The future of atrial fibrillation management: integrated care and stratified therapy

Epigallocatechin-3-Gallate Inhibits Atrial Fibrosis and Reduces the Occurrence and Maintenance of Atrial Fibrillation and its Possible Mechanisms

BACKGROUND

Atrial fibrosis is one of the main causes of the onset and recurrence of atrial fibrillation (AF), for which there is no effective treatment. The aim of this study was to investigate the effect and mechanism of epigallocatechin-3-gallate (EGCG) on AF in rats.

METHODS

The rat model of AF was established by rapid pacing induction after angiotensin-II (Ang-II) induced atrial fibrosis to verify the relationship between atrial fibrosis and the AF. The expression levels of TGF-β/Smad3 pathway molecules and lysyl oxidase (LOX) in AF were detected. Subsequently, EGCG was used to intervene Ang-II-induced atrial fibrosis to explore the role of EGCG in the treatment of AF and its inhibitory mechanism on fibrosis. It was further verified that EGCG inhibited the production of collagen and the expression of LOX through the TGF-β/Smad3 pathway at the cellular level.

RESULTS

The results showed that the induction rate and maintenance time of AF in rats increased with the increase of the degree of atrial fibrosis. Meanwhile, the expressions of Col I, Col III, molecules related to TGF-β/Smad3 pathway, and LOX increased significantly in the atrial tissues of rats in the Ang-II induced group. EGCG could reduce the occurrence and maintenance time of AF by inhibiting the degree of Ang-induced rat atrial fibrosis. Cell experiments confirmed that EGCG could reduce the synthesis of collagen and the expression of LOX in cardiac fibroblast induced by Ang-II. The possible mechanism is to down-regulate the expression of genes and proteins related to the TGF-β/Smad3 pathway.

CONCLUSION

EGCG could downregulate the expression levels of collagen and LOX by inhibiting the TGF-β/Smad3 signaling pathway, alleviating Ang-II-induced atrial fibrosis, which in turn inhibited the occurrence and curtailed the duration of AF.

Reduced plakoglobin increases the risk of sodium current defects and atrial conduction abnormalities in response to androgenic anabolic steroid abuse

Androgenic anabolic steroids (AAS) are commonly abused by young men. Male sex and increased AAS levels are associated with earlier and more severe manifestation of common cardiac conditions, such as atrial fibrillation, and rare ones, such as arrhythmogenic right ventricular cardiomyopathy (ARVC). Clinical observations suggest a potential atrial involvement in ARVC. Arrhythmogenic right ventricular cardiomyopathy is caused by desmosomal gene defects, including reduced plakoglobin expression. Here, we analysed clinical records from 146 ARVC patients to identify that ARVC is more common in males than females. Patients with ARVC also had an increased incidence of atrial arrhythmias and P wave changes. To study desmosomal vulnerability and the effects of AAS on the atria, young adult male mice, heterozygously deficient for plakoglobin (Plako+/-), and wild type (WT) littermates were chronically exposed to 5α-dihydrotestosterone (DHT) or placebo. The DHT increased atrial expression of pro-hypertrophic, fibrotic and inflammatory transcripts. In mice with reduced plakoglobin, DHT exaggerated P wave abnormalities, atrial conduction slowing, sodium current depletion, action potential amplitude reduction and the fall in action potential depolarization rate. Super-resolution microscopy revealed a decrease in NaV1.5 membrane clustering in Plako+/- atrial cardiomyocytes after DHT exposure. In summary, AAS combined with plakoglobin deficiency cause pathological atrial electrical remodelling in young male hearts. Male sex is likely to increase the risk of atrial arrhythmia, particularly in those with desmosomal gene variants. This risk is likely to be exaggerated further by AAS use. KEY POINTS: Androgenic male sex hormones, such as testosterone, might increase the risk of atrial fibrillation in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC), which is often caused by desmosomal gene defects (e.g. reduced plakoglobin expression). In this study, we observed a significantly higher proportion of males who had ARVC compared with females, and atrial arrhythmias and P wave changes represented a common observation in advanced ARVC stages. In mice with reduced plakoglobin expression, chronic administration of 5α-dihydrotestosterone led to P wave abnormalities, atrial conduction slowing, sodium current depletion and a decrease in membrane-localized NaV1.5 clusters. 5α-Dihydrotestosterone, therefore, represents a stimulus aggravating the pro-arrhythmic phenotype in carriers of desmosomal mutations and can affect atrial electrical function.

Borderline personality disorder and risk of atrial fibrillation: insights from a bidirectional Mendelian randomization study

Background

Atrial fibrillation (AF) is one of the most common form of arrhythmia. Previous studies have shown a link between AF and mental illness. However, the causal relationship between mental illness and AF remains unclear. The purpose of this study was to investigate the bidirectional causal relationship between borderline personality disorder (BPD) and AF.

Method

We used the bidirectional Two-sample Mendelian randomization (TSMR) method to evaluate the causal relationship between BPD and AF. Instrumental variables associated with BPD were derived from a genome-wide association study involving 214,816 Europeans (2,637 cases and 212,179 controls). We then obtained atrial fibrillation data from the GWAS meta-analysis (60,620 cases and 970,216 controls). The TSMR analyses were performed in five methods, namely fixed-effect inverse-variance weighted (IVW) method、random-effect IVW method, MR Egger regression method, Weighted median method and Simple mode method. Several sensitivity analyses are used to test the robustness of positive results.

Results

The fixed-effect inverse-variance weighted model [Odds ratio (OR), 1.033, 95% confidence interval (CI), 1.011-1.056, P = 0.0031], random-effect inverse-variance weighted model (OR, 1.033; 95%CI, 1.005-1.062; P = 0.0191) and Weighted median (OR, 1.034; 95%CI, 1.002-1.068; P = 0.0394) all showed that genetically predicted BPD was associated with an increased risk of AF. Sensitivity analysis using other MR Methods, including the MR-Egger intercept, MR-Presso method, and leave-one-out analyses, showed that the results were robust. In reverse MR analysis, there was no causal relationship of AF on BPD.

Conclusion

Our study provides a causal relationship between BPD and AF. This means that patients with BPD should be monitored for the occurrence of AF. Early screening and proper management of BPD may show anti-arrhythmic benefits.

Computational modeling of cardiac electrophysiology and arrhythmogenesis: toward clinical translation

The complexity of cardiac electrophysiology, involving dynamic changes in numerous components across multiple spatial (from ion channel to organ) and temporal (from milliseconds to days) scales, makes an intuitive or empirical analysis of cardiac arrhythmogenesis challenging. Multiscale mechanistic computational models of cardiac electrophysiology provide precise control over individual parameters, and their reproducibility enables a thorough assessment of arrhythmia mechanisms. This review provides a comprehensive analysis of models of cardiac electrophysiology and arrhythmias, from the single cell to the organ level, and how they can be leveraged to better understand rhythm disorders in cardiac disease and to improve heart patient care. Key issues related to model development based on experimental data are discussed, and major families of human cardiomyocyte models and their applications are highlighted. An overview of organ-level computational modeling of cardiac electrophysiology and its clinical applications in personalized arrhythmia risk assessment and patient-specific therapy of atrial and ventricular arrhythmias is provided. The advancements presented here highlight how patient-specific computational models of the heart reconstructed from patient data have achieved success in predicting risk of sudden cardiac death and guiding optimal treatments of heart rhythm disorders. Finally, an outlook toward potential future advances, including the combination of mechanistic modeling and machine learning/artificial intelligence, is provided. As the field of cardiology is embarking on a journey toward precision medicine, personalized modeling of the heart is expected to become a key technology to guide pharmaceutical therapy, deployment of devices, and surgical interventions.

Human induced pluripotent stem cell-derived atrial cardiomyocytes recapitulate contribution of the slowly activating delayed rectifier currents IKs to repolarization in the human atrium

AIMS

Human induced pluripotent stem cell-derived atrial cardiomyocytes (hiPSC-aCM) could be a helpful tool to study the physiology and diseases of the human atrium. To fulfil this expectation, the electrophysiology of hiPSC-aCM should closely resemble the situation in the human atrium. Data on the contribution of the slowly activating delayed rectifier currents (IKs) to repolarization are lacking for both human atrium and hiPSC-aCM.

METHODS AND RESULTS

Human atrial tissues were obtained from patients with sinus rhythm (SR) or atrial fibrillation (AF). Currents were measured in human atrial cardiomyocytes (aCM) and compared with hiPSC-aCM and used to model IKs contribution to action potential (AP) shape. Action potential was recorded by sharp microelectrodes. HMR-1556 (1 µM) was used to identify IKs and to estimate IKs contribution to repolarization. Less than 50% of hiPSC-aCM and aCM possessed IKs. Frequency of occurrence, current densities, activation/deactivation kinetics, and voltage dependency of IKs did not differ significantly between hiPSC-aCM and aCM, neither in SR nor AF. β-Adrenoceptor stimulation with isoprenaline did not increase IKs neither in aCM nor in hiPSC-aCM. In tissue from SR, block of IKs with HMR-1556 did not lengthen the action potential duration, even when repolarization reserve was reduced by block of the ultra-rapid repolarizing current with 4-aminopyridine or the rapidly activating delayed rectifier potassium outward current with E-4031.

CONCLUSION

I Ks exists in hiPSC-aCM with biophysics not different from aCM. As in adult human atrium (SR and AF), IKs does not appear to relevantly contribute to repolarization in hiPSC-aCM.

