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ObjectiveCreeping fat, the wrapping of mesenteric fat around the bowel wall, is a typical feature of Crohn’s disease, and is associated with stricture formation and bowel obstruction. How creeping fat forms is unknown, and we interrogated potential mechanisms using novel intestinal tissue and cell interaction systems.DesignTissues from normal, UC, non-strictured and strictured Crohn’s disease intestinal specimens were obtained. The muscularis propria matrisome was determined via proteomics. Mesenteric fat explants, primary human preadipocytes and adipocytes were used in multiple ex vivo and in vitro cell migration systems on muscularis propria muscle cell derived or native extracellular matrix. Functional experiments included integrin characterisation via flow cytometry and their inhibition with specific blocking antibodies and chemicals.ResultsCrohn’s disease muscularis propria cells produced an extracellular matrix scaffold which is in direct spatial and functional contact with the immediately overlaid creeping fat. The scaffold contained multiple proteins, but only fibronectin production was singularly upregulated by transforming growth factor-β1. The muscle cell-derived matrix triggered migration of preadipocytes out of mesenteric fat, fibronectin being the dominant factor responsible for their migration. Blockade of α5β1 on the preadipocyte surface inhibited their migration out of mesenteric fat and on 3D decellularised intestinal tissue extracellular matrix.ConclusionCrohn’s disease creeping fat appears to result from the migration of preadipocytes out of mesenteric fat and differentiation into adipocytes in response to an increased production of fibronectin by activated muscularis propria cells. These new mechanistic insights may lead to novel approaches for prevention of creeping fat-associated stricture formation.

Background Patients undergoing surgery for thoracic aortic aneurysms receive statin therapy out of proportion to cardiovascular comorbidity. We sought to determine the prevalence of statin use among patients presenting for thoracic aortic aneurysm surgery and investigate its effect on outcomes. Methods From January 1, 2005 to January 1, 2011, 1,839 consecutive patients underwent aortic replacement for degenerative thoracic aortic aneurysm at Cleveland Clinic. Of these, 771 (42%) were on statins preoperatively. Statin users (vs. nonstatin users) were older (65 ± 11 vs. 56 ± 16 years) and had more hypertension (78 vs. 59%). Propensity matching based on 56 preoperative variables other than lipid levels was used to compare outcomes among 570 matched patient pairs (74% of possible pairs). Results Propensity-matched statin and nonstatin users were aged 64 ± 11 years, 394 (69%) versus 387 (68%) were male, and 437 (77%) versus 442 (78%) had ascending aortic aneurysms, respectively. Overall, 25% of patients were followed for more than 8.2 years and 10% for more than 10 years. Perioperative outcomes were similar, including hospital mortality (11 [1.9%] vs. 5 [0.88%]) and stroke (22 [3.9%] vs. 13 [2.3%]), but 16 statin users (2.8%) versus 5 nonstatin users (0.88%) required temporary dialysis after surgery (p = 0.02). At 6 years, 3.7% of statin users versus 5.1% of nonstatin users (p[log-rank] = 0.5) underwent further aortic surgery, and at 10 years, mortality was 25% in both groups (p > 0.5). Conclusion Patients presenting for thoracic aortic aneurysm surgery frequently receive unnecessary statins. Additionally, statin use was associated with more postoperative renal failure, but not less intermediate-term risk for aortic reintervention or all-cause mortality after surgery. Therefore, presence of a thoracic aortic aneurysm should not be considered an indication for statin therapy in the absence of well-established indications.

Atrial fibrillation (AF) is a significant cause of morbidity and mortality, and effective therapeutic interventions are lacking. Here, we harness an integrative, network medicine approach to repurpose FDA-approved drugs for AF. We hypothesize that the use of an unbiased method for prioritizing AF drugs using patient transcriptomics data can help to identify alternative therapeutic strategies and mechanism-of-action for these drugs. To achieve this, we first characterized the molecular networks specific to AF by incorporating transcriptomic data of left atrial tissue. We quantified the network proximity of genes differentially expressed in AF to drug targets to identify putative drugs for repurposing. We identified nine high-confidence drug candidates that were validated using enrichment analysis of drug-gene signatures in human cell lines. We identified metformin for the potential treatment of AF and validated its use in human inducible pluripotent stem cell-derived atrial-like cardiomyocytes. We identified AF-specific dysregulated networks enriched in cardiac metabolism, ion transport, and immune pathways that were improved following metformin treatment. In summary, this study utilized network-based approaches for rapid identification of drugs that may be repurposed for AF treatment and validated metformin as a candidate drug using a robust human atrial cell model.

There has been sustained focus on the secondary prevention of coronary heart disease and heart failure; yet, apart from stroke prevention, the evidence base for the secondary prevention of atrial fibrillation (AF) recurrence, AF progression, and AF‐related complications is modest. Although there are multiple observational studies, there are few large, robust, randomized trials providing definitive effective approaches for the secondary prevention of AF. Given the increasing incidence and prevalence of AF nationally and internationally, the AF field needs transformative research and a commitment to evidenced‐based secondary prevention strategies. We report on a National Heart, Lung, and Blood Institute virtual workshop directed at identifying knowledge gaps and research opportunities in the secondary prevention of AF. Once AF has been detected, lifestyle changes and novel models of care delivery may contribute to the prevention of AF recurrence, AF progression, and AF‐related complications. Although benefits seen in small subgroups, cohort studies, and selected randomized trials are impressive, the widespread effectiveness of AF secondary prevention strategies remains unknown, calling for development of scalable interventions suitable for diverse populations and for identification of subpopulations who may particularly benefit from intensive management. We identified critical research questions for 6 topics relevant to the secondary prevention of AF: (1) weight loss; (2) alcohol intake, smoking cessation, and diet; (3) cardiac rehabilitation; (4) approaches to sleep disorders; (5) integrated, team‐based care; and (6) nonanticoagulant pharmacotherapy. Our goal is to stimulate innovative research that will accelerate the generation of the evidence to effectively pursue the secondary prevention of AF.

The incidence of inflammatory bowel diseases (IBD) worldwide has resulted in a global public health challenge. Intestinal fibrosis leading to stricture formation and bowel obstruction is a frequent complication in Crohn's disease (CD), and the lack of anti-fibrotic therapies makes elucidation of fibrosis mechanisms a priority. Progress has shown that mesenchymal cells, cytokines, microbial products, and mesenteric adipocytes are jointly implicated in the pathogenesis of intestinal fibrosis. This recent information puts prevention or reversal of intestinal strictures within reach through innovative therapies validated by reliable clinical trial endpoints. Here, we review the role of immune and non-immune components of the pathogenesis of intestinal fibrosis, including new cell clusters, cytokine networks, host-microbiome interactions, creeping fat, and their translation for endpoint development in anti-fibrotic clinical trials.

Standard sleep apnea (SA) screening instruments perform suboptimally in the atrial fibrillation (AF) population. We evaluated and optimized common OSA screening tools in the AF population. Participants of the Sleep Apnea and Atrial Fibrillation Biomarkers and Electrophysiologic Atrial Triggers (SAFEBEAT, NCT02576587) age (±5 years)-, sex-, body mass index (BMI ± 5 kg/m2)-matched case control study (n = 150 each group) completed concurrent questionnaires and overnight polysomnography. Models based on STOP, STOP-BANG, Berlin, NoSAS and Epworth Sleepiness Scale and also models with STOP-BANG predictors with resting heart rate or left atrial volume were constructed. “Best subset” analysis was used to select a predictor subset for evaluation. We assessed test performance for two outcome thresholds: apnea-hypopnea index (AHI) ≥ 5 and AHI ≥ 15. Paroxysmal AF participants were: 61.3 ± 12.1 years, BMI = 31.2 ± 6.6 kg/m2 with median AHI = 11.8(IQR: 3.8, 24.5); 65 (43.3%) with AHI ≥ 15. Only STOP and STOP-BANG did not perform worse in AF relative to controls. For AHI ≥ 15, STOP-BANG (AUC 0.71, 95%CI:0.55–0.85) did not perform as well as NABS – a composite of neck circumference, age, and BMI as continuous variables and snoring (AUC 0.88, 95%CI:0.76–0.96). Optimal model for AHI ≥ 15 was NABS (sensitivity = 45%, specificity = 97%). For AHI ≥ 5, NABS was also the best performing (AUC 0.82, 95%CI:0.68–0.92, sensitivity = 78%, specificity = 67%). We identify a novel, short-item SA screening instrument for use in paroxysmal AF, i.e. NABS, with improved discriminative ability compared to commonly-used instruments. Further validation studies are needed to assess utility in other AF subtypes. Trial registration: clinicaltrials.gov NCT02576587.

