C-Reactive protein in lone atrial fibrillation

Forecasting Atrial Fibrillation: The Predictive Power of N-terminal Prohormone of Brain Natriuretic Peptide in a Five-Year Study

Introduction Atrial fibrillation (AF) is a major global health concern, and early prediction is essential for managing high-risk individuals. N-terminal prohormone of brain natriuretic peptide (NT-proBNP) has emerged as a crucial biomarker for predicting AF. While most studies have concentrated on cohorts already diagnosed with AF or other cardiac diseases, this research investigates the predictive value of NT-proBNP for AF development in a population without prior AF diagnosis. Methods and materials A five-year prospective observational study was conducted on 4090 individuals aged 45 to 75 with no previous diagnosis of AF. Baseline demographic characteristics, comorbid conditions, cardiac-specific measures, and NT-proBNP levels were systematically recorded. The primary endpoint was the onset of AF, confirmed through annual 12-lead ECG or 24-hour Holter monitoring. Univariate and multivariate analyses identified factors associated with AF onset. Results Out of the total population, 16.6% (679 individuals) developed AF. Notably, increased NT-proBNP levels (P=0.001), older age (P=0.001), and hypertension (P=0.001) were significantly associated with the onset of AF. The mean NT-proBNP levels in the AF group were significantly higher than in the non-AF group (P<0.001). The AF group also showed a higher mean age and a greater prevalence of hypertension (P<0.001 for both). Conclusion This study confirms the predictive value of NT-proBNP for AF onset in a non-AF population, highlighting older age and hypertension as significant risk factors for AF development. The findings underscore the potential of NT-proBNP not only as a predictive biomarker but also as a therapeutic target. These insights emphasize the potential role of NT-proBNP in early intervention and management strategies for AF, suggesting that future research should include additional variables, such as lifestyle factors and genetic predisposition, in assessing AF risk.

Inflammatory activation and endothelial dysfunction markers in patients with permanent atrial fibrillation: a cross-sectional study

In recent years a growing body of evidence supported the role of inflammation in the initiation, maintenance and outcome of atrial fibrillation (AF). Nevertheless, despite a large amount of information, whether AF or the underlying structural heart disease (SHD) is the cause of the inflammatory process is still under debate. We, therefore, sought to determine if the inflammatory process reflect an underlying disease or the arrhythmia ‘per se’. We evaluated plasma levels of soluble Interleukin 2 Receptor Alpha (sIL-2Rα), TNF-α and IL-18 in 100 consecutive patients with permanent AF, (43 with a SHD and 57 without a SHD) compared to 121 age and sex-matched controls which had normal sinus rhythm. We also evaluated the endothelial function in both groups of patients using reactive hyperemia index (RHI) values measured by Endo-PAT2000. Compared to controls, AF patients showed higher circulating levels of inflammatory markers and a lower mean value of RHI. At multiple logistic regression analysis, the inflammatory markers and RHI were significantly associated with AF presence, whereas ROC curve analysis had good sensitivity and specificity in inflammatory variables and RHI for AF presence. No significant association was observed in the group of permanent AF patients, between inflammatory markers and the presence of an underlying SHD. These findings could help to clarify the role of inflammation in subjects with AF and suggest that the markers of systemic inflammation are not associated with the underlying cardiovascular disease, rather with the atrial fibrillation ‘per se’.

Biomarkers of Atrial Fibrillation in Hypertension

Background:

Atrial fibrillation (AF) is the most frequently encountered cardiac arrhythmia globally and substantially increases the risk for thromboembolic disease. Albeit, 20% of all cases of AF remain undiagnosed. On the other hand, hypertension amplifies the risk for both AF occurrences through hemodynamic and non-hemodynamic mechanisms and cerebrovascular ischemia. Under this prism, prompt diagnosis of undetected AF in hypertensive patients is of pivotal importance.

Method:

We conducted a review of the literature for studies with biomarkers that could be used in AF diagnosis as well as in predicting the transition of paroxysmal AF to sustained AF, especially in hypertensive patients.

Results:

Potential biomarkers for AF can be broadly categorized into electrophysiological, morphological and molecular markers that reflect the underlying mechanisms of adverse atrial remodeling. We focused on P-wave duration and dispersion as electrophysiological markers, and left atrial (LA) and LA appendage size, atrial fibrosis, left ventricular hypertrophy and aortic stiffness as structural biomarkers, respectively. The heterogeneous group of molecular biomarkers of AF encompasses products of the neurohormonal cascade, including NT-pro BNP, BNP, MR-pro ANP, polymorphisms of the ACE and convertases such as corin and furin. In addition, soluble biomarkers of inflammation (i.e. CRP, IL-6) and fibrosis (i.e. TGF-1 and matrix metalloproteinases) were assessed for predicting AF.

Conclusion:

The reviewed individual biomarkers might be a valuable addition to current diagnostic tools but the ideal candidate is expected to combine multiple indices of atrial remodeling in order to effectively detect both AF and adverse characteristics of high risk patients with hypertension.

Biomarkers and arrhythmia recurrence following radiofrequency ablation of atrial fibrillation

Objective

Atrial fibrillation (AF) is the most common cardiac arrhythmia, and radiofrequency catheter ablation of AF (RCAAF) has become increasingly popular. Cardiac stress and inflammation have been associated with AF. This study was performed to determine whether the pre- or post-AF ablation levels of high-sensitivity C-reactive protein (hs-CRP) and N-terminal pro–B-type natriuretic peptide (NT-proBNP) are predictive of AF recurrence.

Methods

This multicenter prospective cohort study involved patients undergoing RCAAF in Switzerland and Canada. The primary endpoint was the recurrence of AF or atrial flutter at 6 months.

Results

Of 202 patients, 195 completed follow-up (age, 57.5 ± 9 years; mean left ventricular ejection fraction, 62%; mean left atrial size, 19.4 cm²). Patients with AF recurrence had larger atrial surfaces and longer total RCAAF times. Both the pre-ablation hs-CRP level and 1-day post-RCAAF NT-proBNP level were significantly associated with an increased risk of recurrence.

Conclusions

The pre-ablation hs-CRP level and immediate post-ablation NT-proBNP level were markers for atrial arrhythmia recurrence after RCAAF. This confirms growing evidence of the role of inflammation in the pathogenesis of AF. These biomarkers appear to be promising stratification tools for selection and management of patients undergoing RCAAF.

