution of circulating bone marrow-derived blood mononuclear cells. Macrophages are integral component of the heart, accounting for 8% of the non-cardiac cells. The use of innovative molecular techniques in paradigm shifting researches has revealed the complexity of cardiac macrophages, including their heterogeneity and ontological diversity. Resident cardiac macrophages modulate the physiological and pathophysiological processes of the cardiovascular system, with distinct and crucial roles in healthy and injured hearts. Their functions include sensing of pathogens, antigen presentation, digesting cell debris, regulating inflammatory responses, generating distinct cytokines, and secreting some regulatory factors. More recent studies have revealed further functions of cardiac macrophages. This review focuses on macrophages within the cardiovascular system. We discuss evidence that has changed our collective view of cardiac macrophage subgroups, and improved our understanding of the different phenotypes, cell surface markers, heterogeneities, origins, developments, and the dynamic and separate roles of these cardiac macrophage subgroups in the steady state and injured hearts. This review may provide novel insights concerning the pathophysiology of cardiac-resident macrophages in cardiovascular diseases and innovative therapeutic strategies that could include the modulation of the role of macrophages in cardiovascular injuries.

Sex and Cardiovascular Involvement in Inflammatory Joint Diseases

The term inflammatory joint disease (IJD) encompasses a group of chronic conditions with predominant joint involvement. They share an increased risk of cardiovascular (CV) complications. However, the implication of the sex in the risk of CV disease in IJD has not been specifically addressed. The aim of this work is to assess the influence of sex on the clinical expression of CV manifestations associated to IJD. With this objective, an update of the current knowledge of the sex influence on CV disease in patients with IJD was conducted. A PubMed database search of the most relevant literature on this topic was performed mainly based on studies published in English over the last 10 years. Although most studies on IJD were not specifically designed to address sex differences regarding CV complications, it seems that men with rheumatoid arthritis (RA) are at higher risk of pericarditis, ischemic heart disease, heart failure (HF) with reduced ejection fraction (EF), and CV mortality than women with RA. In contrast, HF with preserved EF and diastolic dysfunction is more frequent in women with RA. Men with ankylosing spondylitis present more frequently disorders of the conduction system and aortic valvulopathy than women. A limited number of studies addressed CV differences according to sex in psoriatic arthritis. Although there are some differences according to sex in the clinical expression of CV complications in patients with IJD, much research is still needed to better identify the implication of sex in the risk of CV disease in these patients.

Association Between Atrial Fibrillation and Dementia: A Meta-Analysis

Background: A potential evidence from previous epidemiological studies remains conflicting findings regarding the association between atrial fibrillation (AF) and dementia risk. We, therefore, carried out a meta-analysis of relevant studies to investigate the magnitude of the association between AF and dementia risk.

Methods: We performed a systematic literature search of PubMed, EMBASE, and Google Scholar for potential studies between January 1, 1990, and December 31, 2018, with no restriction on the publication language. All potential studies were independently assessed by two reviewers. We only included observational studies that calculated the odds ratio (OR)/hazards ratio (HR) for dementia associated with atrial fibrillation. We first assessed the heterogeneity among study-specific HRs using the Q statistic and I² statistic. We then used the random-effects model to obtain the overall HR and its 95% CI for all studies. We also tested and corrected for publication bias by funnel plot–based methods. The quality of each study was assessed with the Newcastle Ottawa Scale.

Results: A total of 16 studies with 2,415,356 individuals, and approximately 200,653 cases of incidence dementia were included in this study. Patients with AF had a greater risk of incidence dementia than those without AF (random-effect hazard ratio HR: 1.36, 95% CI: 1.23–1.51, p < 0.0001; I² = 83.58). Funnel plot and Egger test did not reveal significant publication bias. However, limitations of the study included high heterogeneity and varying degrees of confounder adjustment across individual studies.

Conclusion: This study serves as added evidence supporting the hypothesis that AF is associated with an increased risk of dementia. More studies are needed to establish whether optimal treatment of AF can reduce or mitigate the risk of dementia.