Management of cerebral amyloid angiopathy and atrial fibrillation: We are still far from precision medicine

The use of anticoagulation therapy could prove to be controversial when trying to balance ischemic stroke and intracranial bleeding risks in patients with concurrent cerebral amyloid angiopathy (CAA) and atrial fibrillation (AF). In fact, CAA is an age-related cerebral vasculopathy that predisposes patients to intracerebral hemorrhage. Nevertheless, many AF patients require oral systemic dose-adjusted warfarin, direct oral anticoagulants (such as factor Xa inhibitors) or direct thrombin inhibitors to control often associated with cardioembolic stroke risk. The prevalence of both CAA and AF is expected to rise, due to the aging of the population. This clinical dilemma is becoming increasingly common. In patients with coexisting AF and CAA, the risks/benefits profile of anticoagulant therapy must be assessed for each patient individually due to the lack of a clear-cut consensus with regard to its risks in scientific literature. This review aims to provide an overview of the management of patients with concomitant AF and CAA and proposes the implementation of a risk-based decision-making algorithm.

The SK4 channel allosteric blocker, BA6b9, reduces atrial fibrillation substrate in rats with reduced ejection fraction

Atrial fibrillation (AF), the most common cardiac arrhythmia, is strongly associated with several comorbidities including heart failure (HF). AF in general, and specifically in the context of HF, is progressive in nature and associated with poor clinical outcomes. Current therapies for AF are limited in number and efficacy and do not target the underlying causes of atrial remodeling such as inflammation or fibrosis. We previously identified the calcium-activated SK4 K+ channels, which are preferentially expressed in the atria relative to the ventricles in both rat and human hearts, as attractive druggable target for AF treatment. Here, we examined the ability of BA6b9, a novel allosteric inhibitor of SK4 channels that targets the specific calmodulin-PIP2 binding domain, to alter AF susceptibility and atrial remodeling in a systolic HF rat postmyocardial infarction (post-MI) model. Daily BA6b9 injection (20 mg/kg/day) for 3 weeks starting 1-week post-MI prolonged the atrial effective refractory period, reduced AF induction and duration, and dramatically prevented atrial structural remodeling. In the post-MI left atrium (LA), pronounced upregulation of the SK4 K+ channel was observed, with corresponding increases in collagen deposition, α-SMA levels, and NLRP3 inflammasome expression. Strikingly, BA6b9 treatment reversed these changes while also significantly reducing the lateralization of the atrial connexin Cx43 in the LA of post-MI rats. Our findings indicate that the blockade of SK4 K+ channels using BA6b9 not only favors rhythm control but also remarkably reduces atrial structural remodeling, a property that is highly desirable for novel AF therapies, particularly in patients with comorbid HF.

Treatment Outcomes of Catheter Ablation Versus Medical Therapy in Patients With Atrial Fibrillation: A Systematic Review

Atrial fibrillation (AF) management has witnessed a paradigm shift, with an increasing emphasis on rhythm control strategies. This systematic review aims to comprehensively assess and compare the efficacy and safety of catheter ablation versus medical therapy in the treatment of AF. A systematic search was conducted across major electronic databases, including PubMed, Embase, and the Cochrane Library, from inception to the present. Randomized controlled trials (RCTs) and observational studies comparing catheter ablation with medical therapy for AF were included. The primary outcomes included rhythm control success, recurrence rates, and adverse events. Secondary outcomes encompassed quality of life, hospitalization rates, and mortality. A total of six studies met the inclusion criteria, comprising 2,859 participants. Catheter ablation significantly improved rhythm control success compared to medical therapy. Subgroup analyses demonstrated variations in outcomes based on patient characteristics, procedural techniques, and follow-up durations. Recurrence rates favored ablation; however, ablation was associated with a higher incidence of minor complications and major adverse events. Catheter ablation demonstrates superior efficacy in achieving and maintaining rhythm control compared to medical therapy in the management of AF. Despite the increased risk of procedural complications, the overall safety profile remains acceptable. This systematic review provides valuable insights for clinicians and informs shared decision-making between patients and healthcare providers when choosing between catheter ablation and medical therapy for AF treatment.

Secondary stroke prevention in people with atrial fibrillation: treatments and trials

Atrial fibrillation is one of the most common cardiac arrhythmias and is a major cause of ischaemic stroke. Recent findings indicate the importance of atrial fibrillation burden (device-detected, subclinical, or paroxysmal and persistent or permanent) and whether atrial fibrillation was known before stroke onset or diagnosed after stroke for the risk of recurrence. Secondary prevention in patients with atrial fibrillation and stroke aims to reduce the risk of recurrent ischaemic stroke. Findings from randomised controlled trials assessing the optimal timing to introduce direct oral anticoagulant therapy after a stroke show that early start (ie, within 48 h for minor to moderate strokes and within 4-5 days for large strokes) seems safe and could reduce the risk of early recurrence. Other promising developments regarding early rhythm control, left atrial appendage occlusion, and novel factor XI inhibitor oral anticoagulants suggest that these therapies have the potential to further reduce the risk of stroke. Secondary prevention strategies in patients with atrial fibrillation who have a stroke despite oral anticoagulation therapy is an unmet medical need. Research advances suggest a heterogeneous spectrum of causes, and ongoing trials are investigating new approaches for secondary prevention in this vulnerable patient group. In patients with atrial fibrillation and a history of intracerebral haemorrhage, the latest data from randomised controlled trials on stroke prevention shows that oral anticoagulation reduces the risk of ischaemic stroke but more data are needed to define the safety profile.

Blood pressure in atrial fibrillation and in sinus rhythm during ambulatory blood pressure monitoring: data from the TEMPLAR project

The coexistence of hypertension and atrial fibrillation (AF) is common and accounts for a worse prognosis. Uncertainties exist regarding blood pressure (BP) measurements in AF patients by automated oscillometric devices. The Microlife WatchBP 03 AFIB ambulatory BP monitoring (ABPM) device including an AF algorithm with each measurement was used in 430 subjects aged >65 years referred for ABPM and with assumed paroxysmal AF to perform intra-individual comparisons of BP during both AF-indicated and sinus rhythm. Only subjects with >30% of measurements indicating AF and episodes >30 min for assumed AF and for sinus rhythm were included. Mean age was 78 ± 7 years, 43% were male, 77% hypertensive, and 72% were treated. Compared to sinus rhythm, 24-h mean arterial pressure was similar (87.2 ± 9.5 vs 87.5 ± 10.6 mm Hg, p = 0.47), whereas 24-h systolic BP tended to be lower (123.6 ± 13.9 vs 124.7 ± 16.1 mm Hg, p = 0.05) and night-time diastolic BP higher (64.6 ± 10.9 vs 63.3 ± 10.4 mm Hg, p = 0.01) in assumed AF. Diastolic (not systolic) BP variability was higher in AF (p < 0.001). Results were similar with heart rates <90 and ≥90 bpm. In conclusion, this is the first study to use intra-individual comparisons of averaged BP during an ABPM in assumed paroxysmal AF and sinus rhythm. Our results imply that ABPM is feasible and informative also in patients with AF. We also suggest that an AF detection algorithm offers a new approach to evaluate the reliability of averaged BP values in AF compared to SR during an ABPM.

Machine learning-based risk models for procedural complications of radiofrequency ablation for atrial fibrillation

BACKGROUND

Radiofrequency ablation (RFA) for atrial fibrillation (AF) is associated with a risk of complications. This study aimed to develop and validate risk models for predicting complications after radiofrequency ablation of atrial fibrillation patients.

METHODS

This retrospective cohort study included 3365 procedures on 3187 patients with atrial fibrillation at a single medical center from 2018 to 2021. The outcome was the occurrence of postoperative procedural complications during hospitalization. Logistic regression, decision tree, random forest, gradient boosting machine, and extreme gradient boosting were used to develop risk models for any postoperative complications, cardiac effusion/tamponade, and hemorrhage, respectively. Patients' demographic characteristics, medical history, signs, symptoms at presentation, electrocardiographic features, procedural characteristics, laboratory values, and postoperative complications were collected from the medical record. The prediction results were evaluated by performance metrics (i.e., the area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, specificity, F score, and Brier score) with repeated fivefold cross-validation.

RESULTS

Of the 3365 RFA procedures, there were 62 procedural complications with a rate of 1.84% in the entire cohort. The most common complications were cardiac effusion/tamponade (28 cases, 0.83%), and hemorrhage (21 cases, 0.80%). There was no procedure-related mortality. The machine learning algorithms of random forest (RF) outperformed other models for any complication (AUC 0.721 vs 0.627 to 0.707), and hemorrhage (AUC 0.839 vs 0.649 to 0.794). The extreme gradient boosting (XGBoost) model outperformed other models for cardiac effusion/tamponade (AUC 0.696 vs 0.606 to 0.662).

CONCLUSIONS

The developed risk models using machine learning algorithms showed good performance in predicting complications after RFA of AF patients. These models help identify patients at high risk of complications and guiding clinical decision-making.