Inflammation and atrial fibrillation: A comprehensive review

Atrial fibrillation (AF) has different underlying substrates. Atrial remodeling involves electrophysiological and structural abnormalities that promote the development and perpetuation of AF. Experimental and clinical data indicate that inflammation is implicated in the pathophysiology of atrial remodeling. The mechanistic links between atrial remodeling and inflammation are complex while diverse underlying diseases and conditions may affect these pathways. Inflammatory markers have also been associated with AF development, recurrence, perpetuation, total AF burden as well as with thromboembolic complications. The development of specific anti-inflammatory interventions in this setting seems to be challenging and complicated. Several agents with pleiotropic properties, including anti-inflammatory, have been tested in experimental and clinical settings with variable results. This updated review provides a concise overview of all available data regarding the role of inflammation in AF including the predictive role of inflammatory markers. Also, current knowledge and future directions on anti-inflammatory strategies are critically discussed.

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.

Activated factor IX, factor XI and tissue factor identify patients with permanent atrial fibrillation treated with warfarin who are at risk of ischemic stroke

INTRODUCTION

Previously, we have demonstrated that significant proportions of patients with various cardiovascular diseases have active tissue factor and active factor XIa in their plasma. In the current study, we evaluated active tissue factor and active factors (F)XI and FIX in plasma from patients with atrial fibrillation.

MATERIAL AND METHODS

In 110 consecutive patients with permanent atrial fibrillation receiving warfarin, we determined active tissue factor, together with plasma FIXa and FXIa, using clotting assays by measuring the response to inhibitory monoclonal antibodies.

RESULTS

Sixteen (14.5%) patients had detectable active tissue factor and active FXIa, including 11 subjects with both factors, while FIXa was observed in 28 (25.7%) patients. The three positive groups did not differ from the patients without these factors with regard to demographic and clinical characteristics. Von Willebrand factor was higher in the active tissue factor-positive group (p < 0.0001) and FXIa-positive group (p = 0.0037). Individuals positive for active tissue factor and FXIa had higher plasma interleukin-6 levels (p = 0.0014 and 0.0322, respectively). The presence of active tissue factor, FXIa and FIXa in anticoagulated patients with permanent atrial fibrillation correlated with elevated von Willebrand factor and interleukin-6. During a 3-year follow-up, ischemic stroke (n = 12, 10.9%) occurred more commonly among atrial fibrillation patients who had circulating TF (p = 0.002) or FXIa (p = 0.013).

CONCLUSIONS

These data suggest that circulating active coagulation factors, in particular TF and FXIa, can be detected despite oral anticoagulation in a significant proportion of patients with atrial fibrillation, and could represent novel markers of persistent prothrombotic alterations predisposing to ischemic stroke.

Relation of Biomarkers of Inflammation and Oxidative Stress with Hypertension Occurrence in Lone Atrial Fibrillation

We compared plasma levels of biomarkers of inflammation (CRP) and oxidation (oxLDL), determined at study inclusion in lone atrial fibrillation (LAF) patients (48.6 ± 11.5 years; 74.0% men) and sinus rhythm controls (49.7 ± 9.3 years; 72.7% men, P > 0.05), and investigated the association of baseline CRP and oxLDL levels with the risk for vascular disease (VD) development (hypertension, cerebrovascular disease, coronary/peripheral artery disease, and pulmonary embolism) during prospective follow-up. Baseline CRP (1.2 [0.7–1.9] mg/L versus 1.1 [0.7–1.6] mg/L) and oxLDL levels (66.3 ± 21.2 U/L versus 57.1 ± 14.6 U/L) were higher in LAF patients (both P < 0.05). Following a median of 36 months, incident VD occurred in 14 (28.0%) LAF patients, all of whom developed arterial hypertension, and in 5 (11.4%) controls (hypertension, n = 4; coronary artery disease, n = 1), P < 0.05. LAF patients developed VD more frequently and at a younger age. Both CRP (HR, 2.54; 95% CI, 1.26–5.12; P = 0.009) and oxLDL (HR, 2.24; 95% CI, 1.14–4.40; P = 0.019) were multivariate predictors of incident hypertension in LAF patients, but not in the controls. Further research should clarify clinical relevance of investigated biomarkers for risk stratification and treatment of LAF patients.

Predictors of atrial fibrillation recurrence after cryoballoon ablation

Objective

Cryoballoon ablation (CA) is a safe and efficient method for pulmonary vein isolation in the treatment of paroxysmal atrial fibrillation (AF). There are conflicting results about the predictors of AF recurrence. The aim of this study is to evaluate the role of hematological indices to predict AF recurrence after CA.

Methods

A total of 49 patients (mean age 58.3±12.2 years, 51.02% female) with symptomatic paroxysmal AF underwent CA procedure. One hundred and sixty-eight pulmonary veins were used for pulmonary vein isolation with the second-generation cryoballoon. The hematological samples were obtained before and 24 hours after ablation.

Results

At a mean follow-up of 10.2±2.4 months, the probability of being arrhythmia-free after a single procedure was 86%. Patients with AF recurrence had higher red cell distribution width levels (16.10%±1.44% vs 14.87%±0.48%, P=0.035). The neutrophil/lymphocyte ratio, erythrocyte sedimentation rate, and C-reactive protein levels were detected in the patients with or without recurrence. Left atrial diameter (46.28±4.30 mm vs 41.02±4.10 mm, P=0.002), duration of AF (6.71±4.57 years vs 3.59±1.72 years, P=0.003), and age (65.01±15.39 years vs 54.29±11.32 years, P=0.033) were the other independent predictors of clinical recurrence after CA. Multiple regression analysis revealed that left atrial diameter was the only independent predictor for AF recurrence (P=0.012).

Conclusion

In this study of patients with paroxysmal AF undergoing cryoablation, increased preablation red cell distribution width levels, and not C-reactive protein or erythrocyte sedimentation rate, was associated with a higher rate of AF recurrence. Our results support the role of a preablation, proinflammatory, and pro-oxidant environment in the development of AF recurrence after ablation therapy but suggest that other factors are also important.