CTRP9 Ameliorates Atrial Inflammation, Fibrosis, and Vulnerability to Atrial Fibrillation in Post-Myocardial Infarction Rats

Background

Inflammation and fibrosis play an important role in the pathogenesis of atrial fibrillation (AF) after myocardial infarction (MI). CTRP9 (C1q/tumor necrosis factor‐related protein‐9) as a secreted glycoprotein can reverse left ventricle remodeling post‐MI, but its effects on MI‐induced atrial inflammation, fibrosis, and associated AF are unknown.

Methods and Results

MI model rats received adenoviral supplementation of CTRP9 (Ad‐CTRP9) by jugular‐vein injection. Cardiac function, inflammatory, and fibrotic indexes and related signaling pathways, electrophysiological properties, and AF inducibility of atria in vivo and ex vivo were detected in 3 or 7 days after MI. shCTRP9 (short hairpin CTRP9) and shRNA were injected into rat and performed similar detection at day 5 or 10. Adverse atrial inflammation and fibrosis, cardiac dysfunction were induced in both MI and Ad‐GFP (adenovirus‐encoding green fluorescent protein)+MI rats. Systemic CTRP9 treatment improved cardiac dysfunction post‐MI. CTRP9 markedly ameliorated macrophage infiltration and attenuated the inflammatory responses by downregulating interleukin‐1β and interleukin‐6, and upregulating interleukin‐10, in 3 days post‐MI; depressed left atrial fibrosis by decreasing the expressions of collagen types I and III, α‐SMA, and transforming growth factor β1 in 7 days post‐MI possibly through depressing the Toll‐like receptor 4/nuclear factor‐κB and Smad2/3 signaling pathways. Electrophysiologic recordings showed that increased AF inducibility and duration, and prolongation of interatrial conduction time induced by MI were attenuated by CTRP9; moreover, CTRP9 was negatively correlated with interleukin‐1β and AF duration. Downregulation of CTRP9 aggravated atrial inflammation, fibrosis, susceptibility of AF and prolonged interatrial conduction time, without affecting cardiac function.

Conclusions

CTRP9 is effective at attenuating atrial inflammation and fibrosis, possibly via its inhibitory effects on the Toll‐like receptor 4/nuclear factor‐κB and Smad2/3 signaling pathways, and may be an original upstream therapy for AF in early phase of MI.

Atria-selective antiarrhythmic drugs in need of alliance partners

Atria-selective antiarrhythmic drugs in need of alliance partners. Guideline-based treatment of atrial fibrillation (AF) comprises prevention of thromboembolism and stroke, as well as antiarrhythmic therapy by drugs, electrical rhythm conversion, ablation and surgical procedures. Conventional antiarrhythmic drugs are burdened with unwanted side effects including a propensity of triggering life-threatening ventricular fibrillation. In order to solve this therapeutic dilemma, 'atria-selective' antiarrhythmic drugs have been developed for the treatment of supraventricular arrhythmias. These drugs are designed to aim at atrial targets, taking advantage of differences in atrial and ventricular ion channel expression and function. However it is not clear, whether such drugs are sufficiently antiarrhythmic or whether they are in need of an alliance partner for clinical efficacy. Atria-selective Na⁺ channel blockers display fast dissociation kinetics and high binding affinity to inactivated channels. Compounds targeting atria-selective K⁺ channels include blockers of ultra rapid delayed rectifier (Kv1.5) or acetylcholine-activated inward rectifier K⁺ channels (Kir3.x), inward rectifying K⁺ channels (Kir2.x), Ca²⁺-activated K⁺ channels of small conductance (SK), weakly rectifying two-pore domain K⁺ channels (K_2P), and transient receptor potential channels (TRP). Despite good antiarrhythmic data from in-vitro and animal model experiments, clinical efficacy of atria-selective antiarrhythmic drugs remains to be demonstrated. In the present review we will briefly summarize the novel compounds and their proposed antiarrhythmic action. In addition, we will discuss the evidence for putative improvement of antiarrhythmic efficacy and potency by addressing multiple pathophysiologically relevant targets as possible alliance partners.

