Influence of electrical cardioversion on inflammation and indexes of structural remodeling, in persistent atrial fibrillation

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.

Mechanism and prevention of atrial remodeling and their related genes in cardiovascular disorders

Atrial fibrillation (AF) is associated with profound structural and functional changes in the atrium. Inflammation mediated atrial fibrosis is one of the key mechanisms in the pathogenesis of AF. The collagen deposition in extracellular matrix (ECM) is mainly mediated by transforming growth factor β1 (TGF-β1) which promotes AF via controlling smads mediated-collagen gene transcription and regulating the balance of metalloproteinases (MMPs)/ tissue inhibitor of metalloproteinases (TIMPs). Although many processes can alter atrial properties and promote AF, animal models and clinical studies have provided insights into two major forms of atrial remodeling: Atrial tachycardia remodeling (ATR), which occurs with rapid atrial tachyarrhythmia's such as AF and atrial flutter, and atrial structural remodeling (ASR), which is associated with CHF and other fibrosis-promoting conditions. The mechanism of atrial remodeling such as atrial enlargement, ultra structural changes of atrial muscle tissue and myocardial interstitial fibrosis in AF is still unclear. At present, many studies focus on calcium overload, renin angiotensin aldosterone system and transforming growth factor β1, that effect on atrial structural remodeling. Recent experimental studies and clinical investigations have provided structural remodeling is important contributor to the AF. This paper reviews the current understanding of the progresses about mechanism of atrial structural remodeling, and highlights the potential therapeutic approaches aimed at attenuating structural remodeling to prevent AF. Now some recent advancements of this area are reviewed in this paper.

Atrial fibrillation and the prothrombotic state: revisiting Virchow’s triad in 2020

Atrial fibrillation (AF) is characterised by an increased risk of pathological thrombus formation due to a disruption of physiological haemostatic mechanisms that are better understood by reference to Virchow’s triad of ‘abnormal blood constituents’, ‘vessel wall abnormalities’ and ‘abnormal blood flow’. First, there is increased activation of the coagulation cascade, platelet reactivity and impaired fibrinolysis as a result of AF per se, and these processes are amplified with pre-existing comorbidities. Several prothrombotic biomarkers including platelet factor 4, von Willebrand factor, fibrinogen, β-thromboglobulin and D-dimer have been implicated in this process. Second, structural changes such as atrial fibrosis and endothelial dysfunction are linked to the development of AF which promote further atrial remodelling, thereby providing a suitable platform for clot formation and subsequent embolisation. Third, these factors are compounded by the presence of reduced blood flow secondary to dilatation of cardiac chambers and loss of atrial systole which have been confirmed using various imaging techniques. Overall, an improved understanding of the various factors involved in thrombus formation will allow better clinical risk stratification and targeted therapies in AF.

Association of MMPs and TIMPs With the Occurrence of Atrial Fibrillation: A Systematic Review and Meta-analysis

BACKGROUND

The roles of matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) in the occurrence of atrial fibrillation (AF) remain inconclusive.

METHODS

We conducted a systematic review and meta-analysis of observational studies to evaluate the associations of MMPs and TIMPs in blood and atrial tissues with AF risk. A subgroup analysis was performed to explore the potential sources of heterogeneity.

RESULTS

A total of 33 studies met our inclusion criteria. Patients with AF had significantly higher messenger RNA (mRNA) levels of MMP-1 in atrial tissue than did the controls, with a pooled standardized mean difference (SMD) of 0.54 (95% confidence interval [CI], 0.30-0.78; P < 0.001). The positive pooled estimates of studies of MMP-2 and MMP-9 in circulating proteins and atrial tissue mRNA and proteins were likely to be susceptible to the effects of significant publication bias. Decreased circulating TIMP-2 levels were significantly associated with increased risk of AF, with a pooled SMD of -0.49 (95% CI, -0.97 to -0.01; P = 0.04).

CONCLUSIONS

Increased MMP-1 in tissue mRNA and decreased circulating TIMP-2 levels are significantly associated with increased AF risk. The positive associations of MMP-2 and MMP-9 in blood and atrial tissue with AF risk have significant publication bias. Prospective registries of biomarker research and strict confirmation to reporting guidelines are needed in this field.

Psoriasis and risk of atrial fibrillation and ischaemic stroke: a Danish Nationwide Cohort Study

AIMS

Psoriasis is a chronic inflammatory disease and inflammation contributes to the pathogenesis of atrial fibrillation (AF) and ischaemic stroke. We therefore investigated the risk of these endpoints in patients with psoriasis.

METHODS AND RESULTS

Cohort study of the entire Danish population followed from 1997 to 2006 by individual-level-linkage of nationwide prospectively recorded registers. Multivariable Poisson's regression and sensitivity analyses were used to assess the psoriasis-related risk of AF and ischaemic stroke. A total of 36 765 patients with mild psoriasis and 2793 with severe psoriasis were compared with 4 478 926 individuals, i.e., the reference population. In patients with mild psoriasis, the adjusted rate ratios (RRs) for AF were 1.50 (1.21-1.86) and 1.16 (1.08-1.24) in patients aged <50 and ≥50 years, respectively. Patients with severe psoriasis had a higher risk of AF with RRs 2.98 (1.80-4.92) in patients aged <50 years and 1.29 (1.01-1.65) in patients aged ≥50 years. Patients with psoriasis also demonstrated a disease severity-dependent increased risk of ischaemic stroke, i.e. RRs 1.97 (1.66-2.34) and 2.80 (1.81-4.34) in patients aged <50 years with mild and severe psoriasis, and RRs 1.13 (1.04-1.21) and 1.34 (1.04-1.71) in patients aged ≥50 years with mild and severe psoriasis, respectively. A range of sensitivity analyses yielded comparable results.

CONCLUSION

Psoriasis is associated with increased risk of AF and ischaemic stroke. These novel results add to a growing body of evidence, suggesting that patients with psoriasis could be considered at increased cardiovascular risk.

Plasma YKL-40, a new biomarker for atrial fibrillation?

AIMS

The aim of this study was to determine changes in a new potential biomarker plasma YKL-40 in patients with atrial fibrillation (AF) before and after electrical cardioversion (CV).

METHODS AND RESULTS

Plasma concentrations of YKL-40 were measured in 56 patients (mean age 65 years, range 34-84) with persistent AF (lasting mean 128 days, range 14-960), in 19 age-matched patients with permanent AF, and in 19 healthy subjects. The patients with persistent AF underwent CV. Plasma YKL-40 was measured prior to CV, and at follow-up after 24 h, 30 and 180 days. Patients with persistent AF had lower plasma YKL-40 than patients with permanent AF [70 microg/L (42-105)] vs. [138 microg/L (48-225)] (P = 0.003), and higher levels than healthy subjects [41 microg/L (29-52)] (P = 0.001). Patients (n = 22) who were still in sinus rhythm (SR) at follow-up 30 days after CV had unchanged plasma YKL-40 compared with baseline levels. The baseline levels of YKL-40 were correlated to the levels of IL-6, but not to high sensitivity C-reactive protein.

CONCLUSION

Patients with AF have significantly elevated levels of YKL-40. YKL-40 was not a significant predictor of successful CV to SR. Plasma levels of YKL-40 did not fall after restoration of SR.