Elevated levels of RDW is associated with non-valvular atrial fibrillation

Red cell distribution width (RDW) and neutrophil/lymphocyte ratio (NLR) have been found to be associated with cardiovascular diseases. Only a few trials have investigated the correlation of these parameters with postoperative atrial fibrillation (AF). However, the correlation of these parameters in non-valvular AF is still unclear. We retrospectively analyzed consecutive AF patients from medical records and included 117 non-valvular AF patients (103 paroxysmal and 14 chronic AF). All subjects underwent physical examination and echocardiographic imaging. Complete blood counts (CBCs) were analyzed for hemoglobin, RDW, neutrophil and lymphocyte counts as well as mean corpuscular volume. Results of CBC tests within the previous year were also included and the averages were used. The demographic and echocardiographic properties of non-valvular AF group were comparable to the control group except for left atrial volumes which were increased in AF (median 33.1, IQR 26.3-41.1 cm(3) vs. median 26.4, IQR 24.2-28.9 cm(3); p = 0.01). RDW levels were significantly higher in the AF group (median 13.4 %, IQR 12.9-14.1 %) compared to the control (median 12.6 %, IQR 12.0-13.1 %; p = 0.01). NLR was not statistically different in the AF group and the controls (2.04 ± 0.94 vs. 1.93 ± 0.64, respectively; p = 0.32). Hs-CRP levels were higher in the AF group compared to the controls (median 0.84, IQR 0.30-1.43 mg/L vs. median 0.29, IQR 0.18-0.50 mg/L, respectively; p = 0.01). Multivariate logistic regression analysis revealed RDW (OR 4.18, 95 % CI 2.15-8.15; p = 0.01), hs-CRP (OR 3.76, 95 % CI 1.43-9.89; p = 0.01) and left atrial volume (OR 1.31, 95 % CI 1.06-1.21; p = 0.01) as the independent markers of non-valvular AF. Multivariate linear regression analysis revealed that hemoglobin levels (standardized β coefficient = -0.252; p = 0.01) and the presence of AF (standardized β coefficient = 0.336; p = 0.01) were the independent correlates of RDW levels. Elevated RDW levels, not NLR, may be an independent risk marker for non-valvular AF.

Scarcity of atrial fibrillation in a traditional African population: a community-based study

Background

In western societies, atrial fibrillation is an increasingly common finding among the elderly. Established risk factors of atrial fibrillation include obesity, diabetes, hypertension, and cardiovascular disease. Atrial fibrillation has almost exclusively been studied in western populations where these risk factors are widely present. Therefore, we studied the epidemiology of atrial fibrillation in a traditional African community.

Methods

In rural Ghana, among 924 individuals aged 50 years and older, we recorded electrocardiograms to detect atrial fibrillation. As established risk factors, we documented waist circumference, body mass index (BMI), capillary glucose level, blood pressure, and electrocardiographic myocardial infarction. In addition, we determined circulating levels of interleukin-6 (IL6), a proinflammatory cytokine, and C-reactive protein (CRP), a marker of systemic inflammation. We compared the risk factors with reference data from the USA.

Results

Atrial fibrillation was detected in only three cases, equalling 0.3% (95% CI 0.1–1.0%). Waist circumference, BMI, and capillary glucose levels were very low. Hypertension and myocardial infarction were uncommon. Circulating levels of IL6 were similar, but those of CRP were lower compared with the USA.

Conclusion

Atrial fibrillation is very scarce in this traditional African community. Its low prevalence compared with western societies can be explained by the rareness of its established risk factors, which are closely related to lifestyle, and by possible unmeasured differences in other risk factors or genetic factors.

Whole-exome sequencing in familial atrial fibrillation

AIMS

Positional cloning and candidate gene approaches have shown that atrial fibrillation (AF) is a complex disease with familial aggregation. Here, we employed whole-exome sequencing (WES) in AF kindreds to identify variants associated with familial AF.

METHODS AND RESULTS

WES was performed on 18 individuals in six modestly sized familial AF kindreds. After filtering very rare variants by multiple metrics, we identified 39 very rare and potentially pathogenic variants [minor allele frequency (MAF) ≤0.04%] in genes not previously associated with AF. Despite stringent filtering >1 very rare variants in the 5/6 of the kindreds were identified, whereas no plausible variants contributing to familial AF were found in 1/6 of the kindreds. Two candidate AF variants in the calcium channel subunit genes (CACNB2 and CACNA2D4) were identified in two separate families using expression data and predicted function.

CONCLUSION

By coupling family data with exome sequencing, we identified multiple very rare potentially pathogenic variants in five of six families, suggestive of a complex disease mechanism, whereas none were identified in the remaining AF pedigree. This study highlights some important limitations and challenges associated with performing WES in AF including the importance of having large well-curated multi-generational pedigrees, the issue of potential AF misclassification, and limitations of WES technology when applied to a complex disease.

Lone atrial fibrillation - an overview

Atrial fibrillation (AF) sometimes develops in younger individuals without any evident cardiac or other disease. To refer to these patients who were considered to have a very favourable prognosis compared with other AF patients, the term 'lone' AF was introduced in 1953. However, there are numerous uncertainties associated with 'lone' AF, including inconsistent entity definitions, considerable variations in the reported prevalence and outcomes, etc. Indeed, increasing evidence suggests a number of often subtle cardiac alterations associated with apparently 'lone' AF, which may have relevant prognostic implications. Hence, 'lone' AF patients comprise a rather heterogeneous cohort, and may have largely variable risk profiles based on the presence (or absence) of overlooked subclinical cardiovascular risk factors or genetically determined subtle alterations at the cellular or molecular level. Whether the implementation of various cardiac imaging techniques, biomarkers and genetic information could improve the prediction of risk for incident AF and risk assessment of 'lone' AF patients, and influence the treatment decisions needs further research. In this review, we summarise the current knowledge on 'lone' AF, highlight the existing inconsistencies in the field and discuss the prognostic and treatment implications of recent insights in 'lone' AF pathophysiology.

Value of high-sensitivity C-reactive protein assays in predicting atrial fibrillation recurrence: a systematic review and meta-analysis

OBJECTIVES

We performed a systematic review and meta-analysis of studies on high-sensitivity C-reactive protein (hs-CRP) assays to see whether these tests are predictive of atrial fibrillation (AF) recurrence after cardioversion.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, EMBASE and Cochrane databases as well as a hand search of the reference lists in the retrieved articles from inception to December 2013.

STUDY ELIGIBILITY CRITERIA

This review selected observational studies in which the measurements of serum CRP were used to predict AF recurrence. An hs-CRP assay was defined as any CRP test capable of measuring serum CRP to below 0.6 mg/dL.

PRIMARY AND SECONDARY OUTCOME MEASURES

We summarised test performance characteristics with the use of forest plots, hierarchical summary receiver operating characteristic curves and bivariate random effects models. Meta-regression analysis was performed to explore the source of heterogeneity.

RESULTS

We included nine qualifying studies comprising a total of 347 patients with AF recurrence and 335 controls. A CRP level higher than the optimal cut-off point was an independent predictor of AF recurrence after cardioversion (summary adjusted OR: 3.33; 95% CI 2.10 to 5.28). The estimated pooled sensitivity and specificity for hs-CRP was 71.0% (95% CI 63% to 78%) and 72.0% (61% to 81%), respectively. Most studies used a CRP cut-off point of 1.9 mg/L to predict long-term AF recurrence (77% sensitivity, 65% specificity), and 3 mg/L to predict short-term AF recurrence (73% sensitivity, 71% specificity).