Atrial contractility and fibrotic biomarkers are associated with atrial fibrillation after elective coronary artery bypass grafting

OBJECTIVE

New-onset postoperative atrial fibrillation is common after cardiac surgery. Less has been reported about the relationship among fibrosis, inflammation, calcium-induced left atrial and right atrial contractile forces, and postoperative atrial fibrillation. We sought to identify predictors of postoperative atrial fibrillation.

METHODS

From August 2016 to February 2018, we evaluated 229 patients who had preoperative sinus rhythm before elective primary coronary artery bypass grafting. Of 229 patients, 191 maintained sinus rhythm postoperatively, whereas 38 patients developed atrial fibrillation. Preoperative tissue inhibitor of metalloproteinase-1, pentraxin-3, matrix metallopeptidase-9, galectin-3, high-sensitivity C-reactive protein, growth differentiation factor 15, and transforming growth factor-ß were measured. Clinical and echocardiographic findings (tricuspid annular plane systolic excursion for right heart function) and calcium-induced force measurements from left atrial and right atrial-derived skinned myocardial fibers were recorded.

RESULTS

Patients with atrial fibrillation were older (P = .001), had enlarged left atrial (P = .0001) and right atrial areas (P = .0001), and had decreased tricuspid annular plane systolic excursion (P = .001). Levels of matrix metallopeptidase-9 and pentraxin-3 were decreased (P < .05), whereas growth differentiation factor 15 was increased (P = .001). We detected lower left atrial force values at calcium-induced force measurements 5.5 (P < .05), 5.4 (P < .01), and 5.3 to 4.52 (P = .0001) and right atrial force values at calcium-induced force measurements 5.0 to 4.52 (P < .05) in patients with postoperative atrial fibrillation. Multivariable analysis showed that advanced age (P = .033), decreased left atrial force value at calcium-induced force measurement of 5.5 (P = .033), enlarged left atrial (P = .013) and right atrial (P = .081) areas, and reduced tricuspid annular plane systolic excursion (P = .010) independently predicted postoperative atrial fibrillation.

CONCLUSIONS

Advanced age, decreased left atrial force value at calcium-induced force measurement of 5.5, enlarged left atrial and right atrial areas, and reduced tricuspid annular plane systolic excursion were identified as independent predictors for postoperative atrial fibrillation.

Reduction of atrial fibrillation burden by pulmonary vein isolation leads to a decrease of CD11b expression on inflammatory cells

Aims

It is hypothesized that inflammation could promote structural and electrical remodelling processes in atrial fibrillation (AF). Atrial infiltration of monocytes and granulocytes has been shown to be dependent on CD11b expression. The aim of this study was to investigate whether treatment of AF by pulmonary vein isolation (PVI) may lead to reduced inflammation, as indicated by a decrease of CD11b expression on monocytes and granulocytes.

Methods and results

Flow-cytometric quantification analysis and determination of systemic inflammatory markers of peripheral blood were performed in 75 patients undergoing PVI 1 day before and 6 months after PVI. The extent of activation of monocytes and granulocytes was measured by quantifying the cell adhesion molecule CD11b. The mean expression of CD11b on monocytes (20.9 ± 2.5 vs. 10.2 ± 1.4; P < 0.001) and granulocytes (13.9 ± 1.6 vs. 6.8 ± 0.5; P < 0.001), as well as the relative count of CD11b-positive monocytes (P < 0.05) and CD11b-positive granulocytes (P < 0.01) were significantly reduced when comparing the identical patients before and 6 months after PVI. Systemic inflammatory parameters showed only a declining tendency after 6 months. Patients with unsuccessful PVI and ongoing AF on the day of follow-up showed no decrease in CD11b expression.

Conclusions

A significant reduction of CD11b expression on monocytes and granulocytes, as a sign of reduced cellular inflammation, was achieved by treatment of AF using PVI. These data strongly support that AF is not only a consequence of but also a cause for inflammatory processes, which, in turn, may contribute to atrial remodelling.

