Inflammation as a Mediator of the Association Between Race and Atrial Fibrillation: Results from the Health, Aging, and Body Composition Study

Exploring the link between blood pressure variability and atrial fibrillation: current insights and future directions

Atrial fibrillation (AF) is the most common heart rhythm disorder, especially in people over the age of 50, which affects more than 40 million people worldwide. Many studies have highlighted the association between hypertension with the development of AF. Blood pressure variability (BPV) is a dynamic size obtained by recording blood pressure oscillations using specific readings and at specific time intervals. A multitude of internal and external factors shape BPV while at the same time constituting a common pathogenetic pathway with the development of AF. Until recently, BPV has been applied exclusively in preclinical and clinical studies, without significant implications in clinical practice. Indeed, even from the research side, the determination of BPV is limited to patients without AF due to doubts about the accuracy of its measurement methods in patients with AF. In this review, we present the current evidence on common pathogenic pathways between BPV and AF, the reliability of quantification of BPV in patients with AF, the prognostic role of BPV in these patients, and discuss the future clinical implications of BPV in patients with AF.

Circulating adipose tissue proteins involved in atrial fibrillation: An explorative scoping review

Obesity increases the risk of atrial fibrillation (AF), potentially through proteins secreted by adipose tissue (AT) that affect atrial electrical and structural remodeling. We aim to give a comprehensive overview of circulating AT proteins involved in inflammation and fibrosis, that are associated with prevalent AF (paroxysmal or persistent) and the risk on developing new-onset AF. These include adipokines, defined as proteins enriched in AT as adiponectin, but also proteins less specific to AT. We systematically performed an explorative search for studies reporting associations between proteins secreted from cells residing in the AT and AF, and additionally assessed the effect of obesity on these proteins by a secondary search. The AT proteins involved in inflammation were mostly increased in patients with prevalent and new-onset AF, and with obesity, while the AT enriched adipokines were mostly not associated with AF. This review provides insight into circulating adipose tissue proteins involved in AF substrate formation.

Associations of variability in body mass index with cardiovascular outcomes in the general population: A systematic review

In today's world, high variability of body mass index (BMI) is known as a significant global health problem that can lead to many negative impacts on the cardiovascular system, including atrial fibrillation (AF) and coronary heart disease. The current systematic review aims to elucidate the effect of variability in BMI on the risk of cardiovascular outcomes. Four databases, including PubMed, Scopus, MEDLINE, and CENTRAL, were searched. All related articles up to 10 June 2022, were obtained. Titles, abstracts, and full texts were reviewed. After screening abstracts and full texts, four articles were included in our study. In these four cohort studies, 7,038,873 participants from the USA and South Korea were involved. These articles generally considered the BMI and outcomes including cardiovascular disease, AF, and coronary heart disease. All these articles reported an association between the variability of BMI and increased risk of cardiovascular outcomes. Due to the negative impact of the high variability of BMI on the risk of cardiovascular outcomes, health policymakers and practitioners should pay more attention to the significant role of BMI in health problems and physicians might better check the variability of BMI visits to visit.

An Exploration of the Relationship Between Atrial Fibrillation and Obesity

In the past 40 years, the prevalence of atrial fibrillation and obesity have skyrocketed. It has long been established that obesity can lead to adverse cardiovascular outcomes due to its myriad of effects on cardiovascular architecture, cardiovascular hemodynamics, and electrical conduction interference. The goal of this article is to explore the pathogenesis of atrial fibrillation in obese patients and examine the role of atrial enlargement, increased adipose deposits surrounding the pericardium, interstitial fibrosis, and inflammation in the development and worsening of atrial fibrillation in obese patients.

American Indians and atrial fibrillation

The American Indian population is known to experience high rates of cardiovascular disease and have a heightened vulnerability to severe outcomes driven by an overall poor health status and lower access to quality health care. Our group has previously published an analysis demonstrating that American Indians have the highest risk of atrial fibrillation (AF), as well as of AF-related stroke, when compared with other races and ethnicities. Despite this, AF in this population has not been extensively studied and additional publications are scarce. Our review article provides an up-to-date summary of the relevant literature addressing the relationship between race, ethnicity, and AF by focusing on American Indians.