CONCLUSIONS

hs-CRP assays are moderately accurate in predicting AF recurrence after successful cardioversion.

Improved understanding of the pathophysiology of atrial fibrillation through the lens of discrete pathological pathways

Atrial fibrillation (AF) is a common disorder with a complex and incompletely understood pathophysiology. Genetic approaches to understanding the pathophysiology of AF have led to the identification of several biological pathways important in the pathogenesis of the arrhythmia. These include pathways important for cardiac development, generation and propagation of atrial electrical impulses, and atrial remodeling and fibrosis. While common and rare genetic variants in these pathways are associated with increased susceptibility to AF, they differ substantially among patients with lone versus typical AF. Furthermore, how these pathways converge to a final common clinical phenotype of AF is unclear and might also vary among different patient populations. Here, we review the contemporary knowledge of AF pathogenesis and discuss how derangement in cardiac development, ion channel dysfunction, and promotion of atrial fibrosis may contribute to this common and important clinical disorder.

Risk factors between patients with lone and non-lone atrial fibrillation

Clinical factors such as tall stature, lean body mass, obstructive sleep apnea, alcohol or caffeine, smoking, endurance sports, and genetic factors are proposed as risk factors for lone atrial fibrillation (LAF). The KORAF (KORean Atrial Fibrillation) study is a retrospective multicenter registry that enrolled 3,570 consecutive atrial fibrillation (AF) patients. Data on risk factors were available for 2,133 patients, of whom 398 (18.7%) were identified as having LAF. In univariate analysis, patients with LAF were more likely to be men (82.4% vs 59.8%, P < 0.001) and current smokers (25.9% vs 15.6%, P < 0.01), alcohol drinkers (55.3% vs 31.2%, P < 0.01) and frequent consumers of caffeinated beverages (> 2 cups/day) (31.7% vs 19.3%, P < 0.01), and have a family history of AF (9.0% vs 2.6%, P < 0.001) than the non-LAF patients. Multivariate analysis showed that male gender (OR, 2.30; 95% CI, 1.61-3.27, P < 0.01), family history of AF (OR, 3.12; 95% CI, 1.91-5.12, P < 0.01), current alcohol use (OR, 2.01; 95% CI, 1.46-2.76, P < 0.01), and frequent caffeinated beverage consumption (OR, 1.66; 95% CI, 1.20-2.29, P < 0.01) were independently associated with LAF. In Korean patients, LAF is more closely associated with male gender, family history of AF, current alcohol and frequent caffeinated beverage consumption than non-LAF.

The relevance of the association between inflammation and atrial fibrillation

BACKGROUND

The relevance of the association between inflammation and atrial fibrillation (AF) is not firmly established. The clinical importance is considerable because inflammation is usually not targeted as a treatment option, minimizing a probable benefit.

MATERIALS AND METHODS

We have used a case-control study with a Mendelian randomization rationale to assess whether proposed risk factors that have a genetic component and are readily detected in circulating blood are causally related to AF. The studied variables were C-reactive protein (CRP) and a representative of the chemokine system, the monocyte chemoattractant protein-1 (CCL2).

RESULTS

Plasma CRP and CCL2 concentrations were significantly higher in AF patients than in the unaffected population. However, when segregated between paroxysmal and permanent, the difference for CRP was only observed in patients with a permanent condition. Plasma CCL2 was raised in both subgroups. Confounding factors were carefully considered, and multivariable analyses revealed that circulating CCL2 was significant and CRP was negligible to explain the presence of AF. The duration of the episode also bore a significant predictive value. Odd ratios for AF as a function of genotype did not differ from 1·0 for any of the individual CRP and CCL2 polymorphisms, or any combinations.

CONCLUSIONS

Elevated plasma CRP concentration per se does not increase atrial fibrillation risk. Values obtained for CCL2 suggest that inflammation is probably a consequence of AF. Our data also suggest that the effect of the duration of the episode should be further studied in the assessment of the actual role of inflammation.

Comparison of Atrial Fibrillation in the Young versus That in the Elderly: A Review

The incidence and prevalence of atrial fibrillation (AF) are projected to increase significantly worldwide, imposing a significant burden on healthcare resources. The disease itself is extremely heterogeneous in its epidemiology, pathophysiology, and treatment options based on individual patient characteristics. Whilst ageing is well recognised to be an independent risk factor for the development of AF, this condition also affects the young in whom the condition is frequently symptomatic and troublesome. Traditional thinking suggests that the causal factors and pathogenesis of the condition in the young with structurally normal atria but electrophysiological "triggers" in the form of pulmonary vein ectopics leading to lone AF are in stark contrast to that in the elderly who have AF primarily due to an abnormal substrate consisting of fibrosed and dilated atria acting in concert with the pulmonary vein triggers. However, there can be exceptions to this rule as there is increasing evidence of structural and electrophysiological abnormalities in the atrial substrate in young patients with "lone AF," as well as elderly patients who present with idiopathic AF. These reports seem to be blurring the distinction in the pathophysiology of so-called idiopathic lone AF in the young versus that in the elderly. Moreover with availability of improved and modern investigational and diagnostic techniques, novel causes of AF are being reported thereby seemingly consigning the diagnosis of "lone AF" to a rather mythical existence. We shall also elucidate in this paper the differences seen in the epidemiology, causes, pathogenesis, and clinical features of AF in the young versus that seen in the elderly, thereby requiring clearly defined management strategies to tackle this arrhythmia and its associated consequences.

Inflammatory biomarkers as risk factors for future atrial fibrillation. An eleven-year follow-up of 6315 men and women: the Tromsø study

BACKGROUND

Inflammatory biomarkers are reported as risk factors for atrial fibrillation (AF), but their impact is uncertain.

OBJECTIVE

We investigated the associations between inflammatory biomarkers and future AF in a large general cohort.

METHODS

Available markers were white blood cells (WBCs) with subgroups, fibrinogen, high-sensitivity C-reactive protein (hs-CRP), and osteoprotegerin (OPG). A total of 6315 men and women from a population survey in Tromsø, Norway in 1994 to 1995 were followed for a mean of 10.9 years. Mean age at baseline was 60 years. Measurements of height, weight, blood pressure, heart rate, total cholesterol, high-density lipoprotein (HDL) cholesterol, WBC count, and information on diabetes, angina, myocardial infarction, and antihypertensive treatment, were obtained at baseline. Fibrinogen, hs-CRP, and OPG were obtained at a follow-up visit. The outcome measure was first-ever AF, documented on an electrocardiogram. The Cox proportional hazards regression model was used to estimate hazard ratios of AF.

