Atrial fibrillation: current knowledge and future directions in epidemiology and genomics

Atrial fibrillation and flutter and ocular diseases. The Ural eye and medical study and the Ural very old study

PURPOSE

To assess associations between atrial fibrillation/atrial flutter (AF) and ocular parameters and diseases.

METHODS

The population-based Ural Eye and Medical Study (UEMS) and the Ural Very Old Study (UVOS) included 4894 individuals (age: 40+ years) and 835 individuals (age: 85+ years), respectively.

RESULTS

In the UEMS, AF prevalence (80/4894; 1.6%; 95% CI: 1.3, 2.0) increased from 1/1029 (0.1%) in the age group of 40 to <50 years to 29/619 (4.7%) and 12/159 (7.5%) in the age groups of 70 to <80 years and 80+ years, respectively. Higher AF prevalence correlated with older age (OR: 1.08; 95% CI: 1.04, 1.12; p < 0.001), urban region of habitation (OR: 1.08; 95% CI: 1.04, 1.12; p < 0.001), higher prevalence of cardiovascular disease/stroke (OR: 2.50; 95% CI: 1.32, 4.72; p < 0.001) and lower prevalence of neck pain (OR: 0.35; 95% CI: 0.14, 0.85; p = 0.02), higher serum concentration of bilirubin (OR: 1.03; 95% CI: 1.02, 1.05; p < 0.001) and lower prothrombin index (OR: 0.96; 95% CI: 0.93, 0.99; p = 0.003), higher stage of arterial hypertension (OR: 1.52; 95% CI: 1.01, 2.28; p = 0.04) and higher ankle-brachial index (OR: 22.1; 95% CI: 4.45, 1.10; p < 0.001). In that model, AF prevalence was not associated with ocular parameters such as intraocular pressure (p = 0.52), retinal nerve fibre layer thickness (p = 0.70), refractive error (p = 0.13), axial length (p = 0.14), nuclear cataract degree (p = 0.50) and prevalence (p = 0.40), cortical cataract degree (p = 0.43) and presence (p = 0.17), lens pseudoexfoliation (p = 0.58), status after cataract surgery (p = 0.38), age-related macular degeneration prevalence (p = 0.63), open-angle glaucoma presence (p = 0.90) and stage (p = 0.55), angle-closure glaucoma prevalence (p = 0.99) and stage (p = 0.99), diabetic retinopathy prevalence presence (p = 0.37) and stage (p = 0.32), and myopic macular degeneration (p = 0.98). In the UVOS, similar results were obtained.

CONCLUSIONS

In these multi-ethnic populations from Russia, AF prevalence was not associated with any major ocular disease and may not play a major role in the pathogenesis of these disorders.

Computer Simulation of Catheter Cryoablation for Pulmonary Vein Isolation

Cryoablation is a well-established medical procedure for surgically treating atrial fibrillation. Cryothermal catheter therapy induces cellular necrosis by freezing the insides of pulmonary veins, with the goal of disrupting abnormal electrical heart signals. Nevertheless, tissue damage induced by cold temperatures may also lead to other complications after cardiac surgery. In this sense, the simulation of catheter ablation can provide safer environments for training and the performance of cryotherapy interventions. Therefore, in this paper, we propose a novel approach to help better understand how temperature rates can affect this procedure by using computer tools to develop a simulation framework to predict lesion size and determine optimal temperature conditions for reducing the risk of major complications. The results showed that a temperature profile of around -40 °C caused less penetration, reduced necrotic damage, and smaller lesion size in the tissue. Instead, cryotherapy close to -60 °C achieved a greater depth of temperature flow inside the tissue and a larger cross-section area of the lesion. With further development and validation, the framework could represent a cost-effective strategy for providing personalized modeling, better planning of cryocatheter-based treatment, and preventing surgical complications.

External electrical and pharmacological cardioversion for atrial fibrillation, atrial flutter or atrial tachycardias: a network meta-analysis

BACKGROUND

Atrial fibrillation (AF) is the most frequent sustained arrhythmia. Cardioversion is a rhythm control strategy to restore normal/sinus rhythm, and can be achieved through drugs (pharmacological) or a synchronised electric shock (electrical cardioversion).

OBJECTIVES

To assess the efficacy and safety of pharmacological and electrical cardioversion for atrial fibrillation (AF), atrial flutter and atrial tachycardias.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Conference Proceedings Citation Index-Science (CPCI-S) and three trials registers (ClinicalTrials.gov, WHO ICTRP and ISRCTN) on 14 February 2023.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) at the individual patient level. Patient populations were aged ≥ 18 years with AF of any type and duration, atrial flutter or other sustained related atrial arrhythmias, not occurring as a result of reversible causes.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology to collect data and performed a network meta-analysis using the standard frequentist graph-theoretical approach using the netmeta package in R. We used GRADE to assess the quality of the evidence which we presented in our summary of findings with a judgement on certainty. We calculated differences using risk ratios (RR) and 95% confidence intervals (CI) as well as ranking treatments using a P value. We assessed clinical and statistical heterogeneity and split the networks for the primary outcome and acute procedural success, due to concerns about violating the transitivity assumption.

MAIN RESULTS

We included 112 RCTs (139 records), from which we pooled data from 15,968 patients. The average age ranged from 47 to 72 years and the proportion of male patients ranged from 38% to 92%. Seventy-nine trials were considered to be at high risk of bias for at least one domain, 32 had no high risk of bias domains, but had at least one domain classified as uncertain risk, and one study was considered at low risk for all domains. For paroxysmal AF (35 trials), when compared to placebo, anteroapical (AA)/anteroposterior (AP) biphasic truncated exponential waveform (BTE) cardioversion (RR: 2.42; 95% CI 1.65 to 3.56), quinidine (RR: 2.23; 95% CI 1.49 to 3.34), ibutilide (RR: 2.00; 95% CI 1.28 to 3.12), propafenone (RR: 1.98; 95% CI 1.67 to 2.34), amiodarone (RR: 1.69; 95% CI 1.42 to 2.02), sotalol (RR: 1.58; 95% CI 1.08 to 2.31) and procainamide (RR: 1.49; 95% CI 1.13 to 1.97) likely result in a large increase in maintenance of sinus rhythm until hospital discharge or end of study follow-up (certainty of evidence: moderate). The effect size was larger for AA/AP incremental and was progressively smaller for the subsequent interventions. Despite low certainty of evidence, antazoline may result in a large increase (RR: 28.60; 95% CI 1.77 to 461.30) in this outcome. Similarly, low-certainty evidence suggests a large increase in this outcome for flecainide (RR: 2.17; 95% CI 1.68 to 2.79), vernakalant (RR: 2.13; 95% CI 1.52 to 2.99), and magnesium (RR: 1.73; 95% CI 0.79 to 3.79). For persistent AF (26 trials), one network was created for electrical cardioversion and showed that, when compared to AP BTE incremental energy with patches, AP BTE maximum energy with patches (RR 1.35, 95% CI 1.17 to 1.55) likely results in a large increase, and active compression AP BTE incremental energy with patches (RR: 1.14, 95% CI 1.00 to 1.131) likely results in an increase in maintenance of sinus rhythm at hospital discharge or end of study follow-up (certainty of evidence: high). Use of AP BTE incremental with paddles (RR: 1.03, 95% CI 0.98 to 1.09; certainty of evidence: low) may lead to a slight increase, and AP MDS Incremental paddles (RR: 0.95, 95% CI 0.86 to 1.05; certainty of evidence: low) may lead to a slight decrease in efficacy. On the other hand, AP MDS incremental energy using patches (RR: 0.78, 95% CI 0.70 to 0.87), AA RBW incremental energy with patches (RR: 0.76, 95% CI 0.66 to 0.88), AP RBW incremental energy with patches (RR: 0.76, 95% CI 0.68 to 0.86), AA MDS incremental energy with patches (RR: 0.76, 95% CI 0.67 to 0.86) and AA MDS incremental energy with paddles (RR: 0.68, 95% CI 0.53 to 0.83) probably result in a decrease in this outcome when compared to AP BTE incremental energy with patches (certainty of evidence: moderate). The network for pharmacological cardioversion showed that bepridil (RR: 2.29, 95% CI 1.26 to 4.17) and quindine (RR: 1.53, (95% CI 1.01 to 2.32) probably result in a large increase in maintenance of sinus rhythm at hospital discharge or end of study follow-up when compared to amiodarone (certainty of evidence: moderate). Dofetilide (RR: 0.79, 95% CI 0.56 to 1.44), sotalol (RR: 0.89, 95% CI 0.67 to 1.18), propafenone (RR: 0.79, 95% CI 0.50 to 1.25) and pilsicainide (RR: 0.39, 95% CI 0.02 to 7.01) may result in a reduction in this outcome when compared to amiodarone, but the certainty of evidence is low. For atrial flutter (14 trials), a network could be created only for antiarrhythmic drugs. Using placebo as the common comparator, ibutilide (RR: 21.45, 95% CI 4.41 to 104.37), propafenone (RR: 7.15, 95% CI 1.27 to 40.10), dofetilide (RR: 6.43, 95% CI 1.38 to 29.91), and sotalol (RR: 6.39, 95% CI 1.03 to 39.78) probably result in a large increase in the maintenance of sinus rhythm at hospital discharge or end of study follow-up (certainty of evidence: moderate), and procainamide (RR: 4.29, 95% CI 0.63 to 29.03), flecainide (RR 3.57, 95% CI 0.24 to 52.30) and vernakalant (RR: 1.18, 95% CI 0.05 to 27.37) may result in a large increase in maintenance of sinus rhythm at hospital discharge or end of study follow-up (certainty of evidence: low). All tested electrical cardioversion strategies for atrial flutter had very high efficacy (97.9% to 100%). The rate of mortality (14 deaths) and stroke or systemic embolism (3 events) at 30 days was extremely low. Data on quality of life were scarce and of uncertain clinical significance. No information was available regarding heart failure readmissions. Data on duration of hospitalisation was scarce, of low quality, and could not be pooled.