The association of coagulation and atrial fibrillation: a systematic review and meta-analysis

AIMS

While atrial fibrillation (AF) is suggested to induce a prothrombotic state, increasing thrombotic risk, it is also hypothesized that coagulation underlies AF onset. However, conclusive evidence is lacking. With this systematic review and meta-analysis, we aimed to summarize and combine the evidence on the associations between coagulation factors with AF in both longitudinal and cross-sectional studies.

METHODS AND RESULTS

We systematically searched for longitudinal cohort and cross-sectional studies investigating AF and thrombosis. For longitudinal studies, pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated. For cross-sectional studies, we determined pooled standardized mean differences (SMDs) and 95% CIs. A total of 17 longitudinal and 44 cross-sectional studies were included. In longitudinal studies, we found significant associations between fibrinogen (HR 1.05, 95% CI 1.00-1.10), plasminogen activator inhibitor 1 (PAI-1) (HR 1.06, 95% CI 1.00-1.12), and D-dimer (HR 1.10, 95% CI 1.02-1.19) and AF incidence. In cross-sectional studies, we found significantly increased levels of fibrinogen (SMD 0.47, 95% CI 0.20-0,74), von Willebrand factor (SMD 0.96, 95% CI 0.28-1.66), P-selectin (SMD 0.31, 95% CI 0.08-0.54), ß-thromboglobulin (SMD 0.82, 95% CI 0.61-1.04), Platelet Factor 4 (SMD 0.42, 95% CI 0.12-0.7), PAI-1 (1.73, 95% CI 0.26-3.19), and D-dimer (SMD 1.74, 95% CI 0.36-3.11) in AF patients, as opposed to controls.

CONCLUSION

These findings suggest that higher levels of coagulation factors are associated with prevalent and incident AF. These associations are most pronounced with prevalent AF in cross-sectional studies. Limited evidence from longitudinal studies suggests a prothrombotic state underlying AF development.

Antiarrhythmic drug therapy after catheter ablation for atrial fibrillation-Insights from the German Ablation Registry

Data on the optimal treatment strategy for antiarrhythmic drug therapy (AAD) after catheter ablation for atrial fibrillation (AF) are inconsistent. The present study investigates whether postinterventional AAD leads to an improved long-term outcome. Patients from the prospective German Ablation Registry (n = 3275) discharged with or without AAD after catheter ablation for AF were compared regarding the rates of recurrences, reablations and cardiovascular events as well as patient reported outcomes during 12 months follow-up. In patients with paroxysmal AF (n = 2138) the recurrence rate did not differ when discharged with (n = 1051) or without (n = 1087) AAD (adjusted odds ratio (OR) 1.13, 95% confidence interval (CI) [0.95-1.35]). The reablation rate was higher and reduced treatment satisfaction was reported more often in those discharged with AAD (reablation: OR 1.30, 95% CI [1.05-1.61]; reduced treatment satisfaction: OR 1.76, 95% CI [1.20-2.58]). Similar rates of recurrences, reablations and treatment satisfaction were found in patients with persistent AF (n = 1137) discharged with (n = 641) or without (n = 496) AAD (recurrence: OR 1.22, 95% CI [0.95-1.56]; reablation: OR 1.21, 95% CI [0.91-1.61]; treatment satisfaction: OR 1.24, 95% CI [0.74-2.08]). The incidence of cardiovascular events and mortality did not differ at follow-up in patients discharged with or without AAD. In conclusion, the rates of recurrences, cardiovascular events and mortality did not differ between patients discharged with or without AAD after AF catheter ablation. However, AAD should be considered carefully in patients with paroxysmal AF, in whom it was associated with a higher reablation rate and reduced treatment satisfaction. Clinical trial registration: The trial has been registered under the number NCT01197638.