RESULTS

In the multivariable analysis, adjusted for traditional cardiovascular risk factors and other inflammatory biomarkers, hs-CRP was associated with AF in men only (hazard ratio = 1.14 for a 1 SD increase; 95% CI, 1.02-1.28). There was a significant increase in AF across quartiles of WBCs in men (P = 0.007) and in the total study population (P = 0.004). OPG was associated with AF in patients free of coronary heart disease at baseline. Fibrinogen and subgroups of WBCs showed no significant association with AF.

CONCLUSION

This population-based cohort study showed that hs-CRP was independently associated with AF in men, but apparently not in women, and that patients with WBCs in the upper quartile had increased risk of AF.

Impact of MCP-1 and CCR-2 gene polymorphisms on coronary artery disease susceptibility

Coronary artery disease (CAD) was the second leading cause of death during the last 3 years in Taiwan. Smooth muscle cells, monocytes/macrophages, and endothelial cells produce monocyte chemoattractant protein-1 (MCP-1) within atherosclerotic plaques following binding to the chemokine receptor-2 (CCR-2). Previous studies have well-documented the association between MCP-1 expression and susceptibility to, or clinicopathological features, of CAD. This study investigated the relationships between MCP-1-2518A/G and CCR-2-V64I genetic polymorphisms and CAD in the Taiwanese population. A total of 608 subjects, including 392 non-CAD controls and 216 patients with CAD, were recruited and subjected to polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) to evaluate the effects of these two polymorphic variants on CAD. Results indicated a significant association between MCP-1 -2548 gene polymorphism and susceptibility to CAD. GG genotypes (OR = 1.629; 95 % CI = 1.003-2.644), or individuals with at least one G allele (OR = 1.511; 95 % CI = 1.006-2.270), had a higher risk of CAD as compared with AA genotypes. Results also revealed that subjects with at least one A allele of the V64I CCR2 gene polymorphism had significantly increased risk of CAD. G allele in MCP-1-2518 might contribute to higher prevalence of atrial fibrillation in CAD patients (OR = 4.254; p < 0.05). In conclusion, MCP-1-2518G and CCR-2 64I gene polymorphisms represent important factors in determining susceptibility to CAD, and the contribution of MCP-1-2518G could be through effects on atrial fibrillation in CAD patients.

YKL-40 levels and atrial fibrillation in the general population

BACKGROUND

Atrial fibrillation is associated with inflammation. In contrast to inflammatory markers like C-reactive protein (CRP) and fibrinogen produced in the liver, YKL-40 is produced at the site of inflammation including in the myocardium. We hypothesized that elevated plasma YKL-40 levels associate with increased risk of atrial fibrillation.

METHOD AND RESULTS

We measured plasma YKL-40 in 8731 participants from the prospective Copenhagen City Heart Study including 896 individuals who developed atrial fibrillation during up to 18 years of follow-up. Additionally, we measured YKL-40 in 6621 individuals from the cross-sectional Copenhagen General Population Study including 337 cases with atrial fibrillation. A YKL-40 level >95% percentile (>204 μg/L) versus <25% percentile (<36 μg/L) associated prospectively with a 2.10-fold (95%CI:1.43-3.09) increased risk of atrial fibrillation. Hazard ratios attenuated slightly after multifactorial adjustment to 2.01 (1.35-2.98), and further after additional adjustment for heart failure to 1.89 (1.27-2.80), for plasma CRP to 1.79 (1.20-2.67), and for fibrinogen levels to 1.89 (1.27-2.81). Adjusting multifactorially including both heart failure, CRP, and fibrinogen attenuated the risk of atrial fibrillation to 1.79 (1.20-2.67). These findings were supported in the cross-sectional study with an odds ratio of 2.73 (1.46-5.11) for a YKL-40 level >95% percentile versus <25% percentile, attenuating to an odds ratio of 2.13 (1.09-4.18) when adjusting multifactorially including heart failure, CRP, and fibrinogen.

CONCLUSIONS

Elevated plasma YKL-40 levels robustly associated with increased risk of atrial fibrillation originating from hospital admissions or visits to the emergency department, independent of heart failure, and CRP and fibrinogen levels. These findings need to be confirmed in other independent studies.

Lone atrial fibrillation: where are we now?

There is a growing pandemic of atrial fibrillation (AF), affecting nearly 2% of the general adult population. Atrial fibrillation is commonly associated with structural heart disease, and AF itself causes a sequence of complex processes of electrical, contractile, and structural remodeling of the atrial myocardium, which facilitate further AF progression. Nonetheless, AF may also affect individuals aged ≤ 65 years who have no evidence of associated cardiopulmonary or other disease, including hypertension; this is otherwise referred to as "lone" AF and is considered to have a generally favorable prognosis. The true prevalence of lone AF is unknown. Growing insights into the diversity of numerous mechanisms involved in the pathogenesis of AF, including acute atrial stretch, structural and electrophysiological alterations, systemic inflammation, oxidative stress, autonomic imbalance, genetic predisposition, and many others, and increasing recognition of novel risk factors for AF, including obesity, metabolic syndrome, subclinical atherosclerosis, sleep apnea, alcohol consumption, and endurance sports, suggest that apparently lone AF might not be so "lone" in many patients, which could have important prognostic and therapeutic implications. In this article, we summarize the current knowledge of epidemiology, etiopathogenesis, and pathophysiology of so-called lone AF and discuss the issues of long-term prognosis and management of patients who have an apparently lone AF.

Extracellular matrix alterations in the atria: insights into the mechanisms and perpetuation of atrial fibrillation

Atrial fibrillation is the most common arrhythmia in clinical practice and is associated with increased cardiovascular morbidity and mortality. Atrial fibrosis, a detrimental process that causes imbalance in extracellular matrix deposition and degradation, has been implicated as a substrate for atrial fibrillation, but the precise mechanisms of structural remodelling and the relationship between atrial fibrosis and atrial fibrillation are not completely understood. A large number of experimental and clinical studies have shed light on the mechanisms of atrial fibrosis at the molecular and cellular level, including interactions between matrix metalloproteinases and their endogenous tissue inhibitors, and profibrotic signals through specific molecules and mediators such as angiotensin II, transforming growth factor-β1, connective tissue growth factor, and platelet-derived growth factor. This review focuses on the mechanisms of atrial fibrosis and highlights the relationship between atrial fibrosis and atrial fibrillation.

