Circulating biomarkers of fibrosis and cardioversion of atrial fibrillation: A prospective, controlled cohort study

Factors predicting the recurrence of atrial fibrillation after catheter ablation: A review

Atrial fibrillation (AF) is the most common and clinically significant type of cardiac arrhythmia. Although catheter ablation (CA) can restore sinus rhythm in patients with AF, some patients experience recurrence after the procedure. This requires us to find a simple and effective way to identify patients at a high risk of recurrence and to intervene early in the high-risk population to improve patient prognosis. The mechanism of AF recurrence is unclear, but it involves several aspects including patient history, inflammation, myocardial fibrosis, and genes. This article summarizes the current predictors of AF recurrence after CA, including myocardial fibrosis markers, inflammatory markers, MicroRNAs, Circular RNAs, AF recurrence scores, and imaging indicators. Each predictor has its own scope of application, and the predictive capacity and joint application of multiple predictors may improve the predictive power. In addition, we summarize the mechanisms involved in AF recurrence. We hope that this review will assist researchers understand the current predictors of AF recurrence and help them conduct further related studies.

The role of galectin-3 in atrial fibrillation

Numerous risk factors for atrial fibrillation (AF) progression have been identified. However, the biomarkers mentioned in the guidelines do not have any clinically relevant predictive value. Some research groups investigated the potential utility of galectin-3 (gal-3) as a diagnostic, prognostic, and predictive biomarker in AF. In this review, we have thoroughly summarized the current data on the role of gal-3 in AF based on the original research in this field. Patients suffering from AF present with increased levels of gal-3. The concentration of gal-3 differs between patients with AF depending on the type of AF - it is higher in patients with persistent AF than in patients with paroxysmal AF. Multiple studies investigating the reappearance of AF in patients who underwent ablation have shown that gal-3 is a promising biomarker to predict the outcome of this therapy. Patients with increased levels of gal-3 are at higher risk of AF recurrence. Although the research considered in this work addressed many aspects of the role of gal-3 in AF, most of it has been conducted on a small group of patients. Therefore, further research and extensive clinical trials confirming described findings are highly warranted.

Biomarkers of Atrial Fibrillation Recurrence in Patients with Paroxysmal or Persistent Atrial Fibrillation Following External Direct Current Electrical Cardioversion

Atrial fibrillation (AF) is associated with atrial remodeling, cardiac dysfunction, and poor clinical outcomes. External direct current electrical cardioversion is a well-developed urgent treatment strategy for patients presenting with recent-onset AF. However, there is a lack of accurate predictive serum biomarkers to identify the risks of AF relapse after electrical cardioversion. We reviewed the currently available data and interpreted the findings of several studies revealing biomarkers for crucial elements in the pathogenesis of AF and affecting cardiac remodeling, fibrosis, inflammation, endothelial dysfunction, oxidative stress, adipose tissue dysfunction, myopathy, and mitochondrial dysfunction. Although there is ample strong evidence that elevated levels of numerous biomarkers (such as natriuretic peptides, C-reactive protein, galectin-3, soluble suppressor tumorigenicity-2, fibroblast growth factor-23, turn-over collagen biomarkers, growth differential factor-15) are associated with AF occurrence, the data obtained in clinical studies seem to be controversial in terms of their predictive ability for post-cardioversion outcomes. Novel circulating biomarkers are needed to elucidate the modality of this approach compared with conventional predictive tools. Conclusions: Biomarker-based strategies for predicting events after AF treatment require extensive investigation in the future, especially in the presence of different gender and variable comorbidity profiles. Perhaps, a multiple biomarker approach exerts more utilization for patients with different forms of AF than single biomarker use.

Usefulness of systemic immune-inflammation index in predicting atrial fibrillation recurrence after direct current cardioversion

Background: We aimed to determine whether there is a relationship between the systemic immune-inflammation (SII) index and the recurrence of atrial fibrillation (AF) after successful direct current cardioversion (DCCV). Methods: The study included 99 patients with persistent AF who underwent successful cardioversion between 2015 and 2020. Results: In multiple regression analyses, the SII index was found to be a better independent predictor of AF recurrence after successful DCCV (p < 0.001). The cut-off value of SII (563) was associated with 96.9% sensitivity and 55.2% specificity to predict AF recurrence after DCCV. Conclusion: As a simple biomarker, SII index is an independent parameter for predicting AF recurrence after successful DCCV in patients with persistent AF. Also, SII levels can predict AF recurrence better than neutrophil-to-lymphocyte ratio.