MD1 Deficiency Promotes Inflammatory Atrial Remodelling Induced by High-Fat Diets

BACKGROUND

Myeloid differentiation protein 1 (MD1) is expressed in various tissues, including the heart. However, the role of MD1 in obesity-related atrial remodelling remains incompletely understood. Here, this study intends to determine the regulatory role and underlying mechanisms of MD1 in obesity-related atrial remodelling.

METHODS

A high-fat diet (HFD) feeding was performed in 6-week-old MD1-knockout (MD1-KO) mice and wild-type (WT) littermates for 20 weeks. Morphological, biochemical, functional, histological, and electrophysiological studies were conducted at the age of 26 weeks.

RESULTS

Our results revealed that the MD1 expression levels were downregulated in the atrium of the HFD-fed induced obesity mice. An increase in body weight, glucose intolerance, hyperlipidemia, and adverse atrial remodelling, such as atrial inflammation and fibrosis, were induced by HFD feeding in WT mice. Vulnerability to atrial fibrillation (AF) was also significantly increased by HFD feeding in WT mice. In addition, these adverse effects caused by HFD-fed induced obesity were further exaggerated in MD1-KO mice compared with WT mice. Mechanistically, MD1-KO activated TLR4/NF-κB signaling pathways, which led to atrial remodelling in mice fed by HFD by increasing the phosphorylation of p65 and IκBα.

CONCLUSIONS

Our data suggested that MD1 deficiency played an important role in accelerating the development of inflammatory atrial fibrosis and increasing vulnerability to AF in mice with HFD-fed induced obesity, providing an essential target for improving HFD-induced atrial remodelling.

Inflammation-Nature's Way to Efficiently Respond to All Types of Challenges: Implications for Understanding and Managing "the Epidemic" of Chronic Diseases

Siloed or singular system approach to disease management is common practice, developing out of traditional medical school education. Textbooks of medicine describe a huge number of discrete diseases, usually in a systematic fashion following headings like etiology, pathology, investigations, differential diagnoses, and management. This approach suggests that the body has a multitude of ways to respond to harmful incidences. However, physiology and systems biology provide evidence that there is a simple mechanism behind this phenotypical variability. Regardless if an injury or change was caused by trauma, infection, non-communicable disease, autoimmune disorders, or stress, the typical physiological response is: an increase in blood supply to the area, an increase in white cells into the affected tissue, an increase in phagocytic activity to remove the offending agent, followed by a down-regulation of these mechanisms resulting in healing. The cascade of inflammation is the body's unique mechanism to maintain its integrity in response to macroscopic as well as microscopic injuries. We hypothesize that chronic disease development and progression are linked to uncontrolled or dysfunctional inflammation to injuries regardless of their nature, physical, environmental, or psychological. Thus, we aim to reframe the prevailing approach of management of individual diseases into a more integrated systemic approach of treating the "person as a whole," enhancing the patient experience, ability to a make necessary changes, and maximize overall health and well-being. The first part of the paper reviews the local immune cascades of pro- and anti-inflammatory regulation and the interconnected feedback loops with neural and psychological pathways. The second part emphasizes one of nature's principles at work-system design and efficiency. Continually overwhelming this finely tuned system will result in systemic inflammation allowing chronic diseases to emerge; the pathways of several common conditions are described in detail. The final part of the paper considers the implications of these understandings for clinical care and explore how this lens could shape the physician-patient encounter and health system redesign. We conclude that healthcare professionals must advocate for an anti-inflammatory lifestyle at the patient level as well as at the local and national levels to enhance population health and well-being.

