Relation of elevated C-reactive protein and interleukin-6 levels to left atrial size and duration of episodes in patients with atrial fibrillation

Association of Autoimmune Vasculitis and Incident Atrial Fibrillation: A Population-Based Case-Control Study

Background

Recent investigations suggest that inflammation and autoimmunity might have a role in the pathophysiology of atrial fibrillation (AF). Given that abnormal ventriculovascular coupling often coexists with AF, we hypothesize that autoimmune vasculitis plays a significant role in the pathogenetic mechanism of AF.

Methods and Results

A standardized retrospective population‐based case–control study was conducted to evaluate the association between autoimmune vasculitis and AF, and all‐cause mortality. The study included 8459 patients with a new diagnosis of AF and 8459 age‐, sex‐, and registration calendar year–matched controls in Olmsted County, Minnesota, between January 1, 1980 and December 31, 2010. The association of each clinical characteristic, diagnosis, and treatment was assessed using conditional logistic regression to account for the matched case–control study design. Cox proportional hazards regression models and Kaplan‐Meier curves were used to detect independent predictors of mortality and examine cumulative survival. Of a total of 16 918 patients (mean age 72.3+14.4 years; 48.7% women), 320 (1.9%) were diagnosed with autoimmune vasculitis before the index date during the 30‐year period. Among the cases, the prevalence of any autoimmune vasculitis was 2.3%, whereas the frequency of autoimmune vasculitis in controls was 1.5% (P<0.001). After adjusting for potential confounders, the odds of autoimmune vasculitis in AF cases was 1.5 times higher than in controls (odds ratio, 1.47; 95% CI, 1.04–2.01; P=0.03). Patients with AF and autoimmune vasculitis had worse 5‐year survival than those without autoimmune vasculitis or AF (44.7% versus 77.2%; log‐rank P<0.001).

Conclusions

Autoimmune vasculitis is significantly associated with AF and independently confers worse survival. These observations may represent one mechanism linking autoimmunity and inflammation to the pathogenesis and prognosis of AF.

The preablation monocyte/ high density lipoprotein ratio predicts the late recurrence of paroxysmal atrial fibrillation after radiofrequency ablation

Background

The monocyte/high-density lipoprotein ratio (MHR) has emerged as a promising alternative biomarker in the fields of cardiovascular disease and atrial fibrillation (AF). This retrospective study was aimed to explore the predictive value of the MHR for the late recurrence of AF after radiofrequency ablation.

Methods

From April 2015 to October 2018, patients with paroxysmal AF who had undergone radiofrequency catheter ablation at Subei People’s Hospital of Jiangsu Province were enrolled in our study. All the participants were observed until November 2019 after the procedure. During the postoperative follow up, the patients were categorized into the recurrence group and maintenance of sinus rhythm group based on who had experienced AF recurrence.

Results

One hundred twenty-five patients were diagnosed with paroxysmal AF, with an average age of 61.2 ± 9.3 years. Forty-seven patients had developed late recurrence during a mean follow up of 25.1 ± 12.0 months. The AF recurrence event rates were significantly increased in the highest MHR tertile compared with those in the lowest MHR tertile (22.0% vs. 57.1%; P < 0.05). On multivariate logistic regression analysis, the preablation MHR (OR = 1.34; 95% CI = 1.12 ~ 1.60; P = 0.001) and left atrial diameter (LAD) (OR = 1.21, 95% CI = 1.08 ~ 1.35; P = 0.001) were independent risk factors predicting the recurrence of AF after radiofrequency ablation. Furthermore, receiver operating characteristic (ROC) curve analysis revealed that the area under the curve (AUC) of the MHR was 0.712 (95% CI = 0.618 ~ 0.806; P = 0.000) and that of LAD was 0.739 (95% CI = 0.653 ~ 0.814; P = 0.000). Z-test found no significant difference between the MHR and LAD regarding the AUC (Z = 0.451; P = 0.652).

Conclusion

An elevated preablation MHR was associated with an increased risk of the postoperative recurrence of AF. Additionally, the MHR independently predicted the late recurrence of paroxysmal AF after radiofrequency ablation, with the same predictive value as LAD.

Comparison of apolipoprotein-A1 levels between paroxysmal atrial fibrillation patients and healthy subjects

Introduction: Studies found that the inflammation plays a key role in the pathogenesis of paroxysmal atrial fibrillation (PAF). It is well-known that apolipoprotein-A1 (Apo-A1) demonstrates antiinflammatory and anti-oxidant properties in a healthy physiological system. In the present study, we aimed to determine whether there is any difference of Apo-A1 levels in patients with PAF and healthy subjects.

Methods: In this prospective cohort study, we enrolled a total of 35 PAF patients and 34 comparable healthy participants. Apo-A1 levels were measured from each subject using an immunophelometric method. All enrolled subjects were followed-up for one year during the study period. Results: Serum high-sensitivity C-reactive protein (hs-CRP) levels were statistically higher in PAF patients compared to healthy subjects (1.54±1.99 vs. 1.06±2.01, P = 0.016, respectively). Of note, patients with PAF had lower Apo-A1 levels (1.84±0.74 vs. 2.55±0.44, P = 0.001, respectively). There was no statistical difference between the groups in terms of apolipoprotein-B levels (1.08±0.36 vs. 0.99±0.38, P = 0.339, respectively). We did not find any correlation between Apo-A1 levels and PAF attacks in the study.

Conclusion: The main finding of this study was that Apo-A1 levels were significantly lower in PAF patients compared to healthy participants. Based on our results, we considered that Apo-A1 may have a key role in the pathogenesis of PAF.

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.

