Variations in the human soluble epoxide hydrolase gene and recurrence of atrial fibrillation after catheter ablation

Genome-wide association studies reveal differences in genetic susceptibility between single events vs. recurrent events of atrial fibrillation and myocardial infarction: the HUNT study

Genetic research into atrial fibrillation (AF) and myocardial infarction (MI) has predominantly focused on comparing afflicted individuals with their healthy counterparts. However, this approach lacks granularity, thus overlooking subtleties within patient populations. In this study, we explore the distinction between AF and MI patients who experience only a single disease event and those experiencing recurrent events. Integrating hospital records, questionnaire data, clinical measurements, and genetic data from more than 500,000 HUNT and United Kingdom Biobank participants, we compare both clinical and genetic characteristics between the two groups using genome-wide association studies (GWAS) meta-analyses, phenome-wide association studies (PheWAS) analyses, and gene co-expression networks. We found that the two groups of patients differ in both clinical characteristics and genetic risks. More specifically, recurrent AF patients are significantly younger and have better baseline health, in terms of reduced cholesterol and blood pressure, than single AF patients. Also, the results of the GWAS meta-analysis indicate that recurrent AF patients seem to be at greater genetic risk for recurrent events. The PheWAS and gene co-expression network analyses highlight differences in the functions associated with the sets of single nucleotide polymorphisms (SNPs) and genes for the two groups. However, for MI patients, we found that those experiencing single events are significantly younger and have better baseline health than those with recurrent MI, yet they exhibit higher genetic risk. The GWAS meta-analysis mostly identifies genetic regions uniquely associated with single MI, and the PheWAS analysis and gene co-expression networks support the genetic differences between the single MI and recurrent MI groups. In conclusion, this work has identified novel genetic regions uniquely associated with single MI and related PheWAS analyses, as well as gene co-expression networks that support the genetic differences between the patient subgroups of single and recurrent occurrence for both MI and AF.

Untargeted metabolomics of saliva in pregnant women with and without gestational diabetes mellitus and healthy non-pregnant women

Objective

The aim of this study was to compare the differences in salivary metabolites between pregnant women with gestational diabetes mellitus (GDM), healthy pregnant women (HPW), and healthy non-pregnant women (HNPW), and analyze the possible associations between the identified metabolites and gingivitis.

Method

The study included women with GDM (n = 9, mean age 28.9 ± 3.6 years, mean gestational age 30.1 ± 3.2 weeks), HPW (n = 9, mean age 27.9 ± 3.0 years, mean gestational age 28.6 ± 4.7 weeks), and HNPW (n = 9, mean age 27.7 ± 2.1 years). Saliva samples were collected from all participants and were analyzed with LC-MS/MS-based untargeted metabolomic analysis. Metabolite extraction, qualitative and semi-quantitative analysis, and bioinformatics analysis were performed to identify the differential metabolites and metabolic pathways between groups. The identified differential metabolites were further analyzed in an attempt to explore their possible associations with periodontal health and provide evidence for the prevention and treatment of periodontal inflammation during pregnancy.

Results

In positive ion mode, a total of 2,529 molecular features were detected in all samples, 166 differential metabolites were identified between the GDM and HPW groups (89 upregulated and 77 downregulated), 823 differential metabolites were identified between the GDM and HNPW groups (402 upregulated and 421 downregulated), and 647 differential metabolites were identified between the HPW and HNPW groups (351 upregulated and 296 downregulated). In negative ion mode, 983 metabolites were detected in all samples, 49 differential metabolites were identified between the GDM and HPW groups (29 upregulated and 20 downregulated), 341 differential metabolites were identified between the GDM and HNPW groups (167 upregulated and 174 downregulated), and 245 differential metabolites were identified between the HPW and HNPW groups (112 upregulated and 133 downregulated). A total of nine differential metabolites with high confidence levels were identified in both the positive and negative ion modes, namely, L-isoleucine, D-glucose 6-phosphate, docosahexaenoic acid, arachidonic acid, adenosine, adenosine-monophosphate, adenosine 5'-monophosphate, xanthine, and hypoxanthine. Among all pathways enriched by the upregulated differential metabolites, the largest number of pathways were enriched by four differential metabolites, adenosine, adenosine 5'-monophosphate, D-glucose 6-phosphate, and adenosine-monophosphate, and among all pathways enriched by the downregulated differential metabolites, the largest number of pathways were enriched by three differential metabolites, L-isoleucine, xanthine, and arachidonic acid.

