Atrial APD prolongation caused by the upregulation of RAGE and subsequent I NaL increase in diabetic patients

Diabetes mellitus (DM) is a risk factor for the development of atrial fibrillation (AF). The action potential duration (APD) has been demonstrated to be prolonged in the atrium of diabetic mice. In contrast, the APD is generally shortened in AF patients. It is unclear what change occurs in the atrial APD of diabetic patients. In this study, we explore the APD change of atrial myocytes from diabetic patients and the underlying molecular mechanisms. The whole-cell patch-clamp technique is used to detect single-cell electrical activity in diabetic and nondiabetic human samples. The results show that both APD 50 and APD 90, the APD at 50% and 90% repolarization, are increased in diabetic patients compared with those in nondiabetic controls. The density of late sodium current ( I NaL) in the atrial myocytes of diabetic patients is greater than that in the myocytes of nondiabetic patients. The expression of receptor for advanced glycation end products (RAGE) is increased in the atria of diabetic patients. In cultured HL-1 cells, high glucose (HG) treatment increases I NaL, and the expression of RAGE prolongs APD. The siRNA-mediated knockdown of RAGE reduces the I NaL and shortens the APD. The APD is prolonged in the atria of diabetic patients because of the upregulation of RAGE and the subsequent increase in I NaL. Our findings provide novel insights into atrial electrical remodeling in diabetic patients.

Lifestyle changes in atrial fibrillation management and intervention

Atrial fibrillation (AF) is one of the most common arrhythmias in adults, and its continued rise in the United States is complicated by the increased incidence and prevalence of several AF risk factors, such as obesity, physical inactivity, hypertension, obstructive sleep apnea, diabetes mellitus, coronary artery disease, and alcohol, tobacco, or caffeine use. Lifestyle and risk factor modification has been proposed as an additional pillar of AF therapy, added to rhythm control, rate control, and anticoagulation, to reduce AF burden and risk. Although emerging evidence largely supports the integration of lifestyle and risk factor management in clinical practice, randomized clinical trials investigating the long-term sustainability and reproducibility of these benefits remain sparse. The purpose of this review is to discuss potentially reversible risk factors on AF, share evidence for the impact on AF by modification of these risk factors, and then provide an overview of the effects of reversing or managing these risk factors on the success of various AF management strategies, such as antithrombotic, rate control, and rhythm control therapies.

An Update on the Current and Emerging Use of Thiazolidinediones for Type 2 Diabetes

Guidelines have increasingly stressed the concept that adequate glycemic control is required to prevent or decrease the macro- and microvascular complications of type 2 diabetes mellitus (T2DM). PPAR-gamma agonists ("glitazones") are no longer prioritized due to their effects on heart failure. However, the association between these drugs and innovative therapies could be a valuable tool to attenuate the risk factors of the metabolic syndrome. Glitazones are used for the treatment of diabetes and associated comorbidities. There is substantial scientific evidence demonstrating the effect of glitazones at a cardiometabolic level, as well as on hematological and neurological pathologies that point to their usefulness. The use of glitazones has always been controversial both for the type of patients who must take these drugs and for the side effects associated with them. Unfortunately, the recent guidelines do not include them among the preferred drugs for the treatment of hyperglycemia and rosiglitazone is out of the market in many countries due to an adverse cardiovascular risk profile. Even though real-life studies have proven otherwise, and their pleiotropic effects have been highlighted, they have been unable to achieve primacy in the choice of antihyperglycemic drugs. It would be appropriate to demonstrate the usefulness of pioglitazone and its therapeutic benefit with further cardiovascular safety studies.

