Inflammation, atrial fibrillation, and the potential role for colchicine therapy

Periodontal Treatment During the Blanking Period Improves the Outcome of Atrial Fibrillation Ablation

BACKGROUND

Periodontitis has not been recognized as a modifiable risk factor for atrial fibrillation (AF). This prospective nonrandomized study investigated whether periodontal treatment improves the AF ablation outcome.

METHODS AND RESULTS

We prospectively enrolled 288 AF patients scheduled to undergo initial radiofrequency catheter ablation. Each patient underwent periodontal inflamed surface area (PISA; a quantitative index of periodontal inflammation) measurement. All eligible patients were recommended to receive periodontal treatment within the blanking period, and 97 consented. During the mean follow-up period of 507±256 days, 70 (24%) AF recurrences were documented. Patients who exhibited AF recurrences had a higher PISA than those who did not (456.8±403.5 versus 277.7±259.0 mm2, P=0.001). These patients were categorized into high-PISA (>615 mm2) and low-PISA (<615 mm2) groups according to the receiver operating characteristic analysis for AF recurrence (area under the curve, 0.611; sensitivity, 39%; specificity, 89%). A high PISA, as well as female sex, AF duration, and left atrial volume, were the statistically significant predicter for AF recurrence (hazard ratio [HR], 2.308 [95% CI, 1.234-4.315]; P=0.009). In patients with a high PISA, those who underwent periodontal treatment showed significantly fewer AF recurrences (P=0.01, log-rank test). The adjusted HR of periodontal treatment for AF recurrence was 0.393 (95% CI, 0.215-0.719; P=0.002).

CONCLUSIONS

Periodontitis may serve as a modifiable risk factor for AF. PISA is a hallmark of AF recurrence, and periodontal treatment improves the AF ablation outcome, especially for those with poor periodontal condition.

Pathophysiology and clinical relevance of atrial myopathy

Atrial myopathy is a condition that consists of electrical, structural, contractile, and autonomic remodeling of the atria and is the substrate for development of atrial fibrillation, the most common arrhythmia. Pathophysiologic mechanisms driving atrial myopathy are inflammation, oxidative stress, atrial stretch, and neurohormonal signals, e.g., angiotensin-II and aldosterone. These mechanisms initiate the structural and functional remodeling of the atrial myocardium. Novel therapeutic strategies are being developed that target the pathophysiologic mechanisms of atrial myopathy. In this review, we will discuss the pathophysiology of atrial myopathy, as well as diagnostic and therapeutic strategies.

Detection and modification of biomarkers of inflammation determining successful rhythm control in patients with atrial fibrillation

INTRODUCTION

Multiple pathophysiological mechanisms are involved in the pathogenesis of atrial fibrillation (AF). Growing evidence suggests that both local and systemic inflammation plays a key role even in early stages and its progression towards persisting and permanent AF. Rhythm control therapy via pulmonary vein isolation or cardioversion is the cornerstone of AF therapy for most symptomatic patients, yet arrhythmia recurrence after treatment is still common, especially in patients with persistent AF.

MATERIAL AND METHODS

In this review, we summarize the current state of knowledge of biomarkers of inflammation with prognostic value in patients with atrial fibrillation as well as anti-inflammatory medication with potential benefits after rhythm control therapy.

RESULTS AND DISCUSSION

Both onset of AF, progression and arrhythmia recurrence after rhythm control therapy can be caused by local and systemic inflammation. Various inflammatory biomarkers have been established to predict treatment success. Furthermore, additional anti-inflammatory therapy may significantly improve success rates.

Depression and atrial fibrillation in a reciprocal liaison: a neuro-cardiac link

OBJECTIVE

To explore the reciprocal relationship of depression and atrial fibrillation (AF).

METHODS

A literature search was conducted in Pub Med, Scopus, and Google Scholar using relevant terms for depression and AF and respective therapies.

RESULTS

There is evidence that depression is involved in the aetiology and prognosis of AF. AF, independently of its type, incurs a risk of depression in 20-40% of patients. Also, depression significantly increases cumulative incidence of AF (from 1.92% to 4.44% at 10 years); 25% increased risk of new-onset AF is reported in patients with depression, reaching 32% in recurrent depression. Hence, emphasis is put on the importance of assessing depression in the evaluation of AF and vice versa. Persistent vs paroxysmal AF patients may suffer from more severe depression. Furthermore, depression can impact the effectiveness of AF treatments, including pharmacotherapy, anticoagulation, cardioversion and catheter ablation.