Background: Elevated intracardiac pressure attributable to heart failure induces electrical and structural remodeling in the left atrium (LA) that begets atrial myopathy and arrhythmias. The underlying molecular pathways that drive atrial remodeling during cardiac pressure overload are poorly defined. The purpose of this study is to characterize the response of the ETV1 (ETS translocation variant 1) signaling axis in the LA during cardiac pressure overload in humans and mouse models and explore the role of ETV1 in atrial electrical and structural remodeling. Methods: We performed gene expression profiling in 265 left atrial samples from patients who underwent cardiac surgery. Comparative gene expression profiling was performed between 2 murine models of cardiac pressure overload, transverse aortic constriction banding and angiotensin II infusion, and a genetic model of Etv1 cardiomyocyte-selective knockout ( Etv1 f/f Mlc2a Cre /+ ). Results: Using the Cleveland Clinic biobank of human LA specimens, we found that ETV1 expression is decreased in patients with reduced ejection fraction. Consistent with its role as an important mediator of the NRG1 (Neuregulin 1) signaling pathway and activator of rapid conduction gene programming, we identified a direct correlation between ETV1 expression level and NRG1 , ERBB4 , SCN5A , and GJA5 levels in human LA samples. In a similar fashion to patients with heart failure, we showed that left atrial ETV1 expression is downregulated at the RNA and protein levels in murine pressure overload models. Comparative analysis of LA RNA sequencing datasets from transverse aortic constriction and angiotensin II–treated mice showed a high Pearson correlation, reflecting a highly ordered process by which the LA undergoes electrical and structural remodeling. Cardiac pressure overload produced a consistent downregulation of ErbB4 , Etv1 , Scn5a , and Gja5 and upregulation of profibrotic gene programming, which includes Tgfbr1/2, Igf1 , and numerous collagen genes. Etv1 f/f Mlc2a Cre /+ mice displayed atrial conduction disease and arrhythmias. Correspondingly, the LA from Etv1 f/f Mlc2a Cre /+ mice showed downregulation of rapid conduction genes and upregulation of profibrotic gene programming, whereas analysis of a gain-of-function ETV1 RNA sequencing dataset from neonatal rat ventricular myocytes transduced with Etv1 showed reciprocal changes. Conclusions: ETV1 is downregulated in the LA during cardiac pressure overload, contributing to both electrical and structural remodeling.

Introduction: SYNE2 encodes a nuclear membrane protein that connects the nucleus with the cytoskeleton. rs1152591 is a common SNP in the SYNE2 gene that is associated with atrial fibrillation (AF) and with reduced expression of SYNE2α1 , a short isoform, in human left atrial appendage tissue. We previously found that SYNE2α1 over expression (OE) acts as a dominant negative for the nuclear phenotype, similar to the SYNE2 knockdown (KD), leading to enlarged nuclear size and decreased nuclear stiffness. Objectives: To determine if GFP- SYNE2α1 (OE) and KD of all SYNE2 isoforms show similar effects on gene expression and cell physiology in human induced pluripotent stem cell-derived cardiomyocytes (iCMs). Methods and Results: RNAseq after SYNE2α1 OE or SYNE2 KD revealed both congruent changes in expression of specific genes, supporting the dominant negative role of SYNE2α1 , but also divergent changes in expression of some genes, showing specific effects of the SYNE2α1 short isoform. We identified both mitochondrial function and sarcoplasmic reticulum (SR) function as differentially expressed pathways comparing OE vs. KD iCMs. Fura-2 photometry was used to study Ca 2+ cycling in beating iCMs, and revealed delayed calcium reuptake in the SYNE2 KD cells (15.9% increase in reuptake time as % of each contraction, pSYNE2α1 OE cells (not significant). Flow cytometry showed significantly lower SERCA2 expression in the SYNE2 KD cells but not in the SYNE2α1 OE cells (12% decrease, p=0.029). Immunofluorescence microscopy revealed that GFP-SYNE2α1 not only localized to the nuclear membrane but also to the SR, stained with anti-SERCA2. Flow cytometry after MitoTracker Orange staining, to monitor the cellular volume of functional mitochondria, was significantly increased in both the SYNE2α1 OE and SYNE2 KD iCMs vs. their respective controls. Thus, despite differential expression of mitochondrial pathway genes, SYNE2α1 mimics the KD of all SYNE2 isoforms in regard to mitochondrial function. Conclusions: SYNE2α1 OE, unlike KD of all SYNE2 isoforms, preserves SR Ca 2+ reuptake activity, and this may contribute to the mechanism by which the AF risk allele in the SYNE2 gene, associated with decreased expression of SYNE2α1, predisposes carriers to AF.

Introduction: Over 135 genetic loci have been linked to atrial fibrillation (AF), yet the biological pathways of AF pathophysiology remain elusive. Weighted gene coexpression network analysis (WGCNA) constructs gene modules within a network based on correlations in gene expression, and identifies mechanisms related to AF risk. Objective: To identify biological pathways of candidate AF risk genes that will advance our understanding of AF mechanisms. Methods: RNA-sequencing was performed on left atrial appendage tissue from 265 patients. RNA-seq data were adjusted for differences in AF rhythm state and other known AF risk factors. Correlations from adjusted data were further adjusted for latent factors then spatial quantile normalized to correct for mean-variance bias. WGCNA was applied to the resulting adjusted and normalized gene-gene correlations to identify gene modules. Ingenuity Pathway Analysis and gene set over representation analysis (GSOR) were applied to each module. Results: WGCNA identified 63 modules from 17,434 genes; 47 of these contained at least one candidate AF risk gene. AF risk genes were overrepresented in 7 modules (Table 1). Notable top pathways of AF overrepresented modules include apelin signaling, heme metabolism, intracellular ion homeostasis, and the unfolded protein response. These are known to be involved in calcium signaling, iron homeostasis, glucose regulation, heat shock response, and protein ubiquitination during states of high energy demand and stress. These pathways coincide with larger cellular processes of myocyte remodeling, apoptosis, and cell survival, which were also prominent. Conclusions: Biological pathways identified through WGCNA and GSOR suggest that sustained increases in energy demand during AF promotes stress-induced cellular remodeling. Changes in calcium signaling, iron homeostasis, the unfolded protein response and glucose regulation are likely primary mechanisms of AF pathophysiology.

Atrial fibrillation (AF) is strongly associated with risk of stroke and heart failure. AF promotes atrial remodeling that increases risk of stroke due to left atrial thrombogenesis, and increases energy demand to support high rate electrical activity and muscle contraction. While many transcriptomic studies have assessed AF-related changes in mRNA abundance, fewer studies have assessed proteomic changes. We performed a proteomic analysis on left atrial appendage (LAA) tissues from 12 patients with a history of AF undergoing elective surgery; atrial rhythm was documented at time of surgery. Proteomic analysis was performed using liquid chromatography with mass spectrometry (LC/MS-MS). Data-dependent analysis identified 3090 unique proteins, with 408 differentially expressed between sinus rhythm and AF. Ingenuity Pathway Analysis of differentially expressed proteins identified mitochondrial dysfunction, oxidative phosphorylation, and sirtuin signaling among the most affected pathways. Increased abundance of electron transport chain (ETC) proteins in AF was accompanied by decreased expression of ETC complex assembly factors, tricarboxylic acid cycle proteins, and other key metabolic modulators. Discordant changes were also evident in the contractile unit with both up- and down-regulation of key components. Similar pathways were affected in a comparison of patients with a history of persistent vs. paroxysmal AF, presenting for surgery in sinus rhythm. Together, these data suggest that while the LAA attempts to meet the energetic demands of AF, an uncoordinated response may reduce ATP availability, contribute to tissue contractile and electrophysiologic heterogeneity, and promote a progression of AF from paroxysmal episodes to development of a substrate amenable to persistent arrhythmia.