[Catheter treat-ment of patients with atrial fibrillation and myocardial inflammation]

The review presents current data on atrial fibrillation, therapeutic approaches, and possibilities of interventional treatment and addresses inflammatory heart damage and its interrelation with arrhythmia.The review presents current data on atrial fibrillation, therapeutic approaches, and possibilities of interventional treatment and addresses inflammatory heart damage and its interrelation with arrhythmia.

Cardiac Arrhythmias in Autoimmune Diseases

Autoimmune diseases (ADs) affect approximately 10% of the world's population. Because ADs are frequently systemic disorders, cardiac involvement is common. In this review we focus on typical arrhythmias and their pathogenesis, arrhythmia-associated mortality, and possible treatment options among selected ADs (sarcoidosis, systemic lupus erythematosus, scleroderma, type 1 diabetes, Graves' disease, rheumatoid arthritis, ankylosing spondylitis [AS], psoriasis, celiac disease [CD], and inflammatory bowel disease [IBD]). Rhythm disorders have different underlying pathophysiologies; myocardial inflammation and fibrosis seem to be the most important factors. Inflammatory processes and oxidative stress lead to cardiomyocyte necrosis, with subsequent electrical and structural remodeling. Furthermore, chronic inflammation is the pathophysiological basis linking AD to autonomic dysfunction, including sympathetic overactivation and a decline in parasympathetic function. Autoantibody-mediated inhibitory effects of cellular events (i.e., potassium or L-type calcium currents, M₂muscarinic cholinergic or β₁-adrenergic receptor signaling) can also lead to cardiac arrhythmia. Drug-induced arrhythmias, caused, for example, by corticosteroids, methotrexate, chloroquine, are also observed among AD patients. The most common arrhythmia in most AD presentations is atrial arrhythmia (primarily atrial fibrillation), expect for sarcoidosis and scleroderma, which are characterized by a higher burden of ventricular arrhythmia. Arrhythmia-associated mortality is highest among patients with sarcoidosis and lowest among those with AS; there are scant data related to mortality in patients with psoriasis, CD, and IBD.

Atrial inflammation in different atrial fibrillation subtypes and its relation with clinical risk factors

Objective

Inflammation of the atria is an important factor in the pathogenesis of atrial fibrillation (AF). Whether the extent of atrial inflammation relates with clinical risk factors of AF, however, is largely unknown. This we have studied comparing patients with paroxysmal and long-standing persistent/permanent AF.

Methods

Left atrial tissue was obtained from 50 AF patients (paroxysmal = 20, long-standing persistent/permanent = 30) that underwent a left atrial ablation procedure either or not in combination with coronary artery bypass grafting and/or valve surgery. Herein, the numbers of CD45+ and CD3+ inflammatory cells were quantified and correlated with the AF risk factors age, gender, diabetes, and blood CRP levels.

Results

The numbers of CD45+ and CD3+ cells were significantly higher in the adipose tissue of the atria compared with the myocardium in all AF patients but did not differ between AF subtypes. The numbers of CD45+ and CD3+ cells did not relate significantly to gender or diabetes in any of the AF subtypes. However, the inflammatory infiltrates as well as CK-MB and CRP blood levels increased significantly with increasing age in long-standing persistent/permanent AF and a moderate positive correlation was found between the extent of atrial inflammation and the CRP blood levels in both AF subtypes.

Conclusion

The extent of left atrial inflammation in AF patients was not related to the AF risk factors, diabetes and gender, but was associated with increasing age in patients with long-standing persistent/permanent AF. This may be indicative for a role of inflammation in the progression to long-standing persistent/permanent AF with increasing age.

Graphic abstract

Inflammatory cell infiltration in left atrial appendageal tissues of patients with atrial fibrillation and sinus rhythm

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in clinical practice and is known to be associated with significant morbidity and mortality. Previous studies suggested a link between inflammation and AF by findings of increased inflammatory markers in AF patients. However, it has not been finally clarified whether inflammation is a systemic or a local phenomenon reflecting an active inflammatory process in the heart. To address this subject, human left atrial appendage tissues were obtained from 10 patients who underwent cardiac surgery and subjected to immunohistochemical analysis. The number of inflammatory CD3-positive T cells significantly increased from patients with sinus rhythm to paroxysmal AF and persistent AF, respectively. Interestingly, in patients with persistent AF, these cells were frequently arranged in small clusters. Subsequently, the number of inflammatory CD3-positive T cells decreased and was significantly lower in patients with permanent AF than in patients with persistent AF. Inflammatory CD20-positive B cells could only be detected very occasionally in all AF subgroups and were not locatable in patients with SR. Hence, our data emphasize the potential prominent role of the cellular component of the immune system in the development and perpetuation of AF.

Meta-analysis of Effect of Modest (≥10%) Weight Loss in Management of Overweight and Obese Patients With Atrial Fibrillation

Obesity and atrial fibrillation (AF) are growing epidemics with significant overlap in co-morbidities. Multiple smaller studies have evaluated the effects of weight loss and risk factor modification on recurrence of AF, reduction in AF burden and improvement in AF symptom severity. The objective of this study was to determine if a modest weight loss of ≥10% of initial body weight is enough to improve outcomes in overweight or obese patients with established AF. We performed an extensive literature search and systematic review of studies that compared weight loss of ≥10% versus weight loss of less than 10% or weight gain and assessed outcomes including recurrence of AF as determined through a Holter monitor, AF burden and improvement in AF symptom severity. Risk ratio 95% confidence intervals (CI) were measured for dichotomous variables and mean difference (MD) 95% CI were measured for continuous variables, where MD >0 favors the group with ≥10% weight loss. Five studies with a total of 548 patients were included. Patients who lost ≥10% of their initial body weight experienced less recurrence of AF (risk ratio 0.29; 95% CI 0.19 to 0.44) and a larger reduction in reported event frequency (MD 1.74; 95% CI 0.70 to 2.79), episode duration (MD 2.14; 95% CI 0.04 to 4.23), global episode severity (MD 1.89; 95% CI 1.34 to 2.45), and symptom severity (MD 5.36; 95% CI 3.75 to 6.97). In conclusion, weight loss is associated with less risk of recurrent AF, reduction in AF burden, and improvement in AF symptom severity.