Taurine Reverses Atrial Structural Remodeling in Ach-Cacl2 Induced Atrial Fibrillation Rats

Taurine has been reported to have anti-arrhythmia effects, but the anti-atrial fibrillation (AF) effects and its mechanism remain incompletely understood. In the present study, the therapy effects and partly mechanisms were investigated. AF animal model was established by intravenous administered with the mixture of acetylcholine (Ach) and CaCl2 (66 μg/mL + 10 mg/mL) (i.v.) for 7 days. The actions of taurine (99 mg/kg∙d, introgastric administration) on the levels of Hs-CRP, IL-6, TNF-α, MMP-9, AngII, the extent of the fibrosis and ultrastructural changes in left atrial were studied. The data showed that the serum levels of TNF-α, IL-6, AngII and the plasma levels of Hs-CRP and MMP-9 were significantly elevated in automatic recovery group relative to the control group (p < 0.01), which were all decreased by taurine administration (p < 0.01) similar to Verapamil treatment. Masson's trichrome staining of the left atrial tissue showed an obvious interstitial fibrosis in rats of automatic recovery group. The alteration could be reversed by additional taurine. Electron microscopy revealed that taurine administration could significantly alleviate the ultrastructural damage of atrial cells, and the effects were similar to the Verapamil treatment. In conclusion, the results suggested that taurine could inhibit the structural remodeling of AF in rats partly by decreasing the levels of inflammatory factors and profibrotic molecules, attenuating the extent of myocardial fibrosis and protecting the integrity of myocardial ultrastructure.

Cardiac magnetic resonance using late gadolinium enhancement and atrial T1 mapping predicts poor outcome in patients with atrial fibrillation after catheter ablation therapy

To determine the pre-procedural value of different fibrotic biomarkers and comprehensive cardiac magnetic resonance (CMR) for the prediction of poor response to ablation therapy in patients with atrial fibrillation (AF). Left atrial (LA) late gadolinium enhancement (LGE) and native LA T1 relaxation times were assessed using CMR. Plasma levels of relaxin, myeloperoxidase and serum levels of matrix metalloproteinase (MMP)-mediated cardiac specific titin fragmentation and MMP-mediated type IV collagen degradation were obtained. Poor outcome was defined by the recurrence of AF during 1-year follow-up. 61 patients were included in final analysis. Twenty (32.8%) patients had recurrence of AF. Patients with a recurrence of AF had a higher percentage of LA LGE (26.7 ± 12.5% vs. 17.0 ± 7.7%; P < 0.001), higher LA T1 relaxation times (856.7 ± 112.2 ms vs. 746.8 ± 91.0 ms; P < 0.001) and higher plasma levels of relaxin (0.69 ± 1.34 pg/ml vs. 0.37 ± 0.88 pg/ml; P = 0.035). In the multivariate Cox regression analysis, poor ablation outcome was best predicted by advanced LGE stage (hazard ratio (HR):5.487; P = 0.001) and T1 relaxation times (HR:1.007; P = 0.001). Pre-procedural CMR is a valuable tool for prediction of poor response to catheter ablation therapy in patients with AF. It offers various imaging techniques for outcome prediction and might be valuable for a better patient selection prior to ablation therapy.

Atrial Fibrillation, Cognitive Decline, and Dementia: an Epidemiologic Review

PURPOSE OF REVIEW

Atrial fibrillation (AF) and dementia are both prevalent diseases in aging societies, which exert a great economic burden worldwide. Although a handful of epidemiologic studies have indicated that AF is independently associated with faster cognitive decline and a higher risk of dementia, there is still a lack of comprehensive understanding of the observed association. In this review, we summarize evidence from major epidemiologic studies concerning AF-related cognitive decline and dementia, the potential mechanisms underlying their association, and the cognitive benefits of treatment options.

RECENT FINDINGS

A large majority of population-based longitudinal studies have consistently shown an independent association of AF with cognitive decline and dementia with varying effect sizes, depending on the age of the study population and the presence of clinical stroke. The underlying pathways linking AF to cognitive phenotypes may involve systemic inflammation, cerebral hypoperfusion, and cerebral small vessel disease and microemboli. However, current evidence is insufficient to support the potential benefits of AF treatment in reducing risk of cognitive decline and dementia.