Left Atrial Strain and Incident Atrial Fibrillation in Older Adults

Atrial fibrillation (AF) is frequent in older adults and associated with left atrial (LA) dysfunction. LA strain (LAε) and LA strain rate (LASR) may detect subclinical LA disease. We investigated whether reduced LAε and LASR predict new-onset AF in older adults without history of AF or stroke. LAε and LASR were assessed by speckle-tracking echocardiography in 824 participants from the community-based Cardiovascular Abnormalities and Brain Lesions study. Positive longitudinal LAε and LASR during ventricular systole, LASR during early ventricular diastole, and LASR during LA contraction were measured. Cause-specific hazards regression model evaluated the association of LAε and LASR with incident AF, adjusting for pertinent covariates. The mean age was 71.1 ± 9.2 years (313 men, 511 women). During a mean follow-up of 10.9 years, new-onset AF occurred in 105 participants (12.7%). Lower LAε and LASR at baseline were observed in patients with new-onset AF (all p <0.01). In multivariable analysis, positive longitudinal LAε (adjusted hazard ratio [HR] per SD decrease 2.05, confidence interval [CI] 1.24 to 3.36) and LASR during LA contraction (HR per SD increase 2.24, CI 1.37 to 3.65) remained associated with new-onset AF, independently of LA volumes and left ventricular function. Along with positive longitudinal LAε, reduced LASR during ventricular systole predicted AF in participants with LA volume below the median value (HR 2.54, CI 1.10 to 6.09), whereas reduced LASR during LA contraction predicted AF in participants with larger LA (HR 2.35, CI 1.31 to 4.23). In conclusion, reduced positive longitudinal LAε and LASR predict new-onset AF in older adults regardless of LA size and may improve AF risk stratification.

Qi-Po-Sheng-Mai granule ameliorates Ach-CaCl2 -induced atrial fibrillation by regulating calcium homeostasis in cardiomyocytes

BACKGROUND

Atrial fibrillation (AF) is one of the most common arrhythmias encountered in clinical settings. Currently, the pathophysiology of AF remains unclear, which severely limits the effectiveness and safety of medical therapies. The Chinese herbal formula Qi-Po-Sheng-Mai Granule (QPSM) has been widely used in China to treat AF. However, its pharmacological and molecular mechanisms remain unknown.

PURPOSE

The purpose of this study was to investigate the molecular mechanisms and potential targets of QPSM for AF.

STUDY DESIGN AND METHODS

The AF model was induced by Ach (66 μg/ml) and CaCl2 (10 mg/kg), and the dose of 0.1 ml/100 g was injected into the tail vein for 5 weeks. QPSM was administered daily at doses of 4.42 and 8.84 g/kg, and amiodarone (0.18 g/kg) was used as the positive control. The effect of QPSM on AF was assessed by electrocardiogram, echocardiography, and histopathological analysis. Then, we employed network pharmacology with single nucleus RNA sequencing (snRNA-Seq) to investigate the molecular mechanisms and potential targets of QPSM for AF. Furthermore, high performance liquid chromatography (HPLC) method was used for component analysis of QPSM, and molecular docking was used to verify the potential targets. Using the IonOptix single cell contraction and ion synchronization test equipment, single myocyte length and calcium ion variations were observed in real time. The expression levels of calcium Transporter-related proteins were detected by western blot and immunohistochemistry.

RESULTS

Based on an Ach-CaCl2-induced AF model, we found that QPSM treatment significantly reduced atrial electrical remodeling-related markers, such as AF inducibility and duration, and attenuated atrial dilation and fibrosis. Network pharmacology identified 52 active ingredients and 119 potential targets for QPSM in the treatment of AF, and 45 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were enriched, among which calcium pathway had the greatest impact. Using single nucleus sequencing (snRNA-seq), we identified cardiomyocytes as the most differentially expressed in response to drug treatment, with nine differentially expressed genes enriched in calcium signaling pathways. High performance liquid chromatography and molecular docking confirmed that the core components of QPSM strongly bind to the key factors in the calcium signaling pathway. Additional experiments have shown that QPSM increases calcium transients (CaT) and contractility in the individual cardiomyocyte. This was accomplished by increasing the expression of CACNA1C and SERCA2a and decreasing the expression of CAMK2B and NCX1.

CONCLUSION

The present study has systematically elucidated the role of QPSM in maintaining calcium homeostasis in cardiomyocytes through the regulation of calcium transporters, which could lead to new drug development ideas for AF.

Management and Prognosis of Acute Stroke in Atrial Fibrillation

Atrial fibrillation (AF) is an important risk factor for ischemic stroke (IS). Oral anticoagulation (OAC) significantly reduces the risk of IS in AF but also increases the risk of systemic bleeding, including intracerebral hemorrhage (ICH). AF-related strokes are associated with greater disability and mortality compared to non-AF strokes. The management of patients with AF-related strokes is challenging, and it involves weighing individual risks and benefits in the acute treatment and preventive strategies of these patients. This review summarizes the current knowledge of the acute management of ischemic and hemorrhagic stroke in patients with AF, and the prognosis and potential implications for management both in the acute and long-term setting.

Deciphering the genetic architecture of atrial fibrillation offers insights into disease prediction, pathophysiology and downstream sequelae

Aims

The study aimed to discover novel genetic loci for atrial fibrillation (AF), explore the shared genetic etiologies between AF and other cardiovascular and cardiometabolic traits, and uncover AF pathogenesis using Mendelian randomization analysis.

Methods and results

We conducted a genome-wide association study meta-analysis including 109,787 AF cases and 1,165,920 controls of European ancestry and identified 215 loci, among which 91 were novel. We performed Genomic Structural Equation Modeling analysis between AF and four cardiovascular comorbidities (coronary artery disease, ischemic stroke, heart failure, and vneous thromboembolism) and found 189 loci shared across these diseases as well as a universal genetic locus shared by atherosclerotic outcomes (i.e., rs1537373 near CDKN2B). Three genetic loci (rs10740129 near JMJD1C, rs2370982 near NRXN3, and rs9931494 near FTO) were associated with AF and cardiometabolic traits. A polygenic risk score derived from this genome-wide meta-analysis was associated with AF risk (odds ratio 2.36, 95% confidence interval 2.31-2.41 per standard deviation increase) in the UK biobank. This score, combined with age, sex, and basic clinical features, predicted AF risk (AUC 0.784, 95% CI 0.781-0.787) in Europeans. Phenome-wide association analysis of the polygenic risk score identified many AF-related comorbidities of the circulatory, endocrine, and respiratory systems. Phenome-wide and multi-omic Mendelian randomization analyses identified associations of blood lipids and pressure, diabetes, insomnia, obesity, short sleep, and smoking, 27 blood proteins, one gut microbe (genus.Catenibacterium), and 11 blood metabolites with risk to AF.

Conclusions

This genome-wide association study and trans-omic Mendelian randomization analysis provides insights into disease risk prediction, pathophysiology and downstream sequelae.

A systematic review and meta-analysis of cohort studies on the potential association between NAFLD/MAFLD and risk of incident atrial fibrillation

Background and objective

The association between atrial fibrillation (AF) and non-alcoholic fatty liver disease (NAFLD) or metabolic-associated fatty liver disease (MAFLD) has been explored in recent cohort studies, however, the results have been controversial and inconclusive. This meta-analysis aimed to explore this potential association.

Methods

We systematically searched PubMed, Embase, and Web of Science databases to identify all relevant cohort studies investigating the association between NAFLD/MAFLD and AF published from database inception to October 30, 2022. Random-effects models were utilized to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for summary purposes. Additionally, subgroup and sensitivity analyses were performed.

Results

A total of 13 cohort studies with 14 272 735 participants were included. Among these, 12 cohort studies with 14 213 289 participants (median follow-up of 7.8 years) showed a significant association between NAFLD and an increased risk of incident AF (HR = 1.18, 95% CI: 1.12-1.23, P < 0.00001). Our subgroup analyses mostly yielded similar results, and the results of sensitivity analyses remained unchanged. However, meta-analysis of data from 2 cohort studies with 59 896 participants (median follow-up of 2.15 years) showed that MAFLD was not linked to incident AF (HR = 1.36, 95% CI: 0.63-2.92, P = 0.44).

Conclusion

Current evidence shows that NAFLD may be linked to a slightly higher risk of developing AF, particularly among Asian populations and those diagnosed with NAFLD using FLI criteria. Nevertheless, there is not enough evidence to support the proposed association between MAFLD and an increased risk of AF. To better understand this relationship, future studies should consider factors such as specific population, the severity of NAFLD/MAFLD, diagnostic methods of NAFLD and AF, and cardiometabolic risk factors.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero, identifier CRD42022371503.

The rising death burden of atrial fibrillation and flutter in low-income regions and younger populations

Objective

The aim of the study was to depict the global death burden of atrial fibrillation and/or flutter (AFF) between 1990 and 2019 and predict this burden in the next decade.

Methods

We retrieved annual death data on cases and rates of AFF between 1990 and 2019 from the Global Burden of Disease (GBD) Study 2019 and projected the trends for 2020-2029 by developing the Bayesian age-period-cohort model.

Results

The global number of deaths from AFF increased from 117,038.00 in 1990 to 315,336.80 in 2019. This number is projected to reach 404,593.40 by 2029. The age-standardized mortality rates (ASMRs) of AFF have increased significantly in low- to middle-sociodemographic index (SDI) regions, which will surpass that in high SDI regions and reach above 4.60 per 100,000 by 2029. Globally, women have a higher ASMR than men, which is largely attributed to disproportionately higher mortality in women than men in lower SDI regions. Notably, AFF-related premature mortality continues to worsen worldwide. A pandemic of high systolic blood pressure and high body mass index (BMI) largely contributes to AFF-associated death. In particular, low- to middle-SDI regions and younger populations are increasingly affected by the rapidly growing current and future risk of high BMI.