Rapid Atrial Pacing Promotes Atrial Fibrillation Substrate in Unanesthetized Instrumented Rats

Aim

The self-perpetuating nature of atrial fibrillation (AF) has been a subject of intense research in large mammalian models exposed to rapid atrial pacing (RAP). Recently, rodents are increasingly used to gain insight into the pathophysiology of AF. However, little is known regarding the effects of RAP on the atria of rats and mice. Using an implantable device for electrophysiological studies in rodents, we examined on a daily basis, the effects of continuous RAP on the developed AF substrate of unanesthetized rats and mice.

Methods and Results

Aggressive burst pacing did not induce AF at baseline in the large majority of rodents, but repeatedly induced AF episodes in rats exposed to RAP for more than 2 days. A microarray study of left atrial tissue from rats exposed to RAP for 2 days vs. control pacing identified 304 differentially expressed genes. Enrichment analysis and comparison with a dataset of atrial tissue from AF patients revealed indications of increased carbohydrate metabolism and changes in pathways that are thought to play critical roles in human AF, including TGF-beta and IL-6 signaling. Among 19 commonly affected genes in comparison with human AF, downregulation of FOXP1 and upregulation of the KCNK2 gene encoding the Kir2.1 potassium channel were conspicuous findings, suggesting NFAT activation. Further results included reduced expression of MIR-26 and MIR-101, which is in line with NFAT activation.

Conclusion

Our results demonstrate electrophysiological evidence for AF promoting effects of RAP in rats and several molecular similarities between the effects of RAP in large and small mammalian models.

A Mendelian randomization study of IL6 signaling in cardiovascular diseases, immune-related disorders and longevity

Growing evidence suggests that inflammation is a significant contributor to different cardiovascular diseases (CVDs). Mendelian randomization (MR) was performed to assess the causal inference between plasma soluble IL6 receptor (sIL6R), a negative regulator of IL6 signaling, and different cardiovascular and immune-related disorders. Cis-MR with multiple instrumental variables showed an inverse association of sIL6R with rheumatoid arthritis, atrial fibrillation, stroke, coronary artery disease, and abdominal aortic aneurysm. However, genetically-determined sIL6R level was positively associated with atopic dermatitis and asthma. Also, sIL6R level was associated with longevity, as evaluated by parental age at death, a heritable trait. Gene-based association analysis with S-PrediXcan by using tissues from GTExV7 showed that IL6R tissue expression-disease pair associations were consistent with the directional effect of IL6 signaling identified in MR. Genetically-determined reduced IL6 signaling lowers the risk of multiple CVDs and is associated with increased longevity, but at the expense of higher atopic risk.

Association between atrial fibrillation and Helicobacter pylori

The connection between atrial fibrillation (AF) and H. pylori (HP) infection is still matter of debate. We performed a systematic review and metanalysis of studies reporting the association between AF and HF. A systematic review of all available reports in literature of the incidence of HP infection in AF and comparing this incidence with subjects without AF were analysed. Risk ratio and 95% confidence interval (CI) and risk difference with standard error (SE) were the main statistics indexes. Six retrospective studies including a total of 2921 were included at the end of the selection process. Nine hundred-fifty-six patients (32.7%) were in AF, whereas 1965 (67.3%) were in normal sinus rhythm (NSR). Overall, 335 of 956 patients with AF were HP positive (35%), whereas 621 were HP negative (65%). In addition, 643 of 1965 NSR patients (32.7%) were HP positive while 1,322 were negative (67.3%; Chi-square 2.15, p = 0.21). The Cumulative Risk Ratio for AF patients for developing an HP infection was 1.19 (95% CI 1.08-1.41). In addition, a small difference risk towards AF was found (0.11 [SE = 0.04]). Moreover, neither RR nor risk difference were influenced by the geographic area at meta-regression analysis. Finally, there was a weak correlation between AF and HP (coefficient = 0.04 [95% CI -0.01-0.08]). We failed to find any significant correlation between H. pylori infection and AF and, based on our data, it seems unlikely than HP can be considered a risk factor for AF. Further larger research is warranted.

Increased risk of atrial fibrillation in patients with inflammatory bowel disease: A nationwide population-based study

BACKGROUND

Inflammatory bowel disease (IBD), a chronic inflammatory disease of the gastrointestinal tract, could play a role in the pathophysiology of atrial fibrillation (AF).

AIM

To investigate the association between IBD and AF development.

METHODS

We performed a population-based cohort study using records in the Korean National Health Insurance Services database between 2010 and 2014. A total of 37696 patients with IBD (12349 with Crohn’s disease and 25397 with ulcerative colitis) were identified. The incidence rate of newly diagnosed AF in patients with IBD was compared with that in a 3 times larger cohort of 113088 age- and sex-matched controls without IBD.

RESULTS

During 4.9 ± 1.3 years of follow-up, 1120 patients newly diagnosed with AF (348 in the IBD group and 772 in controls) were identified. After adjustments using multivariable Cox proportional hazards, patients with IBD were at a 36% [95% confidence interval (CI) 20%-54%] higher risk of AF than controls. The association between IBD and the development of AF was stronger in younger than in older patients. Patients without cardiovascular risk factors showed a higher risk of AF primarily. Additionally, patients receiving immun-omodulators [Hazard ration (HR) 1.46, 95%CI 1.31-1.89], systemic corticosteroids (HR 1.37, 95%CI 1.10-1.71), or biologics agents (HR 2.38, 95%CI 1.51-3.75) were at higher risk of AF than patients without them.