Conclusion

Untargeted metabolomic analysis of saliva samples from pregnant women with GDM, HPW, and HNPW identified nine differential metabolites with high confidence. The results are similar to findings from previous metabolomics studies of serum and urine samples, which offer the possibility of using saliva for regular noninvasive testing in the population of pregnant women with and without GDM. Meanwhile, the associations between these identified differential metabolites and gingivitis need to be further validated by subsequent studies.

Microprotein Dysregulation in the Serum of Patients with Atrial Fibrillation

The incidence rate of atrial fibrillation (AF) has stayed at a high level in recent years. Despite the intensive efforts to study the pathologic changes of AF, the molecular mechanism of disease development remains unclarified. Microproteins are ribosomally translated gene products from small open reading frames (sORFs) and are found to play crucial biological functions, while remain rare attention and indistinct in AF study. In this work, we recruited 65 AF patients and 65 healthy subjects for microproteomic profiling. By differential analysis and cross-validation between independent datasets, a total of 4 microproteins were identified as significantly different, including 3 annotated ones and 1 novel one. Additionally, we established a diagnostic model with either microproteins or global proteins by machine learning methods and found the model with microproteins achieved comparable and excellent performance as that with global proteins. Our results confirmed the abnormal expression of microproteins in AF and may provide new perspectives on the mechanism study of AF.

A hypothesis-driven study to comprehensively investigate the association between genetic polymorphisms in EPHX2 gene and cardiovascular diseases: Findings from the UK Biobank

BACKGROUND

Epoxyeicosatrienoic acids (EETs) are protective factors against cardiovascular diseases (CVDs) because of their vasodilatory, cholesterol-lowering, and anti-inflammatory effects. Soluble epoxide hydrolase (sEH), encoded by the EPHX2 gene, degrades EETs into less biologically active metabolites. EPHX2 is highly polymorphic, and genetic polymorphisms in EPHX2 have been linked to various types of CVDs, such as coronary heart disease, essential hypertension, and atrial fibrillation recurrence.

METHODS

Based on a priori hypothesis that EPHX2 genetic polymorphisms play an important role in the pathogenesis of CVDs, we comprehensively investigated the associations between 210 genetic polymorphisms in the EPHX2 gene and an array of 118 diseases in the circulatory system using a large sample from the UK Biobank (N = 307,516). The diseases in electronic health records were mapped to the phecode system, which was more representative of independent phenotypes. Survival analyses were employed to examine the effects of EPHX2 variants on CVD incidence, and a phenome-wide association study was conducted to study the impact of EPHX2 polymorphisms on 62 traits, including blood pressure, blood lipid levels, and inflammatory indicators.

RESULTS

A novel association between the intronic variant rs116932590 and the phenotype "aneurysm and dissection of heart" was identified. In addition, the rs149467044 and rs200286838 variants showed nominal evidence of association with arterial aneurysm and cerebrovascular disease, respectively. Furthermore, the variant rs751141, which was linked with a lower hydrolase activity of sEH, was significantly associated with metabolic traits, including blood levels of triglycerides, creatinine, and urate.

CONCLUSIONS

Multiple novel associations observed in the present study highlight the important role of EPHX2 genetic variation in the pathogenesis of CVDs.

Hemodialysis and Plasma Oxylipin Biotransformation in Peripheral Tissue

Factors causing the increased cardiovascular morbidity and mortality in hemodialysis (HD) patients are largely unknown. Oxylipins are a superclass of lipid mediators with potent bioactivities produced from oxygenation of polyunsaturated fatty acids. We previously assessed the impact of HD on oxylipins in arterial blood plasma and found that HD increases several oxylipins. To study the phenomenon further, we now evaluated the differences in arterial and venous blood oxylipins from patients undergoing HD. We collected arterial and venous blood samples in upper extremities from 12 end-stage renal disease (ESRD) patients before and after HD and measured oxylipins in plasma by LC-MS/MS tandem mass spectrometry. Comparison between cytochrome P450 (CYP), lipoxygenase (LOX), and LOX/CYP ω/(ω-1)-hydroxylase metabolites levels from arterial and venous blood showed no arteriovenous differences before HD but revealed arteriovenous differences in several CYP metabolites immediately after HD. These changes were explained by metabolites in the venous blood stream of the upper limb. Decreased soluble epoxide hydrolase (sEH) activity contributed to the release and accumulation of the CYP metabolites. However, HD did not affect arteriovenous differences of the majority of LOX and LOX/CYP ω/(ω-1)-hydroxylase metabolites. The HD treatment itself causes changes in CYP epoxy metabolites that could have deleterious effects in the circulation.