Conclusion

The global death burden of AFF in low-income countries and younger generations have not been sufficiently controlled in the past and will continue growing in the future, which is largely attributed to metabolic risks, particularly for high BMI. There is an urgent need to implement effective measures to control AFF-related mortality.

An objective tool for quantifying atrial fibrillation substrate in rats

The utility of rodents for research related to atrial fibrillation (AF) is growing exponentially. However, the obtained arrhythmic waveforms are often mixed with ventricular signals and the ability to analyze regularity and complexity of such events is limited. Recently, we introduced an implantable quadripolar electrode adapted for advanced atrial electrophysiology in ambulatory rats. Notably, we have found that the implantation itself leads to progressive atrial remodeling, presumably because of mechanical loading of the atria. In the present study, we developed an algorithm to clean the atrial signals from ventricular mixing and thereafter quantify the AF substrate in an objective manner based on waveform complexity. Rats were sequentially examined 1-, 4-, and 8-wk postelectrode implantation using a standard AF triggering protocol. Preburst ventricular mixing was sampled and automatically subtracted based on QRS detection in the ECG. Thereafter, the "pure" atrial signals were analyzed by Lempel-Ziv complexity algorithm and a complexity ratio (CR) was defined for each signal by normalizing the postburst to the preburst values. Receiver operating characteristic (ROC) curve analysis indicated an optimal CR cutoff of 1.236 that detected irregular arrhythmic events with high sensitivity (94.5%), specificity (93.1%), and area under the curve (AUC) (0.96, 95% confidence interval, 0.945-0.976). Automated and unbiased analysis indicated a gradual increase in signal complexity over time with augmentation of high frequencies in power spectrum analysis. Our findings indicate that CR algorithm detects irregularity in a highly efficient manner and can also detect the atrial remodeling induced by electrode implantation. Thus, CR analysis can strongly facilitate standardized AF research in rodents.NEW & NOTEWORTHY Rodents are increasingly used in AF research. However, because of technical difficulties including atrial waveform mixing by ventricular signals, most studies do not discriminate between irregular (i.e., AF) and regular atrial arrhythmias. Here, we develop an unbiased computerized tool to "pure" the atrial signals from ventricular mixing and thereafter analyze AF substrate based on the level of irregularity in an objective manner. This novel tool can facilitate standardized AF research in rodents.

Clinical outcomes of a short-term family-focused intervention for patients with atrial fibrillation-A randomised clinical trial

AIMS

To evaluate a family-focused intervention for patients with atrial fibrillation (AF) in addition to conventional care and to establish its effect on health-related quality of life (HRQoL), anxiety, depression, AF symptoms, and family support.

BACKGROUND

AF is a widespread heart disease affecting the well-being of patients and their family members physically and psychologically. Supporting patients and their family members could potentially facilitate regaining family strength and improve HRQoL.

METHODS

Patients with newly diagnosed AF were randomised to standard care or additional family-focused intervention with change in global score of the Atrial Fibrillation Quality of Life Questionnaire (AFEQT) as primary outcome after six months' follow-up. Secondary outcomes included the Hospital Anxiety and Depression Score, the European Heart Rhythm Association score, the Ice Expressive Family Functioning Questionnaire, and the Ice Family-Perceived Support Questionnaire (ICE-FPSQ).

RESULTS

Sixty-eight patients received standard care (n = 35) or family focused intervention (n = 33). The median change at the six-month follow-up on the global AFEQT score was 4.17 (-1.46-9.17) in the control group and 5.83 (-2.5-30) in the intervention group, yielding a median difference of -1.67 (p = 0.500). Change in ICE-FPSQ showed significant positive scores in favour of intervention (p < 0.001); other secondary outcome changes were non-significant.

CONCLUSION

The family-focused intervention had a small positive but non-significant effect on HRQoL compared to standard care. To address the impact of AF on the patients and family members seems to improve anxiety and depression scores and perceived family support.

Catheter ablation for patients with atrial fibrillation and heart failure with reduced and preserved ejection fraction: insights from the KiCS-AF multicentre cohort study

AIMS

The usefulness of catheter ablation (CA) for atrial fibrillation (AF) across a broad spectrum of heart failure (HF) patients remains to be established. We assessed the association of CA with both health-related quality of life (QoL) and cardiovascular events among HF patients with reduced and preserved left ventricular ejection fraction (LVEF) in an 'all-comer' outpatient-based AF registry.

METHODS AND RESULTS

Of 3303 patients with AF consecutively enrolled in a retrospective multicentre registry that mandated the Atrial Fibrillation Effect on QualiTy-of-life (AFEQT) questionnaire at registration and 1-year follow-up, we extracted data from 530 patients complicating clinical HF. The association between CA and both 1-year change in AFEQT Overall Summary (AFEQT-OS) scores and 2-year composite clinical outcomes (including all-cause death, stroke, and HF hospitalization) was assessed by multivariable analyses. The median duration of AF was 108 days (52-218 days), and 83.4% had LVEF >35%. Overall, 75 patients (14.2%) underwent CA for AF within 1-year after registration. At 1-year follow-up, 67.2% in the ablation group showed clinically meaningful improvements of ≥ 5 points in AFEQT-OS score than 47.8% in the non-ablation group {adjusted odds ratio, 2.03 [95% confidence interval (CI): 1.13-3.64], P = 0.017}. Furthermore, the composite endpoint of all-cause death, stroke, and HF hospitalization occurred less frequently in the ablation group than the non-ablation group [adjusted hazard ratio, 0.27 (95% CI: 0.09-0.86), P = 0.027].

CONCLUSION

Among AF-HF patients, CA was associated with improved QoL and lower risk of cardiovascular events against drug therapy alone, even for patients with mildly reduced and preserved LVEF.

Sex and gender differences in the use of oral anticoagulants for non-valvular atrial fibrillation: A population-based cohort study in primary health care in catalonia

Objectives: To describe the sex and gender differences in the treatment initiation and in the socio-demographic and clinical characteristics of all patients initiating an oral anticoagulant (OAC), and the sex and gender differences in prescribed doses and adherence and persistence to the treatment of those receiving direct oral anticoagulants (DOAC). Material and methods: Cohort study including patients with non-valvular atrial fibrillation (NVAF) who initiated OAC in 2011-2020. Data proceed from SIDIAP, Information System for Research in Primary Care, in Catalonia, Spain. Results: 123,250 people initiated OAC, 46.9% women and 53.1% men. Women were older and the clinical characteristics differed between genders. Women had higher risk of stroke than men at baseline, were more frequently underdosed with DOAC and discontinued the DOAC less frequently than men. Conclusion: We described the dose adequacy of patients receiving DOAC, finding a high frequency of underdosing, and significantly higher in women in comparison with men. Adherence was generally high, only with higher levels in women for rivaroxaban. Persistence during the first year of treatment was also high in general, being significantly more persistent women than men in the case of dabigatran and edoxaban. Dose inadequacy, lack of adherence and of persistence can result in less effective and safe treatments. It is necessary to conduct studies analysing sex and gender differences in health and disease.

The Nine RNA Methylation Regulatory Gene Signature Is Associated with the Pathogenesis of Atrial Fibrillation by Modulating the Immune Microenvironment in the Atrial Tissues

Background. Atrial fibrillation (AF) is the most common type of cardiac arrhythmias and a major cause of cardiovascular disease (CVD)-related deaths globally. RNA methylation is the most frequent posttranscriptional modification in the eukaryotic RNAs. Previous studies have demonstrated close associations between the status of RNA methylation and CVD. Methods. We comprehensively evaluated the relationship between RNA methylation and AF. Least absolute shrinkage and selection operator (LASSO) logistic regression analysis was used to establish a risk score model in AF. Biological functional analysis was used to explore the relationship between RNA methylation related signatures and immune microenvironment characteristics. Machine learning was used to recognize the outstanding RNA methylation regulators in AF. Results. There was a significant variant of the mRNA expression of RNA methylation regulators in AF. RNA methylation related risk score could predict the onset of AF and closely associated with immune microenvironment features. XG-Boost algorithm and SHAP recognized that NSUN3 and DCPS might play a key role in the development of AF. Meanwhile, NSUN3 and DCPS had potential diagnostic value in AF. Conclusion. RNA methylation regulatory genes are associated with the onset of AF by modulating the immune microenvironment. The nine AF risk-related RNA methylation regulatory gene signature is a potential diagnostic biomarker and therapeutic target for AF.

Novel Pulmonary Delivery of Drugs for the Management of Atrial Fibrillation

Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia, affecting approximately 335 million patients worldwide. Comprehensive pharmacological treatment of AF includes medications for rate or rhythm control and anticoagulants to reduce the risk of thromboembolism; yet, these agents have significant limitations. Oral anti-arrhythmic agents have a slow onset of action, and rapid onset formulations require hospitalization for intravenous therapy. Orally administered drugs also require high doses to attain therapeutic levels, and thus dose-related severe adverse effects are often unavoidable. Given the therapeutic benefits of inhaled drug delivery, including rapid onset of action and very low doses to achieve therapeutic efficacy, this review will discuss the benefits of novel pulmonary delivery of drugs for the management of AF.

Using a Clinical Decision Support System to Improve Anticoagulation in Patients with Nonvalve Atrial Fibrillation in China's Primary Care Settings: A Feasibility Study

BACKGROUND

To primarily investigate the effect of using a clinical decision support system (CDSS) in community health centers in Shanghai, China, on the proportion of patients prescribed guideline-directed antithrombotic therapy. This study also gauged the general practitioner (GP)'s acceptance of the CDSS who worked in the atrial fibrillation (AF) special consulting room of the CDSS group.