CONCLUSION

IBD significantly increased the risk of AF, and the impact of IBD on developing AF was in patients with moderate to severe disease.

Biomarkers of Atrial Fibrillation in Metabolic Syndrome

Whether the increased atrial fibrillation (AF) risk in metabolic syndrome (MetS) patients is due to the syndrome as a whole or simply the sum of the risks of its individual component parts is still obscure. These two clinical entities share many pathophysiological links and thus distinction between a casual observation and a significant association is difficult. Biomarkers associated with pathogenesis of AF in the context of MetS have the ability to refine future risk prediction. In the present review we identify circulating substances that could be regarded as potential biomarkers for prediction of incident AF, or of cardiovascular events in the setting of AF in patients with MetS. Cardiac myocyte injury and stress markers (troponin and natriuretic peptides), markers of renal function (glomeral filtration rate, cystatin-C), and inflammation markers/mediators (interleukin- 6, CRP) are promising biomarkers of patients with AF and MetS.

Biomarkers in Atrial Fibrillation and Heart Failure

Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice and an important contributor to cardiovascular morbidity and mortality. Although the exact mechanisms behind AF are not completely elucidated, the underlying pathophysiological changes have been well described. Predisposal factors for AF include the older age, the increased left atrial size, the decreased left atrial function, the presence of heart failure and left ventricular systolic dysfunction and the presence of coronary heart disease or pulmonary or mitral valve disease. In addition to these factors, emerging evidence demonstrate that myocardial strain, fibrosis and inflammation, are associated with AF as well as the pathogenesis of the arrhythmia. The natruretic peptide system including Atrial Natriuretic Peptide (ANP), Brain Natriuretic Peptide (BNP) and C-type Natriuretic Peptide (CNP) is indicative of the level of myocardial strain which may predispose to AF. As a result, the aforementioned peptides are increased in AF patients. The levels of myocardial fibrosis biomarkers, such as ST2 and Galectin-3, are elevated suggesting atrial structural abnormalities, while the increased levels of CRP and Interleukin-6 supplement the inflammatory profile of AF patients. Emerging data for the aforementioned biomarkers are discussed in the present review.

Biomarkers Associated with Stroke Risk in Atrial Fibrillation

Background:

Atrial fibrillation (AF) is associated with an increased risk of cardioembolic stroke. The risk of cardioembolism is not adequately reduced with the administration of oral anticoagulants, since a number of patients continue to experience thromboembolic events despite receiving treatment. Therefore, identification of a circulating biomarker to identify these high-risk patients would be clinically beneficial.

Objective:

In the present article, we aim to review the available data regarding use of biomarkers to predict cardioembolic stroke in patients with AF.

Methods:

We performed a thorough search of the literature in order to analyze the biomarkers identified thus far and critically evaluate their clinical significance.

Results:

A number of biomarkers have been proposed to predict cardioembolic stroke in patients with AF. Some of them are already used in the clinical practice, such as d-dimers, troponins and brain natriuretic peptide. Novel biomarkers, such as the inflammatory growth differentiation factor-15, appear to be promising, while the role of micro-RNAs and genetics appear to be useful as well. Even though these biomarkers are associated with an increased risk for thromboembolism, they cannot accurately predict future events. In light of this, the use of a scoring system, that would incorporate both circulating biomarkers and clinical factors, might be more useful.

Conclusions:

Recent research has disclosed several biomarkers as potential predictors of cardioembolic stroke in patients with AF. However, further research is required to establish a multifactorial scoring system that will identify patients at high-risk of thromboembolism, who would benefit from more intensive treatment and monitoring.

Which Method to Use for Surgical Ablation of Atrial Fibrillation Performed Concomitantly with Mitral Valve Surgery: Radiofrequency Ablation versus Cryoablation

Objective

The effects of energy source on the maintenance of sinus rhythm and the contribution of demographic characteristics to the case selection in patients submitted to ablation performed concurrently with mitral valve surgery were analyzed.

Methods

Cryothermal (n=42; 43.8%) and radiofrequency (n=54; 56.3%) energy were employed in 96 patients submitted to mitral valve replacement and Cox maze IV procedure. Patients were called for control visits between 15 days and 12 months after discharge. The causal relationship between recurrence of atrial fibrillation and factors such as left atrial diameter, C-reactive protein, hypertension, left ventricular ejection fraction, chronic obstructive pulmonary disease, and body mass index was determined.

Results

Maintenance rates of the sinus rhythm with radiofrequency and cryoablation were 97.6% and 96.3%, respectively, in the first postoperative month, whereas at the 12^th postoperative month were 88.1% and 83.3%. No significant difference was found between groups in relation to the energy source. Sensitivity and specificity for left atrial diameter with a cut-off value of 50.5 mm were 85.7% and 70.7%, respectively. Sensitivity and specificity for C-reactive protein with a cut-off value of 12 mg/dL on the 15^th postoperative day were 83.3% and 88.9%, respectively. The effect of body mass index on atrial fibrillation recurrence was 3.2 times. Sensitivity and specificity for left ventricular ejection fraction 37% cut-off value were 96.3% and 11.4%, respectively. Atrial fibrillation in hypertensive cases was 5.3 times more. In patients with chronic obstructive pulmonary disease, recurrence of atrial fibrillation was 40%. The causal relation between recurrence of atrial fibrillation and the studied factors was established.

Conclusion

Demographic characteristics have a significant impact on ablation efficiency, while the type of energy source does not.