Genetics of atrial fibrillation-practical applications for clinical management: if not now, when and how?

The prevalence and economic burden of atrial fibrillation (AF) are predicted to more than double over the next few decades. In addition to anticoagulation and treatment of concomitant cardiovascular conditions, early and standardized rhythm control therapy reduces cardiovascular outcomes as compared with a rate control approach, favouring the restoration, and maintenance of sinus rhythm safely. Current therapies for rhythm control of AF include antiarrhythmic drugs (AADs) and catheter ablation (CA). However, response in an individual patient is highly variable with some remaining free of AF for long periods on antiarrhythmic therapy, while others require repeat AF ablation within weeks. The limited success of rhythm control therapy for AF is in part related to incomplete understanding of the pathophysiological mechanisms and our inability to predict responses in individual patients. Thus, a major knowledge gap is predicting which patients with AF are likely to respond to rhythm control approach. Over the last decade, tremendous progress has been made in defining the genetic architecture of AF with the identification of rare mutations in cardiac ion channels, signalling molecules, and myocardial structural proteins associated with familial (early-onset) AF. Conversely, genome-wide association studies have identified common variants at over 100 genetic loci and the development of polygenic risk scores has identified high-risk individuals. Although retrospective studies suggest that response to AADs and CA is modulated in part by common genetic variation, the development of a comprehensive clinical and genetic risk score may enable the translation of genetic data to the bedside care of AF patients. Given the economic impact of the AF epidemic, even small changes in therapeutic efficacy may lead to substantial improvements for patients and health care systems.

Maximal exercise and plasma cytochrome P450 and lipoxygenase mediators: a lipidomics study

Epoxides derived from arachidonic acid (AA) are released during exercise and may contribute to vasodilation. However, exercise may also affect circulating levels of other epoxides derived from cytochromes P450 (CYP) monooxygenase and lipoxygenase (LOX) pathways, many of whose exhibit cardiovascular activity in vitro. The effects of exercise on their levels have not been documented. We tested the hypothesis that acute, maximal exercise would influence the plasma concentrations of these vasoactive substances. We measured plasma CYP and LOX mediators derived from both the n − 3 and n − 6 fatty acid (FA) classes in healthy volunteers before, during and after short‐term exhaustive exercise. Lipid mediators were profiled by means of LC–MS/MS tandem mass spectrometry. A maximal Bruce treadmill test was performed to voluntary exhaustion. Exhaustive exercise increased the circulating levels of epoxyoctadecenoic (12,13‐EpOME), dihydroxyeicosatrienoic (5,6‐DHET), dihydroxyeicosatetraenoic acids (5,6‐DiHETE, 17,18‐DiHETE), but had no effect on the majority of CYP and LOX metabolites. Although our calculations of diol/epoxide ratios revealed preferred hydrolysis of epoxyeicosatrienoic acids (EEQs) into their diols (DiHETEs), this hydrolysis was resistant to maximal exercise. Our study is the first documentation that bioactive endogenous n − 3 and n − 6 CYP lipid mediators are released by short‐term exhaustive exercise in humans. In particular, the CYP epoxy‐metabolite status, 12,13‐EpOME/DiHOME, 5,6‐EET/DHET, 5,6‐EEQ/DiHETE and 17,18‐EEQ/DiHETE may contribute to the cardiovascular response during maximal exercise.