SUMMARY

Current epidemiologic research suggests that AF contributes to cognitive decline and dementia, independent of a history of stroke. Further work is warranted to elucidate the potential mechanisms underlying this association, and more well-designed studies are needed to explore the possible cognitive benefits of different therapeutic options in patients with AF.

Inflammation and the risk of atrial high-rate episodes (AHREs) in patients with cardiac implantable electronic devices

Introduction

Atrial high-rate episodes (AHREs) are associated with an increased risk of developing atrial fibrillation and thromboembolism. The characteristics of ‘real world’ patients developing AHREs are poorly known.

Methods

We included 496 consecutive patients with cardiac implantable electronic devices (CIEDs). Primary endpoint was occurrence of AHREs, defined as > 175 bpm and lasting > 5 min, in a median follow-up of 16.5 (IQR 3.9–38.6) months (1082.4 patient-years). We also tested the predictive value of clinical risk scores for AHREs.

Results

Mean age was 68.8 ± 14.0 years, and 35.5% were women; AHREs were recorded in 173 patients [34.7%, 16.0%/year, 95% confidence interval (CI) 13.7–18.6]. Multivariable Cox regression analysis showed that age [hazard ratio (HR) 1.020, 95% CI 1.004–1.035, p = 0.011], prior AF (HR 3.521, 95% CI 2.831–5.206, p < 0.001), white cell count (HR 1.039, 95% CI 1.007–1.072, p = 0.016) and high C reactive protein (CRP; HR 1.039, 95% CI 1.021–2.056, p = 0.038) were independently associated with AHREs. ROC curve analysis showed that the APPLE score (C statistic 0.53, 95% CI 0.48–0.59; p = 0.296) ALARMEc score (C statistic 0.51, 95% CI 0.44–0.57; p = 0.810) were non-significantly associated with AHRE. Similar results were obtained for CHADS₂ and CHA₂DS₂VASc score

Conclusion

AHREs are common in CIEDs patients, with age, prior AF, inflammatory markers (high CRP, white cell count) being factors associated with AHREs onset. Clinical risk scores showed limited value for AHREs prediction in this cohort.

Electronic supplementary material

The online version of this article (10.1007/s00392-018-1244-0) contains supplementary material, which is available to authorized users.

Elevated Circulating Fibrocytes Is a Marker of Left Atrial Fibrosis and Recurrence of Persistent Atrial Fibrillation

Background

In atrial fibrillation (AF), a more extensively fibrotic left atrium (LA) provides a substrate for arrhythmias and increases risk of relapse following ablation. Fibrocytes are bone marrow–derived circulating mesenchymal progenitors that have been identified in the atrium of patients with AF who have valvular diseases. The present study investigates the associations between circulating fibrocytes and LA fibrosis or the prevalence of recurrence after ablation in patients with persistent AF.

Methods and Results

We measured the proportion, differentiation, and migration of circulating fibrocytes from patients with persistent AF (n=40), those with paroxysmal AF (n=30), and sinus rhythm controls (n=30). LA low‐voltage (fibrosis) area was identified by an electroanatomic mapping system, and patients were followed up for 1 year after ablation. The relationship between circulating fibrocyte percentage and LA low‐voltage area or recurrence was assessed by multivariate regression analysis. Circulating fibrocyte percentage positively associated with LA low‐voltage area in the persistent AF group, and circulating fibrocyte (≥4.05%) was a significant predictor of 1‐year recurrence after ablation. Cultured fibrocytes exhibited enhanced potential of differentiation in the persistent AF group (67.58±1.54%) versus the paroxysmal AF group (56.67±1.52%) and sinus rhythm controls (48.43±1.79%). Furthermore, expression of fibroblast activation markers and cell migratory ability were also elevated in differentiated fibrocytes from patients with persistent AF. Transforming growth factor β1 and stromal cell–derived factor 1 were elevated in the plasma of patients with persistent AF and were shown to promote fibrocyte differentiation and migration, respectively.

Conclusions

In patients with persistent AF, increased circulating fibrocytes served as a marker of LA fibrosis and recurrence.