AUTHORS' CONCLUSIONS

Despite the low quality of evidence, this systematic review provides important information on electrical and pharmacological strategies to help patients and physicians deal with AF and atrial flutter. In the assessment of the patient comorbidity profile, antiarrhythmic drug onset of action and side effect profile versus the need for a physician with experience in sedation, or anaesthetics support for electrical cardioversion are key aspects when choosing the cardioversion method.

Association Between Remnant Cholesterol and Risk of Incident Atrial Fibrillation: Population-Based Evidence From a Large-Scale Prospective Cohort Study

BACKGROUND

Evidence for the relationship between remnant cholesterol (RC) and incident atrial fibrillation (AF) risk remains sparse and limited.

METHODS AND RESULTS

Participants were enrolled between 2006 and 2010 and followed up to 2021. The multivariable Cox proportional hazards model was used to examine the relationship between RC quartiles and risk of incident AF. Subgroup analyses and sensitivity analyses were performed to explore the potential modification of the association and the robustness of the main findings. A total of 422 316 participants (mean age, 56 years; 54% women) were included for analyses. During a median follow-up of 11.9 years (first quartile-third quartile, 11.6-13.2 years), there were 24 774 AF events documented with an incidence of 4.92 events per 1000 person-years (95% CI, 4.86-4.98). Participants in higher RC quartiles had a lower risk of incident AF than those in the lowest quartile (first quartile): hazard ratio (HR)=0.96 (95% CI, 0.91-1.00) for second quartile; HR=0.92 (95% CI, 0.88-0.96) for third quartile; and HR=0.85 (95% CI, 0.81-0.89) for fourth quartile (P for trend <0.001). The association between RC quartiles and risk of incident AF was stronger in participants aged ≥65 years, in men, and in participants without history of diabetes when compared with control groups (P<0.001 for interaction).

CONCLUSIONS

On the basis of data from this large-scale prospective cohort study, elevated RC was associated with a lower risk of incident AF.

Opportunistic Extraction of Quantitative CT Biomarkers: Turning the Incidental Into Prognostic Information

The past two decades have seen a significant increase in the use of CT, with a corresponding rise in the mean population radiation dose. This rise in CT use has caused improved diagnostic certainty in conditions that were not previously routinely evaluated using CT, such as headaches, back pain, and chest pain. Unused data, unrelated to the primary diagnosis, embedded within these scans have the potential to provide organ-specific measurements that can be used to prognosticate or risk-profile patients for a wide variety of conditions. The recent increased availability of computing power, expertise and software for automated segmentation and measurements, assisted by artificial intelligence, provides a conducive environment for the deployment of these analyses into routine use. Data gathering from CT has the potential to add value to examinations and help offset the public perception of harm from radiation exposure. We review the potential for the collection of these data and propose the incorporation of this strategy into routine clinical practice.

Atrial fibrillation ablation in heart failure patients: Where do we stand in 2023? - State of the art review

Atrial fibrillation (AF) and heart failure are common overlapping cardiovascular disorders. Despite important therapeutic advances over the past several decades, controversy persists about whether a rate control or rhythm control approach constitutes the best option in this population. There is also considerable debate about whether antiarrhythmic drug therapy or ablation is the best approach when rhythm control is pursued.  A brief historical examination of the literature addressing this issue will be performed. An analysis of several important clinical outcomes observed in the prospective, randomized studies, which have compared AF ablation to non-ablation treatment options, will be discussed. This review will conclude with recommendations to guide clinicians on the status of AF ablation as a treatment option when considering management options in heart failure patients with atrial fibrillation.

Association Between rs2200733 Polymorphism of PITX2 Gene and the Risk of Atrial Fibrillation

BACKGROUND

As observed in recent genetic studies, PITX2 is one of the most popular genes with atrial fibrillation; single nucleotide polymorphism (rs2200733) at chromosome 4q25 (near PITX2) is found to be strongly associated with atrial fibrillation, but it has a difference among Chinese Han population. The basic aim of conducting this study is to find the correlation between PITX2 gene polymorphism and the risk of atrial fibrillation and to identify the possibility for early diagnosis of silent atrial fibrillation and high-risk atrial fibrillation.

METHODS

The study included 98 cases of atrial fibrillation patients and 88 non-atrial fibrillation patients in Affiliated Hospital of Yangzhou University were enrolled in a case-control study. The single nucleotide polymorphism of rs2200733 at 4q25 near PITX2 was genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis.

RESULTS

A total of 98 patients with atrial fibrillation were genotyped, and the following frequencies were included in genotype percentages (44.9%, 50%, and 5.1%) while distribution of significant single nucleotide polymorphism rs2200733 consisted (29.55%, 53.41%, and 17.05%) which showed (χ2 = 9.159, P =.01). There was no significant difference in TC genotype frequency (P =.642), frequency of T allele (χ2 = 7.447, P =.006), and T allele was 1.806 times that of the control group (odds ratio = 1.806, 95% CI = 1.179-2.766, P =.006). According to logistic regression analysis, following results were concluded for TC genotype (odds ratio = 3.128, 95% CI = 1.053-9.287, P =.04), or TT genotype (odds ratio = 5.077, 95% CI = 1.653-15.595, P =.005) increased the risk of atrial fibrillation.

CONCLUSIONS

The genotype and allele frequency distribution of rs2200733 (T/C) near PITX2 is different in the atrial fibrillation group and the control group. The T allele is a risk factor for atrial fibrillation. Compared with the CC genotype, the TT genotype increased the risk of atrial fibrillation.

Identifying prescribing differences of direct oral anticoagulants for atrial fibrillation within the Military Health System

Background

Direct oral anticoagulants (DOACs) are a first-line anticoagulant therapy for eligible patients with atrial fibrillation. Prescribing differences in the Military Health System have not yet been assessed.

Methods

We conducted a retrospective cross-sectional study using administrative claims data from the Military Health System Data Repository from fiscal years 2018-2019. We identified TRICARE Prime and Prime Plus patients between the ages of 18 and 64 with a diagnosis of atrial fibrillation and a CHA2DS2-VASc score of ≥2. Descriptive statistics and odds of receiving DOACs by gender, age, race, and socioeconomic status were calculated.

Results

A total of 5289 TRICARE Prime and Prime Plus patients within the Military Health System who carried a diagnosis of atrial fibrillation and a CHA2DS2-VASc ≥2 were identified. Of all patients, 2373 (40.71 %) were prescribed a DOAC whereas 287 (4.92 %) were prescribed warfarin within 90 days of diagnosis of atrial fibrillation. Black patients were significantly less likely to be prescribed a DOAC compared to White patients (adjusted odds ratio [aOR], 0.82; 95 % CI 0.68-0.99), as were females compared to males (aOR, 0.64; 95 % CI 0.52-0.79). Senior officers were significantly more likely to be prescribed a DOAC compared to senior enlisted service members (aOR, 0.64; 95 % CI 0.52-0.79).

Conclusions

Our study shows that differences exist within the Military Health System in the prescription of DOACs for atrial fibrillation by race, gender, and socio-economic status. These differences cannot be explained by differences in access to insurance or cost of medications.

Long-term amelioration of an early-onset familial atrial fibrillation model with AAV-mediated in vivo gene therapy

Atrial fibrillation (AF) is a common cardiac disease with high prevalence in the general population. Despite a mild manifestation at the onset stage, it causes serious consequences, including sudden death, when the disease progresses to the late stage. Most available treatments of AF focus on symptom management or alleviation, due to a lack of fundamental knowledge and the fact that considerable variations of AF exist. With the popularisation of the next-generation sequencing technology, several causal genetic factors, including MYL4, have been discovered to contribute to AF, giving hope to developing its gene therapies. In this study, we attempted to treat a previously established rat AF model, which carried Myl4E11K/E11K loss of function mutation, via overexpression of exogenous wild-type Myl4 by AAV9 vectors. Our results showed that delivery of Myl4 expressing AAV9 to postnatal rat models rescued the symptoms of AF, indicating the therapeutic potential that early gene therapy intervention can achieve long-term effects in treating cardiac arrhythmias caused by gene mutations.