Epicardial fat and atrial fibrillation: the perils of atrial failure

Obesity is a heterogeneous condition, characterized by different phenotypes and for which the classical assessment with body mass index may underestimate the real impact on cardiovascular (CV) disease burden. An epidemiological link between obesity and atrial fibrillation (AF) has been clearly demonstrated and becomes even more tight when ectopic (i.e. epicardial) fat deposition is considered. Due to anatomical and functional features, a tight paracrine cross-talk exists between epicardial adipose tissue (EAT) and myocardium, including the left atrium (LA). Alongside-and even without-mechanical atrial stretch, the dysfunctional EAT may determine a pro-inflammatory environment in the surrounding myocardial tissue. This evidence has provided a new intriguing pathophysiological link with AF, which in turn is no longer considered a single entity but rather the final stage of atrial remodelling. This maladaptive process would indeed include structural, electric, and autonomic derangement that ultimately leads to overt disease. Here, we update how dysfunctional EAT would orchestrate LA remodelling. Maladaptive changes sustained by dysfunctional EAT are driven by a pro-inflammatory and pro-fibrotic secretome that alters the sinoatrial microenvironment. Structural (e.g. fibro-fatty infiltration) and cellular (e.g. mitochondrial uncoupling, sarcoplasmic reticulum fragmentation, and cellular protein quantity/localization) changes then determine an electrophysiological remodelling that also involves the autonomic nervous system. Finally, we summarize how EAT dysfunction may fit with the standard guidelines for AF. Lastly, we focus on the potential benefit of weight loss and different classes of CV drugs on EAT dysfunction, LA remodelling, and ultimately AF onset and recurrence.

Rethinking pioglitazone as a cardioprotective agent: a new perspective on an overlooked drug

Since 1985, the thiazolidinedione pioglitazone has been widely used as an insulin sensitizer drug for type 2 diabetes mellitus (T2DM). Although fluid retention was early recognized as a safety concern, data from clinical trials have not provided conclusive evidence for a benefit or a harm on cardiac function, leaving the question unanswered. We reviewed the available evidence encompassing both in vitro and in vivo studies in tissues, isolated organs, animals and humans, including the evidence generated by major clinical trials. Despite the increased risk of hospitalization for heart failure due to fluid retention, pioglitazone is consistently associated with reduced risk of myocardial infarction and ischemic stroke both in primary and secondary prevention, without any proven direct harm on the myocardium. Moreover, it reduces atherosclerosis progression, in-stent restenosis after coronary stent implantation, progression rate from persistent to permanent atrial fibrillation, and reablation rate in diabetic patients with paroxysmal atrial fibrillation after catheter ablation. In fact, human and animal studies consistently report direct beneficial effects on cardiomyocytes electrophysiology, energetic metabolism, ischemia–reperfusion injury, cardiac remodeling, neurohormonal activation, pulmonary circulation and biventricular systo-diastolic functions. The mechanisms involved may rely either on anti-remodeling properties (endothelium protective, inflammation-modulating, anti-proliferative and anti-fibrotic properties) and/or on metabolic (adipose tissue metabolism, increased HDL cholesterol) and neurohormonal (renin–angiotensin–aldosterone system, sympathetic nervous system, and adiponectin) modulation of the cardiovascular system. With appropriate prescription and titration, pioglitazone remains a useful tool in the arsenal of the clinical diabetologist.

Sodium-glucose cotransporter protein-2 (SGLT-2) inhibitors and glucagon-like peptide-1 (GLP-1) receptor agonists for type 2 diabetes: systematic review and network meta-analysis of randomised controlled trials

OBJECTIVE

To evaluate sodium-glucose cotransporter-2 (SGLT-2) inhibitors and glucagon-like peptide-1 (GLP-1) receptor agonists in patients with type 2 diabetes at varying cardiovascular and renal risk.

DESIGN

Network meta-analysis.

DATA SOURCES

Medline, Embase, and Cochrane CENTRAL up to 11 August 2020.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised controlled trials comparing SGLT-2 inhibitors or GLP-1 receptor agonists with placebo, standard care, or other glucose lowering treatment in adults with type 2 diabetes with follow up of 24 weeks or longer. Studies were screened independently by two reviewers for eligibility, extracted data, and assessed risk of bias.

MAIN OUTCOME MEASURES

Frequentist random effects network meta-analysis was carried out and GRADE (grading of recommendations assessment, development, and evaluation) used to assess evidence certainty. Results included estimated absolute effects of treatment per 1000 patients treated for five years for patients at very low risk (no cardiovascular risk factors), low risk (three or more cardiovascular risk factors), moderate risk (cardiovascular disease), high risk (chronic kidney disease), and very high risk (cardiovascular disease and kidney disease). A guideline panel provided oversight of the systematic review.

