Intracardiac expression of markers of endothelial damage/dysfunction, inflammation, thrombosis, and tissue remodeling, and the development of postoperative atrial fibrillation

One-year Aerobic Interval Training Improves Endothelial Dysfunction in Patients with Atrial Fibrillation: A Randomized Trial

Objective To evaluate the effects of one-year aerobic interval training on endothelial dysfunction in patients with atrial fibrillation. Methods Seventy-four patients with atrial fibrillation (53 men, 21 women; mean age 63±6 years old) were randomized into a 1-year continuous aerobic interval training (CT), 6-month detraining after 6 months of aerobic interval training (DT), or medical treatment only (MT) group. Aerobic interval training was performed 3 times a week for 1 year or 6 months, with an exercise intensity of 85-95% of the peak heart rate. The primary outcome was a change in biomarkers of endothelial dysfunction from baseline at six months or at the one-year follow-up. Results Six-month aerobic interval training reduced von Willebrand factor (CT: 103.7±30.7 IU/dL and DT: 106±31.2 IU/dL vs. MT: 145±47.7 IU/dL, p=0.044). Improvements were maintained with continuous aerobic interval training; however, the values increased again to the baseline levels upon detraining (CT: 84.3±39.1 IU/dL vs. DT: 122.2±27.5 IU/dL and MT: 135.9±50.4 IU/dL, p=0.002). Interleukin 1 beta levels decreased after 6 months of aerobic interval training (CT: 0.59±0.1 pg/mL and DT: 0.63±0.09 pg/mL vs. MT: 0.82±0.28 pg/mL, p=0.031), and the improvement was maintained with continuous aerobic interval training and even after detraining (CT: 0.58±0.08 pg/mL and DT: 0.62±0.09 pg/mL vs. MT: 0.86±0.28 pg/mL, p=0.015). Conclusion One-year aerobic interval training improves endothelial dysfunction in patients with atrial fibrillation and is primarily associated with the reduction in circulating thrombogenic and pro-inflammatory factors. A definitive way to sustain these improvements is the long-term continuation of aerobic training.

Advanced Interatrial Block Predicts Recurrence of Atrial Fibrillation and Ischemic Stroke in Elderly Patients With Hypertension

Background: This study aimed to investigate whether advanced interatrial block (IAB) is a predictor of recurrent atrial fibrillation (AF) and/or ischemic stroke in elderly patients with AF and hypertension.

Methods and objectives: Five hundred and sixteen elderly inpatients (mean age 85.53 ± 9.08 years; 5.43% women) with concurrent paroxysmal AF and hypertension were enrolled in this retrospective observational study. Data on comorbidity, medication, digital electrocardiograms (ECG), and outcomes were obtained from the medical records and follow-up examinations. IAB was classified as partial IAB or advanced IAB according to 12-lead surface ECG analysis on admission. Advanced IAB was defined as a maximum P wave duration of >120 ms with biphasic (±) morphology in leads II, Ⅲ, and aVF by two blinded investigators. The endpoints were recurrent AF and ischemic stroke.

Results: We enrolled 120 patients (23.26%) with partial IAB and 187 (36.24%) with advanced IAB. The mean follow-up duration was 19 months. A total of 320 patients (62.02%) developed AF recurrence, and 31 (6.01%) experienced ischemic stroke. Significant predictors of advanced IAB in multivariate analysis were older age (>80 years), increased left atrial diameter (>40 mm), and being overweight (body mass index >25 kg/m2). In the multivariable comprehensive Cox regression analyses, partial IAB was associated with AF recurrence. Advanced IAB was an independent predictor of increased risk of AF recurrence and ischemic stroke.

Conclusion: Both partial and advanced IAB are associated with AF recurrence in elderly patients with hypertension. Furthermore, advanced IAB is an independent predictor of ischemic stroke.