Lipid levels in midlife and risk of atrial fibrillation over 3 decades-Experience from the Swedish AMORIS cohort: A cohort study

BACKGROUND

The role of cholesterol levels in the development of atrial fibrillation (AF) is still controversial. In addition, whether and to what extent apolipoproteins are associated with the risk of AF is rarely studied. In this study, we aimed to investigate the association between blood lipid levels in midlife and subsequent risk of new-onset AF.

METHODS AND FINDINGS

This population-based study included 65,136 individuals aged 45 to 60 years without overt cardiovascular diseases (CVDs) from the Swedish Apolipoprotein-Related Mortality Risk (AMORIS) cohort. Lipids were measured in 1985 to 1996, and individuals were followed until December 31, 2019 for incident AF (i.e., study outcome). Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated using Cox regression, adjusting for age, sex, and socioeconomic status. Over a mean follow-up of 24.2 years (standard deviation 7.5, range 0.2 to 35.9), 13,871 (21.3%) incident AF cases occurred. Higher levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) were statistically significantly associated with a lower risk of AF during the first 5 years of follow-up (HR = 0.61, 95% CI: 0.41 to 0.99, p = 0.013; HR = 0.64, 95% CI: 0.45 to 0.92, p = 0.016), but not thereafter (HR ranging from 0.94 [95% CI: 0.89 to 1.00, p = 0.038] to 0.96 [95% CI: 0.77 to 1.19, p > 0.05]). Lower levels of high-density lipoprotein cholesterol (HDL-C) and apolipoprotein A-I (ApoA-I) and higher triglycerides (TG)/HDL-C ratio were statistically significantly associated with a higher risk of AF during the entire follow-up (HR ranging from 1.13 [95% CI: 1.07 to 1.19, p < 0.001] to 1.53 [95% CI: 1.12 to 2.00, p = 0.007]). Apolipoprotein B (ApoB)/ApoA-I ratio was not associated with AF risk. The observed associations were similar among those who developed incident heart failure (HF)/coronary heart disease (CHD) and those who did not. The main limitations of this study include lack of adjustments for lifestyle factors and high blood pressure leading to potential residual confounding.

CONCLUSIONS

High TC and LDL-C in midlife was associated with a lower risk of AF, but this association was present only within 5 years from lipid measurement and not thereafter. On the contrary, low HDL-C and ApoA-I and high TG/HDL-C ratio were associated with an increased risk of AF over almost 35 years of follow-up. ApoB/ApoA-I ratio was not associated with AF risk.

Premature Atrial Contractions and Their Determinants in a General Population of Japanese Men

BACKGROUND

Premature atrial contractions (PACs) are predictors of atrial fibrillation, stroke, and cardiovascular mortality. The present study aimed to assess relevant factors for PACs among a general population of Japanese men.

METHODS AND RESULTS

This study conducted a population-based, cross-sectional study among 517 men, aged 40-79 years, with neither apparent myocardial infarction nor atrial fibrillation. 24-h Holter electrocardiography to assess PAC frequency was used. Age, body mass index, height, low-density lipoprotein cholesterol, triglycerides, high-density lipoprotein cholesterol, mean heart rate, diabetes mellitus, hypertension, physical activity, smoking, alcohol consumption, and lipid-lowering therapy were included in multivariable negative binomial regression analyses to assess correlation for the number of PACs per hour. Almost all participants (99%) had at least 1 PAC in 1 h (median number 2.84 PACs per h). In multivariable negative binomial regression after adjusting for all covariates simultaneously, age (relative risk [95% confidence interval], 1.30 [1.08-1.57] per 1-standard deviation [SD] increment), height (1.19 [1.02-1.39] per 1-SD increment), triglycerides (0.79 [0.65-0.97] per 1-SD increment), mean heart rate (0.69 [0.59-0.80] per 1-SD increment), physical activity (0.63 [0.43-0.93]), current smoking (1.69 [1.06-2.69]), current moderate (1.97 [1.23-3.16]) and heavy (1.84 [1.12-3.01]) alcohol consumption were independently associated with PAC frequency.

CONCLUSIONS

PAC frequency was independently associated with age, height, smoking, alcohol consumption, heart rate, physical activity, and triglycerides.

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

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

Exosomes in atrial fibrillation: therapeutic potential and role as clinical biomarkers

Atrial fibrillation (AF), the most common cardiac arrhythmia, is a global epidemic. AF can cause heart failure and myocardial infarction and increase the risk of stroke, disability, and thromboembolic events. AF is becoming increasingly ubiquitous and is associated with increased morbidity and mortality at higher ages, resulting in an increasing threat to human health as well as substantial medical and social costs. Currently, treatment strategies for AF focus on controlling heart rate and rhythm with medications to restore and maintain sinus rhythm, but this approach has limitations. Catheter ablation is not entirely satisfactory and does not address the issues underlying AF. Research exploring the mechanisms causing AF is urgently needed for improved prevention, diagnosis, and treatment of AF. Exosomes are small vesicles (30-150 nm) released by cells that transmit information between cells. MicroRNAs in exosomes play an important role in the pathogenesis of AF and are established as a biomarker for AF. In this review, a summary of the role of exosomes in AF is presented. The role of exosomes and microRNAs in AF occurrence, their therapeutic potential, and their potential role as clinical biomarkers is considered. A better understanding of exosomes has the potential to improve the prognosis of AF patients worldwide, reducing the global medical burden of this disease.

Homocysteine and atrial fibrillation: novel evidences and insights

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

Elevated plasma Ninjurin-1 levels in atrial fibrillation is associated with atrial remodeling and thromboembolic risk

BACKGROUND

Nerve injury-induced protein 1 (Ninj1) is elevated in various inflammatory diseases. The soluble form of Ninj1 yield by matrix metalloproteinase cleavage is a secreted protein and inhibits cell adhesion and inflammation. However, the role of plasma Ninj1 in atrial fibrillation (AF) has not been reported. The present study aimed to investigate the correlation between plasma Ninj1 levels and AF.

METHODS

A total of 96 AF patients [age 66.00 (60.00, 72.00) years, male 56 (58.33%)] and 51 controls without AF [age 65.00 (55.00, 68.00) years, male 21 (41.18%)] were enrolled in this study. Plasma Ninj1 concentrations were detected using enzyme-linked immunosorbent assay. Also, the clinical characteristics, left atrial volume index (LAVI), CHA2DS2-VASc score, and HAS-BLED score were evaluated.

RESULTS

Plasma Ninj1 levels were significantly higher in patients with AF than in controls (P < 0.001). Plasma Ninj1 levels were positively correlated with LAVI (P = 0.019) and CHA2DS2-VASc score (P = 0.024). Logistic regression analysis confirmed that the Ninj1 plasma levels were associated with AF (P = 0.009). The receiver operating characteristic analysis showed that plasma Ninj1 had a predictive value for AF (P < 0.001).

CONCLUSIONS

Plasma Ninj1 levels were elevated in patients with AF, associated with left atrial enlargement and thromboembolic risk in AF.

Epicardial adipose tissue in contemporary cardiology

Interest in epicardial adipose tissue (EAT) is growing rapidly, and research in this area appeals to a broad, multidisciplinary audience. EAT is unique in its anatomy and unobstructed proximity to the heart and has a transcriptome and secretome very different from that of other fat depots. EAT has physiological and pathological properties that vary depending on its location. It can be highly protective for the adjacent myocardium through dynamic brown fat-like thermogenic function and harmful via paracrine or vasocrine secretion of pro-inflammatory and profibrotic cytokines. EAT is a modifiable risk factor that can be assessed with traditional and novel imaging techniques. Coronary and left atrial EAT are involved in the pathogenesis of coronary artery disease and atrial fibrillation, respectively, and it also contributes to the development and progression of heart failure. In addition, EAT might have a role in coronavirus disease 2019 (COVID-19)-related cardiac syndrome. EAT is a reliable potential therapeutic target for drugs with cardiovascular benefits such as glucagon-like peptide 1 receptor agonists and sodium–glucose co-transporter 2 inhibitors. This Review provides a comprehensive and up-to-date overview of the role of EAT in cardiovascular disease and highlights the translational nature of EAT research and its applications in contemporary cardiology.

In this Review, Iacobellis provides a comprehensive overview of the role of epicardial adipose tissue (EAT) in cardiovascular disease, including coronary artery disease, heart failure and atrial fibrillation, discusses imaging techniques for EAT assessment and highlights the therapeutic potential of targeting EAT in cardiovascular disease.

Epicardial adipose tissue (EAT) has anatomical and functional interactions with the heart owing to the shared circulation and the absence of muscle fascia separating the two organs.

EAT can be clinically measured with cardiac imaging techniques that can help to predict and stratify cardiovascular risk.

Regional distribution of EAT is important because pericoronary EAT and left atrial EAT differently affect the risk of coronary artery diseases and atrial fibrillation, respectively.

EAT has a role in the development of several cardiovascular diseases through complex mechanisms, including gene expression profile, pro-inflammatory and profibrotic proteome, neuromodulation, and glucose and lipid metabolism.

EAT could be a potential therapeutic target for novel cardiometabolic medications that modulate adipose tissue such as glucagon-like peptide 1 receptor agonists and sodium–glucose co-transporter 2 inhibitors.