Effects of hemodialysis on plasma oxylipins

Chronic kidney disease (CKD) is an important risk factor for cardiovascular and all‐cause mortality. Survival rates among end‐stage renal disease (ESRD) hemodialysis patients are poor and most deaths are related to cardiovascular disease. Oxylipins constitute a family of oxygenated natural products, formed from fatty acid by pathways involving at least one step of dioxygen‐dependent oxidation. They are derived from polyunsaturated fatty acids (PUFAs) by cyclooxygenase (COX) enzymes, by lipoxygenases (LOX) enzymes, or by cytochrome P450 epoxygenase. Oxylipins have physiological significance and some could be of regulatory importance. The effects of decreased renal function and dialysis treatment on oxylipin metabolism are unknown. We studied 15 healthy persons and 15 CKD patients undergoing regular hemodialysis treatments and measured oxylipins (HPLC‐MS lipidomics) derived from cytochrome P450 (CYP) monooxygenase and lipoxygenase (LOX)/CYP ω/(ω‐1)‐hydroxylase pathways in circulating blood. We found that all four subclasses of CYP epoxy metabolites were increased after the dialysis treatment. Rather than resulting from altered soluble epoxide hydrolase (sEH) activity, the oxylipins were released and accumulated in the circulation. Furthermore, hemodialysis did not change the majority of LOX/CYP ω/(ω‐1)‐hydroxylase metabolites. Our data support the idea that oxylipin profiles discriminate ESRD patients from normal controls and are influenced by renal replacement therapies.

Inflammatory and Infectious Processes Serve as Links between Atrial Fibrillation and Alzheimer's Disease

Atrial fibrillation (AF) is one of the most prevalent forms of arrhythmia that carries an increased risk of stroke which, in turn, is strongly associated with cognitive decline. The majority of dementia cases are caused by Alzheimer's disease (AD) with obscure pathogenesis. While the exact mechanisms are unknown, the role of inflammatory processes and infectious agents have recently been implicated in both AD and AF, suggesting a common link between these maladies. Here, we present the main shared pathways underlying arrhythmia and memory loss. The overlapping predictive biomarkers and emerging joint pharmacological approaches are also discussed.

Genetic variants associated with atrial fibrillationand long-term recurrence after catheter ablation for atrialfibrillation in Turkish patients

OBJECTIVE

Genome-wide association studies have revealed that single nucleotide polymorphisms (SNPs) are associated with atrial fibrillation (AF) and can predict AF recurrence after catheter ablation in different populations. However, there exists no such data for the Turkish population. We aimed to investigate whether 11 SNPs in the PITX2, ZFHX3, EPHX2, CAV1, TBX5, TGF-1, and SCN10A were related to AF and whether these SNPs can predict long-term atrial tachyarrhythmia (ATa) recurrence after pulmonary vein isolation (PVI) for AF in Turkish patients.

METHODS

A total of 245 consecutive patients with non-valvular AF (44.9% men, mean age: 60.2±13.2 years, 65.3% paroxysmal AF) and 50 age- and sex-matched controls were included in this analysis. The clinical features and genetic variants were compared between the 2 groups. Of the 245 patients, 128 who underwent PVI with second-generation cryoballoon were further examined for long-term recurrence after the procedure.

RESULTS

Four SNPs in PITX2 were significantly associated with AF (rs10033464_T: OR 3.29, 95%CI: 1.38-7.82, p=0.007; rs6838973_T: OR 3.06, 95% CI 1.36-6.87, p=0.007; rs3853445_C: OR 2.84, 95%CI: 1.27-6.36, p=0.011; rs17570669_T: OR 4.03, 95% CI: 1.71-9.51, p=0.001). Among these patients who underwent PVI, one locus in CAV1 (rs3807989_G: OR 4.50, 95% CI 1.04-19.31, p=0.043) and early recurrence (OR: 8.06, 95% CI: 2.12-30.55, p=0.002) predicted long-term AF recurrence after catheter ablation.

CONCLUSION

Significant associations exists between 4 SNPs in PITX2 and AF (rs10033464, rs6838973, rs3853445, and rs17570669) in Turkish patients. In addition, 1 genetic variant in CAV1 (rs3807989) and early recurrence can predict long-term ATa recurrence after catheter ablation.