Strain Echocardiography to Predict Postoperative Atrial Fibrillation

Postoperative atrial fibrillation (POAF) complicates 15% to 40% of cardiovascular surgeries. Its incidence progressively increases with aging, reaching 50% in octogenarians. This arrhythmia is usually transient but it increases the risk of embolic stroke, prolonged hospital stay, and cardiovascular mortality. Though many pathophysiological mechanisms are known, POAF prediction is still a hot topic of discussion. Doppler echocardiogram and, lately, strain echocardiography have shown significant capacity to predict POAF. Alterations in oxidative stress, calcium handling, mitochondrial dysfunction, inflammation, fibrosis, and tissue aging are among the mechanisms that predispose patients to the perfect “atrial storm”. Manifestations of these mechanisms have been related to enlarged atria and impaired function, which can be detected prior to surgery. Specific alterations in the atrial reservoir and pump function, as well as atrial dyssynchrony determined by echocardiographic atrial strain, can predict POAF and help to shed light on which patients could benefit from preventive therapy.

Mechanism of IL-6-related spontaneous atrial fibrillation after coronary artery grafting surgery: IL-6 knockout mouse study and human observation

Clinical observation and ex vivo studies have established a strong association between inflammation and postoperative atrial fibrillation (POAF). However, it is unclear whether the inflammatory phenotype is causally linked to this event or is an epiphenomenon, and it is not known which inflammatory meditators may increase susceptibility to POAF. The limitations of available animal models of spontaneous POAF (sPOAF) makes it difficult to select an experimental system. Here, we provide experimental and clinical evidence for mechanistic involvement of interleukin-6 (IL-6) in sPOAF.

PHASE I

We established a mouse model of cardiac surgery with nonpaced sPOAF. IL-6 knockout mice were protected from sPOAF compared with wild-type mice.

PHASE II

At 48 hours after surgery, the heart was separated into 6 regions and cultured. IL-6 was expressed in all regions, with highest abundance in the left atrium (LA). In PHASE III, we demonstrated that IL-6 in the LA elicited early profibrotic properties in atria via the pSTAT3/STAT3 signaling pathway and contributed to sPOAF.

PHASE IV

In a translational prospective clinical study, we demonstrated that humans with POAF had a higher IL-6 concentration in pericardial drainage (PD). This study provides preliminary evidence of a causal relationship between IL-6 and POAF in a novel nonpaced sPOAF mouse model. IL-6 is a crucial prerequisite for eliciting profibrotic properties in cardiac myocytes via the pSTAT3 pathway during the early postoperative period, leading to an increased susceptibility to POAF. Measuring IL-6 in PD could be a new noninvasive biomarker for the clinical prediction of POAF.

Endothelial dysfunction and vascular maladaptation in atrial fibrillation

Atrial fibrillation (AF) is the most common arrhythmia and is associated with worsened morbidity and mortality. The prevalence of AF is estimated to increase with an ageing population resulting in an ever-increasing burden on the healthcare system. Despite improvements in AF treatment, several questions remain unanswered in relation to the development and progression of AF. In this review, we discuss the evidence supporting the presence of vascular dysfunction in the development of AF, but also as a final common pathway explaining why AF constitutes a markedly increased risk of cardiovascular morbidity and mortality. Specifically, we summarise the work performed in humans related to the impact of AF on vascular structure and function, and whether measures of vascular function predict AF progression and the development of cardiovascular events. Subsequently, we discuss the potential mechanisms linking AF to the development of vascular dysfunction. Finally, we propose future perspectives of vascular health and AF, advocating a strong focus on regular exercise training as a safe and effective strategy to improve vascular function and, hence, reduce the risk for development and progression of AF and its associated risk for cardiovascular events.

Serum tenascin-C levels in atrium predict atrial structural remodeling processes in patients with atrial fibrillation

BACKGROUND

Fibro-inflammatory processes in the extracellular matrix are closely associated with progressive structural remodeling in atrial fibrillation (AF). Serum concentrations of tenascin-C (TNC), an extracellular matrix glycoprotein, and of high-sensitivity C-reactive protein (CRP) might serve as a marker of remodeling and progressive inflammation of the aorta and in myocardial diseases. This study aimed to clarify relationships between TNC and CRP in patients with AF.

METHODS

This study included 38 patients with AF and five controls without left ventricular dysfunction who underwent catheter ablation. Blood was collected immediately before ablation from the left atrium (LA), right atrium (RA), and femoral artery (FA), and left and right atrial pressure was measured. Levels of TNC in the LA (TNC-LA), RA (TNC-RA), and FA (TNC-FA) and high-sensitivity C-reactive protein (CRP) were measured. Atrial size was also determined by echocardiography.