Homocysteine and atrial fibrillation: novel evidences and insights

Atrial fibrillation (AF) is one of the most prevalent rhythm disorders worldwide, with around 37.574 million cases around the globe (0.51 % global population).  Different studies showed a high informative value of different biomarkers, including such related to the systemic inflammation, biomechanical stress and fibrosis. In this review article we aimed to study only the relation of homocysteine to the AF development. Homocysteine is a sulfur-containing amino acid, that is produced in the process of methionine metabolism. Which is a non-canonical amino acid, that is derived from the food proteins. From the scientific point of view there is a relation between hyperhomocysteinemia and myocardial fibrosis, but these mechanisms are complicated and not sufficiently studied. Homocysteine regulates activity of the ion channels through their redox state. Elevated homocysteine level can condition electrical remodeling of the cardiomyocytes through the increase of sodium current and change in the function of rapid sodium channels, increase of inwards potassium current and decrease in amount of rapid potassium channels. High homocysteine concentration also leads to the shortening of the action potential, loss of the rate adaptation of the action potential and persistent circulation of the re-entry waves. In a series of experimental studies on mice there was an association found between the homocysteine level and activity of vascular inflammation. Elevation of homocysteine level is an independent factor of the thromboembolic events and AF relapses. Population studies showed, that homocysteine is an independent risk factor for AF. So, homocysteine is an interesting target for up-stream therapy.

Analysis of the Correlation of Galectin-3 Concentration with the Measurements of Echocardiographic Parameters Assessing Left Atrial Remodeling and Function in Patients with Persistent Atrial Fibrillation

Galectin-3 (gal-3) is a fibrosis marker and may play a role in fibrosis of the left atrium (LA). Left atrial wall fibrosis may influence the transition from paroxysmal to non-paroxysmal atrial fibrillation (AF). In this study, we assessed the correlation of gal-3 concentration with the main echocardio-graphic parameters evaluating dimensions, volume, compliance, and left atrial contractility during AF and after successful electrical cardioversion (DCCV). The study included 63 patients with left atrial enlargement who qualified for DCCV due to persistent AF. The procedure recovered sinus rhythm in 43 (68.3%) patients. The concentration of gal-3 was negatively correlated with the echocardiographic parameters of LA including dimensions (LA length pre, rho = −0.38; p = 0.003), volume (LAV pre, rho = −0.39; p = 0.003), compliance (LASr mean post, rho = −0.33) and contractility (pLASRct mean post, rho = −0.33; p = 0.038). Negative correlations of gal-3 concentration were also observed in relation to the volume and contractility of the left ventricle. The concentration of gal-3 significantly negatively correlates with the size, systolic function, and compliance of the LA wall in patients with persistent AF. Determining gal-3 concentration in patients with persistent AF may help in the assessment of remodeling of the LA wall.

The prognostic value of soluble suppression of tumourigenicity 2 and galectin-3 for sinus rhythm maintenance after cardioversion due to persistent atrial fibrillation in patients with normal left ventricular systolic function

AIMS

Soluble suppression of tumourigenicity 2 (sST2) and galectin-3 are involved in cardiac fibrosis, inflammation, and remodelling. However, the place of sST2 and galectin-3 in predicting the outcomes of electrical cardioversion of atrial fibrillation (AF) is uncertain. We evaluated whether these biomarkers could predict sinus rhythm (SR) maintenance after cardioversion of persistent AF in patients with normal left ventricular systolic function.

METHODS AND RESULTS

The study included 80 patients with persistent AF, who underwent cardioversion from February 2016 to August 2018. The blood concentrations of sST-2 and galectin-3 were measured with ELISA and the ASPECT-PLUS assays. Clinical and electrocardiographic follow-up was performed at months 1, 6, and 12. Patients who maintained SR at 12 months had significantly lower concentrations of sST2, measured by ELISA and ASPECT-PLUS assays, than the remaining patients (16.9 ± 9.8 vs. 28 ± 22.9 ng/mL; P < 0.001; 28.7 ± 13.4 vs. 40 ± 25.1 ng/mL; P = 0.003); the concentration of galectin-3 did not differ between these patients. Multivariable logistic regression showed that log-transformed sST2 ELISA was a significant predictor of SR maintenance at 12 months [odds ratio 0.14; 95% confidence interval (CI) 0.03-0.58; P = 0.006]. On receiver-operating characteristic curve analysis, the areas under the curve for the concentration of sST2 was 0.752 (95% CI 0.634-0.870; P < 0.001). The concentrations of sST2 measured with the two assays were strongly correlated (rho = 0.8; CI 95% 0.7-0.87; P = 0.001).