Maximal exercise and erythrocyte epoxy fatty acids: a lipidomics study

Fatty acid (FA)-derived lipid products generated by cytochrome P450 (CYP), lipoxygenase (LOX), and cyclo-oxygenase (COX) influence cardiovascular function. However, plasma measurements invariably ignore 40% of the blood specimen, namely the erythrocytes. These red blood cells (RBCs) represent a cell mass of about 3 kg. RBCs are a potential reservoir for epoxy fatty acids, which on release could regulate vascular capacity. We tested the hypothesis that maximal physical activity would influence the epoxy fatty acid status in RBCs. We used a standardized maximal treadmill exercise according to Bruce to ensure a robust hemodynamic and metabolic response. Central hemodynamic monitoring was performed using blood pressure and heart rate measurements and maximal workload was assessed in metabolic equivalents (METs). We used tandem mass spectrometry (LC-MS/MS) to measure epoxides derived from CYP monooxygenase, as well as metabolites derived from LOX, COX, and CYP hydroxylase pathways. Venous blood was obtained for RBC lipidomics. With the incremental exercise test, increases in the levels of various CYP epoxy-mediators in RBCs, including epoxyoctadecenoic acids (9,10-EpOME, 12,13-EpOME), epoxyeicosatrienoic acids (5,6-EET, 11,12-EET, 14,15-EET), and epoxydocosapentaenoic acids (16,17-EDP, 19,20-EDP) occurred, as heart rate, systolic blood pressure, and plasma lactate concentrations increased. Maximal (13.5 METs) exercise intensity had no effect on diols and various LOX, COX, and hydroxylase mediators. Our findings suggest that CYP epoxy-metabolites could contribute to the cardiovascular response to maximal exercise.

Association between the EPHX2 p.Lys55Arg polymorphism and prognosis following an acute coronary syndrome

Inhibition of soluble epoxide hydrolase (sEH, EPHX2) elicits potent cardiovascular protective effects in preclinical models of ischemic cardiovascular disease (CVD), and genetic polymorphisms in EPHX2 have been associated with developing ischemic CVD in humans. However, it remains unknown whether EPHX2 variants are associated with prognosis following an ischemic CVD event. We evaluated the association between EPHX2 p.Lys55Arg and p.Arg287Gln genotype with survival in 667 acute coronary syndrome (ACS) patients. No association with p.Arg287Gln genotype was observed (P = 0.598). Caucasian EPHX2 Arg55 carriers (Lys/Arg or Arg/Arg) had a significantly higher risk of 5-year mortality (adjusted hazard ratio [HR] 1.61, 95% confidence interval [CI] 1.01-2.55, P = 0.045). In an independent population of 2712 ACS patients, this association was not replicated (adjusted HR 0.92, 95% CI 0.70-1.21, P = 0.559). In a secondary analysis, Caucasian homozygous Arg55 allele carriers (Arg/Arg) appeared to exhibit a higher risk of cardiovascular mortality (adjusted HR 2.60, 95% CI 1.09-6.17). These results demonstrate that EPHX2 p.Lys55Arg and p.Arg287Gln polymorphisms do not significantly modify survival after an ACS event. Investigation of other sEH metabolism biomarkers in ischemic CVD appears warranted.

Rare variants in genes encoding the cardiac sodium channel and associated compounds and their impact on outcome of catheter ablation of atrial fibrillation

Aim

Rare variants of genes encoding the cardiac sodium channel and associated compounds have been linked with atrial fibrillation (AF). Nevertheless, current expert consensus does not support genetic testing in AF, which is in part based on the fact that “there is no therapeutic impact derived from AF genetic test results”. However, there are no studies available supporting this recommendation. Consequently, this study analyzed the impact of rare variants affecting the cardiac sodium channel on rhythm outcome of AF catheter ablation.

Methods and results

In 137 consecutive patients with lone AF enrolled in the Leipzig Heart Center AF ablation registry, screening for mutations in SCN5A, SCN1B – 4B, CAV3, GPD1L, SNTA1 and MOG1 was performed. We identified 3 rare non-synonymous variants in SCN5A, 5 in SCN1B, 1 in SCN4B, 1 in CAV3, 6 in GPD1L, 3 in SNTA1 and 3 in MOG1 (16%). Variant carriers were otherwise comparable with non-variant carriers. Analysis of AF recurrence rates after radiofrequency AF catheter ablation by serial 7-day Holter ECG monitoring between 3 and 12 months revealed no difference between groups, i.e. 45% in variant carriers vs. 49% in non-variant carriers.

Conclusions

Rare variants in genes encoding the cardiac sodium channel and associated compounds are frequently found in lone AF but were not found to impact the outcome of AF catheter ablation. This finding supports current recommendations not to screen for rare variants for the ablation outcome in AF. Nevertheless, it may at least be helpful for understanding AF mechanisms and larger studies are needed to further explore the possible association between genotype and response to AF therapies.