RESULTS

764 trials including 421 346 patients proved eligible. All results refer to the addition of SGLT-2 inhibitors and GLP-1 receptor agonists to existing diabetes treatment. Both classes of drugs lowered all cause mortality, cardiovascular mortality, non-fatal myocardial infarction, and kidney failure (high certainty evidence). Notable differences were found between the two agents: SGLT-2 inhibitors reduced admission to hospital for heart failure more than GLP-1 receptor agonists, and GLP-1 receptor agonists reduced non-fatal stroke more than SGLT-2 inhibitors (which appeared to have no effect). SGLT-2 inhibitors caused genital infection (high certainty), whereas GLP-1 receptor agonists might cause severe gastrointestinal events (low certainty). Low certainty evidence suggested that SGLT-2 inhibitors and GLP-1 receptor agonists might lower body weight. Little or no evidence was found for the effect of SGLT-2 inhibitors or GLP-1 receptor agonists on limb amputation, blindness, eye disease, neuropathic pain, or health related quality of life. The absolute benefits of these drugs vary substantially across patients from low to very high risk of cardiovascular and renal outcomes (eg, SGLT-2 inhibitors resulted in 3 to 40 fewer deaths in 1000 patients over five years; see interactive decision support tool (https://magicevidence.org/match-it/200820dist/#!/) for all outcomes.

CONCLUSIONS

In patients with type 2 diabetes, SGLT-2 inhibitors and GLP-1 receptor agonists reduced cardiovascular and renal outcomes, with some differences in benefits and harms. Absolute benefits are determined by individual risk profiles of patients, with clear implications for clinical practice, as reflected in the BMJ Rapid Recommendations directly informed by this systematic review.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019153180.

Impact of Diabetes Mellitus on Stroke and Survival in Patients With Atrial Fibrillation

Although diabetes mellitus (DM) has been established as a risk factor for developing atrial fibrillation (AF) and is a known risk factor for stroke, it is unclear whether the presence or duration of DM is the primary adverse influence on the clinical course of AF. We retrospectively analyzed patients diagnosed with incident AF to examine the impact of DM on ischemic stroke and all-cause mortality. The diagnosis of DM was established by ICD-9 codes and review of medical records. To account for the significant differences in baseline characteristics of patients with and without diabetes, we matched 909 AF patients with DM with 909 AF patients without DM using propensity score matching based on 26 baseline variables. Cox regression analysis was used to identify independent factors associated with ischemic stroke and mortality. The mean age of the propensity matched cohort was 74 ± 11.5 years and 55.4% were male. Over a median follow-up period of 5.4 years (maximum 23.9 years), cumulative survival was significantly lower for patients with DM than those without DM; Log-rank p <0.001. In the propensity-matched comparison, the risk of mortality was significantly higher in the DM group compared with the non-DM group (hazard ratio 1.25; 95% confidence interval 1.12 to 1.69; p <0.001). Likewise, patients with DM had a higher risk of stroke (hazard ratio 1.32; 95% confidence interval 1.02 to 1.69; p = 0.03). Duration of DM was not associated with increased risk for stroke or mortality. In conclusion, the co-morbidity of DM represents an independent predictor of reduced survival and further highlights the excess risk of thromboembolism in patients with AF.

Effect of Dapagliflozin on Atrial Fibrillation in Patients With Type 2 Diabetes Mellitus

Background:

Atrial fibrillation (AF) and atrial flutter (AFL) are associated with both diabetes mellitus and its related comorbidities, including hypertension, obesity, and heart failure (HF). SGLT2 (sodium-glucose cotransporter 2) inhibitors have been shown to lower blood pressure, reduce weight, have salutary effects on left ventricular remodeling, and reduce hospitalization for HF and cardiovascular death in patients with type 2 diabetes mellitus. We therefore investigated whether SGLT2 inhibitors could also reduce the risk of AF/AFL.

Methods:

DECLARE-TIMI 58 (Dapagliflozin Effect on Cardiovascular Events–Thrombolysis in Myocardial Infarction 58) studied the efficacy and safety of the SGLT2 inhibitor dapagliflozin versus placebo in 17 160 patients with type 2 diabetes mellitus and either multiple risk factors for atherosclerotic cardiovascular disease (n=10 186) or known atherosclerotic cardiovascular disease (n=6974). We explored the effect of dapagliflozin on the first and total number of AF/AFL events in patients with (n=1116) and without prevalent AF/AFL using Cox and negative binomial models, respectively. AF/AFL events were identified by search of the safety database using MedDRA preferred terms (“atrial fibrillation,” “atrial flutter”).