METHODS

This was a prospective cohort study that included a semistructured interview and a feasibility study for a cluster-randomized controlled trial. Eligible patients who sought medical care in the AF special consulting rooms in two community health centers in Shanghai, China, between April 1, 2020, and October 1, 2020, were enrolled, and their medical records from the enrollment date, up to October 1, 2021, were extracted. Based on whether the GPs in the AF special consulting rooms of the two sites used the CDSS or not, we classified the two sites as a software group and a control group. The CDSS could automatically assess the risks of stroke and bleeding and provide suggestions on treatment, follow-up, adjustment of anticoagulants or dosage, and other items. The primary outcome was the proportion of patients prescribed guideline-directed antithrombotic therapy. We also conducted a semistructured interview with the GP in the AF special consulting rooms of the software group regarding the acceptance of the CDSS and suggestions on the optimization of the CDSS and the study protocol of the cluster-randomized controlled trial in the future.

RESULTS

Eighty-four patients completed the follow-up. The mean age of these subjects was 75.71 years, the median time of clinical visits was six times per person, and the follow-up duration was 15 months. The basic demographics were similar between the two groups, except for age (t = 2.109, p = 0.038) and the HAS-BLED score (χ ² = 4.363, p = 0.037). The primary outcome in the software group was 8.071 times higher than that in the control group (adjusted odds ratio (OR) = 8.071, 95% confidence interval (2.570-25.344), p < 0.001). The frequency of consultation between groups was not significantly different (p = 0.981). It seemed that the incidence of adverse clinical events in the software group was lower than that in the control group. The main reason for dropouts in both groups was "following up in other hospitals." The GP in the AF special consulting rooms of the software group accepted the CDSS well.

CONCLUSIONS

The findings indicated that it was feasible to further promote the CDSS in the study among community health centers in China. The use of the CDSS might improve the proportion of patients prescribed guideline-directed antithrombotic therapy. The GP in the AF special consulting room of the software group showed a positive attitude toward the CDSS.

Atrial fibrillation and stroke

INTRODUCTION

Stroke is one of the leading causes of mortality and morbidity globally. Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. It is set to reach epidemic proportions. AF is associated with a five-fold increase in risk of stroke. Strokes caused by AF more often are fatal or result in severe disability. Even though the incidence of stroke has been significantly reduced by oral anticoagulation, AF is thought to account for a significant proportion of cryptogenic strokes where no etiology is identified.

AREAS COVERED

This article reviews the literature related to AF and stroke, pathophysiological insights, diagnosis of AF in stroke patients, and its management (Graphical Abstract).

EXPERT OPINION

The pathophysiology of thrombogenesis that links AF and stroke is not well understood and is an area of active research to identify new therapeutic targets to prevent AF and stroke. As the nature of AF and stroke is multifaceted, an integrated care approach to managing AF and stroke is increasingly essential.

Integrated Analysis of the microRNA–mRNA Network Predicts Potential Regulators of Atrial Fibrillation in Humans

Atrial fibrillation (AF) is a form of sustained cardiac arrhythmia and microRNAs (miRs) play crucial roles in the pathophysiology of AF. To identify novel miR–mRNA pairs, we performed RNA-seq from atrial biopsies of persistent AF patients and non-AF patients with normal sinus rhythm (SR). Differentially expressed miRs (11 down and 9 up) and mRNAs (95 up and 82 down) were identified and hierarchically clustered in a heat map. Subsequently, GO, KEGG, and GSEA analyses were run to identify deregulated pathways. Then, miR targets were predicted in the miRDB database, and a regulatory network of negatively correlated miR–mRNA pairs was constructed using Cytoscape. To select potential candidate genes from GSEA analysis, the top-50 enriched genes in GSEA were overlaid with predicted targets of differentially deregulated miRs. Further, the protein–protein interaction (PPI) network of enriched genes in GSEA was constructed, and subsequently, GO and canonical pathway analyses were run for genes in the PPI network. Our analyses showed that TNF-α, p53, EMT, and SYDECAN1 signaling were among the highly affected pathways in AF samples. SDC-1 (SYNDECAN-1) was the top-enriched gene in p53, EMT, and SYDECAN1 signaling. Consistently, SDC-1 mRNA and protein levels were significantly higher in atrial samples of AF patients. Among negatively correlated miRs, miR-302b-3p was experimentally validated to suppress SDC-1 transcript levels. Overall, our results suggested that the miR-302b-3p/SDC-1 axis may be involved in the pathogenesis of AF.

Quantitative Analysis Using Consecutive Time Window for Unobtrusive Atrial Fibrillation Detection Based on Ballistocardiogram Signal

Atrial fibrillation (AF) is the most common clinically significant arrhythmia; therefore, AF detection is crucial. Here, we propose a novel feature extraction method to improve AF detection performance using a ballistocardiogram (BCG), which is a weak vibration signal on the body surface transmitted by the cardiogenic force. In this paper, continuous time windows (CTWs) are added to each BCG segment and recurrence quantification analysis (RQA) features are extracted from each time window. Then, the number of CTWs is discussed and the combined features from multiple time windows are ranked, which finally constitute the CTW-RQA features. As validation, the CTW-RQA features are extracted from 4000 BCG segments of 59 subjects, which are compared with classical time and time-frequency features and up-to-date energy features. The accuracy of the proposed feature is superior, and three types of features are fused to obtain the highest accuracy of 95.63%. To evaluate the importance of the proposed feature, the fusion features are ranked using a chi-square test. CTW-RQA features account for 60% of the first 10 fusion features and 65% of the first 17 fusion features. It follows that the proposed CTW-RQA features effectively supplement the existing BCG features for AF detection.

Comparing atrial fibrillation guidelines: Focus on stroke prevention, bleeding risk assessment and oral anticoagulant recommendations

Clinical practice in atrial fibrillation (AF) patient management is constantly evolving. In the past 3 years, various new AF guidelines or focused updates have been published, given this rapidly evolving field. In 2019, the American College of Cardiology/American Heart Association published a focused update of the 2014 guidelines. In 2020, both the European Society of Cardiology and the Canadian Cardiovascular Society released their new guidelines. Finally, the most recent guidelines were those published in 2021 by the Asian Pacific Heart Rhythm Society, which updates their 2017 version and the 2021 National Institute for Health and Care Excellence (NICE) guidelines. In the present narrative review, we compare these guidelines, emphasizing similarities and differences in the following mainstay elements of patient care: thromboembolic risk assessment, oral anticoagulants (OACs) prescription, bleeding risk evaluation, and integrated patient management. A formal evaluation of baseline thromboembolic and bleeding risks and their reassessment during follow-up is evenly recommended, although some differences in using risk stratification scores. OACs prescription is highly encouraged where appropriate, and prescription algorithms are broadly similar. The importance of an integrated and multidisciplinary approach to patient care is emerging, aiming to address several different aspects of a multifaceted disease.

Documentation of atrial fibrillation among non-conveyed ambulance patients: a new primary prevention opportunity?

Introduction: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and is a significant risk factor for stroke. Prescription of oral anticoagulant (OAC) medication reduces the risk of AF-related stroke by 64% ‐ yet over 400,000 people in England have undiagnosed (and therefore untreated) AF.Emergency medical services (EMS) encounter a wide range of patients, some of whom may not engage with other healthcare services. AF may be detected by EMS in connection with the cause of the call, or as an incidental finding. While EMS are not traditionally utilised for public health screening, they may offer an opportunity to identify patients with undiagnosed or untreated AF and refer onward.This study aimed to explore what proportion of patients seen by EMS who were not transported to hospital had AF and to estimate how many would potentially benefit from OAC.Methods: A retrospective service evaluation was conducted using routinely collected data from a large UK regional ambulance service. The sample included adults attended by EMS on the 15th of each month in 2019, who were not transported to hospital and where an electrocardiogram was recorded. Of those with AF, we calculated the proportion in whom this was possibly new and report whether OAC was prescribed.Results: There were 859 patients who met the inclusion criteria, of whom 91 (11%) had AF documented. Of the 91 patients with AF, 23 (25%) had no documented history of AF or OAC prescription, so were potentially new diagnoses of AF, who would benefit from consideration of OAC therapy.Conclusion: The EMS assessment offers an opportunity for AF to be identified in patients who were not transported to hospital. EMS may have a role in primary prevention of harm, including stroke, by identifying and referring patients with AF for consideration of OAC.

Performance of the imPulse device for the detection of atrial fibrillation in hospital settings

Background

Atrial fibrillation (AF) increases thromboembolism and stroke risk; this can be reduced by oral anticoagulation, but only if AF is detected. A portable, point-of-care device, capable of accurately detecting and identifying AF, could reduce workload and diagnostic delay by minimizing need for follow-up 12-lead electrocardiogram (ECGs).

Objective

To assess the diagnostic performance of the Plessey imPulse lead I ECG device compared with a 12-lead ECG in detecting AF.

Methods

Cross-sectional diagnostic accuracy study. Participants underwent simultaneous 12-lead ECG and imPulse device recordings. The imPulse device reports AF to be “probable,” “possible,” “unlikely,” or “uncontrolled AF unlikely.” imPulse and ECG reference results were cross-tabulated; sensitivity, specificity, positive/negative predictive values, and positive/negative likelihood ratios with 95% confidence interval (CI) were estimated based on different imPulse device report categorizations and heart rate subgroups.