Introduction: Atrial fibrillation after cardiac surgery (AFACS) impacts 10-65% of patients, depending on the complexity and trauma associated with the surgery. AFACS is associated with stroke and other systemic embolic manifestations. Methods: Patients at our hospital who underwent valve surgery procedures including aortic valve replacement (AVR), mitral valve replacement (MVR), AVR with coronary artery bypass grafting (CABG), MVR with CABG, or AVR and MVR with/without CABG were included in this study. Results: 346 patients were included in the current analysis, with a mean age of 51.6±16.1 years; 51% of patients were males. Univariate predictors of AF included age, gender, body mass index (BMI), operation type, ejection fraction (EF), left atrial (LA) diameter, previous history of AF, use of aldosterone antagonists > a month before surgery, use of loop diuretics > a month before surgery, length of ICU stay, total length of stay, cross clamp time > 90 minutes, pump time > 120 minutes, postoperative acute kidney injury, left ventricular systolic and diastolic end dimensions. By multivariate analysis, only age (P=0.028, AOR=10.6), male gender (P=0.021, AOR=3.398), type of surgery (P=0.034, AOR=7.12), history of AF (P=0.018, AOR=2.317), BMI (P

Background: Common genetic variants and inflammatory factors are associated with atrial fibrillation (AF) risk. Although the top AF risk locus is near PITX2 (associated with pulmonary vein (PV) development), regional differential expression (DE) of AF risk genes in the left atrium (LA) and PVs is not well studied. While LAA and PV gene expression have been compared, transcriptome mapping of the entire LA has not been done. We tested the hypothesis that there is significant regional DE in LA structures. Methods: RNAseq was performed in 25 regions within the PVs (n=12), LA body (LAB) (n=10), and LA appendage (LAA) (n=3) from a 75 year old male with hypertension and AF who died of a stroke. DE analysis of regional clusters (R 3.6 Limma package) and gene set enrichment analysis (GSEA) (Broad Institute) were performed. Results: In full transcriptome (n=20664) sequencing, 118 genes were significantly (q < 0.05) upregulated in the LAA, including FOSB (fold change [FC] 67.0), IL6 (FC 15.4), TNF (FC 2.4) and NLRP3 (FC 2.4), and 56 downregulated, including developmental genes such as SHOX2 (FC -12.9) and HOXA4 (FC -4.1). LAA GSEA showed enrichment (FDR < 0.05) of inflammatory response genes and TNF-α, IL-2, IL-6, and IgG signaling pathways. 2454 genes were significantly upregulated and 3737 downregulated in the PVs while 4021 genes were upregulated and 2998 were downregulated in the LAB. In an AF implicated gene set (n=190), 28 genes were upregulated in the PVs, including SIRT1 (FC 1.7), and 31 downregulated, including PMNT (FC -2.1) and CGA (FC -3.2). NEURL1 was significantly upregulated in the inferior PV (n=4) compared to the superior PV (n=8) (FC 3.6). In the LAB, 33 genes were upregulated, including MYH7 (FC 2.2) and PMNT (FC 2.1) , and 38 downregulated including SIRT1 (FC -1.9). PITX2 did not show any significant DE in any gene set. Conclusions: This data shows that genes involved in AF pathogenesis can have substantial regional expression difference, particularly when comparing the LA body, PVs, and LAA. Inflammatory activation in the LAA may contribute to increased stroke risk.

Background: Ablation is a widely used therapy for atrial fibrillation (AF); however, arrhythmia recurrence and repeat procedures are common. Studies examining surrogate markers of genetic susceptibility to AF, such as family history and individual AF susceptibility alleles, suggest these may be associated with recurrence outcomes. Accordingly, the aim of this study was to test the association between AF genetic susceptibility and recurrence after ablation using a comprehensive polygenic risk score for AF. Methods: Ten centers from the AF Genetics Consortium identified patients who had undergone de novo AF ablation. AF genetic susceptibility was measured using a previously described polygenic risk score (N=929 single-nucleotide polymorphisms) and tested for an association with clinical characteristics and time-to-recurrence with a 3 month blanking period. Recurrence was defined as >30 seconds of AF, atrial flutter, or atrial tachycardia. Multivariable analysis adjusted for age, sex, height, body mass index, persistent AF, hypertension, coronary disease, left atrial size, left ventricular ejection fraction, and year of ablation. Results: Four thousand two hundred seventy-six patients were eligible for analysis of baseline characteristics and 3259 for recurrence outcomes. The overall arrhythmia recurrence rate between 3 and 12 months was 44% (1443/3259). Patients with higher AF genetic susceptibility were younger ( P P =0.001). Persistent AF (hazard ratio [HR], 1.39 [95% CI, 1.22–1.58]; P P P =0.008) were associated with increased risk of recurrence. In univariate analysis, higher AF genetic susceptibility trended towards a higher risk of recurrence (HR, 1.08 [95% CI, 0.99–1.18]; P =0.07), which became less significant in multivariable analysis (HR, 1.06 [95% CI, 0.98–1.15]; P =0.13). Conclusions: Higher AF genetic susceptibility was associated with younger age and fewer clinical risk factors but not recurrence. Arrhythmia recurrence after AF ablation may represent a genetically different phenotype compared to AF susceptibility.

Atrial fibrillation (AF) is an age-related arrhythmia of enormous socioeconomic significance. In recent years, our understanding of the basic mechanisms that initiate and perpetuate AF has evolved rapidly, catheter ablation of AF has progressed from concept to reality, and recent studies suggest lifestyle modification may help prevent AF recurrence. Emerging developments in genetics, imaging, and informatics also present new opportunities for personalized care. However, considerable challenges remain. These include a paucity of studies examining AF prevention, modest efficacy of existing antiarrhythmic therapies, diverse ablation technologies and practice, and limited evidence to guide management of high-risk patients with multiple comorbidities. Studies examining the long-term effects of AF catheter ablation on morbidity and mortality outcomes are not yet completed. In many ways, further progress in the field is heavily contingent on the feasibility, capacity, and efficiency of clinical trials to incorporate the rapidly evolving knowledge base and to provide substantive evidence for novel AF therapeutic strategies. This review outlines the current state of AF prevention and treatment trials, including the foreseeable challenges, as discussed by a unique forum of clinical trialists, scientists, and regulatory representatives in a session endorsed by the Heart Rhythm Society at the 12th Global CardioVascular Clinical Trialists Forum in Washington, DC, December 3-5, 2015.

A surge of data has reproducibly identified strong associations of OSA with cardiac arrhythmias. As an extension of epidemiologic and clinic-based findings, experimental investigations have made strides in advancing our understanding of the putative OSA and cardiac arrhythmogenesis mechanistic underpinnings. Although most studies have focused on the links between OSA and atrial fibrillation (AF), relationships with ventricular arrhythmias have also been characterized. Key findings implicate OSA-related autonomic nervous system fluctuations typified by enhanced parasympathetic activation during respiratory events and sympathetic surges subsequent to respiratory events, which contribute to augmented arrhythmic propensity. Other more immediate pathophysiologic influences of OSA-enhancing arrhythmogenesis include intermittent hypoxia, intrathoracic pressure swings leading to atrial stretch, and hypercapnia. Intermediate pathways by which OSA may trigger arrhythmia include increased systemic inflammation, oxidative stress, enhanced prothrombotic state, and vascular dysfunction. Long-term OSA-associated sequelae such as hypertension, atrial enlargement and fibrosis, ventricular hypertrophy, and coronary artery disease also predispose to cardiac arrhythmia. These factors can lead to a reduction in atrial effective refractory period, triggered and abnormal automaticity, and promote slowed and heterogeneous conduction; all of these mechanisms increase the persistence of reentrant arrhythmias and prolong the QT interval. Cardiac electrical and structural remodeling observed in OSA animal models can progress the arrhythmogenic substrate to further enhance arrhythmia generation. Future investigations clarifying the contribution of specific OSA-related mechanistic pathways to arrhythmia generation may allow targeted preventative therapies to mitigate OSA-induced arrhythmogenicity. Furthermore, interventional studies are needed to clarify the impact of OSA pathophysiology reversal on cardiac arrhythmogenesis and related adverse outcomes.

Atrial fibrillation (AF) is an important cause of stroke and risk factor for heart failure and death. Current pharmacologic treatments for AF have limited efficacy, and treatments that more directly target the underlying causes of AF are needed. Oxidant stress and inflammatory activation are inter-related pathways that promote atrial electrical and structural remodeling, leading to atrial ectopy, interstitial fibrosis and increased stroke risk. This review evaluates the impact of common stressors on atrial oxidant stress and inflammatory activation, and the contribution of these pathways to atrial remodeling. Recent studies suggest that integrated efforts to target the underlying risk factors, rather than the AF per se, may have a greater impact on health and outcomes than isolated efforts focused on the electrical abnormalities.