Cardiolipotoxicity, Inflammation, and Arrhythmias: Role for Interleukin-6 Molecular Mechanisms

Fatty acid infiltration of the myocardium, acquired in metabolic disorders (obesity, type-2 diabetes, insulin resistance, and hyperglycemia) is critically associated with the development of lipotoxic cardiomyopathy. According to a recent Presidential Advisory from the American Heart Association published in 2017, the current average dietary intake of saturated free-fatty acid (SFFA) in the US is 11–12%, which is significantly above the recommended <10%. Increased levels of circulating SFFAs (or lipotoxicity) may represent an unappreciated link that underlies increased vulnerability to cardiac dysfunction. Thus, an important objective is to identify novel targets that will inform pharmacological and genetic interventions for cardiomyopathies acquired through excessive consumption of diets rich in SFFAs. However, the molecular mechanisms involved are poorly understood. The increasing epidemic of metabolic disorders strongly implies an undeniable and critical need to further investigate SFFA mechanisms. A rapidly emerging and promising target for modulation by lipotoxicity is cytokine secretion and activation of pro-inflammatory signaling pathways. This objective can be advanced through fundamental mechanisms of cardiac electrical remodeling. In this review, we discuss cardiac ion channel modulation by SFFAs. We further highlight the contribution of downstream signaling pathways involving toll-like receptors and pathological increases in pro-inflammatory cytokines. Our expectation is that if we understand pathological remodeling of major cardiac ion channels from a perspective of lipotoxicity and inflammation, we may be able to develop safer and more effective therapies that will be beneficial to patients.

Usefulness of platelet to lymphocyte ratio for predicting recurrence of atrial fibrillation after direct current cardioversion

OBJECTIVE

Atrial fibrillation (AF) is the most common cardiac rhythm disorder with the associated risks of stroke and mortality. The usefulness of platelet to lymphocyte ratio (PLR), a recently described inflammatory marker, in predicting adverse cardiovascular events has been demonstrated in several studies. In the current study, we investigated the role of PLR in predicting recurrence after successful electrical cardioversion (ECV) in patients with non-valvular persistent AF.

METHODS

A total of 287 patients with non-valvular persistent AF achieving restoration of the sinus rhythm after successful ECV were included in this study. At study entry, complete blood count, routine biochemistry tests, and transthoracic echocardiography (TTE) were performed routinely in all subjects. Patients were followed up for 6 months following the procedure and comparisons were performed between patients who recurred and who maintained the sinus rhythm (SR).

RESULTS

At 6 months of follow-up, AF recurred in 108 patients, corresponding to a recurrence rate of 39%. Mean PLR values in the "AF recurrence group" (mean age 57.4 ± 12.0 years, 47.6% [n = 80] female) and in "SR maintenance" group (mean age 65.0 ± 9.4 years, 55.6% [n = 60] female) were 184.8 ± 44.2 and 103.3 ± 44.2, respectively, with a significant difference between the two groups (p < 0.001). In multiple regression analyses, PLR emerged as a risk factor associated with AF recurrence during the 6-month follow-up period after successful ECV (odds ratio [OR]: 3.029 (1.013-9.055 95% confidence interval [CI]), p = 0.047). When a cutoff value of 147 was used, the sensitivity and specificity of PLR for predicting AF recurrence were 83.3% and 84.5%, respectively.

CONCLUSION

Elevated PLR is a marker of increased inflammation and may serve as a practical and inexpensive predictor for recurrence during 6 months of follow-up in patients with non-valvular persistent AF who had restoration of the sinus rhythm after successful ECV.

Role of the monocyte-to-high-density lipoprotein ratio in predicting atrial high-rate episodes detected by cardiac implantable electronic devices

OBJECTIVE:

Technological advances have allowed cardiac implantable electronic devices (CIEDs) to detect, analyze, and store atrial high-rate episodes (AHREs), which are surrogate for the term silent atrial fibrillation (AF). The association of AHREs with adverse clinical events has been demonstrated in several recent studies, implying that morbidity and mortality can be significantly prevented by prompt recognition and intervention. Inflammation and oxidative stress are among several mechanisms that contribute to the pathogenesis of AF. The monocyte-to-high-density lipoprotein ratio (M/H ratio) is a novel indicator of both inflammation and oxidative stress. In this study, we aimed to investigate the value of the M/H ratio for predicting AHREs detected by CIEDs.

METHODS:

A total of 203 patients (mean age: 57.5+9.1 years, 60.1% male) implanted with a dual pacemaker because of sick sinus syndrome were included. Blood samples were obtained from the patients after 12 h of fasting for the analysis of routine biochemistry tests and the lipid panel in the morning of device implantation. At a clinical visit 6 months after CIED implantation, the devices were interrogated to detect the occurrence of AHREs. AHREs were defined as atrial episodes faster than 220 bpm and lasting longer than 5 min. The patients were divided into two groups depending on the presence of AHREs during pacemaker interrogation: Group 1 (AHRE present) and Group 2 (AHRE absent).

RESULTS:

At the clinical visit 6 months after CIED implantation, 51 (25.1%) patients had at least one AHRE. The M/H ratio was significantly higher in patients in Group 1 (11.41±1.24) than in those in Group 2 (8.17±1.02) (p<0.01). On performing multivariate Cox regression analysis, the M/H ratio was found to be associated with the occurrence of AHREs in patients with CIEDs (OR: 22.813, 95% CI: 6.852–75.953, p<0.01).

CONCLUSION:

The M/H ratio is an indicator of inflammation and oxidative stress, both of which play an important role in the pathogenesis of AF. This ratio was found to be statically higher in patients with AHREs detected by CIEDs than in those without AHREs.

Opposite relations of epicardial adipose tissue to left atrial size in paroxysmal and permanent atrial fibrillation

Objectives:

Atrial fibrillation has been associated with obesity in epidemiological studies. Epicardial adipose tissue is an ectopic fat depot in the proximity of atria, with endocrine and inflammatory properties that is implicated in the pathophysiology of atrial fibrillation. Inflammation also has a role in atrial arrhythmogenesis. The aim of this study was to investigate the potential relations of epicardial adipose tissue to left atrial size and to adiponectin and the pro-inflammatory mediators, high-sensitivity C-reactive protein, and interleukin-6 in paroxysmal and permanent atrial fibrillation.