Differences in Left Atrial Size and Function and Supraventricular Ectopy Between Black and White Participants in the ARIC Study

Background Black Americans have more atrial fibrillation risk factors but lower atrial fibrillation risk than White Americans. Left atrial (LA) enlargement and/or dysfunction, frequent atrial tachycardia (AT), and premature atrial contractions (PAC) are associated with increased atrial fibrillation risk. Racial differences in these factors may exist that could explain the difference in atrial fibrillation risk. Methods and Results We included 2133 ARIC (Atherosclerosis Risk in Communities) study participants (aged 74±4.5 years[mean±SD], 59% women, 27% Black participants) who had echocardiograms in 2011 to 2013 and wore the Zio XT Patch (a 2-week continuous heart monitor) in 2016 to 2017. Linear regression was used to analyze (1) differences in AT/day or PAC/hour between Black and White participants, (2) differences in LA measures between Black and White participants, and (3) racial differences in the association of LA measures with AT or PAC frequency. Compared with White participants, Black participants had a higher prevalence of cardiovascular risk factors and disease, lower AT frequency, greater LA size, and lower LA function. After multivariable adjustments, Black participants had 37% (95% CI, 24%-47%) fewer AT runs/day than White participants. No difference in PAC between races was noted. Greater LA size and reduced LA function are associated with more AT and PAC runs; however, no race interaction was present. Conclusions Differences in LA measures are unlikely to explain the difference in atrial fibrillation risk between Black and White individuals. Despite more cardiovascular risk factors and greater atrial remodeling, Black participants have lower AT frequency than White participants. Future research is needed to elucidate the protective mechanisms that confer resilience to atrial arrhythmias in Black individuals.

Long-term wind turbine noise exposure and the risk of incident atrial fibrillation in the Danish Nurse cohort

BACKGROUND

The potential health effects related to wind turbine noise (WTN) have received increased focus during the past decades, but evidence is sparse. We examined the association between long-term exposure to wind turbine noise and incidence of atrial fibrillation (AF).

METHODS

First ever hospital admission of AF amongst 28,731 female nurses in the Danish Nurse Cohort were identified in the Danish National Patient register until ultimo 2013. WTN levels at residential addresses between 1982 and 2013 were estimated using the Nord2000 noise propagation model, as the annual means of L_den, L_day, L_evening and L_night at the most exposed façade. Time-varying Cox proportional hazard regression models were used to examine the association between the 11-, 5- and 1-year rolling means of WTN levels and AF incidence.

RESULTS

1430 nurses developed AF by end of follow-up in 2013. Mean (standard deviation) baseline residential noise levels amongst exposed nurses were 26.3 (6.7) dB and slightly higher in those who developed AF (27.3 (7.31) dB), than those who didn't (26.2 (6.6)). We observed a 30% statistically significant increased risk (95% CI: 1.05-1.61) of AF amongst nurses exposed to long-term (11-year running mean) WTN levels ≥20 dB(A) at night compared to nurses exposed to levels <20 dB(A). Similar effects were observed with day (HR 1.25; 95% CI: 1.01-1.54), and evening (HR 1.25; 95% CI: 1.01-1.54) noise levels.

CONCLUSIONS

We found suggestive evidence of an association between long-term exposure to WTN and AF amongst female nurses. However, interpretation should be cautious as exposure levels were low.

Association Between Long-Term Exposure to Wind Turbine Noise and the Risk of Stroke: Data From the Danish Nurse Cohort

Background

Epidemiological studies suggest that road traffic noise increases the risk of stroke. Similar effects may be expected from wind turbine noise (WTN) exposure, but epidemiological evidence is lacking. The present study investigated the association between long‐term exposure to WTN and the risk for stroke.

Methods and Results

First‐ever stroke in 28 731 female nurses in the Danish Nurse Cohort was identified in the Danish National Patient register until the end of 2013. WTN, traffic noise, and air pollution exposures were estimated for all historic and present residential addresses between 1982 and 2013. Time‐varying Cox proportional hazard regression was used to examine the associations between the 11‐, 5‐, and 1‐year rolling means of WTN levels and stroke incidence. Of 23 912 nurses free of stroke at the cohort baseline, 1097 nurses developed stroke by the end of follow‐up. At the cohort baseline, 10.3% of nurses were exposed to WTN (≥1 turbine within a 6000‐meter radius of the residence) and 13.3% in 2013. Mean baseline residential noise levels among exposed nurses were 26.3 dB(A). No association between long‐term WTN exposure and stroke incidence was found. The adjusted hazard ratios and 95% CIs for the 11‐, 5‐, and 1‐year running mean residential WTN exposures preceding stroke diagnosis, comparing nurses with residential WTN levels above and below 20 dB(A) were 1.09 (0.90–1.31), 1.08 (0.89–1.31) and 1.08 (0.89–1.32), respectively.