Lone atrial fibrillation: what is known and what is to come

Atrial fibrillation (AF) is the most prevalent sustained cardiac arrhythmia in adults, affecting >1% of general population. Atrial fibrillation is commonly associated with structural heart disease and is a major cause of significant cardiovascular morbidity and mortality. AF sometimes develops in a subset of young patients (e.g. aged ≤60 years), with no evidence of associated cardiopulmonary or other comorbid disease (including hypertension), and has been referred to as 'lone AF'. The latter generally has a favourable prognosis; the prognostic and therapeutic implications of an accurate identification of patients with truly lone AF (that is, truly at low risk of complications), if any, would be of the utmost importance. The true prevalence of lone AF is unknown, varying between 1.6% and 30%, depending on the particular study population. Nonetheless, novel risk factors for AF, including obesity, metabolic syndrome, sleep apnea, alcohol consumption, endurance sports, anger, hostility, subclinical atherosclerosis and others, have been increasingly recognised. Also, various underlying pathophysiological mechanisms predisposing to AF, including increased atrial stretch, structural and electrophysiological alterations, autonomic imbalance, systemic inflammation, oxidative stress and genetic predisposition, have been proposed. The growing evidence of these diverse (and numerous) pathogenic mechanisms and factors related to AF inevitably raises the question of whether 'lone AF' does exist at all. In this review article, we summarise the current knowledge of the epidemiology, pathophysiology, clinical course and treatment of patients with so-called 'lone AF' and outline emerging insights into its pathogenesis and the potential therapeutic implications of a diagnosis of lone AF.

Update on the association of inflammation and atrial fibrillation

Atrial fibrillation (AF) is a common arrhythmia and is associated with significant morbidity and mortality. The pathogenesis of AF remains incompletely understood and management remains a difficult task. Over the past decade there has been accumulating evidence implicating inflammation in the pathogenesis of AF. Inflammation appears to play a significant role in the initiation and perpetuation of AF as well as the prothrombotic state associated with AF. Inflammatory biomarkers (C-reactive protein and interleukin-6) have been shown to be associated with the future development, recurrence and burden of AF, and the likelihood of successful cardioversion. Therapies directed at attenuating the inflammatory burden appear promising. Animal and clinical studies have evaluated statins, angiotensin-converting enzyme inhibitors/angiotensin-II receptor blockers, and corticosteroids for the treatment or prevention of AF. The purpose of this review is to provide current evidence on the relationship between inflammation and AF and potential therapies available to modulate the inflammatory state in AF.

Impact of circulating monocyte CD36 level on atrial fibrillation and subsequent catheter ablation

BACKGROUND

Inflammation, an important mechanism in the pathogenesis of atrial fibrillation (AF), can be regulated by CD36 in monocytes.

OBJECTIVE

The purpose of this study was to test the hypothesis that CD36 in monocytes contributes to the pathogenesis of AF.

METHODS

A prospective study that enrolled 87 patients with AF and 70 without AF was conducted.

RESULTS

Compared to patients without AF, patients with AF had monocytes with a lower level of CD36 protein, which correlated with left atrial diameter, left atrial emptying fraction, and left atrial mean voltage. In AF patients after catheter ablation, Kaplan-Meier analysis showed that the sinus rhythm maintenance rate was higher in patients with high CD36 levels. Low CD36 level was an independent predictor of recurrence. After successful ablation, the CD36 level increased by 57%, reaching that of control patients. CD36 level was not correlated with the level of high-sensitivity C-reactive protein. Analysis of mRNA levels from a buffy coat revealed that AF patients had lower CD36 and interleukin-10 levels and higher peroxisome proliferator-activated receptor-γ and tumor necrosis factor-α levels, with CD36 level positively correlated with interleukin-10 level but inversely correlated with peroxisome proliferator-activated receptor-γ and tumor necrosis factor-α levels.

CONCLUSION

Low CD36 levels in circulating monocytes were associated with AF occurrence and predicted recurrence after catheter ablation. The link between CD36 and AF identified a novel AF-related inflammatory pathway.

Interleukin-18 among atrial fibrillation patients in the absence of structural heart disease

AIMS

Inflammation plays a role in the genesis and perpetuation of atrial fibrillation (AF). Interleukin (IL)-18 is a pleiotropic proinflammatory cytokine with a central role in the inflammatory cascade. We hypothesize that the circulating IL-18 concentration is elevated in AF patients.

METHODS AND RESULTS

In a case-control study design, 56 cases with AF and 26 controls were enrolled. All AF cases were categorized into paroxysmal and persistent AF or lone AF and AF with hypertension. Circulating levels of IL-18, tumour necrosis factor-α, high-sensitivity C-reactive protein, matrix metalloproteinase (MMP)-9, and tissue inhibitor of MMP-1 were measured. In adjusted analyses, only age, MMP-9, and IL-18 were independently associated with AF, in which IL-18 had the most significant association (P = 0.0011, standardized estimate &bgr = 1.76, OR = 1.02, 95% confidence interval: 1.01-1.03). Interleukin-18 levels in persistent AF patients were higher than those in paroxysmal ones (P = 0.0011). Patients who developed AF within 24 h prior to sampling displayed a higher level of IL-18 than those with sinus rhythm (P = 0.0027). Interleukin-18 was positively correlated with left atrial diameter (r = 0.33, P = 0.0117).

CONCLUSION

This study documents the elevated IL-18 in AF patients. Interleukin-18 may be superior to other inflammatory markers which are known to be elevated in AF.

Inducibility of atrial fibrillation depends not on inflammation but on atrial structural remodeling in rat experimental autoimmune myocarditis

INTRODUCTION

There is increasing evidence to support a link between inflammation and atrial fibrillation (AF). However, the role of inflammation on new-onset AF is still to be elucidated.

METHODS

Rats underwent induction of experimental autoimmune myocarditis (EAM). Atrial structural change was evaluated by echocardiography and histological analysis. Electrophysiological data and the in vivo atrial response to burst atrial pacing were evaluated in the acute (2 weeks after EAM induction) and chronic phases (8 weeks after induction). In addition, atrial pacing after 2, 4, and 6 h after lipopolysaccharide (LPS) infusion, when the expression of gap junctions was modified, were challenged with young healthy rats.

RESULTS

AF was induced in 11 of 15 chronic phase EAM rats but not in either acute phase EAM rats or LPS infusion rats (P<.01). Echocardiography showed dilatation of both atrium and ventricle and a decrease in the ejection fraction in the chronic phase. Histology revealed severe inflammatory lesions only in the acute phase. Interstitial atrial fibrosis as well as the area of atrial myocyte increased in the chronic phase but not in the acute phase.