EAT might be a reservoir of severe acute respiratory syndrome coronavirus 2 and an amplifier of coronavirus disease 2019 (COVID-19)-related cardiac syndrome.

Pathophysiological aspects of insulin resistance in Atrial Fibrillation: novel therapeutic approaches

Background

Insulin resistance is associated with metabolic disorders including diabetes, obesity, hypertension, and inflammation which are the risk factors for Atrial Fibrillation. Many studies have reported that type 2 diabetes and AF are related and also their prevalence is increasing globally. Moreover, insulin resistance begins the type 2 diabetes.

Main body

This review explains the pathophysiological aspects of insulin resistance in AF patients and discusses the drugs that are used to manage insulin resistance including Biguanides (metformin), thiazolidinediones (TZDs) [Pioglitazone, rosiglitazone], Sodium-glucose cotransporter 2 (SGLT2) inhibitors, Concentrated Insulin Products, Dipeptidyl peptidase-4 (DPP-4) Inhibitors, Glucagon-like peptide 1 (GLP-1) receptor Agonists, Pramlintide, Sulfonylureas, Meglitinides, α-Glucosidase Inhibitors, Colesevelam, Bromocriptine. This review will highlight a few major drugs that played a significant role in AF patients. For this purpose, many databases were used for reviewing the literature and keywords are used such as Insulin Resistance, Pathophysiology, Atrial Fibrillation, and Drugs.

Conclusion

This review article concludes that insulin resistance is related to AF. It also provides an outlook on the recent pathophysiological aspects of insulin resistance in AF; however, more studies are needed to clarify the management of insulin resistance in AF patients to prevent the development of type 2 diabetes.

The Diagnostic and Therapeutic Potential of Galectin-3 in Cardiovascular Diseases

Galectin-3 plays a prominent role in chronic inflammation and has been implicated in the development of many disease conditions, including heart disease. Galectin-3, a regulatory protein, is elevated in both acute and chronic heart failure and is involved in the inflammatory pathway after injury leading to myocardial tissue remodelling. We discussed the potential utility of galectin-3 as a diagnostic and disease severity/prognostic biomarker in different cardio/cerebrovascular diseases, such as acute ischemic stroke, acute coronary syndromes, heart failure and arrhythmogenic cardiomyopathy. Over the last decade there has been a marked increase in the understanding the role of galectin-3 in myocardial fibrosis and inflammation and as a therapeutic target for the treatment of heart failure and myocardial infarction.

Patient-specific and healthcare real-world costs of atrial fibrillation in individuals treated with direct oral anticoagulant agents or warfarin

BACKGROUND

Anticoagulant therapies are used to prevent atrial fibrillation-related strokes, with warfarin and direct oral anticoagulant (DOAC) the most common. In this study, we incorporate direct health care costs, drug costs, travel costs, and lost working and leisure time costs to estimate the total costs of the two therapies.

METHODS

This retrospective study used individual-level patient data from 4000 atrial fibrillation (AF) patients from North Karelia, Finland. Real-world data on healthcare use was obtained from the regional patient information system and data on reimbursed travel costs from the database of the Social Insurance Institution of Finland. The costs of the therapies were estimated between June 2017 and May 2018. Using a Geographical Information System (GIS), we estimated travel time and costs for each journey related to anticoagulant therapies. We ultimately applied therapy and travel costs to a cost model to reflect real-world expenditures.

RESULTS

The costs of anticoagulant therapies were calculated from the standpoint of patient and the healthcare service when considering all costs from AF-related healthcare visits, including major complications arising from atrial fibrillation. On average, the annual cost per patient for healthcare in the form of public expenditure was higher when using DOAC therapy than warfarin therapy (average cost = € 927 vs. € 805). Additionally, the average annual cost for patients was also higher with DOAC therapy (average cost = € 406.5 vs. € 296.7). In warfarin therapy, patients had considerable more travel and time costs due the different implementation practices of therapies.

CONCLUSION

The results indicated that DOAC therapy had higher costs over warfarin from the perspectives of the patient and healthcare service in the study area on average. Currently, the cost of the DOAC drug is the largest determinator of total therapy costs from both perspectives. Despite slightly higher costs, the patients on DOAC therapy experienced less AF-related complications during the study period.

Biomarkers in the clinical management of patients with atrial fibrillation and heart failure

Atrial fibrillation (AF) and heart failure (HF) are two cardiovascular diseases with an increasing prevalence worldwide. These conditions share common pathophysiologiesand frequently co-exit. In fact, the occurrence of either condition can 'cause' the development of the other, creating a new patient group that demands different management strategies to that if they occur in isolation. Regardless of the temproral association of the two conditions, their presence is linked with adverse cardiovascular outcomes, increased rate of hospitalizations, and increased economic burden on healthcare systems. The use of low-cost, easily accessible and applicable biomarkers may hasten the correct diagnosis and the effective treatment of AF and HF. Both AF and HF effect multiple physiological pathways and thus a great number of biomarkers can be measured that potentially give the clinician important diagnostic and prognostic information. These will then guide patient centred therapeutic management. The current biomarkers that offer potential for guiding therapy, focus on the physiological pathways of miRNA, myocardial stretch and injury, oxidative stress, inflammation, fibrosis, coagulation and renal impairment. Each of these has different utility in current clinincal practice.

Analyzing artificial intelligence systems for the prediction of atrial fibrillation from sinus-rhythm ECGs including demographics and feature visualization

Atrial fibrillation (AF) is an abnormal heart rhythm, asymptomatic in many cases, that causes several health problems and mortality in population. This retrospective study evaluates the ability of different AI-based models to predict future episodes of AF from electrocardiograms (ECGs) recorded during normal sinus rhythm. Patients are divided into two classes according to AF occurrence or sinus rhythm permanence along their several ECGs registry. In the constrained scenario of balancing the age distributions between classes, our best AI model predicts future episodes of AF with area under the curve (AUC) 0.79 (0.72-0.86). Multiple scenarios and age-sex-specific groups of patients are considered, achieving best performance of prediction for males older than 70 years. These results point out the importance of considering different demographic groups in the analysis of AF prediction, showing considerable performance gaps among them. In addition to the demographic analysis, we apply feature visualization techniques to identify the most important portions of the ECG signals in the task of AF prediction, improving this way the interpretability and understanding of the AI models. These results and the simplicity of recording ECGs during check-ups add feasibility to clinical applications of AI-based models.

Oral anticoagulation patterns and prognosis in octogenarian patients with atrial fibrillation

The relationship between oral anticoagulants (OACs) and prognosis in elderly patients with atrial fibrillation (AF) has not been adequately explored. In this retrospective cohort study, we identified subjects aged over 80 from a database of 1140 AF patients discharged from the cardiology ward of a single tertiary center between 2015 and 2018. We examined the OAC treatment of octogenarian patients at discharge [VKA (vitamin K antagonist), NOAC (non-vitamin K antagonist oral anticoagulant), no OAC treatment]. We analyzed follow-up data of patients on OAC at discharge. The primary endpoint was all-cause death. The secondary endpoint was the incidence of stroke and major bleeding. The association of NOAC versus VKA treatment with these endpoints was assessed with multivariable Cox regression, using the VKA group as reference. A total of 330 octogenarian patients with AF were included with a mean (± SD) age of 83.9 ± 3.5 years. At discharge, 53.3% received a NOAC, 30% a VKA, and 16.7% no OAC. Patients on OAC were followed-up over a median of 2.6-years . The adjusted risk of all-cause death was not different in the NOAC group, compared with the VKA group (hazard ratio [HR], 0.72; 95% confidence intervals [CI] 0.50-1.03; P = 0.07). The risk of stroke or major bleeding was not different either (all P > 0.05). In conclusion, in this cohort of post-discharge octogenarian patients with AF, the risk for all-cause death was similar in NOAC versus VKA users, after adjustment for baseline covariates. No differences in stroke and major bleeding events among these treatment groups were revealed.

Establishment and evaluation of a nomogram prediction model for recurrence risk of atrial fibrillation patients after radiofrequency ablation

OBJECTIVE

To explore the risk factors for recurrence of atrial fibrillation (AF) in patients after radiofrequency ablation and construction of a targeted nomogram prediction model.

METHODS

A prospective cohort study design was used to select 312 patients who were separated into two groups; a recurrence group (n = 79) and a non-recurrence group (n = 233) with or without AF, who underwent radiofrequency ablation for the first time between January 2017 and December 2017, with a completed a 12-month follow-up after surgery. The recurrence of AF within 12 months after follow-up was recorded. The nomogram prediction model was established. The original data were resampled using the Bootstrap method. The recurrence risk after resampling was predicted using a nomogram model. The calibration curve and ROC curve of the nomogram model were established. The predicted calibration degree and discrimination degree of the nomogram model were evaluated with the Hosmer-Lemeshow deviation test and area under the curve.

RESULTS

The 12-month follow-up showed that a total of 79 patients (25.32%) had recurrence of AF. The type of AF, sex, gender, disease course, left atrial anteroposterior diameter, left atrial volume, and cardiac function classification were independent risk factors for the recurrence of AF (P < 0.05). After the nomogram prediction model passed the Bootstrap self-sampling 1000 times, Hosmer-Lemeshow deviation test: χ² = 8.070, P = 0.427; the area under ROC curve was 0.852 (95% CI: 0.806-0.898), the sensitivity was 78.48%, and the specificity was 81.12%, suggesting that the nomogram model has better predictive calibration and discrimination.