Conclusions

This comprehensive cohort study lends no support to an association between long‐term WTN exposure and stroke risk.

Adiponectin and the risk of new-onset atrial fibrillation: a meta-analysis of prospective cohort studies

Background: Adiponectin has been suggested as a marker of many cardiovascular diseases. However, the association between serum adiponectin and incidence of atrial fibrillation (AF) in general population remains unclear. A meta-analysis was performed to systematically evaluate the potential influence of serum adiponectin at baseline on the incidence of AF during follow-up in general population.

Methods: Prospective cohort studies were identified via electronic search of PubMed and Embase databases. A randomized effect model was applied to combine the results. Predefined subgroup analyses were performed to evaluate the influence of study characteristics on the association between baseline adiponectin and risk of new-onset AF.

Results: Six cohort studies with 18558 community-derived participants were included, and 3165 AF cases were developed with a mean follow-up duration of up to 22 years. Meta-analysis showed that higher baseline circulating adiponectin was significantly associated with higher risk of new-onset AF during follow-up (hazard ratio [HR]: 1.17, 95% confidence interval [CI]: 1.08–1.27, P<0.001, I² = 52%). Subgroup analyses showed that the association between adiponectin and new-onset AF was significant in studies with mean follow-up duration over 10 years (five cohorts, HR = 1.22, P<0.001), but not in that with a follow-up duration < 10 years (one cohort, HR = 0.95, P=0.51; P for subgroup difference = 0.002).

Conclusions: Higher circulating adiponectin at baseline may be an independent risk factor for the development of new-onset AF during follow-up, particularly in cohort studies with longer follow-up durations.

Triggers for Atrial Fibrillation: The Role of Anxiety

Atrial fibrillation (AF) is the most widely recognized arrhythmia. Systemic arterial hypertension, diabetes, obesity, heart failure, and valvular heart diseases are major risk factors for the onset and progression of AF. Various studies have emphasized the augmented anxiety rate among AF patients due to the poor quality of life; however, little information is known about the possibility of triggering atrial fibrillation by anxiety. The present review sought to underline the possible pathophysiological association between AF and anxiety disorders and suggests that anxiety can be an independent risk factor for AF, acting as a trigger, creating an arrhythmogenic substrate, and modulating the autonomic nervous system. The awareness of the role of anxiety disorders as a risk factor for AF may lead to the development of new clinical strategies for the management of AF.

Association of atrial fibrillation and gastroesophageal reflux disease: Natural and therapeutic linkage of the two common diseases

Atrial fibrillation (AF) is a common arrhythmia and gastroesophageal reflux disease (GERD) is popular in Japan. The two common diseases share several predisposing factors such as lifestyle and senescence, and inflammation and oxidative stress play an important role in their development and progression. Incidental cases of AF treated successfully by proton pump inhibitor (PPI) applied for coexisting GERD have been sporadically reported. An increasing evidence indicates that GERD induces the initiation and the perpetuation of AF. This is caused by the autonomic nerve influence, mechanical compression, and propagation of local inflammation due to proximity of left atrium (LA) and lower esophagus. Meanwhile, AF also develops GERD by mechanical and inflammatory actions of LA characterized by remodeling and inflammation. The robust association of AF with GERD is not limited to their natural interaction, i.e., pharmacological or nonpharmacological treatment of AF is reported to aggravate GERD. Many cardiac drugs (anticoagulants, calcium antagonists, and nitrates) induce esophageal mucosal damage and lower esophageal sphincter relaxation promoting acid reflux. These drugs are frequently prescribed in patients with AF for stroke prevention, rate control, and for coexisting coronary heart disease. Catheter ablation also yields both GERD and esophageal thermal injury, which is a precursor lesion of atrioesophageal fistula. The notion that AF and GERD are mutually interdependent is widely and empirically recognized. However, mechanistic link of the two common diseases and objective evaluation of PPI as an adjunctive AF treatment warrant future large-scale prospective trials.

Clinical implications of serum adiponectin on progression of atrial fibrillation

Background

The association between circulating adiponectin levels and atrial fibrillation (AF) is uncertain. We, therefore, investigated whether an increased serum adiponectin level is implicated in the long-term recurrence of AF after ablation therapy.