Methods:

This was a cross-sectional study of 103 atrial fibrillation patients, divided into two subgroups of paroxysmal and permanent atrial fibrillation, and 81 controls, in sinus rhythm. Echocardiography was used for estimation of epicardial adipose tissue and left atrial size and high-sensitivity C-reactive protein, interleukin-6 and adiponectin were measured in all subjects.

Results:

Atrial fibrillation patients had significantly larger epicardial adipose tissue compared with controls (0.43 ± 0.17 vs 0.34 ± 0.17 cm, p = 0.002). Atrial fibrillation presence was independently related to epicardial adipose tissue thickness (b = 0.09, p = 0.002). Opposite associations of epicardial adipose tissue with left atrial volume existed in atrial fibrillation subgroups; in the paroxysmal subgroup, epicardial adipose tissue was directly related to left atrial volume (R = 0.3, p = 0.03), but in the permanent one the relation was inverse (R = −0.7, p < 0.0001). Adiponectin, high-sensitivity C-reactive protein and interleukin-6 were elevated in both atrial fibrillation groups. Only interleukin-6 was related to epicardial adipose tissue size.

Conclusion:

Opposite associations of epicardial adipose tissue with left atrial size in paroxysmal and permanent Atrial fibrillation and elevated inflammatory markers, suggest a role of epicardial adipose tissue and inflammation in the fibrotic and remodeling process.

Chronic obstructive pulmonary disease and the development of atrial fibrillation

BACKGROUND

Chronic obstructive pulmonary disease (COPD) has been associated with atrial fibrillation (AF). More insight into the epidemiology and underlying mechanisms is required to optimize management.

METHODS

The Rotterdam Study is a large, population-based cohort study with long-term follow-up. Time dependent Cox proportional hazard models were constructed to study the effect of COPD on incident AF, adjusted for age, sex and pack years of cigarette smoking, and additionally stratified according to exacerbation frequency, left atrial size and baseline systemic inflammatory levels.

RESULTS

1369 of 10,943 subjects had COPD, of whom 804 developed AF. The AF incidence rate was 14 per 1000 person years in COPD and 8 per 1000 person years in subjects without COPD. The adjusted hazard ratio (HR) for COPD subjects to develop AF as compared to subjects without COPD was 1.28 (95%CI [1.04, 1.57]). COPD subjects with frequent exacerbations had a twofold increased AF risk (HR 1.99 [1.42, 2.79]) and COPD subjects with a left atrial size ≥40 mm also had an elevated AF risk (HR 1.77 [1.07, 2.94]). COPD subjects with baseline systemic inflammatory levels above the median had significantly increased AF risks (hsCRP≥1.83 mg/L: HR 1.51 [1.13, 2.03] and IL6 ≥ 1.91 ng/L: HR 2.49 [1.18, 5.28]), whereas COPD subjects below the median had in both analyses no significantly increased AF risk.

CONCLUSIONS

COPD subjects had a 28% increased AF risk, which further increased with frequent exacerbations and an enlarged left atrium. The risk was driven by COPD subjects having elevated systemic inflammatory levels.

Potential Impact of Oral Inflammations on Cardiac Functions and Atrial Fibrillation

Inflammation may be a risk factor for atrial fibrillation (AF). Oral infections frequently lead to chronic inflammation, such as gingivitis, periodontitis, and endodontic lesions. In this narrative review, we consider five basic pathogenic mechanisms that involve oral infections and inflammations in the pathogenesis of AF: (1) low level bacteremia by which oral bacteria enter the blood stream at inflamed sites of the oral cavity and invade the heart; (2) Systemic inflammation induced by inflammatory mediators, which are released from the sites of oral inflammation into the blood stream, affecting cardiac remodeling; (3) autoimmunity against molecular structures expressed in the heart caused by the host immune response to specific components of oral pathogens; (4) potentially arrhythmic effects mediated by activation of the autonomous nervous system triggered by oral inflammations; and (5) arrhythmic effects resulting from specific bacterial toxins that are produced by oral pathogenic bacteria. A number of studies support the involvement of all five mechanisms, suggesting a potentially complex contribution of oral inflammations to the pathogenesis of AF.

IL-10(-592A/C) gene variant a predictor of postoperative atrial fibrillation in the north Indian population

BACKGROUND

There is an accumulating body of evidence indicating a strong association between inflammation and the pathogenesis of atrial fibrillation (AF) in different ethnicities across the globe. AF increases the risk of stroke and heart failure. Despite various researches on IL-10 response, there is limited clinical evidence present, which demonstrate a role of these immunity regulators in AF. Therefore, this study was designed to decipher the role of IL-10(-592A/C) polymorphism in the development of postoperative AF (post-OP AF).

METHOD

The study was designed for north Indian patients. The study included 90 patients with AF and 126 controls in sinus rhythm undergoing surgery at Department of Cardiovascular and thoracic surgery, SGPGIMS, Lucknow, India. DNA samples were genotyped for common single nucleotide polymorphism (SNP) in gene IL-10(-592A/C). The PCR-based RFLP technique was used to assess the genotype frequencies. The multivariable logistic regression analysis was performed to study the association of other risk factors with AF.

RESULTS

The distribution of IL-10(-592A/C) genotypes (CC, AC, and AA) was found to be 48.41%, 47.61%, and 3.98% in controls and 41.11%, 45.55%, and 13.34% in cases, respectively (P = .0385). The frequency of allele A in cases was significantly higher than the control group (36.11% vs 27.77%, P = .0654). Compared with CC, AA genotype had increased risk of AF in both unadjusted and adjusted analyses.