Results

A total of 217 participants were recruited (mean age 70.2 [standard deviation 12.7]), 56% male, 57% outpatients, 43% inpatients) and 199 were included in analyses. AF was diagnosed on ECG for 41 of 199 (20.6%) participants and reported by imPulse as possible, probable, or uncontrolled AF unlikely present for 49 of 199 (24.6%). Sensitivity and specificity for imPulse detection of possible, probable, or uncontrolled AF unlikely vs unlikely, compared with ECG, were 80.5% (95% CI, 65.1%–91.2%) and 89.9% (84.1%–94.1%), respectively. When probable or uncontrolled AF unlikely were compared vs possible or unlikely AF, sensitivity and specificity were 63.4% (46.9%–77.9%) and 98.1% (94.6%–99.6%), respectively.

Conclusion

The imPulse device has moderate sensitivity and good specificity compared with ECG AF detection in a hospital setting.

Effect of an artificial intelligence-assisted tool on non-valvular atrial fibrillation anticoagulation management in primary care: protocol for a cluster randomized controlled trial

Background

Atrial fibrillation (AF) is one of the most common cardiac arrhythmia diseases. Thromboembolic prophylaxis plays an essential role in AF therapy, but at present, general practitioners (GPs) are presumed to lack the knowledge and enthusiasm for AF management. Clinical decision support systems (CDSS), assisted by artificial intelligence, help primary care providers (PCPs) make quick, individualized, and correct clinical decisions. This primary aim of the study is to identify whether the promotion of the CDSS would improve the primary care provided to patients with AF. The secondary objectives are mainly to assess the health-economic and clinical benefits from using the CDSS, and the improvement of GPs’ AF management capability.

Methods

This study will be a prospective cluster randomized controlled trial, conducted among 14 community health centers in Shanghai which were randomized as the intervention group and control group in a ratio of 1:1. The intervention group will use the CDSS in the consultation of patients with AF and the control group will maintain their usual care. The trial will include 498 patients with AF and the follow-up period will be 12 months. The primary outcome is set as the proportion of antithrombotic treatment prescriptions in agreement with recommendations in the latest China’s AF-related guidelines. The secondary outcomes are the frequency of consultation, the compliance rate of international normalized ratio (INR) in patients with warfarin, stroke morbidity, treatment compliance, medication satisfaction, and the cost-benefit analysis. Per-protocol (PP) analysis and the intention-to-treat (ITT) analysis will be conducted.

Discussion

This study aims to identify whether the application of CDSS to manage patients with AF in China’s community health centers would bring benefits for patients, physicians, and health economics.

Trial registration

Registry name: 非瓣膜性房颤社区AI辅助管理工具研发及推广效果研究 (Development and promotion of an AI-assisted tool for NVAF management in primary care); registry number: ChiCTR2100052307; registration date: Nov. 22^nd, 2021; http://www.chictr.org.cn/showproj.aspx?proj=133849.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06250-8.

Ameliorative Impact of Liraglutide on Chronic Intermittent Hypoxia-Induced Atrial Remodeling

Atrial fibrillation (AF) is the most frequent form of clinical cardiac arrhythmias. Previous evidence proved that atrial anatomical remodeling (AAR) and atrial electrical remodeling (AER) are crucial for the progression and maintenance of AF. This study is aimed at investigating the impact of the glucagon-like peptide-1 (GLP-1) receptor agonist, Liraglutide (Lir), on atrial remodeling (AR) mouse model induced by chronic intermittent hypoxia (CIH). C57BL/6 mice were categorized randomly into the control, Lir, CIH, and CIH+Lir groups. CIH was performed in CIH and CIH+Lir groups for 12 weeks. Lir (0.3 mg/kg/day, s.c) was administered to the Lir and CIH+Lir groups for four weeks, beginning from the ninth week of CIH. Meanwhile, echocardiography and right atrial endocardial electrophysiology via jugular vein, as well as induction rate and duration of AF, were evaluated. Masson and Sirius red staining assays were utilized to assess the extent of fibrosis in the atrial tissue of the mice. Immunohistochemical staining, RT-qPCR, and Western blotting were performed to evaluate the marker levels of AAR and AER and the expression of genes and proteins of the miR-21/PTEN/PI3K/AKT signaling pathway, respectively. ELISA was also performed to evaluate the changes of serum inflammatory factor levels. The CIH group exhibited significant AR, increased atrial fibrosis, and a higher incidence rate of AF compared to the control group. Lir could significantly downregulate the protein expression level in the PI3K/p-AKT pathway and upregulated that of phosphatase and tensin homolog deleted on chromosome ten (PTEN). Moreover, Lir downregulated the expression of miR-21. However, the protein expressions of CACNA1C and KCNA5 in atrial tissue were not changed significantly. In addition, Lir significantly attenuated the levels of markers of inflammation (TNF-α and IL-6) in the serum. In the mouse model of CIH, Lir treatment could ameliorate AR by the miR-21/PTEN/PI3K/AKT signaling pathway and modulation of inflammatory responses.

Ex Vivo Hydrostatic Pressure Loading of Atrial Tissues Activates Profibrotic Transcription via TGF-β Signal Pathway

Excessive mechanical stress causes fibrosis-related atrial arrhythmia. Herein, we tried to investigate the mechanism of atrial fibrogenesis in response to mechanical stress by ex vivo approach. We collected atrial tissues from mice and then cultured them as "explants" under atmospheric pressure (AP group) or 50 mmHg hydrostatic pressure loading (HP group) conditions. Pathway-specific PCR array analysis on the expression of fibrosis-related genes indicated that the loading of atrial tissues to 50 mmHg for 24 hours extensively upregulated a series of profibrotic genes. qRT-PCR data also showed that loading atrial tissues to 50 mmHg enhanced Rhoa, Rock2, and Thbs1 expression at different time points. Interestingly, the enhanced expression of Thbs1 at 1 hour declined at 6-24 hours and then increased again at 72 hours. In contrast, an enhanced expression of Tgfb1 was observed at 72 hours. In contrast, daily loading to 50 mmHg for 3 hours significantly accelerated the outgrowth of mesenchymal stem-like stromal cells from atrial tissues; however, we did not observe significant phenotypic changes in these outgrowing cells. Our ex vivo experimental data clearly show the induction of profibrotic transcription of atrial tissues by HP loading, which confirms the common pathological feature of atrial fibrosis following pressure overload.

Current Advancement in Diagnosing Atrial Fibrillation by Utilizing Wearable Devices and Artificial Intelligence: A Review Study

Atrial fibrillation (AF) is a common arrhythmia affecting 8–10% of the population older than 80 years old. The importance of early diagnosis of atrial fibrillation has been broadly recognized since arrhythmias significantly increase the risk of stroke, heart failure and tachycardia-induced cardiomyopathy with reduced cardiac function. However, the prevalence of atrial fibrillation is often underestimated due to the high frequency of clinically silent atrial fibrillation as well as paroxysmal atrial fibrillation, both of which are hard to catch by routine physical examination or 12-lead electrocardiogram (ECG). The development of wearable devices has provided a reliable way for healthcare providers to uncover undiagnosed atrial fibrillation in the population, especially those most at risk. Furthermore, with the advancement of artificial intelligence and machine learning, the technology is now able to utilize the database in assisting detection of arrhythmias from the data collected by the devices. In this review study, we compare the different wearable devices available on the market and review the current advancement in artificial intelligence in diagnosing atrial fibrillation. We believe that with the aid of the progressive development of technologies, the diagnosis of atrial fibrillation shall be made more effectively and accurately in the near future.

Rhythm control versus rate control in a contemporary ambulatory atrial fibrillation cohort: Post-hoc analysis of the IMPACT-AF Trial

Background

We examined the characteristics and outcomes in a contemporary ambulatory population of patients with atrial fibrillation (AF), comparing rate control with rhythm control.

Methods

This is a post hoc analysis of a cluster-randomized trial (Integrated Management Program Advancing Community Treatment of Atrial Fibrillation [IMPACT-AF]) in ambulatory AF patients from 2016 to 2018, which compared use of a clinical decision support tool for general practitioners to usual care. This analysis compared patients managed with rate vs rhythm control, at entry into the study. Outcomes included AF-related emergency department (ED) visits, unplanned cardiovascular hospitalizations, and bleeding events at 12 months.

Results

A total of 870 patients were included in this analysis, 99 (11.4%) in the rhythm-control group, and 40% women. In the rhythm-control group, the mean age was younger (70 ± 11.4 vs 72.7 ± 9.5 years, P = 0.03), a higher number were paroxysmal (80% vs 43%, P < 0.001), and CHADS₂ scores were lower. The rate of AF-related ED visits was higher in the rhythm-control group (17.2 vs 7.3%, P = 0.003), and repeat visits (rate ratio 3.03, 95% confidence interval [1.99-4.52], P < 0.001). The number of repeat ED visits was independently associated with female sex and being in the rhythm-control group.

Conclusions

Both rate- and rhythm-control patients have recurrent ED visits, with a higher rate in patients treated with rhythm control. These findings are observational, but taken in the context of current guidelines could help develop further therapies aimed at improving symptom burden in both rhythm- and rate-control patients to broadly improve healthcare utilization in the AF population.