Methods

Our study included 100 consecutive patients (88 men; median age, 57.9±10.9 years) who underwent catheter ablation for AF at our hospital between 2011 and 2013. The adiponectin and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels were measured before ablation and compared between those in whom AF recurred and those in whom AF did not recur.

Results

Elevation in adiponectin levels was significantly associated with female sex, non-paroxysmal AF, heart failure, higher NT-proBNP and matrix metallo-proteinase-2 levels, and lower body mass index. After a stepwise adjustment for any potential confounding variables, the adiponectin levels remained significantly associated with female sex (beta=0.2601, P=0.0041), non-paroxysmal AF (beta=0.2708, P=0.0080), and higher NT-proBNP levels (beta=0.2536, P= 0.0138). During the median follow-up period of 26.2 months, AF recurred in 48 of the 100 patients. Stepwise multivariate adjustment showed that an increased log-transformed NT-proBNP (Hazard ratio [HR], 2.18; 95% confidence interval [CI] 1.25-4.00; P=0.0055), longer duration of AF (HR, 1.87; 95%CI 1.01-3.76; P=0.0465), and decreased left ventricular ejection fraction (HR, 0.96; 95%CI 0.93-0.99; P=0.0391) were independent predictors of recurrent AF after catheter ablation, but adiponectin was not.

Conclusions

Our data indicated that adiponectin was partially responsible for progression of AF, but the correlation between adiponectin levels and AF recurrence was not significant.

Atrial ectopy as a mediator of the association between race and atrial fibrillation

BACKGROUND

Blacks have a lower risk of atrial fibrillation (AF) despite having more AF risk factors, but the mechanism remains unknown. Premature atrial contraction (PAC) burden is a recently identified risk factor for AF.

OBJECTIVE

The purpose of this study was to determine whether the burden of PACs explains racial differences in AF risk.

METHODS

PAC burden (number per hour) was assessed by 24-hour ambulatory electrocardiographic (ECG) monitoring in a randomly selected subset of patients in the Cardiovascular Health Study. Participants were followed prospectively for the development of AF, diagnosed by study ECG and hospital admission records.

RESULTS

Among 938 participants (median age 73 years; 34% black; 58% female), 206 (22%) developed AF over a median follow-up of 11.0 years (interquartile range 6.1-13.4). After adjusting for age, sex, body mass index, coronary disease, congestive heart failure, diabetes, hypertension, alcohol consumption, smoking status, and study site, black race was associated with a 42% lower risk of AF (hazard ratio 0.58, 95% confidence interval [CI] 0.40-0.85; P = .005). The baseline PAC burden was 2.10 times (95% CI 1.57-2.83; P <.001) higher in whites than blacks. There was no detectable difference in premature ventricular contraction (PVC) burden by race. PAC burden mediated 19.5% (95% CI 6.3-52.5) of the adjusted association between race and AF.

CONCLUSION

On average, whites exhibited more PACs than blacks, and this difference statistically explains a modest proportion of the differential risk of AF by race. The differential PAC burden, without differences in PVCs, by race suggests that identifiable common exposures or genetic influences might be important to atrial pathophysiology.

Aging Modulates the Substrate and Triggers Remodeling in Atrial Fibrillation

Aging plays a critical role in the genesis of atrial fibrillation (AF) and also increases the risks of cardiac dysfunction and stroke in AF patients. AF is caused by increased AF triggering from abnormalities of the thoracic vein and/or modulated substrate (atrial) with enhancement of AF maintenance. Clinical and laboratory evidence indicates that aging is significant in the creation of atrial electrical and structural remodeling that leads to increased susceptibility to AF occurrence. Aging is commonly associated with cardiovascular comorbidities, oxidative stress, calcium dysregulation, atrial myopathy with apoptosis, and fibrosis, which all contribute to the genesis of AF. This review updates the current understanding of the effects of aging on the pathophysiology of AF.

Long-Term Exposure to Traffic-Related Air Pollution and Risk of Incident Atrial Fibrillation: A Cohort Study

BACKGROUND

Atrial fibrillation is the most common sustained arrhythmia and is associated with cardiovascular morbidity and mortality. The few studies conducted on short-term effects of air pollution on episodes of atrial fibrillation indicate a positive association, though not consistently.