RESULTS

Levels of TNC corrected by atrial size were maximal in the LA, followed by the RA (3.69 ± 0.32 and 2.87 ± 0.38 ng/mL/cm, respectively). Mean transverse diameter corrected by body surface area was larger and mean atrial pressure was greater in the LA than the RA. A relationship was found between CRP from the femoral vein and TNC-LA and TNC-RA, but not TNC-FA. None of TNC-LA, TNC-RA, or TNC-FA correlated with ANP or BNP in the femoral vein.

CONCLUSIONS

Intracardiac (atrial) TNC expression plays an important role in the development of remodeling processes in the atrium with AF. Tenascin-C from the LA and RA (but not TNC, ANP, and BNP from FA) might serve as novel markers of these processes.

Thrombin Induces Angiotensin II-Mediated Senescence in Atrial Endothelial Cells: Impact on Pro-Remodeling Patterns

BACKGROUND

Besides its well-known functions in hemostasis, thrombin plays a role in various non-hemostatic biological and pathophysiologic processes. We examined the potential of thrombin to promote premature atrial endothelial cells (ECs) senescence.

METHODS AND RESULTS

Primary ECs were isolated from porcine atrial tissue. Endothelial senescence was assessed by measuring beta-galactosidase (SA-β-gal) activity using flow cytometry, oxidative stress using the redox-sensitive probe dihydroethidium, protein level by Western blot, and matrix metalloproteinases (MMPs) activity using zymography. Atrial endothelial senescence was induced by thrombin at clinically relevant concentrations. Thrombin induced the up-regulation of p53, a key regulator in cellular senescence and of p21 and p16, two cyclin-dependent kinase inhibitors. Nicotinamide adenine dinucleotide phosphate NADPH oxidase, cyclooxygenases and the mitochondrial respiration complex contributed to oxidative stress and senescence. Enhanced expression levels of vascular cell adhesion molecule (VCAM)-1, tissue factor, transforming growth factor (TGF)-β and MMP-2 and 9 characterized the senescence-associated secretory phenotype of atrial ECs. In addition, the pro-senescence endothelial response to thrombin was associated with an overexpression of both angiotensin converting enzyme and AT1 receptors and was inhibited by perindoprilat and losartan.

CONCLUSIONS

Thrombin promotes premature ageing and senescence of atrial ECs and may pave the way to deleterious remodeling of atrial tissue by a local up-regulation of the angiotensin system and by promoting pro-inflammatory, pro-thrombotic, pro-fibrotic and pro-remodeling responses. Hence, targeting thrombin and/or angiotensin systems may efficiently prevent atrial endothelial senescence.

Moderate chronic kidney disease and left atrial enlargement independently predict thromboembolic events and mortality in elderly patients with atrial fibrillation: a retrospective single-center study

Objective

This study aimed to evaluate the effects of moderate chronic kidney disease (CKD) and left atrial enlargement on the risks of thromboembolic events, and all-cause and cardiovascular mortalities in elderly patients with atrial fibrillation (AF).

Methods

We retrospectively studied 751 patients (82.16% men, mean age: 79.0±9.1 years) with AF who were followed up for an average of 34.5 months at a single center. Adjusted hazard ratios (HRs) of risk factors for adverse clinical events were calculated using the Cox proportional hazards model.

Results

The risks of thromboembolic events, and all-cause and cardiovascular deaths were higher in patients with moderate CKD compared with patients with normal renal function after adjusting for other traditional risk factors (HR: 1.63, 95% confidence interval (CI): 1.03–2.58; HR: 1.55, 95% CI: 1.08–2.23; HR: 3.49, 95% CI: 1.57–7.74; respectively). Left atrial volume index >28.0 mL/m² was an independent risk factor associated with thromboembolic events and all-cause and cardiovascular deaths (HR: 1.62, 95% CI: 1.21–2.33; HR: 1.56, 95% CI: 1.16–2.10; HR: 1.87, 95% CI: 1.07–3.28; respectively).

Conclusions

Moderate CKD and left atrial enlargement may predict thromboembolic events, and all-cause and cardiovascular mortalities in elderly patients with AF without anticoagulation therapy.