CONCLUSIONS

A reciprocal association of depression and AF, a neurocardiac link, has been suggested. Thus, strategies which can reduce depression may improve AF patients' course and treatment outcomes. Also, AF has a significant impact on risk of depression and quality of life. Hence, effective antiarrhythmic therapies may alleviate patients' depressive symptoms. KEY POINTSAF, independently of its type of paroxysmal, permanent or chronic, appears to have mental besides physical consequences, including depression and anxietyA reciprocal influence or bidirectional association of depression and AF, a neurocardiac link, has been suggestedAF has considerable impact on the risk of depression occurrence with 20-40% of patients with AF found to have high levels of depressionAlso, depression significantly increases 10-year cumulative incidence and risk of AF from 1.92% to 4.44% in people without depression, and the risk of new-onset AF by 25-32%Emphasis should be placed on the importance of assessing depression in the evaluation of AF and vice versaPersistent/chronic AF patients may suffer from more severe depressed mood than paroxysmal AF patients with similar symptom burdenDepression and anxiety can impact the effectiveness of certain AF treatments, including pharmacotherapy, anticoagulation treatment, cardioversion and catheter ablationThus, strategies which can reduce anxiety and depression may improve AF patients' course and treatment outcomesAlso, effective antiarrhythmic therapies to control AF may alleviate patients' depressive mood.

Future Perspectives to Improve CHA2DS2VASc Score: The Role of Left Atrium Remodelling, Inflammation and Genetics in Anticoagulation of Atrial Fibrillation

In 10% of ischemic strokes, non-valvular atrial fibrillation (NVAF) is detected retroactively. Milder, or even asymptomatic forms of NVAF have shown high mortality, thrombotic risk, and deterioration of cognitive function. The current guidelines for the diagnosis and treatment of AF contain "grey areas", such as the one related to anticoagulant treatment in men with CHA2DS2-VASc score 1 and women with score 2. Moreover, parameters such as renal function, patient weight or left atrium remodelling are missing from the recommended guidelines scores. Vulnerable categories of patients including the elderly population, high hemorrhagic risk patients or patients with newly diagnosed paroxysmal episodes of atrial high rate at device interrogation are at risk of underestimation of the thrombotic risk. This review presents a systematic exposure of the most important gaps in evaluation of thrombotic and hemorrhagic risk in patients with NVAF. The authors propose new algorithms and risk factors that should be taken into consideration for an accurate thrombotic and hemorrhagic risk estimation, especially in vulnerable categories of patients.

The bidirectional association between atrial fibrillation and myocardial infarction

Atrial fibrillation (AF) is associated with an increased risk of myocardial infarction (MI) and vice versa. This bidirectional association relies on shared risk factors as well as on several direct and indirect mechanisms, including inflammation, atrial ischaemia, left ventricular remodelling, myocardial oxygen supply-demand mismatch and coronary artery embolism, through which one condition can predispose to the other. Patients with both AF and MI are at greater risk of stroke, heart failure and death than patients with only one of the conditions. In this Review, we describe the bidirectional association between AF and MI. We discuss the pathogenic basis of this bidirectional relationship, describe the risk of adverse outcomes when the two conditions coexist, and review current data and guidelines on the prevention and management of both conditions. We also identify important gaps in the literature and propose directions for future research on the bidirectional association between AF and MI. The Review also features a summary of methodological approaches for the study of bidirectional associations in population-based studies.

Atrial epicardial adipose tissue abundantly secretes myeloperoxidase and activates atrial fibroblasts in patients with atrial fibrillation

BACKGROUND

Epicardial adipose tissue (EAT) secretome induces fibrosis. Fibrosis, primarily extracellular matrix (ECM) produced by fibroblasts, creates a substrate for atrial fibrillation (AF). Whether the EAT secretome from patients with AF activates human atrial fibroblasts and through which components, remains unexplored.

RESEARCH AIMS

(a) To investigate if the EAT secretome from patients with versus without AF increases ECM production in atrial fibroblasts. (b) To identify profibrotic proteins and processes in the EAT secretome and EAT from patients with, who will develop (future onset), and without AF.

METHODS

Atrial EAT was obtainded during thoracoscopic ablation (AF, n = 20), or open-heart surgery (future onset and non-AF, n = 35). ECM gene expression of human atrial fibroblasts exposed to the EAT secretome and the proteomes of EAT secretome and EAT were assessed in patients with and without AF. Myeloperoxidase and neutrophil extracellular traps (NETs) were assessed immunohistochemically in patients with paroxysmal, persistent, future onset, and those who remain free of AF (non-AF).

RESULTS

The expression of COL1A1 and FN1 in fibroblasts exposed to secretome from patients with AF was 3.7 and 4.7 times higher than in patients without AF (p < 0.05). Myeloperoxidase was the most increased protein in the EAT secretome and EAT from patients with versus without AF (FC 18.07 and 21.57, p < 0.005), as was the gene-set neutrophil degranulation. Immunohistochemically, myeloperoxidase was highest in persistent (FC 13.3, p < 0.0001) and increased in future onset AF (FC 2.4, p = 0.02) versus non-AF. Myeloperoxidase aggregated subepicardially and around fibrofatty infiltrates. NETs were increased in patients with persistent versus non-AF (p = 0.03).