OBJECTIVES

The aim of this study was to evaluate the long-term impact of traffic-related air pollution on incidence of atrial fibrillation in the general population.

METHODS

In the Danish Diet, Cancer, and Health cohort of 57,053 people 50-64 years old at enrollment in 1993-1997, we identified 2,700 cases of first-ever hospital admission for atrial fibrillation from enrollment to end of follow-up in 2011. For all cohort members, exposure to traffic-related air pollution assessed as nitrogen dioxide (NO2) and nitrogen oxides (NOx) was estimated at all present and past residential addresses from 1984 to 2011 using a validated dispersion model. We used Cox proportional hazard model to estimate associations between long-term residential exposure to NO2 and NOx and risk of atrial fibrillation, after adjusting for lifestyle and socioeconomic position.

RESULTS

A 10 μg/m3 higher 10-year time-weighted mean exposure to NO2 preceding diagnosis was associated with an 8% higher risk of atrial fibrillation [incidence rate ratio: 1.08; 95% confidence interval (CI): 1.01, 1.14] in adjusted analysis. Though weaker, similar results were obtained for long-term residential exposure to NOx. We found no clear tendencies regarding effect modification of the association between NO2 and atrial fibrillation by sex, smoking, hypertension or myocardial infarction.

CONCLUSION

We found long-term residential traffic-related air pollution to be associated with higher risk of atrial fibrillation. Accordingly, the present findings lend further support to the demand for abatement of air pollution. Citation: Monrad M, Sajadieh A, Christensen JS, Ketzel M, Raaschou-Nielsen O, Tjønneland A, Overvad K, Loft S, Sørensen M. 2017. Long-term exposure to traffic-related air pollution and risk of incident atrial fibrillation: a cohort study. Environ Health Perspect 125:422-427; http://dx.doi.org/10.1289/EHP392.

Genetic Obesity and the Risk of Atrial Fibrillation: Causal Estimates from Mendelian Randomization

BACKGROUND

Observational studies have identified an association between body mass index (BMI) and incident atrial fibrillation (AF). Inferring causality from observational studies, however, is subject to residual confounding, reverse causation, and bias. The primary objective of this study was to evaluate the causal association between BMI and AF by using genetic predictors of BMI.

METHODS

We identified 51 646 individuals of European ancestry without AF at baseline from 7 prospective population-based cohorts initiated between 1987 and 2002 in the United States, Iceland, and the Netherlands with incident AF ascertained between 1987 and 2012. Cohort-specific mean follow-up ranged from 7.4 to 19.2 years, over which period there was a total of 4178 cases of incident AF. We performed a Mendelian randomization with instrumental variable analysis to estimate a cohort-specific causal hazard ratio for the association between BMI and AF. Two genetic instruments for BMI were used: FTO genotype (rs1558902) and a BMI gene score comprising 39 single-nucleotide polymorphisms identified by genome-wide association studies to be associated with BMI. Cohort-specific estimates were combined by random-effects, inverse variance-weighted meta-analysis.

RESULTS

In age- and sex-adjusted meta-analysis, both genetic instruments were significantly associated with BMI (FTO: 0.43 [95% confidence interval, 0.32-0.54] kg/m2 per A-allele, P<0.001; BMI gene score: 1.05 [95% confidence interval, 0.90-1.20] kg/m2 per 1-U increase, P<0.001) and incident AF (FTO, hazard ratio, 1.07 [1.02-1.11] per A-allele, P=0.004; BMI gene score, hazard ratio, 1.11 [1.05-1.18] per 1-U increase, P<0.001). Age- and sex-adjusted instrumental variable estimates for the causal association between BMI and incident AF were hazard ratio, 1.15 (1.04-1.26) per kg/m2, P=0.005 (FTO) and 1.11 (1.05-1.17) per kg/m2, P<0.001 (BMI gene score). Both of these estimates were consistent with the meta-analyzed estimate between observed BMI and AF (age- and sex-adjusted hazard ratio 1.05 [1.04-1.06] per kg/m2, P<0.001). Multivariable adjustment did not significantly change findings.