CONCLUSION

The recurrence rate in patients with AF after radiofrequency ablation is high. The nomogram model based on the risk factors of AF recurrence has high prediction accuracy and can be used to predict the recurrence risk of AF in patients after radiofrequency ablation.

Connexin 43 participates in atrial electrical remodelling through colocalization with calcium channels in atrial myocytes

Atrial fibrillation (AF) is associated with atrial conduction disturbances caused by electrical and/or structural remodelling. In the present study, we hypothesized that connexin might interact with the calcium channel through forming a protein complex and, then, participates in the pathogenesis of AF. Western blot and whole-cell patch clamp showed that protein levels of Cav1.2 and connexin 43 (Cx43) and basal I_{Ca , L} were decreased in AF subjects compared to sinus rhythm (SR) controls. In cultured atrium-derived myocytes (HL-1 cells), knocking-down of Cx43 or incubation with 30 mmol/L glycyrrhetinic acid significantly inhibited protein levels of Cav1.2 and Cav3.1 and the current density of I_{Ca , L} and I_{Ca , T} . Incubation with nifedipine or mibefradil decreased the protein level of Cx43 in HL-1 cells. Moreover, Cx43 was colocalized with Cav1.2 and Cav3.1 in atrial myocytes. Therefore, Cx43 might regulate the I_{Ca , L} and I_{Ca , T} through colocalization with calcium channel subunits in atrial myocytes, representing a potential pathogenic mechanism in AF.

Midterm results of stand-alone thoracoscopic epicardial ablation with box lesion for atrial fibrillation

OBJECTIVES

The short-term results of video-assisted thoracoscopic surgical ablation (VTSA) with box lesion have been highly variable, and the actual efficacy requires clarification through longer follow-ups. We aimed to report which patients might benefit more from VTSA with box lesion by longer follow-up.

METHODS

From September 2010 to November 2016, patients with atrial fibrillation (AF) who underwent VTSA with box lesion were screened. All enrolled patients visited the outpatient clinic and underwent 24-h Holter monitoring at 3, 6 and 12 months after surgery and annually thereafter.

RESULTS

A total of 91 consecutive patients [age, 58.0 (interquartile interval from 52.0 to 62.0) years; male, 71.4%] with paroxysmal (67%) or persistent/long-standing persistent (33%) AF were enrolled. After a median follow-up of 48 months (interquartile interval from 36 to 60 months), freedom from atrial tachyarrhythmias without antiarrhythmic drugs (AADs) was 76.5%, 66.0% and 66.0% for paroxysmal AF and 58.6%, 47.8% and 34.2% for persistent/long-standing persistent AF at 12, 36 and 60 months, respectively (P = 0.017). The preoperative left atrial diameter >40 mm (hazard ratio: 2.837, 95% confidence interval: 1.408-5.716; P = 0.004) and age >50 years (hazard ratio: 2.927, 95% confidence interval: 1.359-6.305; P = 0.006) were associated with recurrences of atrial tachyarrhythmias. In patients with paroxysmal AF and left atrial diameter ≤40 mm (n = 43), freedom from atrial tachyarrhythmias without AADs was 81.4%, 74.3% and 74.3% at 12, 36 and 60 months, respectively.

CONCLUSIONS

In patients with paroxysmal AF and left atrial diameter ≤40 mm, 5-year freedom from atrial tachyarrhythmias without AADs was 74.3%, which was better than that in patients with left atrial diameter >40 mm. A larger sample size and improved study design are needed to confirm our conclusions.

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

AIMS

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

METHODS AND RESULTS

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

CONCLUSION

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

Appraising the Causal Association of Plasma Homocysteine Levels With Atrial Fibrillation Risk: A Two-Sample Mendelian Randomization Study

Background

Although several observational studies have suggested an association of elevated plasma homocysteine (Hcy) levels with increased risk of atrial fibrillation (AF), it remains unclear whether this association reflects causality. In this study, we aimed to investigate the causal association of plasma Hcy levels with AF risk.

Methods

A two-sample Mendelian randomization (MR) study was designed to investigate the causal association of Hcy with AF. Summary data on association of single nucleotide polymorphisms (SNPs) with Hcy were extracted from the hitherto largest genome-wide association study (GWAS) with up to 44,147 individuals, and statistics data on association of SNPs with AF were obtained from another recently published GWAS with up to 1,030,836 individuals. SNPs were selected at a genome-wide significance threshold (p < 5 × 10^–8). Fixed-effect inverse variance weighting (IVW) method was used to calculate the causal estimate. Other statistical methods and leave-one-out analysis were applied in the follow-up sensitivity analyses. MR-Egger intercept test was conducted to detect the potential directional pleiotropy.

Results

In total, nine SNPs were identified as valid instrumental variables in our two-sample MR analysis. Fixed-effect IVW analysis indicated no evidence of causal association of genetically predicted Hcy with AF. The odds ratio (OR) and 95% confidence interval (CI) of AF per standard deviation (SD) increase in Hcy were 1.077 (0.993, 1.168), p = 0.075. Similar results were observed in the sensitivity analyses. MR-Egger intercept test suggested no evidence of potential horizonal pleiotropy.

Conclusions

This two-sample MR analysis found no evidence to support causal association of Hcy with AF.

The relation between the atrial blood supply and the complexity of acute atrial fibrillation

Background

Patients with a history of myocardial infarction and coronary artery disease (CAD) have a higher risk of developing AF. Conversely, patients with atrial fibrillation (AF) have a higher risk of developing myocardial infarction, suggesting a link in underlying pathophysiology. The aim of this study was to assess whether coronary angiographic parameters are associated with a substrate for AF in patients without a history of AF.

Methods

During cardiac surgery in 62 patients (coronary artery bypass grafting (CABG;n = 47), aortic valve replacement (AVR;n = 9) or CABG + AVR (n = 6)) without a history of clinical AF (age 65.4 ± 8.5 years, 26.2% female), AF was induced by burst pacing. The preoperative coronary angiogram (CAG) was assessed for the severity of CAD, and the adequacy of atrial coronary blood supply as quantified by a novel scoring system including the location and severity of right coronary artery disease in relation to the right atrial branches. Epicardial mapping of the right atrium (256 unipolar electrodes) was used to assess the complexity of induced AF.

Results

There was no association between the adequacy of right atrial coronary blood supply on preoperative CAG and AF complexity parameters. Multivariable analysis revealed that only increasing age (B0.232 (0.030;0.433),p = 0.03) and the presence of 3VD (B3.602 (0.187;7.018),p = 0.04) were independently associated with an increased maximal activation time difference.

Conclusions

The adequacy of epicardial right atrial blood supply is not associated with increased complexity of induced atrial fibrillation in patients without a history of clinical AF, while age and the extent of ventricular coronary artery disease are.

The Long-Term Impact of Bariatric Surgery on Development of Atrial Fibrillation and Cardiovascular Events in Obese Patients: An Historical Cohort Study

Objective: To determine whether early Roux-en-Y gastric bypass surgery (RYGB) reduces the risk of Major adverse cardiovascular events (MACE) in patients with obesity. Patients and Methods: We conducted a study of patients with class II and III obesity [body mass index (BMI) > 35 kg/m²] from Olmsted County, Minnesota, who underwent obesity clinic consultation between the years 1993-2012, and had either RYGB surgery within 1 year (RYGB-1Y group), or medically managed (No-RYGB group). The composite endpoint of MACE (all-cause mortality, stroke, heart failure admission and acute myocardial infarction) was the primary endpoint, with new-onset AF as the secondary endpoint. Results: Of the 1,009 study patients, 308 had RYGB-1Y and 701 were medically managed (No-RYGB). Overall, the age was 44.0 ± 12.4 (mean ± SD) years; BMI was 45.0 ± 6.8 kg/m². The RYGB-1Y group had a lower rate of MACE (adjusted hazard ratio (HR), 0.62; 95% CI, 0.44-0.88; P = 0.008) and lower mortality (adjusted HR, 0.51; 95% CI, 0.26-0.96; P = 0.04) than the No-RYGB group. The RYGB-1Y surgery was not associated with lower AF occurrence (HR, 0.66; 95% CI, 0.40-1.10; P = 0.11). Conclusion: An early RYGB approach for BMI reduction was associated with lower rates of MACE.

ZFHX3 knockdown dysregulates mitochondrial adaptations to tachypacing in atrial myocytes through enhanced oxidative stress and calcium overload

AIM

To investigate the role of zinc finger homeobox 3 gene (ZFHX3) in tachypacing-induced mitochondrial dysfunction and explore its molecular mechanisms and potential as a therapeutic target in atrial fibrillation (AF).

METHODS

Through a bioluminescent assay, a patch clamp, confocal fluorescence and fluorescence microscopy, microplate enzyme activity assays and Western blotting, we studied ATP and ADP production, mitochondrial electron transfer chain complex activities, ATP-sensitive potassium channels (I_KATP ), mitochondrial oxidative stress, Ca²⁺ content, and protein expression in control and ZFHX3 knockdown (KD) HL-1 cells subjected to 1 and 5-Hz pacing for 24 hours.