Endothelial function changes in paroxysmal atrial fibrillation and treatment with propafenone

Aim. To evaluate the changes of endothelial function in arterial hypertension (AH) patients with paroxysmal atrial fibrillation (AF) in treatment with propafenone (Propanorm, PRO.MED.CS Praha a. s.) in comparison with bisoprolol.

Material and methods. To the study, 62 AH patients included with paroxysmal AH, age 45-63 y. o. (mean age 54,5±3,7 y. o.). Patients were randomized to 2 groups: 32 of group 1 (main) for rhythm-control were taking propafenone (Propanorm, PRO.MED.CS Praha a. s.) 450 mg daily, and 30 of group 2 (comparison) were taking bisoprolol for rate control. The groups were comparable by gender, age, severity of AH and duration of arrhythmia. Changes in endothelium vascular motion function and biochemical markers of endothelial dysfunction were assessed at inclusion and in 12 months of therapy.

Results. Sinus rhythm retention in propafenone group facilitated the improvement of vascular motion function of endothelium — endothelium dependent vasodilatation of brachial artery showed tendency to rise significantly from 5,4±0,3% to 6,9±0,1% (р=0,01). In patients taking bisoprolol for pulse reduction during 12 months, there was negative tendency from 4,8±0,2% to 3,6±0,1% (р=0,003), that points on worsening of endothelial function with persistent AF. Repeat measurement of biochemical markers of endothelial dysfunction revealed that in 12 months there is raise of endothelin concentration in both groups. Value of the collagen-binding activeness of von Willebrand factor in 12 months significantly reduced from 131±12 to 118±6 U/dL (р<0,05) in those retaining sinus rhythm with propafenone, and increased from 135±11 U/dL to 147±12 U/dL in those with rate control by bisoprolol.

Conclusion. In AH patients with paroxysmal AF retention of sinus rhythm with propafenone facilitated the improvement of vascular motion function of endothelium and decrease of collagen binding activeness of von Willebrand factor.

Th17/Treg Ratio in Serum Predicts Onset of Postoperative Atrial Fibrillation After Off-Pump Coronary Artery Bypass Graft Surgery

BACKGROUND

The aim of this study is to identify whether the balance between T helper 17 (Th17) cells and CD4⁺CD25⁺Foxp3⁺ regulatory T (Treg) cells could predict the postoperative atrial fibrillation (POAF) after coronary artery bypass graft surgery (CABG).

METHODS

We enrolled 88 patients from Xinhua Hospital who received off-pump CABG (OPCABG) surgery. The baseline characteristics of patients were recorded. The preoperative variables C-reactive protein (CRP) level, left atrial (LA) volume, EuroSCORE I score, CHADS₂ score, and CHA₂DS₂-VASc score were calculated at enrolment. Circulating Th17 and Treg cell frequencies were determined by flow cytometry, and expressions of Th17- and Treg-related cytokines were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Compared to patients without POAF, the CRP level and peripheral circulating Th17 cell were significantly increased in POAF patients. Th17/Treg ratio was positively correlated with CRP level, LA volume, CHADS₂ score, and CHA₂DS₂-VASc score. The areas under the receiver-operating characteristic (AUC) curves of Th17/Treg ratio for predicting POAF occurrence was higher than that of CRP level, LA volume, CHADS₂ score and CHA₂DS₂-VASc score. Th17/Treg ratio combined with CRP level has the highest AUC and a greater balance between sensitivity and specificity for predicting POAF.

CONCLUSIONS

Our data suggest that a Th17/Treg imbalance due to a Th17 shift, representing a pro-inflammatory tendency, participates in the development of POAF. Combining the Th17/Treg ratio with CRP level may provide a more accurate, sensitive, and specific indicator for prediction of POAF.

Meta-analysis Identifies Serum C-Reactive Protein as an Indicator of Atrial Fibrillation Risk After Coronary Artery Bypass Graft