CONCLUSIONS

This study suggests that IL-10(-592A/C) polymorphism may have significant association with post-OP AF development in north Indian patients.

Atrial thrombogenesis in atrial fibrillation : Results from atrial fibrillation models and AF-patients

Atrial fibrillation (AF) is the most common cause of thromboembolic complications. The risk of suffering a thromboembolic complication depends on the accompanying cardiac risk factors and the patient's age. For patients who have an increased risk, which is now classified using the CHA2DS2-VASc score, initiation of long-term oral anticoagulation is the first-line treatment. In AF, thrombi arise in the left atrial appendage. The present review will summarize the basic pathophysiology of thrombogenesis in AF and will provide the molecular basis of a process called prothrombotic endocardial remodeling. Despite oral anticoagulation being a central component of therapy, the present results can be used to support concomitant therapy with statins, angiotensin II blockers, etc. to inhibit atrial thromogenesis.

Involvement of IL-1β and IL-6 in antiarrhythmic properties of atorvastatin in ouabain-induced arrhythmia in rats

PURPOSE

Evidence show that statins possess wide beneficial cardioprotective and anti-inflammatory effects; therefore, in the present experiment, we investigated the antiarrhythmic properties of atorvastatin in ouabain-induced arrhythmia in isolated rat atria and the role of several inflammatory cytokines in this effect.

MATERIALS AND METHODS

Male rats were pretreated with either of atorvastatin (10 mg/kg) or vehicle, orally once daily for 6 weeks. After induction of anesthesia, we isolated the atria and after incubation with ouabain, time of onset of arrhythmia and asystole as well as atrial beating rate and contractile force were recorded. We also measured the atrial levels of IL-1β, IL-6, and TNF-α after the injection of ouabain to animals.

RESULTS

Pretreatment with atorvastatin significantly delayed the onset of arrhythmia and asystole compared with vehicle-treated group (p < .01, p < .001, respectively). Incubation of ouabain boosted both atrial beating rate and contractile force in vehicle-treated group (p < .05), while these responses in atorvastatin-treated group were not significant (p > .05). Injection of ouabain elevated the atrial levels of IL-1β, IL-6, and TNF-α, while pretreatment of animals with atorvastatin could reverse the ouabain-induced increase in atrial IL-1β and IL-6 (p < .01 and p < .05, respectively).

CONCLUSIONS

It is concluded that observed antiarrhythmic effects of atorvastatin might be attributed to modulation of some inflammatory cytokines, at least IL-1β and IL-6.

The ambiguity of physical activity, exercise and atrial fibrillation

Although commonly associated with cardiovascular disease or other medical conditions, atrial fibrillation may also occur in individuals without any known underlying conditions. This manifestation of atrial fibrillation has been linked to extensive and long-term exercise, as prolonged endurance exercise has shown to increase prevalence and risk of atrial fibrillation. In contrast, more modest physical activity is associated with a decreased risk of atrial fibrillation, and current research indicates a J-shaped association between atrial fibrillation and the broad range of physical activity and exercise. This has led to the hypothesis that the mechanisms underlying an increased risk of atrial fibrillation with intensive exercise are different from those underlying a reduced risk with moderate physical activity, possibly linked to distinctive characteristics of the population under study. High volumes of exercise over many years performed by lean, healthy endurance trained athletes may lead to cardiac (patho)physiological alterations involving the autonomic nervous system and remodelling of the heart. The mechanisms underlying a reduced risk of atrial fibrillation with light and moderate physical activity may involve a distinctive pathway, as physical activity can potentially reduce the risk of atrial fibrillation through favourable effects on cardiovascular risk factors.

Association of pre-ablation level of potential blood markers with atrial fibrillation recurrence after catheter ablation: a meta-analysis

Aims

The meta-analysis was aimed to search for candidate blood markers whose pre-ablation level was associated with atrial fibrillation (AF) recurrence after radiofrequency catheter ablation (RFCA).

Methods and results

A systematic literature search of PubMed, EMBASE, Springer Link, Web of Science, Wiley-Cochrane library, and supplemented with Google scholar search engine was performed. Thirty-six studies covering 11 blood markers were qualified for this meta-analysis. Compared with the nonrecurrence group, the recurrence group had increased pre-ablation level of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), N-terminal pro-brain natriuretic peptide (NT-pro-BNP), interleukin-6 (IL-6), C-reactive protein, low density lipoprotein (LDL), and tissue inhibitor of metal loproteinase-2 (TIMP-2) [standardized mean difference (95% confidence interval): 0.37 (0.13-0.61), 0.77 (0.40-1.14), 1.25 (0.64-1.87), 0.37 (0.21-0.52), 0.35 (0.10-0.60), 0.24 (0.07-0.42), 0.17 (0.00-0.34), respectively], while no statistical difference of pre-ablation level of white blood cell, total cholesterol, triglyceride, and transforming growth factor-β1 was found. Subgroup analysis demonstrated that ANP was associated with AF recurrence in participants who had no concomitant structural heart diseases (SHD); however, not in participants who had SHD, C-reactive protein was associated with AF recurrence in Asian studies, whereas not in European studies.

Conclusion

Increased pre-ablation level of ANP, BNP, NT-pro-BNP, IL-6, C-reactive protein, LDL, and TIMP-2 was associated with greater risk of AF recurrence after RFCA.

The use of monocyte to HDL ratio to predict postoperative atrial fibrillation after aortocoronary bypass graft surgery

OBJECTIVE:

Postoperative atrial fibrillation (POAF) is a frequent and serious complication after aortocoronary bypass graft (ACBG) surgery and one that, unfortunately, increases morbidity and mortality. Postoperative stroke, hemodynamic instability, renal failure, infection, need for inotropic agent and coronary unit are complications caused by POAF. Inflammation and oxidative stress are among several mechanisms that contribute to pathogenesis of POAF. Monocyte to HDL (M/H) ratio is a newly defined parameter of both inflammation and oxidative stress. In this study, M/H ratio was investigated as predictor of POAF after ACBG surgery.