RESULTS

Compared with 1-Hz pacing, 5-Hz pacing increased ATP and ADP production, I_KATP , phosphorylated adenosine monophosphate-activated protein kinase and inositol 1,4,5-triphosphate (IP₃ ) receptor (IP₃ R) protein expression. Tachypacing induced mitochondrial oxidative stress and Ca²⁺ overload in both cell types. Furthermore, under 1- and 5-Hz pacing, ZFHX3 KD cells showed higher I_KATP , ATP and ADP production, mitochondrial oxidative stress and Ca²⁺ content than control cells. Under 5-Hz pacing, 2-aminoethoxydiphenyl borate (2-APB; 3 μmol/L, an IP₃ R inhibitor) and MitoTEMPO (10 µmol/L, a mitochondria-targeted antioxidant) reduced ADP and increased ATP production in both cell types; however, only 2-APB significantly reduced mitochondrial Ca²⁺ overload in control cells. Under 5-Hz pacing, mitochondrial oxidative stress was significantly reduced by both MitoTEMPO and 2-APB and only by 2-APB in control and ZFHX3 KD cells respectively.

CONCLUSION

ZFHX3 KD cells modulate mitochondrial adaptations to tachypacing in HL-1 cardiomyocytes through Ca²⁺ overload, oxidative stress and metabolic disorder. Targeting IP₃ R signalling or oxidative stress could reduce AF.

Rurality and atrial fibrillation: a pathway to virtual engagement and clinical trial recruitment in response to COVID-19

Study Objective

To summarize trial adaptation from in-clinic to virtual design in response to the SARS-2 coronavirus-2 (COVID-19).

Design

A clinical trial of a mobile health intervention to improve chronic disease self-management for rural individuals with atrial fibrillation (AF). The trial has a 4-month intervention - accessible regardless of health or digital literacy - to enhance AF medication adherence and patient experience with 8- and 12-month assessments of sustainability.

Setting

Rural, western Pennsylvania.

Participants

Rural individuals with AF receiving oral anticoagulation for stroke prevention.

Interventions

Enrolled participants underwent a telephone-based orientation, provided verbal consent, and were randomized using a digital platform. They received a smartphone with intervention or control applications and a curriculum on usage tailored for study arm. Participants received study assessments by mail with telephone-based administration and contact for the 12-month trial.

Main Outcome Measures

Successful adaptation to virtual engagement and recruitment.

Results

The study enrolled 18 participants during in-clinic recruitment (January-March 2020). From 5/1/2020 to 5/6/2021 the study team enrolled 130 individuals (median age 72.4 years, range 40.8-92.2; 49.2% women, 63.1% without college degree, and 45.4% with limited health literacy. Retention of participants enrolled using virtual methods during the 4-month intervention phase is 92%.

Conclusions

We report a virtual trial of a mobile health intervention for rural individuals with AF. Our successful implementation suggests promise for engaging geographically isolated rural individuals, potential to enhance digital health access, and advance rural health equity.

Geographical variation and clustering are found in atrial fibrillation beyond socioeconomic differences: a Danish cohort study, 1987-2015

BACKGROUND

The prevalence and incidence rate of atrial fibrillation (AF) increase worldwide and AF is a risk factor for more adverse cardiovascular diseases including stroke. Approximately 44% of AF cases cannot be explained by common individual risk factors and risk might therefore also be related to the environment. By studying geographical variation and clustering in risk of incident AF adjusted for socioeconomic position at an individual level, potential neighbourhood risk factors could be revealed.

METHODS

Initially, yearly AF incidence rates 1987-2015 were estimated overall and stratified by income in a register-based cohort study. To examine geographical variation and clustering in AF, we used both spatial scan statistics and a hierarchical Bayesian Poisson regression analysis of AF incidence rates with random effect of municipalities (n = 98) in Denmark in 2011-2015.

RESULTS

The 1987-2015 cohort included 5,453,639 individuals whereof 369,800 were diagnosed with an incident AF. AF incidence rate increased from 174 to 576 per 100,000 person-years from 1987 to 2015. Inequality in AF incidence rate ratio between highest and lowest income groups increased from 23% in 1987 to 38% in 2015. We found clustering and geographical variation in AF incidence rates, with incidence rates at municipality level being up to 34% higher than the country mean after adjusting for socioeconomic position.

CONCLUSIONS

Geographical variations and clustering in AF incidence rates exist. Compared to previous studies from Alberta, Canada and the United States, we show that geographical variations exist in a country with free access to healthcare and even when accounting for socioeconomic differences at an individual level. An increasing social inequality in AF was seen from 1987 to 2015. Therefore, when planning prevention strategies, attention to individuals with low income should be given. Further studies focusing on identification of neighbourhood risk factors for AF are needed.

Low prevalence of atrial fibrillation in ischaemic stroke: Underestimating a modifiable risk factor

INTRODUCTION

Cerebrovascular disease remains one of the leading causes of morbidity and mortality globally. In South Africa, it was the fourth leading cause of death in 2016, responsible for 5.1% of all deaths - the leading cause of death in individuals 65 years and older. Atrial fibrillation accounts for 15% of all strokes and 25% are diagnosed when patients present with a stroke. We set out to determine the prevalence of atrial fibrillation in patients with confirmed ischaemic strokes in a district level hospital in the Western Cape, South Africa.

METHODS

This descriptive study was conducted at Mitchells Plain Hospital in Cape Town and data was collected over a one-year period. Patients diagnosed with a stroke were identified from an electronic patient register and relevant radiology and clinical data were sourced retrospectively. The diagnosis of ischaemic stroke was confirmed by a CT scan report and ECGs were independently screened by two Emergency Physicians. Ethical approval was granted by the University of Cape Town Human Research Ethics Committee [790/2018].

RESULTS

The proportion of adult patients with a stroke diagnosis was 2%. Of the included cases, 80% had ischaemic strokes and 11% had haemorrhagic strokes. 11% of all patients with ischaemic strokes had atrial fibrillation, 67% of those presumed new. A total of 60 (15%) of all patients with ischaemic stroke were aged 45 years or younger. The inpatient mortality rate was statistically higher in patients who had atrial fibrillation (26% vs 7%, p < 0.001).

CONCLUSION

With the increasing population life expectancy, and prevalence of cardiovascular disease the prevalence of atrial fibrillation and its complications will increase. Since the risk of stroke related to atrial fibrillation can be reduced significantly by oral anticoagulation, further studies should aim to explore barriers and challenges to effective screening.

Preoperative Levels of the Soluble Urokinase-Type Plasminogen Activator Receptor as Predictor for New Episodes of Atrial Fibrillation After Vascular Surgery

INTRODUCTION

The soluble urokinase-type plasminogen activator receptor (suPAR) in uPAR soluble form is produced when the uPAR is cleaved from the cell membrane during the inflammatory process. Postoperative atrial fibrillation (AF) is the most common perioperative cardiac arrhythmia. It is speculated that elevated suPAR has a role in the development of AF. The aim of our study was to investigate the predictive role of preoperative suPAR in the occurrence of AF during the first 6 months after major vascular surgery.

METHODS

We included 119 male and 63 female patients with an average age of 67.19 ± 6.02 years, without permanent/persistent AF. Basic predictive model (BASIC) included traditional risk factors for AF: age, gender, body mass index-BMI, smoking status, presence of arterial hypertension, diabetes mellitus and dyslipidemia.

RESULTS

Over the 6-month period, 19 (10.4%) patients had one new episode of atrial fibrillation and 2 patients (1.1%) had 2 episodes of paroxysmal atrial fibrillation. Paroxysms of AF were significantly more frequent in patients who had a resection of an abdominal aneurysm than in patients with other types of major vascular surgery. BASIC had good discriminatory ability in the prediction of AF paroxysms during the first 6 months after surgery (AUC = 0.715, 95%CI 0.590-0.840). Adding suPAR to the basic model significantly improved the discriminative ability of the predictive model for AF episodes (ΔAUC = 0.238, p < 0.001). The predictive performance of the model BASIC+CRP+suPAR, measured using AUC, NRI and IDI statistics, was very similar to the model BASIC+suPAR.

CONCLUSION

AF is a common complication in surgical patients with high mortality and morbidity. suPAR could improve the ability of traditional risk factors to predict its occurrence up to 6 months after major vascular surgery.

The combined application of the contrast-to-noise index and 80 kVp for cardiac CTA scanning before atrial fibrillation ablation reduces radiation dose exposure

INTRODUCTION

To compare the radiation dose, diagnostic accuracy, and the resultant ablation procedures using 80 and 120-kVp cardiac computed tomography angiography (CCTA) protocols with the same contrast-to-noise ratio in patients scheduled for atrial fibrillation (AF) ablation.