CONCLUSION

Soluble suppression of tumourigenicity 2, but not galectin-3, can be used to predict SR maintenance after cardioversion of AF in patients with normal left ventricular systolic function. The measurements of sST2 concentrations with the rapid lateral flow and enzyme-linked immunoassays were consistent.

Biomarkers in Atrial Fibrillation: Pathogenesis and Clinical Implications

Biomarkers derived from the key components of the pathophysiology of atrial fibrillation (AF) and its complications have the potential to play an important role in earlier characterization of AF phenotype and in risk prediction of adverse clinical events, which may translate into improved management strategies. C-reactive protein, natriuretic peptides, cardiac troponins, growth differentiation factor-15, and fibroblast growth factor-23 have been shown to be the most promising biomarkers in AF. Some biomarkers have already been included in clinical risk scores to predict postoperative AF, thromboembolism, major bleeding, and death. Considerably more work is needed to bring these novel biomarkers into routine clinical management of patients with AF.

Atrial Cardiomyopathy: An Unexplored Limb of Virchow's Triad for AF Stroke Prophylaxis

The most dreaded complication of atrial fibrillation is stroke, and 70–80% of patients with AF-related stroke die or become disabled. The mechanisms of thromboembolism in AF are multifactorial, with evidence demonstrating that all three criteria of Virchow's triad are satisfied in AF: abnormal stasis of blood, endothelial damage, and hypercoagulability. Mechanistic insights into the latter two limbs have resulted in effective stroke prophylactic therapies (left atrial appendage occlusion and oral anticoagulants); however, despite these advances, there remains an excess of stroke in the AF population that may be due, in part, to a lack of mechanistic understanding of atrial hypocontractility resulting in abnormal stasis of blood within the atrium. These observations support the emerging concept of atrial cardiomyopathy as a cause of stroke. In this Review, we evaluate molecular, translational, and clinical evidence for atrial cardiomyopathy as a cause for stroke from AF, and present a rationale for further investigation of this largely unaddressed limb of Virchow's triad in AF.

Galectin-3 and risk of atrial fibrillation: A systematic review and meta-analysis

BACKGROUND

Galectin-3 is an inflammatory marker that is raised in myocardial fibrosis and inflammation. Recent studies have explored its role in predicting atrial fibrillation (AF) outcomes. The aim of this systematic review and meta-analysis is to examine the association between serum concentration of galectin-3 and AF.

METHODS

PubMed, EMBASE, and the Cochrane Database were searched. A total of 280 studies were identified, of which 28 studies involving 10 830 patients were included in our meta-analysis.

RESULTS

Galectin-3 is present at higher concentrations in patients with AF than those in sinus rhythm (mean difference [MD] = -0.68 ng/mL, 95% CI: -0.92, -0.44, Z = 5.61, P < .00001). Galectin-3 levels were significantly higher in the persistent AF than in the paroxysmal AF group (MD = -0.94 ng/mL, 95% CI: -1.85, -0.03, Z = 2.04, P = .04). Higher galectin-3 levels were associated with a 45% increase in the odds of developing AF (odds ratio [OR] = 1.45, 95% CI: 1.15, 1.83, Z = 3.11, P = .002) and risk of AF recurrence (hazard ratio [HR] =1.17, 95% CI: 1.06, 1.29, Z = 3.12, P = .002).

CONCLUSIONS

Our meta-analysis found that galectin-3 is significantly higher in patients with persistent AF than in those with paroxysmal AF, and can predict both AF development and recurrence after treatment.

Monocyte Chemoattractant Protein-1-Induced Protein in Age-Related Atrial Fibrillation and Its Association with Circulating Fibrosis Biomarkers

BACKGROUND

Atrial fibrillation (AF), for which age is an independent risk factor, is the most common persistent arrhythmia. Monocyte chemoattractant protein-1-induced protein (MCPIP), a transcription factor that induces a series of inflammation and cell death procedures, has been indicated to cause cardiomyocyte death in ischemic cardiomyopathy. The objective of this research was to investigate the relationship between age-related AF and MCPIP.