METHODS:

Total of 311 patients who underwent ACBG surgery were included in the study. Blood samples for analysis of routine biochemistry and lipid panel were obtained from the patients on the morning of ACBG surgery after 12 hours of fasting. Patients were continuously monitored for occurrence of POAF throughout hospitalization.

RESULTS:

POAF was observed in 71 patients following ACBG operation. M/H ratio was significantly higher in POAF(+) group compared with POAF(-) group (p<0.001). Median age of POAF(+) patients was 62.0±10.1 years, which was significantly higher than mean age of POAF(-) patients. Other atrial fibrillation (AF) risk factors, such as hypertension, diabetes mellitus, smoking, and alcohol consumption, were similar between groups. Potassium level was statistically lower in POAF(+) group compared with POAF(-) group (p=0.01).

CONCLUSION:

M/H ratio is an indicator of inflammation and oxidative stress, both of which play important role in pathogenesis of AF. M/H ratio was found be statistically significantly higher in POAF(+) patients than in POAF(-) patients.

Significant Increase in C-Reactive Protein and Serum Amyloid A in the Early Hours of Paroxysmal Atrial Fibrillation

Background

A number of data have been accumulated on inflammation in persistent and permanent atrial fibrillation (AF). Our aim was to study the process in paroxysmal AF (PAF) by measuring plasma concentrations of high-sensitivity C-reactive protein (hs-CRP), serum amyloid A (SAA) and fibrinogen in dynamics.

Methods

The markers were investigated in 51 patients (26 males and 25 females; 59.84 ± 1.60 years) at hospital admission (baseline), 24 hours and 28 days after sinus rhythm restoration. Fifty-two controls (26 males and 26 females; 59.50 ± 1.46 years) were selected.

Results

At baseline, hs-CRP and SAA concentrations were higher in patients (8.12 ± 0.82 vs. 5.57 ± 0.21 mg/L, P = 0.003; 16.04 ± 0.93 vs. 5.12 ± 0.23 ng/mL, P < 0.001, respectively) and these changes persisted 24 hours after sinus rhythm restoration (8.16 ± 0.71 vs. 5.57 ± 0.21 mg/L, P < 0.001; 12.99 ± 0.75 vs. 5.12 ± 0.23 ng/mL, P < 0.001, respectively). On the 28th day, no significant difference was measured (5.42 ± 0.29 vs. 5.57 ± 0.21 mg/L, P = 0.68; 5.89 ± 0.38 vs. 5.12 ± 0.23 ng/mL, P = 0.08, respectively). At any measurement, fibrinogen levels did not differ between patients and controls (3.30 ± 0.17 vs. 3.22 ± 0.11 g/L, P = 0.70; 3.32 ± 0.11 vs. 3.22 ± 0.11 g/L, P = 0.52; 3.24 ± 0.13 vs. 3.22 ± 0.11 g/L, P = 0.90, respectively).

Conclusion

PAF is associated with dynamics in hs-CRP and SAA plasma levels. The results suggest that inflammation is closely related to the arrhythmia initiation.

Supraventricular tachycardia during the first year of life: is subclinical inflammation the trigger?

BACKGROUND

Neutrophil/lymphocyte ratio (NLR) and red cell distribution width (RDW) may be associated with the onset of arrhythmias in adults, thus underlining a possible inflammatory etiology. Paroxysmal supraventricular tachycardia (SVT) is the most frequent pathological tachycardia in childhood.

AIM

To verify NLR and RDW levels in a group of children (<1 year) affected by SVT with a structurally normal heart and without fever or inflammatory diseases; to compare NLR and RDW before and after SVT resolution, to verify whether the latter was related with the reduction in inflammatory state; to identify - in SVT subtypes caused by a reentry mechanism - an NLR and RDW cutoff point beyond which adenosine was ineffective in preventing SVT recurrence.

METHODS

Eighteen SVT patients were recruited (mean age 18.9 ± 3.2 days; 50% males) and compared with 18 healthy peers.

RESULTS

NLR was higher in SVT group than in controls (p < 0.03). A significant difference was revealed between NLR values obtained on admission and at discharge (p < 0.05). On the contrary, no significant differences were found for RDW. It was not possible to identify NLR or RDW cutoffs capable of predicting SVT recurrence. However, all patients featuring SVT recurrence following adenosine injection presented with a lymphocyte count >6000/mm³.

CONCLUSIONS

Elevated NLR is associated with an increased risk of SVT during the first year of life, while its decline looks like to lead the SVT resolution. A subclinical inflammatory status, as assessed by lymphocytes count, influences SVT recurrence. These results provide further support for an inflammatory etiology of SVT in babies.

The Predictive Role of Inflammatory Biomarkers in Atrial Fibrillation as Seen through Neutrophil-Lymphocyte Ratio Mirror

Atrial fibrillation (AF) is the most common arrhythmia and is responsible for significant disease burden worldwide. Current evidence has suggested that systemic inflammatory response plays a crucial role in the initiation, maintenance, and progression of AF. So, recent efforts have been directed in search of measurable inflammatory biomarkers as additional tools in severity and prognosis assessment of AF. A simple, and easily obtainable, inflammatory marker is the neutrophil-lymphocyte ratio (NLR), which has shown good performance in preliminary studies as a potential prognostic biomarker in patients with AF. In this work, we performed a thorough review of clinical studies that evaluated the role of C-reactive protein (CRP), interleukin-6 (IL-6), and NLR as predictors of outcomes in AF. We gave a particular emphasis on the NLR because it is a simpler, widely available, and inexpensive biomarker.