BackgroundEndothelin-1 (ET-1) is a potent vasoconstrictor, mitogen and inflammatory factor that may contribute to development of atrial fibrillation (AF). Plasma ET-1 levels are increased in hyperthyroid patients, but studies evaluating its relation to AF development in hyperthyroid patients are lacking.ObjectiveThe present study seeks to evaluate the relation of plasma ET-1 to AF development as a function of thyroid status.MethodsBlood samples from euthyroid patients (n = 41), hypothyroid (n = 61), hyperthyroid (n = 41), AF with hyperthyroidism (n = 9), and euthyroid AF (n = 10) patients were collected. Plasma ET-1, CRP, and thyroid hormone levels were measured and compared between groups.ResultsPlasma ET-1 levels were higher in hyperthyroid and euthyroid AF patients> hyperthyroid-non-AF > hypo and euthyroid non-AF patients. Plasma ET-1 levels positively correlated with free T3 and T4 levels, and negatively with TSH levels. By multivariate analysis, plasma ET-1 was positively associated with AF, hyperthyroidism, and age. Plasma CRP did not vary by study group in either univariate or multivariate analyses.ConclusionPlasma ET-1 is associated with AF, elevated in hyperthyroid patients and positively correlated with thyroid hormone levels, suggesting that hyperthyroidism may increase ET-1 expression and release. This study may guide development of novel predictors of AF associated with hyperthyroidism, and may help to personalize therapy in hyperthyroid patients.

Publisher's version (útgefin grein). Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations., Electrocardiographic PR interval measures atrio-ventricular depolarization and conduction, and abnormal PR interval is a risk factor for atrial fibrillation and heart block. Our genome-wide association study of over 92,000 European-descent individuals identifies 44 PR interval loci (34 novel). Examination of these loci reveals known and previously not-yet-reported biological processes involved in cardiac atrial electrical activity. Genes in these loci are over-represented in cardiac disease processes including heart block and atrial fibrillation. Variants in over half of the 44 loci were associated with atrial or blood transcript expression levels, or were in high linkage disequilibrium with missense variants. Six additional loci were identified either by meta-analysis of ~105,000 African and European-descent individuals and/or by pleiotropic analyses combining PR interval with heart rate, QRS interval, and atrial fibrillation. These findings implicate developmental pathways, and identify transcription factors, ion-channel genes, and cell-junction/cell-signaling proteins in atrio-ventricular conduction, identifying potential targets for drug development., Acknowledgements per cohort are listed in Supplementary Note 2. We thank the following studies for sharing their summary level results: QRS voltage (van der Harst et al., 2016)[12], heart rate (den Hoed et al., 2013)[35], RR interval (Eijgelsheim et al., 2010)[11], atrial fibrillation (Christophersen et al., 2017[15]), and CARe-COGENT AA PR Consortium (Butler et al., 2012)[33]. We acknowledge Dr. Vinicius Tragante for his help generating the author list.

Electrocardiographic PR interval measures atrial and atrioventricular depolarization and conduction, and abnormal PR interval is a risk factor for atrial fibrillation and heart block. We performed a genome-wide association study in over 92,000 individuals of European descent and identified 44 loci associated with PR interval (34 novel). Examination of the 44 loci revealed known and novel biological processes involved in cardiac atrial electrical activity, and genes in these loci were highly over-represented in several cardiac disease processes. Nearly half of the 61 independent index variants in the 44 loci were associated with atrial or blood transcript expression levels, or were in high linkage disequilibrium with one or more missense variants. Cardiac regulatory regions of the genome as measured by cardiac DNA hypersensitivity sites were enriched for variants associated with PR interval, compared to non-cardiac regulatory regions. Joint analyses combining PR interval with heart rate, QRS interval, and atrial fibrillation identified additional new pleiotropic loci. The majority of associations discovered in European-descent populations were also present in African-American populations. Meta-analysis examining over 105,000 individuals of African and European descent identified additional novel PR loci. These additional analyses identified another 13 novel loci. Together, these findings underscore the power of GWAS to extend knowledge of the molecular underpinnings of clinical processes.

Atrial fibrillation (AF) is the most common clinically relevant arrhythmia, but the methods available for treating AF and its complications (of which the most important is thrombogenesis), as well as for assessing AF risk and underlying pathophysiology, are largely limited. Emerging evidence suggests a significant role of inflammation in the pathogenesis of AF. That evidence includes elevated serum levels of inflammatory biomarkers in AF subjects, the expression of inflammatory markers in cardiac tissues of AF patients and animal models of AF, and beneficial effects of anti-inflammatory drugs in experimental AF paradigms. Inflammation is suggested to be linked to various pathological processes, such as oxidative stress, apoptosis, and fibrosis, that promote AF substrate formation. Inflammation has also been associated with endothelial dysfunction, platelet activation, and coagulation cascade activation, leading to thrombogenesis. Thus, inflammation may contribute to both the occurrence/maintenance of AF and its thromboembolic complications. Here, we review the evidence for a role of inflammation and inflammatory biomarkers in the risk management and treatment of AF. We also summarize the current knowledge of inflammation-dependent cellular and molecular mechanisms in AF pathophysiology and their potential as therapeutic targets.

Coronary artery disease (CAD) is responsible for significant morbidity and mortality. Inflammatory, pro-thrombotic and structural factors contribute to the etiology of CAD. This study sought to determine the relationship of plasma endothelin-1 (pET-1), a potent vasoconstrictor, mitogen and modulator of cardiac inflammation, to clinical characteristics and outcomes of CAD patients.Blood samples were collected from 336 patients with underlying chest pain or recent myocardial infarction (MI), prior to coronary catheterization. pET-1 was correlated with clinical characteristics and outcomes following catheterization and at 30-day follow-up.pET-1 was higher in recent MI patients than in patients with CAD (coronary occlusion≥50%) or without CAD (50%) (Mean±sem (pg/ml): 2.12±0.13, 1.51±0.10, 1.21±0.06; 95% confidence interval (1.85-2.38, 1.31-1.72, 1.07-1.32; respectively, P.0001). Patients with ST elevation MI (STEMI) had higher pET-1 than non-STEMI (P=.008). pET-1 was associated with heart failure (HF) and low left ventricular ejection fraction (LVEF) and was highest in MI patients presented with acute HF. At 30-day follow up, pET-1 was not associated with the change in LVEF. In multivariate analysis, pET-1 was positively associated with age, smoking, HF, CAD status, and need for revascularization by coronary artery bypass surgery (CABG). pET-1 was negatively correlated with LVEF and preoperative statin use.pET-1 is associated with recent MI, HF, age, smoking, CABG, and low LVEF. Preoperative statin use was associated with lower pET-1. pET-1 may serve as a risk marker and a potential therapeutic target in CAD patients.