Fracture risks in patients with atrial fibrillation treated with different oral anticoagulants: a meta-analysis and systematic review

Aims

evidence on the difference in fracture risks for patients with atrial fibrillation (AF) receiving direct oral anticoagulants (DOACs) versus warfarin remains controversial. We aim to compare the fracture risks between the DOAC and warfarin prescriptions among the AF patients.

Methods and Results

we systematically searched PubMed, EMBASE, the Cochrane Library and Web of Science up to 19 April 2021 for relevant studies. And the observational studies regarding the relationship between the DAOC versus warfarin prescriptions and fracture risks among the patients with AF were included in this meta-analysis. Two investigators independently screened the articles and extracted the relevant data. A random- or fixed-effect model was applied to calculate the pooled hazard ratio/relative ratios with 95% confidence intervals of fracture risks associated with the DOAC and warfarin prescriptions. Six studies comprising 351,208 patients and 9,424 fractures were included in this meta-analysis. Overall, the AF patients treated with DOACs tend to present a lower risk of any fracture compared with those treated with warfarin (relative ratio: 0.82, 95% confidence interval (CI): 0.74–0.91). Sub-analyses for each individual DOAC indicate that apixaban and rivaroxan are associated with lower risk of any fracture compared with warfarin (HR: 0.75, 95% CI: 0.60–0.92, and HR: 0.79, 95% CI: 0.71–0.88, respectively).

Conclusion

this meta-analysis suggests that DOAC users have a lower risk of fractures than the warfarin users. The results of this study may provide optimal anticoagulation opportunities for AF patients with high fracture risk factors.

Conditional immortalization of human atrial myocytes for the generation of in vitro models of atrial fibrillation

The lack of a scalable and robust source of well-differentiated human atrial myocytes constrains the development of in vitro models of atrial fibrillation (AF). Here we show that fully functional atrial myocytes can be generated and expanded one-quadrillion-fold via a conditional cell-immortalization method relying on lentiviral vectors and the doxycycline-controlled expression of a recombinant viral oncogene in human foetal atrial myocytes, and that the immortalized cells can be used to generate in vitro models of AF. The method generated 15 monoclonal cell lines with molecular, cellular and electrophysiological properties resembling those of primary atrial myocytes. Multicellular in vitro models of AF generated using the immortalized atrial myocytes displayed fibrillatory activity (with activation frequencies of 6-8 Hz, consistent with the clinical manifestation of AF), which could be terminated by the administration of clinically approved antiarrhythmic drugs. The conditional cell-immortalization method could be used to generate functional cell lines from other human parenchymal cells, for the development of in vitro models of human disease.

Integrated Care of Atrial Fibrillation Using the ABC (Atrial fibrillation Better Care) Pathway Improves Clinical Outcomes in Chinese Population: An Analysis From the Chinese Atrial Fibrillation Registry

Background: “Atrial fibrillation Better Care” (ABC) pathway has been proposed to improve the management of patients suffered from atrial fibrillation (AF). This integrated or holistic management approach comprise of three aspects, including “A” Avoid stroke or Anticoagulation; “B” Better symptom control with rate or rhythm control strategies; “C” Cardiovascular risk factor and Concomitant diseases management. We aimed to confirm the beneficial evidence of ABC pathway compliance in a Chinese AF cohort.

Method and Results: From the Chinese Atrial Fibrillation registry (CAFR) dataset, a total of 19,187 non-valvular AF patients were enrolled, of which 4.365 (22.8%) were ABC pathway compliant (ABC compliance group). During a median follow-up of 4.1 ± 1.8 years, The incident rate of all-cause death in ABC compliance group and non-ABC compliance group is 2.7 and 1.1 per 100 person-year (p < 0.001), the incident rate of ischemic stroke is 1.3 and 0.8% per 100 person-year (p < 0.001), the incident rate of composite outcome, which consist of all-cause death, ischemic stroke and intracranial hemorrhage, is 3.8 and 1.9 per 100 person-year (p < 0.001). On Cox multivariable analysis, ABC pathway shows an independently association with reduction of all-cause death [hazard ratio (HR) = 0.82; 95% confidence interval (CI) = 0.70–0.95] and the composite outcome (HR 0.86, 95% CI 0.76–0.96). The increasingly components of ABC integrated care compliance is associated with lower risk of all-cause death and composite events.

Conclusion: In a large cohort of Chinese AF patients, ABC pathway compliance shows an independently association with reduction of all-cause death and composite outcome of all-cause death, ischemic stroke and intracranial hemorrhage. Better compliance of ABC integrated care contributes to lower HR for adverse events.

Atrial fibrillation in critically ill patients who received prolonged mechanical ventilation: a nationwide inpatient report

BACKGROUND/AIMS

To evaluate temporal trends of atrial fibrillation (AF) prevalence in critically ill patients who received prolonged mechanical ventilation (MV) in the United States.

METHODS

We used the 2008 to 2014 National Inpatient Sample to compute the weighted prevalence of AF among hospitalized adult patients on prolonged MV. We used multivariable-adjusted models to evaluate the association of AF with clinical factors, in-hospital mortality, hospitalization cost, and length of stay (LOS).

RESULTS

We identified 2,578,165 patients who received prolonged MV (21.27% of AF patients). The prevalence of AF increased from 14.63% in 2008 to 24.43% in 2014 (p for trend < 0.0001). Amongst different phenotypes of critically ill patients, the prevalence of AF increased in patients with severe sepsis, asthma exacerbation, congestive heart failure exacerbation, acute stroke, and cardiac arrest. Older age, male sex, white race, medicare access, higher income, urban teaching hospital setting, and Western region were associated with a higher prevalence of AF. AF in critical illness was a risk factor for in-hospital death (odds ratio, 1.13; 95% confidence interval, 1.11 to 1.15), but in-hospital mortality in critically ill patients with AF decreased from 11.6% to 8.3%. AF was linked to prolonged LOS (2%, p < 0.0001) and high hospitalization cost (4%, p < 0.0001). LOS (-1%, p < 0.0001) and hospitalization cost (-4%, p < 0.0001) decreased yearly.

CONCLUSION

The prevalence of comorbid AF is increasing, particularly in older patients. AF may lead to poorer prognosis, and high-quality intensive care is imperative for this population.

Coordinating Healthcare with Artificial intelligence-supported Technology for Atrial Fibrillation patients (CHAT-AF): Protocol for a Randomised Controlled Trial (Preprint)

Background

Atrial fibrillation (AF) is an increasingly common chronic health condition for which integrated care that is multidisciplinary and patient-centric is recommended yet challenging to implement.

Objective

The aim of Coordinating Health Care With Artificial Intelligence–Supported Technology in AF is to evaluate the feasibility and potential efficacy of a digital intervention (AF-Support) comprising preprogrammed automated telephone calls (artificial intelligence conversational technology), SMS text messages, and emails, as well as an educational website, to support patients with AF in self-managing their condition and coordinate primary and secondary care follow-up.

Methods

Coordinating Health Care With Artificial Intelligence–Supported Technology in AF is a 6-month randomized controlled trial of adult patients with AF (n=385), who will be allocated in a ratio of 4:1 to AF-Support or usual care, with postintervention semistructured interviews. The primary outcome is AF-related quality of life, and the secondary outcomes include cardiovascular risk factors, outcomes, and health care use. The 4:1 allocation design enables a detailed examination of the feasibility, uptake, and process of the implementation of AF-Support. Participants with new or ongoing AF will be recruited from hospitals and specialist-led clinics in Sydney, New South Wales, Australia. AF-Support has been co-designed with clinicians, researchers, information technologists, and patients. Automated telephone calls will occur 7 times, with the first call triggered to commence 24 to 48 hours after enrollment. Calls follow a standard flow but are customized to vary depending on patients’ responses. Calls assess AF symptoms, and participants’ responses will trigger different system responses based on prespecified protocols, including the identification of red flags requiring escalation. Randomization will be performed electronically, and allocation concealment will be ensured. Because of the nature of this trial, only outcome assessors and data analysts will be blinded. For the primary outcome, groups will be compared using an analysis of covariance adjusted for corresponding baseline values. Randomized trial data analysis will be performed according to the intention-to-treat principle, and qualitative data will be thematically analyzed.

Results

Ethics approval was granted by the Western Sydney Local Health District Human Ethics Research Committee, and recruitment started in December 2020. As of December 2021, a total of 103 patients had been recruited.

Conclusions

This study will address the gap in knowledge with respect to the role of postdischarge digital care models for supporting patients with AF.

Trial Registration

Australian New Zealand Clinical Trials Registry ACTRN12621000174886; https://www.australianclinicaltrials.gov.au/anzctr/trial/ACTRN12621000174886

International Registered Report Identifier (IRRID)

DERR1-10.2196/34470

Mendelian randomization study on atrial fibrillation and cardiovascular disease subtypes

Atrial fibrillation (AF) has been associated with numerous diseases. However, whether AF is a cause or consequence of these diseases is uncertain. To clarify, we assessed the causal role of AF on ischemic heart disease (IHD), stroke, other cardiovascular disease (CVD) subtypes, type 2 diabetes mellitus (T2DM), and late-onset AD using bi-directional two-sample Mendelian randomization (MR) among people primarily of European descent. Genetically predicted log odds of AF was associated with any stroke (odds ratio (OR) 1.22, 95% CI 1.18 to 1.27), particularly cardioembolic stroke and possibly subdural hemorrhage, with sensitivity analyses showing similar positive findings. Genetically predicted AF was also associated with arterial thromboembolism (1.32, 1.13 to 1.53), and heart failure (1.26, 1.21 to 1.30). No association of genetically predicted AF with IHD, T2DM, cognitive function, or late-onset AD was found. Conversely, genetically predicted IHD, heart failure and possibly ischemic stroke, particularly cardioembolic stroke, were positively associated with AF. Atrial fibrillation plays a role in any stroke, arterial thromboembolism, and heart failure, corroborating current clinical guidelines on the importance of preventing these complications by effective AF management. In addition, patients with IHD, heart failure or possibly ischemic stroke might be predisposed to developing AF, with implications for management.