METHODS

This retrospective study was performed following institutional review board approval. We divided 140 consecutive patients who had undergone CCTA using a 64-MDCT scanner into two equal groups. Standard deviation (SD) of the CT number was set at 25 Hounsfield units (HU) for the 120-kVp protocol. To facilitate a reduction in radiation dose it was set at 40 HU for the 80 kVp protocol. We compared the two protocols with respect to the radiation dose, the diagnostic accuracy for detecting left atrial appendage (LAA) thrombi, matching for surface registration, and the resultant ablation procedures.

RESULTS

At 120 kVp, the dose length product (DLP) was 2.2 times that at 80 kVp (1269.0 vs 559.0 mGy cm, p < 0.01). The diagnostic accuracy for thrombus detection was 100% using both protocols. There was no difference between the two protocols with respect to matching for surface registration. The protocols did not differ with respect to the subsequent time required for the ablation procedures and the ablation fluoroscopy time, and the radiation dose (p = 0.54, 0.33, and 0.32, respectively).

CONCLUSION

For the same CNR, the DLP at 80 kVp (559.0 mGy cm) was 56% of that delivered at 120 kVp (1269.0 mGy cm). There was no reduction in diagnostic accuracy.

IMPLICATIONS FOR PRACTICE

Maintaining CNR allows for a reduction in the radiation dose without reducing the image quality.

Left atrial wall dyskinesia assessed during contractile phase as a predictor of atrial fibrillation recurrence after electrical cardioversion performed due to persistent atrial fibrillation

Direct current cardioversion (DCCV) is one of the basic methods for restoring sinus rhythm (SR) in patients with atrial fibrillation (AF). Left atrial (LA) strain is one of the parameters used to assess the risk of AF recurrence following DCCV. Assessing the strain also allows for the detection of segmental disorders of LA wall contractility, including dispersion or dyskinesia. In the present study, we determined the predictive value of LA wall dyskinesia in assessing the risk of AF recurrence after DCCV. We performed a comprehensive echocardiography in 89 patients with persistent AF following successful DCCV. We assessed the strain and strain rate in the reservoir (r), conduit, and contractile (ct) phases by using speckle tracking echocardiography. Dyskinesia was diagnosed when the strain rate of any segment of the LA wall displayed positive values during contraction. After 12 months, 47.2% of patients maintained SR. Patients who maintained SR had a significantly lower LA strain (LAS)r assessed in the apical 4-chamber view (4c) (11.38 ± 4.63 vs 14.54 ± 5.11; P = .004) and 2-chamber view (2c) (11.05 ± 4.1 vs 14.93 ± 6.82%; P = .006), LASct4c (2.51 ± 2.3 vs 5.09 ± 3.29%; P < .001), LASct2c (3.6 ± 2.98 vs 5.67 ± 4.23%; P = .008), peak strain rate (pLASR) ct4c (0.36 ± 0.24 s vs 0.62 ± 0.4; P < .001) and pLASRct2c (0.49 ± 0.30 vs 0.79 ± 0.53 s; P = .01). LA dyskinesia was observed less frequently in the 4c view in patients who maintained SR (59.57 vs 17.5%; P < .001). Multivariable logistic regression showed that the LASct4c (odds ratio (OR) 0.78; 95%CI 0.63-0.97; P = .027) and LA dyskinesia observed in the 4c view (OR 3.53; 95%CI 1.16-10.76; P = .027) were significant independent predictors of AF recurrence at 12 months. We conclude that LA dyskinesia observed in the 4c view and LASct4c are independent risk factors for AF recurrence following DCCV.

Combined treatment with valsartan and fluvastatin to delay disease progression in nonpermanent atrial fibrillation with hypertension: A clinical trial

BACKGROUND

Atrial fibrillation (AF) is a complex cardiac arrhythmia in clinical practice with increasing incidence. However, the effects of statins on patients with AF are not quite clear.

HYPOTHESIS

To investigate the protective effect of calcium channel blocker (CCB) and valsartan combined fluvastatin on hypertension (HTN) patients with nonpermanent AF.

METHODS

In three and a half years, 189 cases of patients diagnosed as HTN combining nonpermanent AF by eight medical centers, were recruited and randomly assigned to four groups with varied treatments: CCB group; CCB + statin group; valsartan group; and valsartan + statin group. The four groups were followed up for 24 months. The 7-day Holter ultrasound echocardiography (UCG) and biochemical indexes were completed at preset time nodes respectively.

RESULTS

After 24 months of follow-up, 178 patients completed the study. Compared with CCB group, the blood lipid level, inflammatory index, ultrasonic index and electrocardiographic measurement results of CCB + statin group, valsartan group and valsartan + statin group were improved in different degrees and had statistical significance (P < .05 or P < .01). Furthermore, the improvement trend of CCB + statin group and valsartan + statin group was more obvious.

CONCLUSIONS

The results indicated that valsartan can reduce AF load and recurrence rate, and delay the progression of nonpermanent AF to permanent AF in multiple ways, and the effect of combination of valsartan and fluvastatin is more significant. These results provide a new direction for the integrated upstream control strategy of AF.

Diurnal circadian variations in paroxysmal atrial fibrillation: The atherosclerosis risk in communities (ARIC) study

BACKGROUND

Paroxysmal atrial fibrillation (AF) is challenging to diagnose due to its intermittent nature. Circadian rhythmicity has been reported for cardiovascular events such as myocardial infarction; whether diurnal variation exists for paroxysmal AF is less known. We characterized the temporal pattern of AF initiation in the Atherosclerosis Risk in Communities (ARIC) study, a prospective community-based cohort study.

METHODS

We included 74 ARIC study participants with paroxysmal AF detected by the Zio XT Patch at ARIC Visit 6 in 2016-17. We divided each participant's 2-week continuous monitoring data into 3-h intervals and summed the number of AF episodes in each interval. We performed Poisson regression using generalized estimating equations to estimate the effect of time of day on the number of AF episodes.

RESULTS

Compared to the reference interval of time 00:00-02:59, the time intervals 12:00-14:59, 15:00-17:59, and 18:00-20:59 had significantly higher frequency of AF initiation. Rate ratios (95% CI) for mean number of episodes in these three intervals were 1.91 (1.11, 2.92), 2.54 (1.42, 4.53), and 1.99 (1.19, 3.25) respectively. Furthermore, we found no significant association between duration of episode and time of day.

CONCLUSION

There is diurnal variation in the initiation of AF episodes, with a peak in frequency in the late afternoon. Our finding is consistent with sympathetically driven AF. Pulse palpation or obtaining an electrocardiogram in the late afternoon may produce the highest diagnostic yield for AF.

A Percutaneous Catheter for In Vivo Hyperspectral Imaging of Cardiac Tissue: Challenges, Solutions and Future Directions

PURPOSE

Multiple studies have shown that spectral analysis of tissue autofluorescence can be used as a live indicator for various pathophysiological states of cardiac tissue, including ischemia, ablation-induced damage, or scar formation. Yet today there are no percutaneous devices that can detect autofluorescence signals from inside a beating heart. Our aim was to develop a prototype catheter to demonstrate the feasibility of doing so.

METHODS AND RESULTS

Here we summarize technical solutions leading to the development of a percutaneous catheter capable of multispectral imaging of intracardiac surfaces. The process included several iterations of light sources, optical filtering, and image acquisition techniques. The developed system included a compliant balloon, 355 nm laser irradiance, a high-sensitivity CCD, bandpass filtering, and image acquisition synchronized with the cardiac cycle. It enabled us to capture autofluorescence images from multiple spectral bands within the visible range while illuminating the endocardial surface with ultraviolet light. Principal component analysis and other spectral unmixing post-processing algorithms were then used to reveal target tissue.

CONCLUSION

Based on the success of our prototype system, we are confident that the development of ever more sensitive cameras, recent advances in tunable filters, fiber bundles, and other optical and computational components makes it possible to create percutaneous catheters capable of acquiring hyper or multispectral hypercubes, including those based on autofluorescence, in real-time. This opens the door for widespread use of this methodology for high-resolution intraoperative imaging of internal tissues and organs-including cardiovascular applications.

Comprehensive Analysis of Differential Immunocyte Infiltration and Potential ceRNA Networks Involved in the Development of Atrial Fibrillation

This study is aimed at identifying potential molecular mechanisms and candidate biomarkers in the left atrial regions for the diagnosis and treatment of valvular atrial fibrillation (VAF). Multibioinformatics methods, including linear models for microarray analysis (LIMMA), an SVA algorithm, CIBERSORT immune infiltration, and DNA methylation analysis, were employed. In addition, the protein-protein interaction (PPI) network, Gene Ontology (GO), and molecular pathways of differentially expressed genes (DEGs) or differential methylation regions were constructed. In all, compared with the normal rhythm group, 243 different mRNAs (29 downregulated and 214 upregulated) and 26 different lncRNAs (3 downregulated and 23 upregulated) were detected in the left atrium (LA) of atrial fibrillation (AF) patients, and the neutrophil and CD8⁺ T cell were infiltrated. Additionally, 199 different methylation sites (107 downregulated and 92 upregulated) were also identified based on DNA methylation analysis. After integration, ELOVL2, CCR2, and WEE1 were detected for differentially methylated and differentially transcribed genes. Among them, WEE1 was also a core gene identified by the competing endogenous RNA (ceRNA) network that included WEE1-KRBOX1-AS1-hsa-miR-17-5p, in VAF left atrial tissue. We combined the DNA methylation and transcriptional expression differential analysis and found that WEE1 (cg13365543) may well be a candidate gene regulated by DNA methylation modification. Moreover, KRBOX1-AS1 and WEE1 can compete endogenously and may mediate myocardial tissue infiltration into CD8⁺ T cells and participate in the AF process.