Results:

Dapagliflozin reduced the risk of AF/AFL events by 19% (264 versus 325 events; 7.8 versus 9.6 events per 1000 patient-years; hazard ratio [HR], 0.81 [95% CI, 0.68–0.95]; P =0.009). The reduction in AF/AFL events was consistent regardless of presence or absence of a history of AF/AFL at baseline (previous AF/AFL: HR, 0.79 [95% CI, 0.58–1.09]; no AF/AFL: HR, 0.81 [95% CI, 0.67–0.98]; P for interaction 0.89). Similarly, presence of atherosclerotic cardiovascular disease (HR, 0.83 [95% CI, 0.66–1.04]) versus multiple risk factors (HR, 0.78 [95% CI, 0.62–0.99]; P for interaction 0.72) or a history of HF (HF: HR, 0.78 [95% CI, 0.55–1.11]; No HF: HR, 0.81 [95% CI, 0.68–0.97]; P for interaction 0.88) did not modify the reduction in AF/AFL events observed with dapagliflozin. Moreover, there was no effect modification by sex, history of ischemic stroke, glycated hemoglobin A 1c , body mass index, blood pressure, or estimated glomerular filtration rate (all P for interaction >0.20). Dapagliflozin also reduced the total number (first and recurrent) of AF/AFL events (337 versus 432; incidence rate ratio, 0.77 [95% CI, 0.64–0.92]; P =0.005).

Conclusions:

Dapagliflozin decreased the incidence of reported episodes of AF/AFL adverse events in high-risk patients with type 2 diabetes mellitus. This effect was consistent regardless of the patient’s previous history of AF, atherosclerotic cardiovascular disease, or HF.

Registration:

URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01730534.

Pathological Role of Advanced Glycation End Products (AGEs) and their Receptor Axis in Atrial Fibrillation

Accumulating evidence has shown that the incidence of atrial fibrillation (AF) is higher in patients with diabetes, especially those with poor glycemic control or long disease duration. Nonenzymatic glycation of amino acids of proteins, lipids, and nucleic acids has progressed under normal aging process and/or diabetic condition, which could lead to the formation and accumulation of advanced glycation end products (AGEs). AGEs not only alter the tertiary structure and physiological function of macromolecules, but also evoke inflammatory and fibrotic reactions through the interaction of cell surface receptor for AGEs (RAGE), thereby being involved in aging-related disorders. In this paper, we briefly review the association of chronic hyperglycemia and type 1 diabetes with the risk of AF and then discuss the pathological role of AGE-RAGE axis in AF and its thromboembolic complications.

Oxidative stress and inflammation as central mediators of atrial fibrillation in obesity and diabetes

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in humans. Several risk factors promote AF, among which diabetes mellitus has emerged as one of the most important. The growing recognition that obesity, diabetes and AF are closely intertwined disorders has spurred major interest in uncovering their mechanistic links. In this article we provide an update on the growing evidence linking oxidative stress and inflammation to adverse atrial structural and electrical remodeling that leads to the onset and maintenance of AF in the diabetic heart. We then discuss several therapeutic strategies to improve atrial excitability by targeting pathways that control oxidative stress and inflammation.

Linking atrial fibrillation with non-alcoholic fatty liver disease: potential common therapeutic targets

Non-alcoholic fatty liver disease (NAFLD) and atrial fibrillation (AF) are common chronic non-infectious diseases with rising incidences. NAFLD is an independent risk factor for the onset of AF, after adjusting potentially related factors. The pathogenesis of these diseases share several mechanisms including reduced adiponectin level, insulin resistance, and renin angiotensin aldosterone system (RAAS) activation, in addition to activation of common disease pathways that promote inflammation, oxidative stress, and fibrosis. Furthermore, statins and RAAS blockers exert therapeutic effects concurrently on NAFLD and AF. The common pathogenesis of NAFLD and AF may serve as a potential therapeutic target in the future.

Thiazolidinedione use and atrial fibrillation in diabetic patients: a meta-analysis

BACKGROUND

Accumulating evidence suggests that thiazolidinediones (TZDs) may exert protective effects in atrial fibrillation (AF). The present meta-analysis investigated the association between TZD use and the incidence of AF in diabetic patients.

METHODS

Electronic databases were searched until December 2016. Of the 346 initially identified records, 3 randomized clinical trials (RCTs) and 4 observational studies with 130,854 diabetic patients were included in the final analysis.