A meta-analysis-based study was conducted to examine the clinical value of serum C-reactive protein (CRP) levels in predicting postoperative atrial fibrillation (POAF) in patients with coronary artery disease (CAD) who underwent coronary artery bypass graft. Computer-based search of scientific literature databases was performed to identify relevant studies in strict accordance with our inclusion and exclusion criteria. Data extracted from the selected studies were used to perform meta-analysis using the STATA 12.0 statistical software. Standardized mean differences (SMDs) with their 95% confidence interval (95% CI) were calculated. The database search strategy initially identified 62 articles (Chinese = 17, English = 45). After multiple levels of screening and validation, 15 case-control studies (Chinese = 1, English = 14), containing of a total of 3110 atrial fibrillation patients (POAF = 925, non-POAF = 2185), were selected for our meta-analysis. The meta-analysis results confirmed that serum CRP level was remarkably higher in patients with POAF compared with non-POAF (SMD = 1.36; 95% CI, 0.44-2.28; P = 0.004). Ethnicity-stratified analysis revealed that elevated serum CRP levels were associated with an increased risk of POAF in white patients with CAD (SMD = 0.85; 95% CI, 0.12-1.58; P = 0.022), but not Asian patients with CAD (SMD = 3.31, 95% CI, -0.04 to 6.66; P = 0.053). Elevated CRP levels, indicating profound inflammation, may be associated with significantly increased risk of POAF in patients with CAD who underwent coronary artery bypass graft. Thus, serum CRP levels are important for early diagnosis and monitoring of POAF in high-risk patients.

Immunohistochemical determination of the extracellular matrix modulation in a rat model of choline-deprived myocardium: the effects of carnitine

Choline has been identified as an essential nutrient with crucial role in many vital biological functions. Recent studies have demonstrated that heart dysfunction can develop in the setting of choline deprivation even in the absence of underlying heart disease. Matrix metalloproteinases (MMPs) are responsible for extracellular matrix degradation, and the dysregulation of MMP-2 and MMP-9 has been involved in the pathogenesis of various cardiovascular disorders. The aim of the study was to investigate the role of MMPs and their inhibitors (TIMPs), in the pathogenesis of choline deficiency-induced cardiomyopathy, and the way they are affected by carnitine supplementation. Male Wistar Albino adult rats were divided into four groups and received standard or choline-deficient diet with or without L-carnitine in drinking water (0.15% w/v) for 1 month. Heart tissue immunohistochemistry for MMP-2, MMP-9, TIMP-1, and TIMP-2 was performed. Choline deficiency was associated with suppressed immunohistochemical expression of MMP-2 and an increased expression of TIMP-2 compared to control, while it had no impact on TIMP-1. MMP-9 expression was decreased without, however, reaching statistical significance. Carnitine did not affect MMP-2, MMP-9, TIMP-1 or TIMP-2 expression. The pattern of TIMP and MMP modulation observed in a choline deficiency setting appears to promote fibrosis. Carnitine, although shown to suppress fibrosis, does not seem to affect MMP-2, MMP-9, TIMP-1 or TIMP-2 expression. Further studies will be required to identify the mechanism underlying the beneficial effects of carnitine.

Inflammation, oxidative stress and postoperative atrial fibrillation in cardiac surgery

Postoperative atrial fibrillation (POAF) is a common complication of cardiac surgery that occurs in up to 60% of patients. POAF is associated with increased risk of cardiovascular mortality, stroke and other arrhythmias that can impact on early and long term clinical outcomes and health economics. Many factors such as disease-induced cardiac remodelling, operative trauma, changes in atrial pressure and chemical stimulation and reflex sympathetic/parasympathetic activation have been implicated in the development of POAF. There is mounting evidence to support a major role for inflammation and oxidative stress in the pathogenesis of POAF. Both are consequences of using cardiopulmonary bypass and reperfusion following ischaemic cardioplegic arrest. Subsequently, several anti-inflammatory and antioxidant drugs have been tested in an attempt to reduce the incidence of POAF. However, prevention remains suboptimal and thus far none of the tested drugs has provided sufficient efficacy to be widely introduced in clinical practice. A better understanding of the cellular and molecular mechanisms responsible for the onset and persistence of POAF is needed to develop more effective prediction and interventions.