It is unclear whether genetic markers interact with risk factors to influence atrial fibrillation (AF) risk. We performed genome-wide interaction analyses between genetic variants and age, sex, hypertension, and body mass index in the AFGen Consortium. Study-specific results were combined using meta-analysis (88,383 individuals of European descent, including 7,292 with AF). Variants with nominal interaction associations in the discovery analysis were tested for association in four independent studies (131,441 individuals, including 5,722 with AF). In the discovery analysis, the AF risk associated with the minor rs6817105 allele (at the PITX2 locus) was greater among subjects ≤ 65 years of age than among those > 65 years (interaction p-value = 4.0 × 10−5). The interaction p-value exceeded genome-wide significance in combined discovery and replication analyses (interaction p-value = 1.7 × 10−8). We observed one genome-wide significant interaction with body mass index and several suggestive interactions with age, sex, and body mass index in the discovery analysis. However, none was replicated in the independent sample. Our findings suggest that the pathogenesis of AF may differ according to age in individuals of European descent, but we did not observe evidence of statistically significant genetic interactions with sex, body mass index, or hypertension on AF risk., This work is funded by the European Commision’s Horizon 2020 research and innovation programme (grant number 633196: CATCH ME to Dr. Sinner). AGES: The Age, Gene/Environment Susceptibility Reykjavik Study is funded by NIH contract N01-AG-12100. ARIC: The Atherosclerosis Risk in Communities Study is carried out as a collaborative study supported by National Heart, Lung, and Blood Institute contracts (HHSN268201100005C, HHSN268201100006C, HHSN268201100007C, HHSN268201100008C, HHSN268201100009C, HHSN268201100010C, HHSN268201100011C, and HHSN268201100012C), R01HL087641, R01HL59367 and R01HL086694; National Human Genome Research Institute contract U01HG004402; and National Institutes of Health contract HHSN268200625226C. The authors thank the staff and participants of the ARIC study for their important contributions. Infrastructure was partly supported by Grant Number UL1RR025005, a component of the National Institutes of Health and NIH Roadmap for Medical Research. This work was additionally supported by American Heart Association grant 16EIA26410001 (Alonso). BioVU: The dataset used in the analyses described were obtained from Vanderbilt University Medical Centers BioVU which is supported by institutional funding and by the Vanderbilt CTSA grant UL1 TR000445 from NCATS/NIH. Genome-wide genotyping was funded by NIH grants RC2GM092618 from NIGMS/OD and U01HG004603 from NHGRI/NIGMS. CCAF: R01 HL090620 and R01 HL111314 from the National Heart, Lung, and Blood Institute (Chung, Barnard, J. Smith, Van Wagoner); NIH/NCRR, CTSA 1UL-RR024989 (Chung, Van Wagoner); Heart and Vascular Institute, Department of Cardiovascular Medicine, Cleveland Clinic (Chung); Tomsich Atrial Fibrillation Research Fund (Chung); Leducq Foundation 07-CVD 03 (Van Wagoner, Chung); Atrial Fibrillation Innovation Center, State of Ohio (Van Wagoner, Chung). CHS: This Cardiovascular Health Study research was supported by NHLBI contracts HHSN268201200036C, HHSN268200800007C, N01HC55222, N01HC85079, N01HC85080, N01HC85081, N01HC85082, N01HC85083, N01HC85086; and NHLBI grants U01HL080295, R01HL087652, R01HL105756, R01HL103612, R01HL120393, and R01HL130114 with additional contribution from the National Institute of Neurological Disorders and Stroke (NINDS). Additional support was provided through R01AG023629 from the National Institute on Aging (NIA). A full list of principal CHS investigators and institutions can be found at CHS-NHLBI.org. The provision of genotyping data was supported in part by the National Center for Advancing Translational Sciences, CTSI grant UL1TR000124, and the National Institute of Diabetes and Digestive and Kidney Disease Diabetes Research Center (DRC) grant DK063491 to the Southern California Diabetes Endocrinology Research Center. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Dr. Psaty serves on the DSMB of a clinical trial funded by Zoll LifeCor and on the Steering Committee of the Yale Open Data Access Project funded by Johnson & Johnson. FINCAVAS: The Finnish Cardiovascular Study (FINCAVAS) has been financially supported by the Competitive Research Funding of the Tampere University Hospital (Grant 9M048 and 9N035), the Finnish Cultural Foundation, the Finnish Foundation for Cardiovascular Research, the Emil Aaltonen Foundation, Finland, and the Tampere Tuberculosis Foundation. FHS: Funding for SHARe Affymetrix genotyping was provided by NHLBI Contract N02-HL-64278. SHARe Illumina genotyping was provided under an agreement between Illumina and Boston University. Funding support for the FHS through 1R01HL128914; 2R01 HL092577; HHSN268201500001I; N01-HC 25195; and Framingham Atrial Fibrillation/Flutter reviewed through 2012 dataset was provided by NHLBI grants 1R01HL092577, 1R01HL102214, 1RC1HL101056 and NINDS grant 6R01-NS-17950. LURIC: The Ludwigshafen Risk and Cardiovascular Health study was supported by the seventh framework program of the European commission (RiskyCAD, grant agreement number 305739). Support for genotyping was provided by the seventh framework program of the European commission (AtheroRemo, grant agreement number 201668). MESA: The Multi-Ethnic Study of Atherosclerosis study was supported by NIH contracts HHSN2682015000031, N01-HC-95159, N01-HC-95160, N01-HC-95161, N01-HC-95162, N01-HC-95163, N01-HC-95164, N01-HC-95165, N01-HC-95166, N01-HC-95167, N01-HC-95168, N01-HC-95169 and by grants UL1-TR-000040, UL1-TR-001079, and UL1-RR-025005 from NCRR. Funding for MESA SHARe genotyping was provided by NHLBI Contract N02-HL-6-4278. The provision of genotyping data was supported in part by the National Center for Advancing Translational Sciences, CTSI grant UL1TR000124, and the National Institute of Diabetes and Digestive and Kidney Disease Diabetes Research Center (DRC) grant DK063491 to the Southern California Diabetes Endocrinology Research Center. PREVEND: The PREVEND study is supported by the Dutch Kidney Foundation (grant E0.13) and the Netherlands Heart Foundation (grant NHS2010B280). Dr. M. Rienstra is supported by grants from the Netherlands Organization for Scientific Research (Veni grant 016.136.055). PROSPER: The PROSPER study was supported by an investigator initiated grant obtained from Bristol-Myers Squibb. Prof. Dr. J. W. Jukema is an Established Clinical Investigator of the Netherlands Heart Foundation (grant 2001 D 032). Support for genotyping was provided by the seventh framework program of the European commission (grant 223004) and by the Netherlands Genomics Initiative (Netherlands Consortium for Healthy Aging grant 050-060-810). RS: The Rotterdam Study is supported by the Erasmus Medical Center and Erasmus University Rotterdam; the Netherlands Organization for Scientific Research; the Netherlands Organization for Health Research and Development (ZonMw); the Research Institute for Diseases in the Elderly; The Netherlands Heart Foundation; the Ministry of Education, Culture and Science; the Ministry of Health Welfare and Sports; the European Commission; and the Municipality of Rotterdam. Support for genotyping was provided by the Netherlands Organization for Scientific Research (NWO) (175.010.2005.011, 911.03.012) and Research Institute for Diseases in the Elderly (RIDE). Oscar H. Franco works in ErasmusAGE, a center for aging research across the life course funded by Nestlé Nutrition (Nestec Ltd.), Metagenics, Inc., and AXA. Nestlé Nutrition (Nestec Ltd.), Metagenics, Inc., and AXA had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript. SHIP: SHIP is part of the Community Medicine Research net of the University of Greifswald, Germany, which is funded by the Federal Ministry of Education and Research (grants no. 01ZZ9603, 01ZZ0103, and 01ZZ0403), the Ministry of Cultural Affairs as well as the Social Ministry of the Federal State of Mecklenburg-West Pomerania, and the network ‘Greifswald Approach to Individualized Medicine (GANI_MED)’ funded by the Federal Ministry of Education and Research (grant 03IS2061A). Genome-wide data have been supported by the Federal Ministry of Education and Research (grant no. 03ZIK012) and a joint grant from Siemens Healthcare, Erlangen, Germany and the Federal State of Mecklenburg- West Pomerania. The University of Greifswald is a member of the Caché Campus program of the InterSystems GmbH.

Reduced expression of genes regulated by the transcription factors CREB/CREM (cAMP response element-binding protein/modulator) is linked to atrial fibrillation (AF) susceptibility in patients. Cardiomyocyte-directed expression of the inhibitory CREM isoform CREM-IbΔC-X in transgenic mice (TG) leads to spontaneous-onset AF preceded by atrial dilatation and conduction abnormalities. Here, we characterized the altered gene program linked to atrial remodeling and development of AF in CREM-TG mice.Atria of young (TGy, before AF onset) and old (TGo, after AF onset) TG mice were investigated by mRNA microarray profiling in comparison with age-matched wild-type controls (WTy/WTo). Proteomic alterations were profiled in young mice (8 TGy versus 8 WTy). Annotation of differentially expressed genes revealed distinct differences in biological functions and pathways before and after onset of AF. Alterations in metabolic pathways, some linked to altered peroxisome proliferator-activated receptor signaling, muscle contraction, and ion transport were already present in TGy. Electron microscopy revealed significant loss of sarcomeres and mitochondria and increased collagen and glycogen deposition in TG mice. Alterations in electrophysiological pathways became prominent in TGo, concomitant with altered gene expression of KThe most prominent alterations of the gene program linked to CREM-induced atrial remodeling were identified in the expression of genes related to structure, metabolism, contractility, and electric activity regulation, suggesting that CREM transgenic mice are a valuable experimental model for human AF pathophysiology.