RESULTS

Pooled analysis of the included studies demonstrated that patients treated with TZDs had approximately 30% lower risk of developing AF compared to controls [odds ratio (OR): 0.73, 95% confidence interval (CI): 0.62 to 0.87, p = 0.0003]. This association was consistently observed for both new onset AF (OR =0.77, p = 0.002) and recurrent AF (OR =0.41, p = 0.002), pioglitazone use (OR =0.56, p = 0.04) but not rosiglitazone use (OR =0.78, p = 0.12). The association between TZD use and AF incidence was not significant in the pooled analysis of three RCTs (OR =0.77, 95% CI = 0.53-1.12, p = 0.17), but was significantly in the pooled analysis of the four observational studies (OR =0.71, p = 0.0003).

CONCLUSIONS

This meta-analysis suggests that TZDs may confer protection against AF in the setting of diabetes mellitus (DM). This class of drugs can be used as upstream therapy for DM patients to prevent the development of AF. Further large-scale RCTs are needed to determine whether TZDs use could prevent AF in the setting of DM.

The Receptor for Advanced Glycation End Products (RAGE) Is Associated with Persistent Atrial Fibrillation

Objective

Upregulation of the receptor for advanced glycation end products (RAGE) has been proposed as a pathophysiological mechanism underlying the development of atrial fibrillation (AF). We sought to investigate if soluble RAGE levels are associated with AF in Caucasian patients.

Methods

Patients (n = 587) were prospectively recruited and serum levels of soluble RAGE (sRAGE) and endogenous secretory RAGE (esRAGE) measured. The patients included 527 with sinus rhythm, 32 with persistent AF (duration >7 days, n = 32) and 28 with paroxysmal AF (duration <7 days, n = 28).

Results

Patients with AF were older and had a greater prevalence of heart failure than patients in sinus rhythm. Circulating RAGE levels were higher in patients with persistent AF [median sRAGE 1190 (724–2041) pg/ml and median esRAGE 452 (288–932) pg/ml] compared with paroxysmal AF [sRAGE 799 (583–1033) pg/ml and esRAGE 279 (201–433) pg/ml, p ≤ 0.01] or sinus rhythm [sRAGE 782 (576–1039) pg/ml and esRAGE 289 (192–412) pg/ml, p < 0.001]. In multivariable logistic regression analysis, independent predictors of persistent AF were age, heart failure, sRAGE [odds ratio 1.1 per 100 pg/ml, 95% confidence interval (CI) 1.0–1.1, p = 0.001] and esRAGE [odds ratio 1.3 per 100 pg/ml, 95% CI 1.1–1.4, p < 0.001]. Heart failure and age were the only independent predictors of paroxysmal AF. In AF patients, sRAGE [odds ratio 1.1 per 100 pg/ml, 95% CI 1.1–1.2, p = 0.007] and esRAGE [odds ratio 1.3 per 100 pg/ml, 95% CI 1.0–1.5, p = 0.017] independently predicted persistent compared with paroxysmal AF.

Conclusions

Soluble RAGE is elevated in Caucasian patients with AF, and both sRAGE and esRAGE predict the presence of persistent AF.

Is diabetes a hypercoagulable state? A critical appraisal

Diabetes mellitus (DM), a chronic disease with an increasing incidence and prevalence worldwide, is an established risk factor for arterial cardiovascular, cerebrovascular and peripheral vascular diseases including acute myocardial infarction, stroke and peripheral artery disease. On the other hand, its role as independent risk factor for venous thromboembolism (VTE) and for cardioembolic stroke or systemic embolism (SE) in patients with atrial fibrillation (AF) is more conflicting. Venous and arterial thromboses have traditionally been regarded as separate diseases, but recent studies have documented an association between these vascular complications. Cardiovascular risk factors may contribute to unprovoked VTE, and VTE may be an early symptomatic event in patients at high cardiovascular risk, including diabetic patients. Compelling evidences suggest that DM is associated with a higher risk of development and progression of AF. Furthermore, in AF patients with a coexisting DM the risk of cardioembolic stroke/SE appeared increased. Thus, DM has been included as one of the items of the CHADS2 score and of the subsequent CHA2DS2-VASc score that have been developed to assess the arterial tromboembolic risk of AF patients. Such a high incidence of thromboembolic events observed in these clinical subsets may be attributable to the DM-related prothrombotic state due to a number of changes in primary and secondary hemostasis. Although of potential clinical interest, unfortunately, to date, no study has properly evaluated the effects of drugs used to control blood glucose levels on the risk of venous thromboembolism and arterial cardioembolic events in patients with DM.