Inflammation and the pathogenesis of atrial fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia. However, the development of preventative therapies for AF has been disappointing. The infiltration of immune cells and proteins that mediate the inflammatory response in cardiac tissue and circulatory processes is associated with AF. Furthermore, the presence of inflammation in the heart or systemic circulation can predict the onset of AF and recurrence in the general population, as well as in patients after cardiac surgery, cardioversion, and catheter ablation. Mediators of the inflammatory response can alter atrial electrophysiology and structural substrates, thereby leading to increased vulnerability to AF. Inflammation also modulates calcium homeostasis and connexins, which are associated with triggers of AF and heterogeneous atrial conduction. Myolysis, cardiomyocyte apoptosis, and the activation of fibrotic pathways via fibroblasts, transforming growth factor-β and matrix metalloproteases are also mediated by inflammatory pathways, which can all contribute to structural remodelling of the atria. The development of thromboembolism, a detrimental complication of AF, is also associated with inflammatory activity. Understanding the complex pathophysiological processes and dynamic changes of AF-associated inflammation might help to identify specific anti-inflammatory strategies for the prevention of AF.

Atrial fibrillation: state of the art

Atrial fibrillation (AF) is by far the most frequent heart rhythm disorder and is associated with a significantly increased risk of stroke, heart failure and death. Despite improvements in prevention and treatment, the prognosis has not changed significantly. To use new and promising pharmacological and interventional concepts for thromboembolic prophylaxis and treatment of AF, as well as prevention of recurrence, patient compliance has to be improved, physicians have to be trained and experience hast to be gained. A consistently carried 'anticoagulation pass' might be a promising piece of the puzzle.

Effects of radiofrequency catheter ablation of atrial fibrillation on soluble P-selectin, von Willebrand factor and IL-6 in the peripheral and cardiac circulation

Background

Catheter ablation (CA) of atrial fibrillation (AF) is associated with inflammatory response, endothelial damage and with increased risk of thrombosis. However, whether these processes differ in peripheral and cardiac circulation is unknown.

Methods

Plasma markers (von Willebrand factor (vWf), soluble P-selectin (sPsel) and interleukin-6 (IL-6)) were measured by ELISA at three time points in 80 patients (62±10 years, 63% males, 41% paroxysmal AF) undergoing CA. These were at baseline – from femoral vein (FV) and left atrium (LA) before ablation; directly after ablation – from the pulmonary vein (PV), LA and FV; and 24 hours after procedure – from a cubital vein (CV).

Results

The levels of vWF and IL6 – but not sP-sel – increased significantly 24h after procedure (p<0.001). Baseline vWF was significantly associated with persistent AF (Beta = .303, p = 0.006 and Beta = .300, p = 0.006 for peripheral and cardiac levels, respectively), while persistent AF (Beta = .250, p = 0.031) and LAA flow pattern (Beta = .386, p<0.001) remained associated with vWF in cardiac blood after ablation. Advanced age was significantly associated with IL6 levels at baseline and after ablation in peripheral and cardiac blood. There were no clinical, procedural or anti-coagulation characteristics associated with sP-sel levels in cardiac blood, while peripheral sP-sel levels were associated with hypertension before (Beta = −.307, p = 0.007) and with persistent AF after ablation (Beta = −.262, p = 0.020).

Conclusions

vWF levels are higher in persistent AF and are associated with LAA rheological pattern after AF ablation. Increase of peripheral vWF and IL6 levels after procedure supports current AF ablation management with careful control of post-procedural anticoagulation to avoid ablation-related thromboembolism.

Preoperative glucose level has different effects on the endogenous extracellular matrix-related gene expression in saphenous vein of type 2 diabetic patients undergoing coronary surgery

BACKGROUND

Type 2 diabetes mellitus (DM) severely reduces the benefits of coronary artery bypass grafting (CABG). However, few studies investigated the correlation between preoperative glucose level and endogenous extracellular matrix (ECM)-related gene expression of saphenous vein (SV) conduits in diabetic patients.

METHODS

A total of 130 patients were divided into high-glucose (HG), low-glucose (LG) and control group according to the preoperative level of blood glucose. The expression of ECM-related genes was analysed by microarray.

RESULTS

Compared with control group, 30 genes showed at least a threefold change in expression in HG group; up-regulation was observed in 24 genes. However, there were only 21 ECM-related genes showed at least a threefold change in expression between the LG and control group. Compared with HG group, matrix metalloproteinases' (MMPs) expression was significantly decreased in LG and control groups. In contrast to the decrease in MMPs' expression, expression of tissue inhibitors of metalloproteinases (TIMPs) was increased.

CONCLUSION

This study suggested that different preoperative diabetic status affected the expression of ECM-related genes in SV. ECM-related genes were more significantly imbalanced in diabetic patients with uncontrolled preoperative blood glucose than those with well-controlled preoperative blood glucose.