Atrial fibrillation affects more than 33 million people worldwide and increases the risk of stroke, heart failure, and death(1,2). Fourteen genetic loci have been associated with atrial fibrillation in European and Asian ancestry groups(3-7). To further define the genetic basis of atrial fibrillation, we performed large-scale, trans-ancestry meta-analyses of common and rare variant association studies. The genome-wide association studies (GWAS) included 17,931 individuals with atrial fibrillation and 115,142 referents; the exome-wide association studies (ExWAS) and rare variant association studies (RVAS) involved 22,346 cases and 132,086 referents. We identified 12 new genetic loci that exceeded genome-wide significance, implicating genes involved in cardiac electrical and structural remodeling. Our results nearly double the number of known genetic loci for atrial fibrillation, provide insights into the molecular basis of atrial fibrillation, and may facilitate the identification of new potential targets for drug discovery(8).

Atrial fibrillation (AF) is an important and highly prevalent arrhythmia, which is associated with significantly increased morbidity and mortality, including a four- to five-fold increased risk for stroke,1,2 a two-fold increased risk for dementia,3,4 a three-fold risk for heart failure,2 a two-fold increased risk for myocardial infarction,5,6 and a 40–90% increased risk for overall mortality.2,7 The constantly increasing number of AF patients and recognition of increased morbidity, mortality, impaired quality of life, safety issues, and side effects of rhythm control strategies with antiarrhythmic drugs, and high healthcare costs associated with AF have spurred numerous investigations to develop more effective treatments for AF and its complications.8 Although AF treatment has been studied extensively, AF prevention has received relatively little attention, while it has paramount importance in the prevention of morbidity and mortality, and complications associated with arrhythmia and its treatment. Current evidence shows a clear association between the presence of modifiable risk factors and the risk of developing AF. By implementing AF risk reduction strategies aiming at risk factors such as obesity, hypertension, diabetes, and obstructive sleep ap-noea (OSA), which are interrelated, we impact upon the escalating incidence of AF in the population and ultimately decrease the healthcare burden of associated co-morbidities of AF. To address this issue, a Task Force was convened by the European Heart Rhythm Association and the European Association of Cardiovascular Prevention and Rehabilitation, endorsed by the Heart Rhythm Society and Asia-Pacific Heart Rhythm Society, with the remit to comprehensively review the published evidence available, to publish a joint consensus document on the prevention of AF, and to provide up-to-date consensus recommendations for use in clinical practice. In this document, our aim is to summarize the current evidence on the association of each modifiable risk factor with AF and the available data on the impact of possible interventions directed at these factors in preventing or reducing the burden of AF. While the evidence on AF prevention is still emerging, the topic is not fully covered in current guidelines and some aspects are still controversial. Therefore, there is a need to provide expert recommendations for professionals participating in the care of at-risk patients and populations, with respect to addressing risk factors and lifestyle modifications. Health economic considerations Atrial fibrillation is a costly disease, both in terms of direct, and indirect costs, the former being reported by cost of illness studies as per-patient annual costs in the range of US $2000–14200 in North America and of €450–3000 in Europe.9 In individuals with AF or at risk of developing AF, any effective preventive measure, intervention on modifiable risk factors or comorbidities, as well as any effective pharmacological or non-pharmacological treatment has the aim to reduce AF occurrence, thromboembolic events and stroke, morbidity and, possibly, mortality related to this arrhythmia. Apart from the clinical endpoints, achievement of these goals has economic significance, in terms of positive impact on direct and indirect costs and favourable cost–effectiveness at mid- or long-term, in the perspective of healthcare systems.10–12 In view of the epidemiological profile of AF and progressive aging of the population,13 an impressive increase of patients at risk of AF or affected by AF,14 also in an asymptomatic stage, is expected in the next decades, inducing a growing financial burden on healthcare systems, not only in Europe and North America, but also worldwide.15,16 In consideration of this emerging epidemiological threat due to AF, it is worth considering a paradigm shift, going beyond the conventional approach of primary prevention based on treatment of AF risk factors, but, instead, considering the potential for ‘primordial’ prevention, defined as prevention of the development of risk factors predisposing to AF in the first place.17 This approach, aimed at avoiding the emergence and penetration of risk factors into the population, has been proposed in general terms for the prevention of cardiovascular diseases17 and should imply combined efforts of policymakers, regulatory and social service agencies, providers, physicians, community leaders, and consumers, in an attempt to improve social and environmental conditions, as well as individual behaviours, in the pursuit of adopting healthy lifestyle choices.16 Since a substantial proportion of incident AF events can be attributable to elevated or borderline levels of risk factors for AF,18 this approach could be an effective way to reduce the financial burden linked to AF epidemiology. In terms of individual behaviour and adoption of a ‘healthy lifestyle’, it is worth considering that availability of full healthcare coverage (through health insurance or the healthcare system) may in some cases facilitate the unwanted risk of reducing, at an individual level, the motivation to adopt all the preventive measures that are advisable, in line with the complex concept of ‘moral hazard effect’.19 Patient education and patient empowerment are the correct strategies for avoiding this undesirable effect.

Background— The P wave on an ECG is a measure of atrial electric function, and its characteristics may serve as predictors for atrial arrhythmias. Increased mean P-wave duration and P-wave terminal force traditionally have been used as markers for left atrial enlargement, and both have been associated with increased risk of atrial fibrillation. Here, we explore the genetic basis of P-wave morphology through meta-analysis of genome-wide association study results for P-wave duration and P-wave terminal force from 12 cohort studies. Methods and Results— We included 44 456 individuals, of which 6778 (16%) were of African ancestry. Genotyping, imputation, and genome-wide association study were performed at each study site. Summary-level results were meta-analyzed centrally using inverse-variance weighting. In meta-analyses of P-wave duration, we identified 6 significant ( P − 8 ) novel loci and replicated a prior association with S CN10A. We identified 3 loci at SCN5A , TBX5 , and CAV1/CAV2 that were jointly associated with the PR interval, PR segment, and P-wave duration. We identified 6 novel loci in meta-analysis of P-wave terminal force. Four of the identified genetic loci were significantly associated with gene expression in 329 left atrial samples. Finally, we observed that some of the loci associated with the P wave were linked to overall atrial conduction, whereas others identified distinct phases of atrial conduction. Conclusions— We have identified 6 novel genetic loci associated with P-wave duration and 6 novel loci associated with P-wave terminal force. Future studies of these loci may aid in identifying new targets for drugs that may modify atrial conduction or treat atrial arrhythmias.

The American Psychiatric Association estimates that 3 to 7 per cent of all school aged children are diagnosed with attention deficit hyperactivity disorder (ADHD). Even after correcting for general cognitive ability, numerous studies report a negative association between ADHD and educational achievement. With polygenic scores we examined whether genetic variants that have a positive influence on educational attainment have a protective effect against ADHD. The effect sizes from a large GWA meta-analysis of educational attainment in adults were used to calculate polygenic scores in an independent sample of 12-year-old children from the Netherlands Twin Register. Linear mixed models showed that the polygenic scores significantly predicted educational achievement, school performance, ADHD symptoms and attention problems in children. These results confirm the genetic overlap between ADHD and educational achievement, indicating that one way to gain insight into genetic variants responsible for variation in ADHD is to include data on educational achievement, which are available at a larger scale. (C) 2014 Wiley Periodicals, Inc.

Background— Cervical vagal nerve stimulation (VNS) can improve left ventricular dysfunction in the setting of heart failure (HF). However, little is known about the impact of VNS on left atrial (LA) function. The aim of this study was to compare LA mechanics and histology between control and VNS-treated animals during HF development. Methods and Results— Fifteen mongrel dogs were randomized into control (n=7) and VNS (n=8) groups. All dogs underwent 8 weeks of high-rate ventricular pacing (at 220 beats per minute for the first 4 weeks to develop HF and another 4 weeks at 180 beats per minute to maintain HF). LA contractile function (LA negative peak strain), conduit function (LA positive peak strain), and reservoir function (LA total strain) were measured from speckle tracking in 2 groups. At the end of the terminal study, the LA appendage was obtained. Baseline LA strains were comparable in the control and VNS-treated dogs. At 4 and 8 weeks of ventricular pacing, all LA strains were decreased and LA volumes were increased in the control group compared with the VNS group ( P P P Conclusions— VNS improved LA function and volumes and suppressed LA fibrosis in the canine high-rate ventricular pacing model. VNS is a novel and potentially useful therapy for improving LA function during HF.