Atrial fibrillation in patients with diabetes: molecular mechanisms and therapeutic perspectives

Atrial fibrillation (AF) remains the most frequent sustained cardiac arrhythmia worldwide and its incidence increases with ageing, cardiovascular risk factors and comorbidities. Prevalence of diabetes mellitus (DM) is growing fast and is assuming pandemic proportions mostly due to overnutrition and sedentary habits. Experimental and clinical evidences suggest that DM and AF are strongly interconnected. The present review addresses in detail new molecular pathways implicated in the etiology of AF and their relevance for mechanism-based therapeutic strategies in this setting. Advances in risk stratification, drug therapy (i.e., novel anticoagulants) and catheter ablation are also described.

Genetic variants associated with risk of atrial fibrillation regulate expression of PITX2, CAV1, MYOZ1, C9orf3 and FANCC

Genome-wide association studies (GWAS) have identified genetic variants in a number of chromosomal regions that are associated with atrial fibrillation (AF). The mechanisms underlying these associations are unknown, but are likely to involve effects of the risk haplotypes on expression of neighbouring genes. To investigate the association between genetic variants at AF-associated loci and expression of nearby candidate genes in human atrial tissue and peripheral blood. Right atrial appendage (RAA) samples were collected from 122 patients undergoing cardiac surgery, of these, 12 patients also had left atrial appendage samples taken. 22 patients had a history of AF. Peripheral blood samples were collected from 405 patients undergoing diagnostic cardiac catheterisation. In order to tag genetic variation at each of nine loci, a total of 367 single nucleotide polymorphisms (SNPs) were genotyped using the Sequenom platform. Total expression of 16 candidate genes in the nine AF-associated regions was measured by quantitative PCR. The relative expression of each allele of the candidate genes was measured on the Sequenom platform using one or more transcribed SNPs to distinguish between alleles in heterozygotes. We tested association between the SNPs of interest and gene expression using total gene expression (integrating cis and trans acting sources of variation), and allelic expression ratios (specific for cis acting influences), in atrial tissue and peripheral blood. We adjusted for multiple comparisons using a Bonferroni approach. In subsidiary analyses, we compared the expression of candidate genes between patients with and without a history of AF. Total expression of 15 transcripts of 14 genes and allelic expression ratio of 14 transcripts of 14 genes in genomic regions associated with AF were measured in right atrial appendage tissue. 8 of these transcripts were also expressed in peripheral blood. Risk alleles at AF-associated SNPs were associated in cis with an increased expression of PITX2a (2.01-fold, p=6.5×10(-4)); and with decreased expression of MYOZ1 (0.39 fold; p=5.5×10(-15)), CAV1 (0.89 fold; p=5.9×10(-8)), C9orf3 (0.91 fold; 1.5×10(-5)), and FANCC (0.94-fold; p=8.9×10(-8)) in right atrial appendage. Of these five genes, only CAV1 was expressed in peripheral blood; association between the same AF risk alleles and lower expression of CAV1 was confirmed (0.91 fold decrease; p=4.2×10(-5)). A history of AF was also associated with a decrease in expression of CAV1 in both right and left atria (0.84 and 0.85 fold, respectively; p=0.03), congruent with the magnitude of the effect of the risk SNP on expression, and independent of genotype. The analyses in peripheral blood showed association between AF risk SNPs and decreased expression of KCNN3 (0.85-fold; p=2.1×10(-4)); and increased expression of SYNE2 (1.12-fold; p=7.5×10(-24)); however, these associations were not detectable in atrial tissue. We identified novel cis-acting associations in atrial tissue between AF risk SNPs and increased expression of PITX2a/b; and decreased expression of CAV1 (an association also seen in peripheral blood), C9orf3 and FANCC. We also confirmed a previously described association between AF risk variants and MYOZ1 expression. Analyses of peripheral blood illustrated tissue-specificity of cardiac eQTLs and highlight the need for larger-scale genome-wide eQTL studies in cardiac tissue. Our results suggest novel aetiological roles for genes in four AF-associated genomic regions.