CONCLUSIONS

Our data are consistent with a causal relationship between BMI and incident AF. These data support the possibility that public health initiatives targeting primordial prevention of obesity may reduce the incidence of AF.

Body mass index, abdominal fatness, fat mass and the risk of atrial fibrillation: a systematic review and dose-response meta-analysis of prospective studies

Different adiposity measures have been associated with increased risk of atrial fibrillation, however, results have previously only been summarized for BMI. We therefore conducted a systematic review and meta-analysis of prospective studies to clarify the association between different adiposity measures and risk of atrial fibrillation. PubMed and Embase databases were searched up to October 24th 2016. Summary relative risks (RRs) were calculated using random effects models. Twenty-nine unique prospective studies (32 publications) were included. Twenty-five studies (83,006 cases, 2,405,381 participants) were included in the analysis of BMI and atrial fibrillation. The summary RR was 1.28 (95% confidence interval: 1.20-1.38, I² = 97%) per 5 unit increment in BMI, 1.18 (95% CI: 1.12-1.25, I² = 73%, n = 5) and 1.32 (95% CI: 1.16-1.51, I² = 91%, n = 3) per 10 cm increase in waist and hip circumference, respectively, 1.09 (95% CI: 1.02-1.16, I² = 44%, n = 4) per 0.1 unit increase in waist-to-hip ratio, 1.09 (95% CI: 1.02-1.16, I² = 94%, n = 4) per 5 kg increase in fat mass, 1.10 (95% CI: 0.92-1.33, I² = 90%, n = 3) per 10% increase in fat percentage, 1.10 (95% CI: 1.08-1.13, I² = 74%, n = 10) per 5 kg increase in weight, and 1.08 (95% CI: 0.97-1.19, I² = 86%, n = 2) per 5% increase in weight gain. The association between BMI and atrial fibrillation was nonlinear, p _nonlinearity < 0.0001, with a stronger association at higher BMI levels, however, increased risk was observed even at a BMI of 22-24 compared to 20. In conclusion, general and abdominal adiposity and higher body fat mass increase the risk of atrial fibrillation.

Permanent atrial fibrillation impairs the function of circulating endothelial progenitor cells

OBJECTIVE

to determine whether functions of endothelial progenitor cells (EPCs) were impaired in patients with permanent atrial fibrillation (AF).

METHODS

35 patients with permanent AF (AF group) and 35 age and sex matched controls (control group) were collected. The numbers of circulating CD34⁺/KDR⁺ cells were determined with flow cytometry in the two groups. Cell proliferation, tube formation, nitric oxygen (NO) and vascular endothelial growth factor (VEGF) were assayed.

RESULTS

the numbers of CD34⁺/KDR⁺ cells were lower in the AF group than the control group (20.01 ± 12.66 /10⁵ vs 77.93 ± 58.93 /10⁵，p = 0.022). Colony formation unit (CFU) of EPCs were decreased in AF group compared to the control group（1.76 ± 0.59 CFU vs 3.45 ± 0.82 CFU, p = 0.0000). The AF group had lower cell proliferation ability than control group（0.401 ± 0.113 A vs 0.558 ± 0.130 A, p = 0.004). Tube formation ability was decreased in AF patients compared to controls（434.30 ± 96.22μm/mm² vs 568.09 ± 196.17μm/mm²，p = 0.041). AF patients had lower VEGF secretion than controls (27.35 ± 9.93 ng/L vs 41.86 ± 7.31 ng/L，p = 0.001），they also had lower NO secretion than controls（16.55 ± 6.92μmol/l vs 23.65 ± 5.48，p = 0.012).

CONCLUSIONS

proliferation, tube formation and paracrine of EPCs were reduced in patients with permanent AF.

Effect of Interleukin-27 Genetic Variants on Atrial Fibrillation Susceptibility

AIM

Atrial fibrillation (AF) is the most common cardiac arrhythmia. No data are available on the association between the polymorphisms of interleukin-27 (IL-27) and AF in the Chinese Han population. This study was performed to determine if polymorphisms within the IL-27 gene are involved in the AF susceptibility.

METHODS

Two hundred seventy AF patients and 303 healthy individuals were examined for two IL-27 gene polymorphisms (rs153109 and rs17855750) by polymerase chain reaction-restriction fragment length polymorphism methodology.