Mitochondrial DNA copy number and incident atrial fibrillation

BACKGROUND

Mechanistic studies suggest that mitochondria DNA (mtDNA) dysfunction may be associated with increased risk of atrial fibrillation (AF). The association between mtDNA copy number (mtDNA-CN) and incident AF in the general population, however, remains unknown.

METHODS

We conducted prospective analyses of 19,709 participants from the Atherosclerosis Risk in Communities Study (ARIC), the Multi-Ethnic Study of Atherosclerosis (MESA), and the Cardiovascular Health Study (CHS). mtDNA-CN from the peripheral blood was calculated from probe intensities on the Affymetrix Genome-Wide Human single nucleotide polymorphisms (SNP) Array 6.0 in ARIC and MESA and from multiplexed real-time quantitative polymerase chain reaction (qPCR) in CHS. Incident AF cases were identified through electrocardiograms, review of hospital discharge codes, Medicare claims, and death certificates.

RESULTS

The median follow-up time was 21.4 years in ARIC, 12.9 years in MESA, and 11.0 years in CHS, during which 4021 participants developed incident atrial fibrillation (1761 in ARIC, 790 in MESA, and 1470 in CHS). In fully adjusted models, participants with the lowest quintile of mitochondria DNA copy number had an overall 13% increased risk (95% CI 1 to 27%) of incident atrial fibrillation compared to those with the highest quintile. Dose-response spline analysis also showed an inverse association between mitochondria DNA copy number and hazard for atrial fibrillation for all three cohorts. These associations were consistent across subgroups.

CONCLUSIONS

Mitochondria DNA copy number was inversely associated with the risk of AF independent of traditional cardiovascular risk factors. These findings implicate mitochondria DNA copy number as a novel risk factor for atrial fibrillation. Further research is warranted to understand the underlying mechanisms and to evaluate the role of mitochondria DNA copy number in the management of atrial fibrillation risk.

Use of Anticoagulants in Patients With Non-Valvular Atrial Fibrillation Who Are at Risk of Falls

Atrial fibrillation (AF) is a relatively common clinical entity with significant morbidity and mortality, particularly in the elderly. Stroke is one of the most significant complications of AF, which can be prevented with the use of anticoagulation. Elder population are at an increased risk of falls and the use of anticoagulation in this group can lead to intracranial hemorrhage. Therefore, it is unclear whether patients at high risk of falls should be anticoagulated. This review article discusses the epidemiology of AF and falls in the elder population, and whether the benefit of anticoagulation outweighs the risks in this group.

Left atrial emptying fraction determined during atrial fibrillation predicts maintenance of sinus rhythm after direct current cardioversion in patients with persistent atrial fibrillation

Echocardiography is the basic imaging technique used to determine the odds of maintaining sinus rhythm (SR) following direct current cardioversion (DCCV) for persistent atrial fibrillation (AF). However, most studies are focused on the echocardiographic parameters obtained during SR resulting from successful DCCV. The aim of this study was to assess the value of the echocardiographic parameters measured before DCCV for the prognosis of SR maintenance after DCCV. The study included 146 patients with persistent AF who underwent DCCV. Clinical and echocardiographic data were collected directly before DCCV and, for patients with SR, one month, six months, and 12 months after DCCV. We found that left atrial emptying fraction (LAEF) assessed during atrial fibrillation was significantly larger in the group with SR maintenance after 12 months than in the group with AF recurrence (30.8±8.3 vs. 24.6±10.4%; p<0.001). In multivariable logistic regression analysis with a model containing echocardiographic parameters, LAEF (OR 1.053; 95% CI 1.011-1.096; p = 0.013) and the E/e'mean ratio (OR 0.883; 95% CI 0.788-0.990; p = 0.033) were independent predictors of SR maintenance. Analyzing a model including clinical and echocardiographic variables, only LAEF (OR 1.046; 95% CI 1-1.095; p = 0.049) and beta-blockers used before DCCV (OR 14.694; 95% CI 1.622-133.139; p = 0.017) were independent predictors of SR maintenance after 12 months. Our results indicate that LAEF measured during AF is a significant predictor of SR maintenance in the 12 months following DCCV due to persistent AF. Our findings confirm the recently raised hypothesis about the superiority of echocardiographic parameters assessing mechanical remodeling over parameters assessing structural remodeling of left atrium in predicting sinus rhythm maintenance after electrical cardioversion.

Interleukin-22 is elevated in the atrium and plasma of patients with atrial fibrillation and increases collagen synthesis in transforming growth factor-β1-treated cardiac fibroblasts via the JNK pathway

Our previous studies demonstrated that interleukin (IL)-22 is involved in cardiovascular diseases such as hypertension, cardiac fibrosis and aortic dissection. The purpose of the present study was to detect IL-22 expression in patients with atrial fibrillation (AF). Atrial tissue was collected from donors with sinus rhythm and patients with permanent AF, and the expression level of IL-22 and its receptors (IL-22R1 and IL-10R2) in both the left atrium (LA) and right atrium (RA) of each sample was detected. Blood samples were also obtained from donors with paroxysmal, persistent and permanent AF and from donors without AF history, and IL-22 levels were measured. In addition, the effects of IL-22 on collagen synthesis in TGF-β1-treated cardiac fibroblasts were investigated. IL-22R1, IL-10R2 and IL-22 expression was elevated in both the LA and RA in permanent AF patients. Elevated IL-22 expression positively correlated with the collagen areas and fibrosis marker levels in the atria of these patients. Plasma IL-22 levels were higher in AF patients compared with healthy donors and increased with increasing AF duration (from paroxysmal to persistent to permanent AF). A positive correlation was observed between IL-22 levels and TGF-β1 levels in AF patients. In vitro, recombinant mouse IL-22 treatment upregulated α-SMA, collagen I and collagen III expression in TGF-β1-treated cardiac fibroblasts. These effects were reversed by SP600125, an inhibitor of the JNK pathway. To conclude, IL-22 levels are elevated in patients with AF and may exacerbate collagen synthesis in TGF-β1-induced cardiac fibroblasts. IL-22 may also influence AF by activating the JNK pathway.

Endocardial and Epicardial Rhythmia HDx™ Mapping Verifies Surgical Cox Maze IV Lesion Pattern

Atrial fibrillation (AF) remains the most common cardiac dysarrhythmia, with a significant impact on the health-care economy. AF occurs as a result of electrical conduction delays within the atrial tissue, which may stem from fibrosis or other mediators that alter atrial tissue conduction substrate. The Cox maze III and IV procedures block these reentry circuits by directly dividing, or breaking, the self-perpetuating circuit and by isolating these circuits away from the intrinsic cardiac conduction pathway. The Convergent procedure, a hybrid approach to AF ablation, coordinates the electrophysiologist and the cardiac surgeon in a simultaneous or sequential endocardial and epicardial procedure. Because the heart remains electrically active, electroanatomical maps, not anatomical landmarks, guide therapy. However, lesion transmurality and contiguity remain inconsistent. The Rhythmia HDx™ mapping system (Boston Scientific, Natick, MA, USA) offers detailed maps of acute lesion patterns during the ablation procedure. However, these maps require instrumentation and technology found in the electrophysiology laboratory, not in the operating room. We herein present a case during which we performed a Cox maze IV procedure and also applied the Rhythmia HDx™ electroanatomical mapping system (Boston Scientific, Natick, MA, USA) at the time of operation. Through this novel approach, we were able to verify the completeness of the lesions created and reach a procedural endpoint confirmed by both epicardial and endocardial maps of successful electrical isolation of the left atrium posterior wall and pulmonary vein pedicle.

Association between insulin resistance and risk of atrial fibrillation in non-diabetics

AIMS

Previous studies from Western countries have been unable to demonstrate a relationship between insulin resistance and new-onset atrial fibrillation. We aimed to evaluate this relationship in the nondiabetic Asian population.

METHODS

Between 2001-2003, 8175 adults (mean age 51.5 years, 53% women) without both existing atrial fibrillation and diabetes and with insulin resistance measures at baseline were enrolled and were followed by biennial electrocardiograms thereafter until 2014. We constructed multivariable-adjusted Cox proportional hazard models for risk of incident atrial fibrillation.

RESULTS

Over a median follow-up of 12.3 years, 136 participants (1.89/1000 person-years) developed atrial fibrillation. Higher homeostasis model assessment of insulin resistance (HOMA-IR) was independently associated with newly developed atrial fibrillation (hazard ratio 1.61, 95% confidence interval 1.14-2.28). Atrial fibrillation development increased at the HOMA-IR levels approximately between 1-2.5, and then plateaued afterwards (p = 0.031).

CONCLUSION

There is a significant relationship between insulin resistance and atrial fibrillation development independent of other known risk factors, including obesity in a nondiabetic Asian population.