Atrial fibrillation: inflammation in disguise?

Atrial fibrillation is highly prevalent, and affected patients are at an increased risk of a number of complications, including heart failure and thrombo-embolism. Over the past years, there has been increasing interest in the role of inflammatory processes in atrial fibrillation, from the first occurrence of the arrhythmia to dreaded complications such as strokes or peripheral emboli. As the standard drug combination which aims at rate control and anticoagulation only offers partial protection against complications, newer agents are needed to optimize treatment. In this paper, we review recent knowledge regarding the impact of inflammation on the occurrence, recurrence, perpetuation and complications of the arrhythmia, as well as the role of anti-inflammatory therapies in the treatment for the disease.

Progressive endothelial damage revealed by multilevel von Willebrand factor plasma concentrations in atrial fibrillation patients

AIMS

Abnormal plasma concentrations of von Willebrand factor (vWF), a marker of prothrombotic risk, have been found in atrial fibrillation (AF) patients, but the extent of this variation is not clear. This study aimed to investigate the effect of different clinical forms of AF on plasma concentrations of vWF at different levels of the circulatory tree, both intracardiac and extracardiac.

METHODS AND RESULTS

Peripheral (Pf), left atrial (LA), and coronary sinus (CS) blood samples were obtained during cardiac catheterization from 52 patients with paroxysmal AF (PAF), 36 with persistent AF (PsAF), and 17 control subjects (Ct) with left-sided accessory pathway Wolff-Parkinson-White syndrome. Plasma concentrations of vWF were determined by immunoturbidimetry. Compared with Ct, patients with PAF had higher LA plasma levels of vWF (P = 0.004), but similar Pf and CS levels (both P > 0.30). In contrast, patients with PsAF had higher plasma concentrations of vWF in Pf (P = 0.04), LA (P < 0.001), and CS (P = 0.04) samples compared with Ct. Left atrial plasma concentrations of vWF in patients with PsAF were also higher than in the PAF group (P = 0.04).

CONCLUSION

Regardless of the clinical form of the arrhythmia, AF patients presented significantly higher plasma concentrations of vWF compared with sinus rhythm controls. Multilevel vWF plasma concentration assessment suggests an association between the clinical evolution of AF and the progression of endothelial dysfunction. Further studies will have to establish the exact mechanisms that link endothelial dysfunction and stroke in the context of AF.

Atherosclerosis and thromboembolic risk in atrial fibrillation: focus on peripheral vascular disease

Atrial fibrillation (AF) is the most common cardiac arrhythmia in clinical practice. It results in a 5-fold increased risk for stroke and thromboembolism and is associated with a high morbidity and mortality. AF shares several risk factors and pathophysiological features with atherosclerosis. Hence AF is often complicated by a variety of other cardiovascular conditions. Indeed, peripheral vascular disease (PVD) is highly prevalent among AF patients and associates with increased mortality. Inclusion of PVD within stroke risk scoring systems such as the CHA2DS2-VASc score improves risk stratification of AF patients. Of note, PVD has not been previously well documented nor looked for in observational studies or clinical trials. The aim of this present review article is to provide an overview of the association between atherosclerosis (with particular focus on PVD) and AF as well as its complications.

A proposal for new clinical concepts in the management of atrial fibrillation

Atrial fibrillation (AF) represents a growing public health burden. It is a complex condition, involving a number of etiologic factors and arrhythmia mechanisms associated with atrial remodeling. Greater understanding of these mechanisms may improve therapy. Current AF classification schemes are limited by simplicity. A number of risk factors predict AF onset, and additional factors are being evaluated in registry studies. Doppler imaging and Holter monitoring in high-risk patients to predict the onset of AF and progression from paroxysmal to permanent AF are promising. There is a need for a novel multifactorial classification model encompassing AF duration, symptoms, markers of atrial remodeling, and a risk score for AF onset, persistence, progression, and complications to guide treatment and prognostication. Preventing AF onset with upstream therapy is of great interest, but current data are conflicting. More study is needed to optimize rhythm control with antiarrhythmic drugs and targeted ablation to specific patient populations at an earlier stage. There is little consensus on optimal rate control and no information relating to optimum rate control in specific populations. This article highlights new concepts in AF and directions for future research.