RESULTS

An association between the IL-27 single nucleotide polymorphism (SNP) rs153109 and AF was found in Chinese Han population. The G allele and GG genotype of rs153109 were associated with increased AF risk (odds ratio [OR]: 1.35, 95% confidence intervals [CI] = 1.06-1.71, p = 0.02 and OR: 1.66, 95% CI = 1.03-2.65, p = 0.03 in the recessive genetic model, respectively). The significance of the association between the GG genotype and AF risk did not survive a Bonferroni's correction. Similarly, no significant differences in the allele and genotype frequencies of the rs17855750 SNP was observed between the AF patients and controls.

CONCLUSIONS

Our findings indicated that the IL-27 genetic polymorphisms may be associated with susceptibility of AF in Chinese Han population.

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.

Residential exposure to traffic noise and risk of incident atrial fibrillation: A cohort study

BACKGROUND

Studies have found long-term exposure to traffic noise to be associated with higher risk for hypertension, ischemic heart disease and stroke. We aimed to investigate the novel hypothesis that traffic noise increases the risk of atrial fibrillation (A-fib).

METHODS

In a population-based cohort of 57,053 people aged 50-64years at enrolment in 1993-1997, we identified 2692 cases of first-ever hospital admission of A-fib from enrolment to end of follow-up in 2011 using a nationwide registry. The mean follow-up time was 14.7years. Present and historical residential addresses were identified for all cohort members from 1987 to 2011. For all addresses, exposure to road traffic and railway noise was estimated using the Nordic prediction method and exposure to air pollution was estimated using a validated dispersion model. We used Cox proportional hazard model for the analyses with adjustment for lifestyle, socioeconomic position and air pollution.

RESULTS

A 10dB higher 5-year time-weighted mean exposure to road traffic noise was associated with a 6% higher risk of A-fib (incidence rate ratio (IRR): 1.06; 95% confidence interval (95% CI): 1.00-1.12) in models adjusted for factors related to lifestyle and socioeconomic position. The association followed a monotonic exposure-response relationship. In analyses with adjustment for air pollution, NOx or NO2, there were no statistically significant associations between exposure to road traffic noise and risk of A-fib; IRR: 1.04; (95% CI: 0.96-1.11) and IRR: 1.01; (95% CI: 0.94-1.09), respectively. Exposure to railway noise was not associated with A-fib.

CONCLUSION

Exposure to residential road traffic noise may be associated with higher risk of A-fib, though associations were difficult to separate from exposure to air pollution.

Short-term Antiarrhythmic Drugs After Catheter Ablation for Atrial Fibrillation: A Meta-analysis of Randomized Controlled Trials

BACKGROUND

The incidence of recurrent arrhythmia after catheter ablation (CA) for atrial fibrillation (AF) is unacceptable. Short-term antiarrhythmic drug (AAD) treatment following CA was presumed to be effective in reducing recurrent arrhythmia.

OBJECTIVE

To fully evaluate the efficacy of short-term use of AADs following CA for AF in preventing recurrence of atrial tachyarrhythmias.

METHODS

PubMed, Embase, Cochrane Library, and ClinicalTrials.gov were searched up until May 1, 2016. We enrolled randomized controlled trials (RCTs) that evaluated the efficacy of short-term use of AADs following CA for AF in preventing early and/or late recurrence of atrial tachyarrhythmias. The statistical analyses were performed using Review Manager Version 5.3.

RESULTS

Six RCTs were included in this analysis, involving a total of 2764 patients. The frequency of early recurrence of atrial tachyarrhythmias was 39.5% in the AAD group (556 of 1407) and 47.2% (640 of 1357) in the control group. The pooled risk ratio of the AAD group to the control group was 0.78 (95% CI = 0.62-0.98). Regarding late recurrence of AF (LRAF), the incidence in the AAD group and the control group was 32.5% (420 of 1293) and 34.6% (450 of 1300), respectively. No significant difference was identified between the 2 groups (relative risk = 0.94, 95% CI = 0.85-1.05).

CONCLUSIONS

Short-term use of AADs following CA for AF reduced the incidence of early recurrent atrial tachyarrhythmias but did not prevent LRAF.