Importance Atrial fibrillation (AF) is the most common arrhythmia affecting 1% of the population. Young individuals with AF have a strong genetic association with the disease, but the mechanisms remain incompletely understood. Objective To perform large-scale whole-genome sequencing to identify genetic variants related to AF. Design, setting, and participants The National Heart, Lung, and Blood Institute's Trans-Omics for Precision Medicine Program includes longitudinal and cohort studies that underwent high-depth whole-genome sequencing between 2014 and 2017 in 18 526 individuals from the United States, Mexico, Puerto Rico, Costa Rica, Barbados, and Samoa. This case-control study included 2781 patients with early-onset AF from 9 studies and identified 4959 controls of European ancestry from the remaining participants. Results were replicated in the UK Biobank (346 546 participants) and the MyCode Study (42 782 participants). Exposures Loss-of-function (LOF) variants in genes at AF loci and common genetic variation across the whole genome. Main outcomes and measures Early-onset AF (defined as AF onset in persons Results Among 2781 participants with early-onset AF (the case group), 72.1% were men, and the mean (SD) age of AF onset was 48.7 (10.2) years. Participants underwent whole-genome sequencing at a mean depth of 37.8 fold and mean genome coverage of 99.1%. At least 1 LOF variant in TTN, the gene encoding the sarcomeric protein titin, was present in 2.1% of case participants compared with 1.1% in control participants (odds ratio [OR], 1.76 [95% CI, 1.04-2.97]). The proportion of individuals with early-onset AF who carried a LOF variant in TTN increased with an earlier age of AF onset (P value for trend, 4.92 × 10-4), and 6.5% of individuals with AF onset prior to age 30 carried a TTN LOF variant (OR, 5.94 [95% CI, 2.64-13.35]; P = 1.65 × 10-5). The association between TTN LOF variants and AF was replicated in an independent study of 1582 patients with early-onset AF (cases) and 41 200 control participants (OR, 2.16 [95% CI, 1.19-3.92]; P = .01). Conclusions and relevance In a case-control study, there was a statistically significant association between an LOF variant in the TTN gene and early-onset AF, with the variant present in a small percentage of participants with early-onset AF (the case group). Further research is necessary to understand whether this is a causal relationship.

Under ischemic conditions, adenosine triphosphate (ATP) production is compromised and cell viability is challenged. A homeostatic pathway present to reduce ATP utilization is the reduction of calcium influx and excitability triggered by opening of ATP-sensitive potassium (KATP) channels in the

Atrial fibrillation (AF), the most common cardiac arrhythmia, is an electrocardiographic description of a condition with multiple and complex underlying mechanisms. Oxidative stress is an important driver of structural remodeling that creates a substrate for AF. Oxidant radicals may promote increase of atrial oxidative damage, electrical and structural remodeling, and atrial inflammation. AF and other cardiovascular morbidities activate angiotensin (Ang-II)-dependent and independent cascades. A key component of the renin–angiotensin-aldosterone system (RAAS) is the mineralocorticoid aldosterone. Recent studies provide evidence of myocardial aldosterone synthesis. Aldosterone promotes cardiac oxidative stress, inflammation and structural/electrical remodeling via multiple mechanisms. In HF patients, aldosterone production is enhanced. In patients and in experimental HF and AF models, aldosterone receptor antagonists have favorable influences on cardiac remodeling and oxidative stress. Therapeutic approaches that seek to reduce AF burden by modulating the aldosterone system are likely beneficial but underutilized.

Background— Genetic mechanisms of atrial fibrillation (AF) remain incompletely understood. Previous differential expression studies in AF were limited by small sample size and provided limited understanding of global gene networks, prompting the need for larger-scale, network-based analyses. Methods and Results— Left atrial tissues from Cleveland Clinic patients who underwent cardiac surgery were assayed using Illumina Human HT-12 mRNA microarrays. The data set included 3 groups based on cardiovascular comorbidities: mitral valve (MV) disease without coronary artery disease (n=64), coronary artery disease without MV disease (n=57), and lone AF (n=35). Weighted gene coexpression network analysis was performed in the MV group to detect modules of correlated genes. Module preservation was assessed in the other 2 groups. Module eigengenes were regressed on AF severity or atrial rhythm at surgery. Modules whose eigengenes correlated with either AF phenotype were analyzed for gene content. A total of 14 modules were detected in the MV group; all were preserved in the other 2 groups. One module (124 genes) was associated with AF severity and atrial rhythm across all groups. Its top hub gene, RCAN1 , is implicated in calcineurin-dependent signaling and cardiac hypertrophy. Another module (679 genes) was associated with atrial rhythm in the MV and coronary artery disease groups. It was enriched with cell signaling genes and contained cardiovascular developmental genes including TBX5 . Conclusions— Our network-based approach found 2 modules strongly associated with AF. Further analysis of these modules may yield insight into AF pathogenesis by providing novel targets for functional studies.

Background Postoperative atrial fibrillation (POAF) is common and associated with poor outcomes. Perioperative ischemia can alter arrhythmic substrate. Objective To demonstrate an association between perioperative measurements of heart-type fatty acid binding protein (HT-FABP), a sensitive marker of ischemic myocardial injury. Methods Blood samples from 63 inpatients undergoing coronary artery bypass surgery, valve surgery, or both were obtained before and up to 4 days after surgery. Continuous telemetry monitoring was used to detect POAF. Fifty-nine patients had at least 3 HT-FABP measurements. The relationship of enzyme-linked immunosorbent assay-measured HT-FABP with POAF was assessed by using joint logistic regression adjusted for age and surgery type. Results Thirty-five patients (55%) developed POAF; these were, on average, older (69.3±10 years vs 60±11 years; P = .0019), with a higher prevalence of heart failure (43% vs 17%; P = .034), chronic obstructive lung disease (26% vs 4%; P = .017), preoperative calcium channel blocker use (29% vs 7%; P = .031), and more likely to undergo combined surgery (21% vs 11%, P = .049). The joint age- and coronary artery bypass surgery-adjusted model revealed that postoperative but not preoperative HT-FABP levels predicted POAF (coefficient 1.9±0.87; P = .03). Longer bypass time, prior infarction, and worse renal function were all associated with higher postoperative HT-FABP . Conclusions A greater rise of HT-FABP is associated with atrial fibrillation after cardiac surgery, suggesting that ischemic myocardial damage is a contributing underlying mechanism. Interventions that decrease perioperative ischemic injury may also decrease the occurrence of POAF.

Objective: Bicuspid aortic valve (BAV), the most common congenital heart condition, is frequently associated with thoracic aortic aneurysm (TAA). Aortic mRNA expression patterns in BAV patients and expression differences between BAV and tricuspid aortic valve (TAV) patients are unclear. We sought to compare mRNA expressions in TAA in patients with BAV and TAV. Methods and Results: Ascending aorta tissue was obtained from 58 aortic aneurysm repair patients (31 BAV, 27 TAV) and from 8 heart transplant donors. Illumina Human HT-12v4 microarrays were used to assess mRNA expression. After standard QC and filtering, probes were analyzed using multivariable linear regression analysis, adjusting for age, gender, medication use (beta blockers, ACE-Is, ARBs), and 10 surrogate variables. Ingenuity Pathway Analysis (IPA) was used to identify pathways and top regulator effect networks that were differentially expressed in BAV vs. TAV and BAV vs. donors. In BAV vs. TAV, MMP9, ESM1 and IL1B were downregulated 0.63, 0.74 and 0.77 fold, whereas COMP was upregulated 2.29 fold (p < 0.05 for all). In BAV vs. donors, IL1R2, MCEMP1, IL18RAP and ACAN were downregulated 0.66, 0.2, 0.2 and 0.05 fold, while ADAMTS8, CCL21 and CIDEA were upregulated 6.97, 6.24 and 4.65 fold (p < 0.0001). IPA analysis showed P53 as the top upstream regulator for both BAV vs. TAV (p = 1.9e-8) and BAV vs. donors (p = 2.3e-25). IRF7, which protects against angiotensin II-induced hypertrophy in cardiomyocytes, was also a significant upstream regulator for BAV vs. TAV (p = 3.6e-7). Additionally, miR-124-3p in BAV vs. TAV (p = 6.3e-7) and BAV vs. donors (p = 1.7e-22), as well as miR-96-5p in BAV vs. TAV (p = 4e-7) were predicted significant upstream regulators. Immune response was shown to be the top regulator effect network in BAV vs. TAV, whereas perivascular fibrosis was shown to be an important regulator effect network in BAV vs. donors. Cell stress pathways were also activated in BAV vs. donors. Conclusions: Distinct pathways and regulator effect networks exist in TAA with BAV or TAV. TAV associated TAA is more associated with inflammatory responses, while BAV aortopathy is more associated with extracellular matrix remodelling and cell stress. MiRs may also play an important role in BAV aortopathy.