User Perceptions and Experiences of a Handheld 12-Lead Electrocardiographic Device in a Clinical Setting: Usability Evaluation

Background

Cardiac arrhythmias are a leading cause of death. The mainstay method for diagnosing arrhythmias (eg, atrial fibrillation) and cardiac conduction disorders (eg, prolonged corrected QT interval [QTc]) is by using 12-lead electrocardiography (ECG). Handheld 12-lead ECG devices are emerging in the market. In tandem with emerging technology options, evaluations of device usability should go beyond validation of the device in a controlled laboratory setting and assess user perceptions and experiences, which are crucial for successful implementation in clinical practice.

Objective

This study aimed to evaluate clinician and patient perceptions and experiences, regarding the usability of a handheld 12-lead ECG device compared to a conventional 12-lead ECG machine, and generalizability of this user-centered approach.

Methods

International Organization for Standardization Guidelines on Usability and the Technology Acceptance Model were integrated to form the framework for this study, which was conducted in outpatient clinics and cardiology wards at Westmead Hospital, New South Wales, Australia. Each patient underwent 2 ECGs (1 by each device) in 2 postures (supine and standing) acquired in random sequence. The times taken by clinicians to acquire the first ECG (efficiency) using the devices were analyzed using linear regression. Electrocardiographic parameters (QT interval, QTc interval, heart rate, PR interval, QRS interval) and participant satisfaction surveys were collected. Device reliability was assessed by evaluating the mean difference of QTc measurements within ±15 ms, intraclass correlation coefficient, and level of agreement of the devices in detecting atrial fibrillation and prolonged QTc. Clinicians’ perceptions and feedback were assessed with semistructured interviews based on the Technology Acceptance Model.

Results

A total of 100 patients (age: mean 57.9 years, SD 15.2; sex: male: n=64, female n=36) and 11 clinicians (experience acquiring ECGs daily or weekly 10/11, 91%) participated, and 783 ECGs were acquired. Mean differences in QTc measurements of both handheld and conventional devices were within ±15 ms with high intraclass correlation coefficients (range 0.90-0.96), and the devices had a good level of agreement in diagnosing atrial fibrillation and prolonged QTc (κ=0.68-0.93). Regardless of device, QTc measurements when patients were standing were longer duration than QTc measurements when patients were supine. Clinicians’ ECG acquisition times improved with usage (P<.001). Clinicians reported that device characteristics (small size, light weight, portability, and wireless ECG transmission) were highly desired features. Most clinicians agreed that the handheld device could be used for clinician-led mass screening with enhancement in efficiency by increasing user training. Regardless of device, patients reported that they felt comfortable when they were connected to the ECG devices.

Conclusions

Reliability and usability of the handheld 12-lead ECG device were comparable to those of a conventional ECG machine. The user-centered evaluation approach helped us identify remediable action to improve the efficiency in using the device and identified highly desirable device features that could potentially help mass screening and remote assessment of patients. The approach could be applied to evaluate and better understand the acceptability and usability of new medical devices.

Atrial Fibrillation Recurrence Prevention after Electrical Cardioversion in High-Risk Patients – Benefits of Non-Antiarrhythmic Drugs

Background:

Recurrence prevention after Atrial Fibrillation (AF) termination by Eelectrical Cardioversion (ECV) remains challenging. Increasing attention is paid to pathophysiological effects of non-Antiarrhythmic Drugs (non-AADs), nevertheless, with heterogeneous results.

Objective:

We evaluated the potential benefits of different non-AADs as adjunctive therapy to Antiarrhythmic Drugs (AADs) for AF recurrence prevention after sinus rhythm restoration by ECV in high-risk patients.

Methods:

The study was conducted among high-risk AF patients after successful ECV. Prescription of class IC or class III AAD was required. Data were acquired in a face-to-face baseline interview and 1-, 3-, 6-, 9-, 12-month follow-up interviews.

Results:

113 patients were included. Total AF recurrence rate reached 48.7%. Angiotensin-Converting Enzyme Inhibitor (ACEI) or angiotensin receptor blocker (ARB) intake, compared with non-use, demonstrated AF recurrence rate reduction by 8.5% (46.3 vs. 54.8%), with odds ratio (OR) reduced by 28.9% (OR 0.711, 95% confidence interval (CI) 0.310-1.631, p = 0.420). Among mineralocorticoid receptor antagonist (MRA) users, AF recurrence rate was reduced by 25.1% (29.6 vs. 54.7%) and OR by 65.1% (OR 0.349, 95%CI 0.138-0.884, p = 0.023). Present statin therapy reduced AF recurrence rate by 4.2% (46.8 vs. 51.0%) and OR by 15.5% (OR 0.845, 95%CI 0.402-1.774, p = 0.656). Diuretic use showed reduction of AF recurrence rate by 10.2% (41.7 vs. 51.9%) and OR by 33.9% (OR 0.661, 95%CI 0.297-1.469, p = 0.308).

Conclusion:

Non-AADs demonstrated practical benefits as adjunctive therapy to AADs for AF recurrence prevention after ECV in high-risk patients, with statistically significant results established for concomitant MRA intake.

The information needs of patients with atrial fibrillation: A scoping review

AIMS AND OBJECTIVES

To identify the atrial fibrillation (AF)-specific information needs of patients with AF.

BACKGROUND

Patients' understanding of AF is pertinent to optimising treatment and outcomes, thus highlighting the need for effective patient education. The information required to deliver effective AF-specific patient education is less examined.

METHODS

Guided by Arksey and O'Malley's framework, a scoping review was conducted for studies reporting the AF-specific information needs of patients with AF. Systematic searches were conducted across six databases (Medline, PubMed, CINAHL, Scopus, PsycINFO and ProQuest). All analyses were narrated in prose and outlined in tables. The PRISMA-ScR checklist was used to report this review.

RESULTS

The systematic search yielded 3816 articles, of which 22 were included. Three major themes emerged from the thematic analysis. Each theme was supported by three subthemes. First, in 'Understanding AF', patients reported the need for 'Easy-to-understand information', information on the 'Screening and diagnosis' of AF and 'Trajectory of disease and its associated risks'. Second, in 'Treating AF', patients required information on the 'Role of anticoagulation', 'Existing or novel therapeutic options' and 'Monitoring effectiveness of treatment'. Lastly, in 'Living with AF', patients needed education in 'Symptom management', 'Secondary prevention of risks' and 'Recognition of emergency situations'.

CONCLUSIONS

This review has identified the key AF-specific information needs of patients with AF. Being cognisant of the information needs of patients with AF, healthcare providers may become more effective in developing person-centred patient education interventions.

RELEVANCE TO CLINICAL PRACTICE

Delivering relevant patient education is an important cornerstone for atrial fibrillation care. Nurses by convention play a professional role in patient education. It may be facilitative for nurses to refer to the review findings when developing and implementing patient education interventions. Being in the midst of an ongoing pandemic, patient education strategies may require the use of telecommunication technologies.

Under-recognition of heart failure in patients with atrial fibrillation and the impact of gender: a UK population-based cohort study

BACKGROUND

Patients with atrial fibrillation (AF) complicated by heart failure (HF) have a poor prognosis. We investigated whether long term loop-diuretic therapy in patients with AF and no known diagnosis of HF, as a potential surrogate marker of undiagnosed HF, is also associated with worse outcomes.

METHODS

Adults with incident AF were identified from UK primary and secondary care records between 2004 and 2016. Repeat prescriptions for loop diuretics, without a diagnosis of HF or documented non-cardiac indication, were classified as 'isolated' loop diuretic use.

RESULTS

Amongst 124,256 people with incident AF (median 76 years, 47% women), 22,001 (17.7%) had a diagnosis of HF, and 22,325 (18.0%) had isolated loop diuretic use. During 2.9 (LQ-UQ 1-6) years' follow-up, 12,182 patients were diagnosed with HF (incidence rate 3.2 [95% CI 3.1-3.3]/100 person-years). Of these, 3999 (32.8%) had prior isolated loop diuretic use, including 31% of patients diagnosed with HF following an emergency hospitalisation. The median time from AF to HF diagnosis was 3.6 (1.2-7.7) years in men versus 5.1 (1.8-9.9) years in women (p = 0.0001). In adjusted models, patients with isolated loop diuretic use had higher mortality (HR 1.42 [95% CI 1.37-1.47], p < 0.0005) and risk of HF hospitalisation (HR 1.60 [95% CI 1.42-1.80], p < 0.0005) than patients with no HF or loop diuretic use, and comparably poor survival to patients with diagnosed HF.

CONCLUSIONS

Loop diuretics are commonly prescribed to patients with AF and may indicate increased cardiovascular risk. Targeted evaluation of these patients may allow earlier HF diagnosis, timely intervention, and better outcomes, particularly amongst women with AF, in whom HF appears to be under-recognised and diagnosed later than in men.