CONCLUSION

In AF, the EAT secretome induces ECM gene expression in atrial fibroblasts and contains abundant myeloperoxidase. EAT myeloperoxidase was increased prior to AF onset, and both myeloperoxidase and NETs were highest in persistent AF, highlighting the role of EAT neutrophils in the pathophysiology of AF.

Myocarditis and Autoimmunity

INTRODUCTION

Autoimmune myocarditis may develop due to heterogeneous causes. Myocarditis is often caused by viral infections, but it can also be caused by systemic autoimmune diseases. Immune checkpoint inhibitors and virus vaccines induce immune activation, and they can cause the development of myocarditis, as well as several immune-related adverse events. The development of myocarditis is dependent on the genetic factors of the host, and the major histocompatibility complex (MHC) may be an important determinant of the type and severity of the disease. However, non-MHC immunoregulatory genes may also play a role in determining susceptibility.

AREA COVERED

This review summarizes the current knowledge of the etiology, pathogenesis, diagnosis and treatment of autoimmune myocarditis with a particular focus on viral infection and autoimmunity, and biomarkers of myocarditis.

EXPERT OPINION

An endomyocardial biopsy may not be the gold standard for the diagnosis of myocarditis. Cardiac magnetic resonance imaging is useful in diagnosing autoimmune myocarditis. Recently identified biomarkers of inflammation and myocyte injury are promising for the diagnosis of myocarditis when measured simultaneously. Future treatments should focus on the appropriate diagnosis of the etiologic agent, as well as on the specific stage of the evolution of immune and inflammatory processes.

Atrial fibrillation and coronary artery disease: An integrative review focusing on therapeutic implications of this relationship

The incidence of both atrial fibrillation (AF) and coronary artery disease (CAD) increases with advancing age. They share common risk factors and very often coexist. Evidence points to an intricate relationship between atrial tissue excitability and neuronal remodeling with ischemia at the microcirculatory level. In this review, we delineated this complex relationship, identified a common theme between the two, and discussed how the knowledge of this relationship translates into a positive and meaningful impact in patient management. Recent research indicates a high prevalence of CAD among AF patients undergoing coronary angiography. Further, the incidence of AF is much higher in those suffering from CAD compared to age-matched adults without CAD underlying this reciprocal relationship. CAD adversely affects AF by promoting progression via re-entry and increasing excitability of atrial tissue as a result of ischemia and electrical inhomogeneity. AF in turn accelerates atherosclerosis via endothelial dysfunctional and inflammation and together with enhanced thrombogenicity and hypercoagulability contribute to micro and macrothrombi throughout cardiovascular system. In a nutshell, the two form a vicious cycle wherein one disease promotes the other. Most AF recommendations focuses on rate/rhythm control and prevention of thromboembolism. Very few studies have discussed the importance of unmasking coexistent CAD and how the treatment of underlying ischemia will impact the burden of AF in these patients. Inflammation and endothelial dysfunction remain central to both disease processes and form a handsome therapeutic target in the management of the two diseases. The relationship between AF and CAD is complex and much more than mere coincidence. The two diseases share common risk factor and pathophysiology. Hence, it is impractical to treat them in isolation. Accordingly, we share the implications of managing underlying ischemia and inflammation to positively impact and improve quality of life among AF patients.

Inflammatory signalling in atrial cardiomyocytes: a novel unifying principle in atrial fibrillation pathophysiology

Inflammation has been implicated in atrial fibrillation (AF), a very common and clinically significant cardiac rhythm disturbance, but its precise role remains poorly understood. Work performed over the past 5 years suggests that atrial cardiomyocytes have inflammatory signalling machinery - in particular, components of the NLRP3 (NACHT-, LRR- and pyrin domain-containing 3) inflammasome - that is activated in animal models and patients with AF. Furthermore, work in animal models suggests that NLRP3 inflammasome activation in atrial cardiomyocytes might be a sufficient and necessary condition for AF occurrence. In this Review, we evaluate the evidence for the role and pathophysiological significance of cardiomyocyte NLRP3 signalling in AF. We first summarize the evidence for a role of inflammation in AF and review the biochemical properties of the NLRP3 inflammasome, as defined primarily in studies of classic inflammation. We then briefly consider the broader evidence for a role of inflammatory signalling in heart disease, particularly conditions that predispose individuals to develop AF. We provide a detailed discussion of the available information about atrial cardiomyocyte NLRP3 inflammasome signalling in AF and related conditions and evaluate the possibility that similar signalling might be important in non-myocyte cardiac cells. We then review the evidence on the role of active resolution of inflammation and its potential importance in suppressing AF-related inflammatory signalling. Finally, we consider the therapeutic potential and broader implications of this new knowledge and highlight crucial questions to be addressed in future research.