METHODS

A total of 1,084 participants were included in this study, including 542 AF patients and 542 non-AF controls. Their medical histories were collected and analyzed. Moreover, blood samples were collected, and ELISA tests for expression of the inflammatory factor MCPIP and the fibrosis biomarkers pro-collagen type III N-terminal peptide (PIIINP) and type I collagen C-terminal telopeptide (ICTP) were conducted. Finally, a correlation analysis of these inflammatory factors and biomarkers was performed based on the ELISA results.

RESULTS

We compared the echocardiography results of AF patients and found that the left ventricular ejection fraction and left atrial appendage velocity decreased with age (p < 0.05). Moreover, ELISA analysis of these samples showed that the expression of MCPIP was the highest in elderly patients with AF (p < 0.05), and there was no significant difference in expression between adult AF patients and elderly controls (p > 0.05). Finally, the correlation analysis demonstrated that the expressions of MCPIP, PIIINP, and ICTP were positively correlated in the elderly AF patient group, the adult AF group, and the elderly control group (p < 0.05).

CONCLUSION

MCPIP expression was higher in age-related AF than in the other patient groups and it was associated with AF-induced fibrosis.

Catheter ablation of atrial fibrillation with box isolation of fibrotic areas: Lessons on fibrosis distribution and extent, clinical characteristics, and their impact on long-term outcome

INTRODUCTION

The BIFA concept (box isolation of fibrotic areas) supplementing pulmonary vein isolation (PVI) was implemented in atrial fibrillation (AF) patients with fibrotic atrial cardiomyopathy (FACM) to improve catheter ablation outcomes.

METHODS AND RESULTS

Ninety-two patients with FACM underwent PVI + BIFA. We investigated patient characteristics (58 persistent/34 paroxysmal, 68 ± 8 years, LA 44 ± 7 mm, CHA₂ DS₂ -VASc 2.6 ± 1.3, FACM I: 15.2%, II: 53.3%, III: 26.1%, IV: 5.4%), periprocedural data concerning fibrosis extent/distribution, and their impact on outcome. Based on severe fibrosis areas (SFAs) of 13.5 ± 13.9 cm² detected by voltage mapping, 1.4 ± 0.5 boxes (n = 1-3, 2.2-35.3 cm² ) were applied in the left atrium. With higher grade FACM, SFAs increased and maximum voltage decreased (I/IV: 6.29/3.18 mV). Anterior (ant.) SFAs were found to be more common and larger than posterior (post.) SFAs (58.3% vs. 42.6%, ant. 8.0 ± 8.0 vs. post. 4.7 ± 6.8 cm² ). In 40 of 92 (43%) patients, both atrial walls were affected with rare cases of solely post. fibrosis (6 of 92, 6.6%). Women (39 of 92, 42%) showed FACM III+IV more often than men (P = 0.022) and can still present paroxysmal while persistent males are more likely to have FACM I-II. Single and multiple procedure (1.2/patient) success was 69% and 83% after 16 ± 8 months with an unfavorable impact of large SFA size, both-sided fibrosis and reduced maximum voltage, independently of patient characteristics and AF type.

CONCLUSION

FACM patients are a challenging AF subgroup for catheter ablation. Women seem to show FACM III+IV more often than men. The distribution of left atrial fibrosis is variable but more pronounced anteriorly. Atrial disease is characterized by SFA size but also maximum voltage reduction, both with implications on ablation outcome. Using BIFA, success rates of patients without fibrosis can be approached but are limited in FACM III+IV.

Novel bone metabolism-associated hormones: the importance of the pre-analytical phase for understanding their physiological roles

The endocrine function of bone is now a recognized feature of this tissue. Bone-derived hormones that modulate whole-body homeostasis, are being discovered as for the effects on bone of novel and classic hormones produced by other tissues become known. Often, however, the data regarding these last generation bone-derived or bone-targeting hormones do not give about a clear picture of their physiological roles or concentration ranges. A certain degree of uncertainty could stem from differences in the pre-analytical management of biological samples. The pre-analytical phase comprises a series of decisions and actions (i.e., choice of sample matrix, methods of collection, transportation, treatment and storage) preceding analysis. Errors arising in this phase will inevitably be carried over to the analytical phase where they can reduce the measurement accuracy, ultimately, leading discrepant results. While the pre-analytical phase is all important, in routine laboratory medicine, it is often not given due consideration in research and clinical trials. This is particularly true for novel molecules, such as the hormones regulating the endocrine function of bone. In this review we discuss the importance of the pre-analytical variables affecting the measurement of last generation bone-associated hormones and describe their, often debated and rarely clear physiological roles.