CONCLUSIONS

AF could be induced in the chronic phase of myocarditis rats, but not in the acute phase of myocarditis rats or in rats with LPS infusion. Acute inflammation per se did not increase the occurrence of AF induction. Atrial structural remodeling caused by inflammation and hemodynamic effects is necessary to induce AF.

Lone AF - Etiologic Factors and Genetic Insights into Pathophysiolgy

Ever since atrial fibrillation (AF) was first recognized in young people (so called "lone" AF) over 4 decades ago, there has been increasing focus on determining the underlying pathophysiology of the condition. Although lone AF is presumed to be a highly heterogeneous disease, recent studies have identified novel risk factors such as inflammation, oxidative stress, endurance sports and genetics, for the arrhythmia. This monograph aims to highlight some of the recent advances in our understanding of the molecular pathophysiology of lone AF especially insight provided by contemporary genetic studies. These insights may provide novel therapeutic targets for treatment of this challenging arrhythmia in young patients.

Role of inflammation and oxidative stress in atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is the most common arrhythmia seen in clinical practice. Increasing evidence indicates that inflammation and oxidative stress contribute to the pathogenesis of AF, but their role remains poorly defined. In addition, whether inflammation and oxidative stress are associated with particular types of AF is unclear.

OBJECTIVE

The purpose of this study was to define the role of inflammation and oxidative stress in AF.

METHODS

Using a case-control study design, 305 patients with AF were compared with 150 control patients. AF was categorized into lone and typical AF and further subcategorized as paroxysmal, persistent, or permanent AF. Serum concentrations of interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor (TNF)-alpha, monocyte chemoattractant protein (MCP)-1, vascular endothelial growth factor (VEGF), N-terminal pro-brain (B-type) natriuretic peptide (NTpBNP), and urinary F(2)-isoprostanes, a measure of oxidative stress, were measured.

RESULTS

IL-6, IL-8, IL-10, TNF-alpha, MCP1, VEGF, and NTpBNP concentrations were independently associated with AF (all P <.05). However, F(2)-isoprostane excretion was not elevated (P = .50). Graded increases in TNF-alpha [median (interquartile range) 6.8 (3.4-11.3), 8.0 (5.6-10.9), 10.1 (5.7-12.4) pg/mL, P <.05] and NTpBNP [170.6 (67.3-481.9), 681.39 (310.3-1,439.0), 1,179.9 (653.1-2,096.0) pg/mL, P <.001] were seen among the subgroups of paroxysmal, persistent, and permanent AF, respectively.

CONCLUSION

Inflammatory biomarkers were significantly increased in patients with AF, supporting a strong association between inflammation and AF. Surprisingly, urinary F(2)-isoprostanes, a sensitive index of systemic oxidative stress in vivo, were not increased in AF overall or in different subtypes of AF.

Relation of urotensin II levels to lone atrial fibrillation

Human urotensin II (U-II) is an 11-amino acid peptide that plays an important role in hypertension and coronary artery disease. However, because there is no information on the role of U-II in the development of lone atrial fibrillation (AF), the goal of this study was to clarify the role of U-II in the development of lone AF. The study enrolled 42 patients (42.1 +/- 4.0 years old) with paroxysmal lone AF and 30 healthy gender- and age-matched control subjects. The following factors were measured in blood collected after an overnight fast: glucose, total cholesterol, low-density lipoprotein cholesterol, triglycerides, high-sensitivity C-reactive protein (hs-CRP), U-II, and vascular cell adhesion molecule 1 (VCAM-1). U-II levels were significantly higher in the lone AF than in the control group (4.09 +/- 1.28 vs 2.85 +/- 0.63 ng/ml, p <0.001). VCAM-1 levels were also higher in the lone AF than in the control group (337 +/- 250 vs 218 +/- 117 ng/ml, p = 0.018). In addition, hs-CRP levels were higher in the lone AF than in the control group (0.88 +/- 0.29 mg/dl vs 0.67 +/- 0.31 mg/dl, p = 0.004). Multivariate logistic regression analysis that included U-II, VCAM-1, hs-CP, and conventional AF risk factors showed that only U-II and hs-CRP were independently associated with lone AF. In conclusion, the results indicate that increased levels of U-II are associated with the development of lone AF. Additional studies will be necessary to determine whether the elevation of U-II is the cause or the result of AF.

C-reactive protein and atrial fibrillation in idiopathic dilated cardiomyopathy

BACKGROUND

Previous studies have found elevated plasma C-reactive protein (CRP) levels in atrial fibrillation (AF) patients. Most of these studies included AF patients with various heart diseases, but few studies were designed to investigate CRP in idiopathic dilated cardiomyopathy (IDCM) patients with AF.

METHOD AND RESULTS

CRP levels in 242 IDCM patients with AF were compared with CRP levels in 280 control IDCM patients. Among control patients, 70 had atrial premature beats or atrial tachycardia and 210 had normal sinus rhythm. CRP was higher in the AF group than in the control group (median, 4.59 versus 2.81 mg/L; p < 0.001). The prevalence of AF in IDCM patients increased as plasma CRP levels increased, and the patients with the highest plasma CRP levels had the highest probability of suffering from AF. Outcome of multivariate logistic regression analysis showed body mass index, AF, and white blood cell count significantly correlated with the plasma CRP levels.

CONCLUSION

Our data demonstrated that the plasma CRP level in IDCM patients with AF was higher than in IDCM patients without AF, and an increase in plasma CRP levels was associated with an increased prevalence of AF in IDCM patients. Also, body mass index, AF, and white blood cell count correlate with plasma CRP levels in IDCM patients. These data suggest there is presence of inflammation in IDCM patients with AF.

Inflammation in lone atrial fibrillation

OBJECTIVES

This study was designed to evaluate the correlation between lone atrial fibrillation and inflammation.

METHODS

A total of 411 subjects were enrolled in this study, including 333 patients with lone atrial fibrillation, and 78 controls. C-reactive protein (CRP) and echocardiography were evaluated, and the electrocardiograph was monitored to identify cardiac rhythm at the time of blood sampling. According to the rhythm, paroxysmal atrial fibrillation was divided into presence and absence of atrial fibrillation.