The Role of NLRP3 Inflammasome Signaling on Arrhythmias in Diabetes

Diabetes is a significant risk factor for arrhythmias. However, the pathophysiology of diabetes-related arrhythmias still needs to be elucidated, presumably associated with structural and electrical remodeling. There is growing evidence that inflammation and arrhythmias are intimately associated, which has spurred significant interest in exploring the regulatory links in diabetes. Recent research findings have revealed a vital role for the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome signaling, and facilitated the occurrence of arrhythmias in diabetes, including NLRP3 inflammasome activation by multiple stressors and its downstream cytokines, interleukin-1β (IL-1β) and interleukin-18 (IL-18). This narrative review aims to summarize the complex interaction between NLRP3 inflammasomes signaling and diabetes-related arrhythmias. Articles regarding the role of NLRP3 inflammasome in diabetes-related arrhythmias and relevant mechanisms were selected. Relevant articles were selected from PubMed. The search terms were "NLRP3 inflammasome" and "diabetes" and "arrhythmia". Important references from selected articles were also retrieved. The role of NLRP3 inflammasome signaling in diabetes-induced arrhythmias may provide a new option for the prevention and treatment diabetes-related arrhythmias.

Management of Atrial Fibrillation Using Immunoglobulin Free Light Chains, Novel Biomarkers of Inflammation

AF is the most common cardiac arrhythmia. There is growing evidence that inflammatory mechanisms play an important role in its pathogenesis; inflammasome activation contributes to the onset and progression of AF. An increase in NOD-like-receptor-pyrin domain-containing-3 (NLRP3) inflammasome activation releases proinflammatory cytokines that activate nuclear factor (NF)-κB, which regulates the production of immunoglobulin free light chains (FLCs). Serum FLC levels are increased in patients with AF, and FLCs are biomarkers of inflammation. Inflammasomes and NF-κB may be targets for anti-inflammatory strategies to prevent and treat AF when FLC levels are elevated. This review discusses the role of inflammation in the pathogenesis of AF, as well as FLCs as novel inflammatory biomarkers for the management of AF.

Mechanisms Underlying Antiarrhythmic Properties of Cardioprotective Agents Impacting Inflammation and Oxidative Stress

The prevention of cardiac life-threatening ventricular fibrillation and stroke-provoking atrial fibrillation remains a serious global clinical issue, with ongoing need for novel approaches. Numerous experimental and clinical studies suggest that oxidative stress and inflammation are deleterious to cardiovascular health, and can increase heart susceptibility to arrhythmias. It is quite interesting, however, that various cardio-protective compounds with antiarrhythmic properties are potent anti-oxidative and anti-inflammatory agents. These most likely target the pro-arrhythmia primary mechanisms. This review and literature-based analysis presents a realistic view of antiarrhythmic efficacy and the molecular mechanisms of current pharmaceuticals in clinical use. These include the sodium-glucose cotransporter-2 inhibitors used in diabetes treatment, statins in dyslipidemia and naturally protective omega-3 fatty acids. This approach supports the hypothesis that prevention or attenuation of oxidative and inflammatory stress can abolish pro-arrhythmic factors and the development of an arrhythmia substrate. This could prove a powerful tool of reducing cardiac arrhythmia burden.

Colchicine: protection of the brain beyond the heart?

Not applicable for an editorial.

Colchicine in Cardiovascular Disease: In-Depth Review

Inflammation plays a prominent role in the development of atherosclerosis and other cardiovascular diseases, and anti-inflammatory agents may improve cardiovascular outcomes. For years, colchicine has been used as a safe and well-tolerated agent in diseases such as gout and familial Mediterranean fever. The widely available therapeutic has several anti-inflammatory effects, however, that have proven effective in a broad spectrum of cardiovascular diseases as well. It is considered standard-of-care therapy for pericarditis, and several clinical trials have evaluated its role in postoperative and postablation atrial fibrillation, postpericardiotomy syndrome, coronary artery disease, percutaneous coronary interventions, and cerebrovascular disease. We aim to summarize colchicine's pharmacodynamics and the mechanism behind its anti-inflammatory effect, outline thus far accumulated evidence on treatment with colchicine in cardiovascular disease, and present ongoing randomized clinical trials. We also emphasize real-world clinical implications that should be considered on the basis of the merits and limitations of completed trials. Altogether, colchicine's simplicity, low cost, and effectiveness may provide an important addition to other standard cardiovascular therapies. Ongoing studies will address complementary questions pertaining to the use of low-dose colchicine for the treatment of cardiovascular disease.