Objective Augmentation of left ventricular (LV) contractility and heart rate (HR) by sympathetic nerve stimulation and amelioration of heart failure by vagal nerve stimulation has been reported. However, the effects of concomitant electrical stimulation of both sympathetic and parasympathetic cardiac nerves in tissues such as those of the cardiac plexus remain unclear. This study sought to assess acute changes in cardiac function and hemodynamics in response to endovascular cardiac plexus stimulation (CPS). Methods Twelve dogs received endovascular CPS via a bipolar catheter within the right pulmonary artery. Stimulation frequency (20 Hz) and pulse width (4 milliseconds) were fixed; voltage varied (range, 15–60 V). Results Results fell into three categories: 1, no response (n = 4); 2, an increase in systemic arterial pressure that was dependent on electrode placement (n = 4); and 3, a very reproducible and stable increase in aortic pressure (n = 4). In the third group, mean systolic aortic pressures, maximum value of the first derivative of LV pressure, and LV stroke work increased with stimulation (P < 0.02 for all parameters) as did cardiac output, end-systolic elastance, and preload recruitable stroke work (P = 0.03). Systemic and pulmonary vascular resistance, central venous pressure, pulmonary arterial pressure, and HR remained unchanged (P > 0.05). Conclusions In contrast to conventional inotropic agents, endovascular CPS induced significant and selective increases in LV contractility without increasing HR. Efforts to optimize electrode placement and fixation will improve the reproducibility of endovascular CPS treatment.

Atrial fibrillation is a highly prevalent arrhythmia and a major risk factor for stroke, heart failure and death. We conducted a genome-wide association study (GWAS) in individuals of European ancestry, including 6,707 with and 52,426 without atrial fibrillation. Six new atrial fibrillation susceptibility loci were identified and replicated in an additional sample of individuals of European ancestry, including 5,381 subjects with and 10,030 subjects without atrial fibrillation (P < 5 × 10(-8)). Four of the loci identified in Europeans were further replicated in silico in a GWAS of Japanese individuals, including 843 individuals with and 3,350 individuals without atrial fibrillation. The identified loci implicate candidate genes that encode transcription factors related to cardiopulmonary development, cardiac-expressed ion channels and cell signaling molecules.

Background— The left and right atria have different susceptibilities toward developing arrhythmias, with left atrial arrhythmias more commonly observed. To understand the molecular basis for such differences, we catalogued micro (mi)RNA and mRNA expression differences by next generation sequencing. Methods and Results— Four human left-right atrial pairs were subjected to whole-genome expression analyses via next-generation sequencing of small RNAs, including miRNAs, and poly-A–enriched mRNAs. Using a paired sample design, significant differences in the expression of 32 miRNAs were found in between the left and right atria at a probability value of Conclusions— There are significant differences in miRNA and mRNA expression profiles between the left and right atria, which may yield insight into increased the arrhythmogenesis of the left atria.

Atrial fibrillation (AF) is the most common sustained arrhythmia. Previous studies have identified several genetic loci associated with typical AF. We sought to identify common genetic variants underlying lone AF. This condition affects a subset of individuals without overt heart disease and with an increased heritability of AF. We report a meta-analysis of genome-wide association studies conducted using 1,335 individuals with lone AF (cases) and 12,844 unaffected individuals (referents). Cases were obtained from the German AF Network, Heart and Vascular Health Study, the Atherosclerosis Risk in Communities Study, the Cleveland Clinic and Massachusetts General Hospital. We identified an association on chromosome 1q21 to lone AF (rs13376333, adjusted odds ratio = 1.56; P = 6.3 x 10(-12)), and we replicated this association in two independent cohorts with lone AF (overall combined odds ratio = 1.52, 95% CI 1.40-1.64; P = 1.83 x 10(-21)). rs13376333 is intronic to KCNN3, which encodes a potassium channel protein involved in atrial repolarization.

Background— Autonomic dysfunction, characterized by sympathetic activation and vagal withdrawal, contributes to the progression of heart failure (HF). Although the therapeutic benefits of sympathetic inhibition with β-blockers in HF are clear, the role of increased vagal tone in this setting has been less studied. We have investigated the impact of enhancing vagal tone (achieved through chronic cervical vagus nerve stimulation, [VNS]) on HF development in a canine high-rate ventricular pacing model. Methods and Results— Fifteen dogs were randomized into control (n=7) and VNS (n=8) groups. All dogs underwent 8 weeks of high-rate ventricular pacing (at 220 bpm for the first 4 weeks to develop HF and another 4 weeks at 180 bpm to maintain HF). Concomitant VNS, at an intensity reducing sinus rate ≈20 bpm, was delivered together with the ventricular pacing in the VNS group. At 4 and 8 weeks of ventricular pacing, both left ventricular end-diastolic and -systolic volumes were lower and left ventricular ejection fraction was higher in the VNS group than in the control group. Heart rate variability and baroreflex sensitivity improved in the VNS dogs. Rises in plasma norepinephrine, angiotensin II, and C-reactive protein levels, ordinarily expected in this model, were markedly attenuated with VNS treatment. Conclusions— Chronic VNS improves cardiac autonomic control and significantly attenuates HF development in the canine high-rate ventricular pacing model. The therapeutic benefit of VNS is associated with pronounced anti-inflammatory effects. VNS is a novel and potentially useful therapy for treating HF.

Although the problem of atrial fibrillation is now widely appreciated, the fundamental mechanisms that lead to arrhythmia onset and persistence have been difficult to elucidate. As a result, available pharmacologic therapies have focused more on modifying ion channel activity than on the underlying mechanisms. Recent studies suggest an important role for alterations in autonomic regulation, neurohormonal activation, and a systemic inflammatory state in the genesis and persistence of atrial fibrillation. The relative contributions of these distinct pathways to atrial fibrillation likely vary from patient to patient, and within a patient, as a function of age. Tailored therapies, together with patient-specific ablative interventions, may increase the success with which atrial fibrillation is treated and minimize the occurrence of life-threatening thromboembolic complications.

An association between lower educational attainment (EA) and an increased risk for depression has been confirmed in various western countries. This study examines whether pleiotropic genetic effects contribute to this association. Therefore, data were analyzed from a total of 9662 major depressive disorder (MDD) cases and 14 949 controls (with no lifetime MDD diagnosis) from the Psychiatric Genomics Consortium with additional Dutch and Estonian data. The association of EA and MDD was assessed with logistic regression in 15 138 individuals indicating a significantly negative association in our sample with an odds ratio for MDD 0.78 (0.75-0.82) per standard deviation increase in EA. With data of 884 105 autosomal common single-nucleotide polymorphisms (SNPs), three methods were applied to test for pleiotropy between MDD and EA: (i) genetic profile risk scores (GPRS) derived from training data for EA (independent meta-analysis on similar to 120 000 subjects) and MDD (using a 10-fold leave-one-out procedure in the current sample), (ii) bivariate genomic-relationship-matrix restricted maximum likelihood (GREML) and (iii) SNP effect concordance analysis (SECA). With these methods, we found (i) that the EA-GPRS did not predict MDD status, and MDD-GPRS did not predict EA, (ii) a weak negative genetic correlation with bivariate GREML analyses, but this correlation was not consistently significant, (iii) no evidence for concordance of MDD and EA SNP effects with SECA analysis. To conclude, our study confirms an association of lower EA and MDD risk, but this association was not because of measurable pleiotropic genetic effects, which suggests that environmental factors could be involved, for example, socioeconomic status. Refereed/Peer-reviewed