Association of SCN10A Polymorphisms with the Recurrence of Atrial Fibrillation after Catheter Ablation in a Chinese Han Population

The nonsynonymous SCN10A single nucleotide polymorphism (SNP) rs6795970 has been reported to associate with PR interval and atrial fibrillation (AF) and in strong linkage disequilibrium (LD) with the AF-associated SNP rs6800541. In this study, we investigated whether rs6795970 polymorphisms are associated with AF recurrence after catheter ablation. A total of 502 consecutive patients with AF who underwent catheter ablation were included. AF recurrence was defined as a documented episode of any atrial arrhythmias lasting ≥30 s after a blanking period of 3 months. AF recurrence was observed between 3 and 12 months after catheter ablation in 24.5% of the patients. There was a significant difference in the allele distribution (p = 7.86 × 10⁻⁵) and genotype distribution (p = 1.42 × 10⁻⁵) of rs6795970 between the AF recurrence and no recurrence groups. In a multivariate analysis, we identified the following independent predictors of AF recurrence: the rs6795970 genotypes in an additive model (OR 0.36, 95%CI 0.22~0.60, p = 7.04 × 10⁻⁵), a history of AF ≥36 months (OR 3.57, 95%CI 2.26~5.63, p = 4.33 × 10⁻⁸) and left atrial diameter (LAD) ≥40 mm (OR 1.85, 95%CI 1.08~3.19, p = 0.026). These data suggest that genetic variation in SCN10A may play an important role in predicting AF recurrence after catheter ablation in the Chinese Han population.

Dysregulation of soluble epoxide hydrolase and lipidomic profiles in anorexia nervosa

Individuals with anorexia nervosa (AN) restrict eating and become emaciated. They tend to have an aversion to foods rich in fat. Because epoxide hydrolase 2 (EPHX2) was identified as a novel AN susceptibility gene, and because its protein product, soluble epoxide hydrolase (sEH), converts bioactive epoxides of polyunsaturated fatty acid (PUFA) to the corresponding diols, lipidomic and metabolomic targets of EPHX2 were assessed to evaluate the biological functions of EPHX2 and their role in AN. Epoxide substrates of sEH and associated oxylipins were measured in ill AN, recovered AN and gender- and race-matched controls. PUFA and oxylipin markers were tested as potential biomarkers for AN. Oxylipin ratios were calculated as proxy markers of in vivo sEH activity. Several free- and total PUFAs were associated with AN diagnosis and with AN recovery. AN displayed elevated n-3 PUFAs and may differ from controls in PUFA elongation and desaturation processes. Cytochrome P450 pathway oxylipins from arachidonic acid, linoleic acid, alpha-linolenic acid and docosahexaenoic acid PUFAs are associated with AN diagnosis. The diol:epoxide ratios suggest the sEH activity is higher in AN compared with controls. Multivariate analysis illustrates normalization of lipidomic profiles in recovered ANs. EPHX2 influences AN risk through in vivo interaction with dietary PUFAs. PUFA composition and concentrations as well as sEH activity may contribute to the pathogenesis and prognosis of AN. Our data support the involvement of EPHX2-associated lipidomic and oxylipin dysregulations in AN, and reveal their potential as biomarkers to assess responsiveness to future intervention or treatment.

Rhythm outcomes after catheter ablation of atrial fibrillation. Clinical implication of biomarkers

Atrial fibrillation (AF) occurs as the result of numerous complex physiological processes in the atria leading to AF promotion and maintenance. Improved diagnostic techniques have identified various biomarkers which may play an important role in the prediction of AF related outcomes (cardio- and cerebrovascular events, as well as mortality and rhythm outcomes). Biomarkers refer to 'biological markers' and biomarkers in blood, urine as well as imaging marker (eg, dimensions (left atrial diameter and volume), anatomical features (left appendage and pulmonary vein anatomy), and physiological pattern (LAA flow velocity)) may play important role(s) as clinically important indices in relation to outcomes after different therapeutic strategies. However, the main domain in the biomarker field has focused on blood-based biomarkers, which are widely used to predict therapeutic success regarding underlying pathophysiological mechanism, such as inflammation, fibrosis, endothelial damage. This review provides an update of the role of clinically relevant biomarkers in AF, with particular focus on AF rhythm outcomes.