RESULTS

Subjects with lone atrial fibrillation had higher CRP levels than controls (media, 1.00 mg/L; IQR, 1.00-2.54 versus media, 1.00 mg/L; IQR, 1.00-1.55; p = 0.016) and subjects with persistent atrial fibrillation had higher CRP levels than those with paroxysmal atrial fibrillation (media, 1.62 mg/L; IQR, 1.00-3.98 versus media, 1.00 mg/L, IQR, 1.00-2.10; p = 0.022), and so did presence of atrial fibrillation rather than absence of atrial fibrillation (media, 2.11 mg/L; IQR, 1.00-3.60 versus media, 1.00 mg/L; IQR, 1.00-1.76; p = 0.000) in paroxysmal atrial fibrillation. However, there was no significant difference in CRP levels between persistent atrial fibrillation and presence of atrial fibrillation in paroxysmal atrial fibrillation (p = 0.992). Neither was there any difference between absence of atrial fibrillation in paroxysmal atrial fibrillation and controls (p = 0.483). In patients with lone atrial fibrillation, atrial fibrillation rhythm (B = 4.85, 95%CI: 2.61-8.99) was the only independent predictor of elevated CRP levels after adjusted covariants.

CONCLUSIONS

Patients with lone atrial fibrillation had elevated CRP levels only when they were in atrial fibrillation rhythm and an elevated CRP level was not related to duration of time or history of atrial fibrillation.

Role of proinflammatory markers and NT-proBNP in patients with an implantable cardioverter-defibrillator and an electrical storm

BACKGROUND

Several studies have attempted to identify risk factors for the development of an electrical storm (ES), which is defined as 3 separate ventricular tachyarrhythmic (VT/VF) events, but in the majority of studies no triggers have been found. However, little is known about the role of inflammation and NT-proBNP in patients with ES. The aim of this study was therefore to assess the relationship of Interleukin-6 (IL-6), high-sensitivity C-reactive protein (hs-CRP) and NT-proBNP serum concentrations in ICD-patients with or without single spontaneous ventricular tachyarrhythmic events (VT/VF) and in ES.

METHODS

Markers were determined in 51 patients without ICD-intervention, in 15 ICD-patients with single VT/VF-episodes during 9-months follow-up and in 20 ICD-patients with ES (blood sampling performed within 60min after fulfilling ES criteria). VT/VF-episodes were analysed by stored ICD-electrograms.

RESULTS

All patients had idiopathic dilated cardiomyopathy (n=23) or coronary artery disease (n=63). Patients with ES revealed significantly higher mean serum concentrations of all markers (IL-6 15.19+/-10.34 pg/mL, hs-CRP 20.12+/-14.4 mg/L, NT-proBNP 4799+/-4596 pg/mL) compared to baseline values of patients with single VT/VF-events during follow-up (IL-6 8.37+/-5.8 pg/mL (p=0.03), hs-CRP 4.7+/-5.3 mg/dL (p<0.001), NT-proBNP 1913+/-2665pg/mL (p=0.04)) and compared to baseline values of ICD-patients without device intervention (IL-6 4.62+/-3.66 pg/mL (p<0.001), hs-CRP 4.1+/-3.4 mg/L (p<0.001), NT-proBNP 1461+/-2281pg/mL (p<0.001)). In 9/20 patients presenting with ES (45%) baseline values were available. All markers were significantly higher during ES compared to event-free determination (IL-6 14.54+/-10.43 vs. 7.03+/-2.83 pg/mL (p=0.04), hs-CRP 19.07+/-16.07 vs. 6.5+/-3.9 mg/L (p=0.02), NT-proBNP 4218+/-2561 vs. 2099+/-1279 pg/mL (p=0.03)).

CONCLUSIONS

Electrical storm is associated with significantly elevated IL-6, hs-CRP and NT-proBNP serum concentrations in ICD-patients with structural heart disease. Thus, ES may be triggered by proinflammatory activity. Combined intraindividual elevation of determined markers might help to identify patients at risk of impending electrical storm.

Atrial Fibrillation: The New Epidemic of the Ageing World

The prevalence of atrial fibrillation (AF) increases with age. As the population ages, the burden of AF increases. AF is associated with an increased incidence of mortality, stroke, and coronary events compared to sinus rhythm. AF with a rapid ventricular rate may cause a tachycardia-related cardiomyopathy. Immediate direct-current (DC) cardioversion should be performed in patients with AF and acute myocardial infarction, chest pain due to myocardial ischemia, hypotension, severe heart failure, or syncope. Intravenous beta blockers, diltiazem, or verapamil may be administered to reduce immediately a very rapid ventricular rate in AF. An oral beta blocker, verapamil, or diltiazem should be used in persons with AF if a fast ventricular rate occurs at rest or during exercise despite digoxin. Amiodarone may be used in selected patients with symptomatic life-threatening AF refractory to other drugs. Digoxin should not be used to treat patients with paroxysmal AF. Nondrug therapies should be performed in patients with symptomatic AF in whom a rapid ventricular rate cannot be slowed by drugs. Paroxysmal AF associated with the tachycardia-bradycardia syndrome should be treated with a permanent pacemaker in combination with drugs. A permanent pacemaker should be implanted in patients with AF and symptoms such as dizziness or syncope associated with ventricular pauses greater than 3 seconds which are not drug-induced. Elective DC cardioversion has a higher success rate and a lower incidence of cardiac adverse effects than does medical cardioversion in converting AF to sinus rhythm. Unless transesophageal echocardiography has shown no thrombus in the left atrial appendage before cardioversion, oral warfarin should be given for 3 weeks before elective DC or drug cardioversion of AF and continued for at least 4 weeks after maintenance of sinus rhythm. Many cardiologists prefer, especially in elderly patients , ventricular rate control plus warfarin rather than maintaining sinus rhythm with antiarrhythmic drugs. Patients with chronic or paroxysmal AF at high risk for stroke should be treated with long-term warfarin to achieve an International Normalized Ratio of 2.0 to 3.0. Patients with AF at low risk for stroke or with contraindications to warfarin should be treated with aspirin 325 mg daily.

Current concepts in the pathogenesis of atrial fibrillation

Current evidence suggests that the pathogenesis of atrial fibrillation (AF) is multifactorial. The observation that AF, once present, alters the electrophysiologic properties of the atrial myocardium causing self-perpetuation of the arrhythmia raised the importance of electrical remodeling in its pathogenesis. Although these changes are potentially reversible, maintenance of AF continues even after electrical remodeling has occurred. Clinical and experimental studies have highlighted the role of a susceptible atrial anatomical substrate with features of myocyte degeneration and interstitial fibrosis in the initiation and maintenance of AF. Finally, the association of increased inflammatory burden with the presence and future development of AF has implicated inflammation in the pathogenesis of the arrhythmia. The purpose of this review is to provide current evidence on the dominant theories on AF pathogenesis, namely, electrical remodeling, structural remodeling, and inflammation; describe the various experimental models and methods used; and identify a cause-effect association, when present. In addition, the interrelation between different mechanisms responsible for AF will be demonstrated, providing further insight into the complex pathophysiology.