Genetic Investigation Into the Differential Risk of Atrial Fibrillation Among Black and White Individuals

Association Between Family History and Early-Onset Atrial Flutter Across Racial and Ethnic Groups

BACKGROUND

Genetic and familial contributions to early-onset atrial fibrillation are described primarily in individuals of European ancestry. However, the role of racial and familial contributions in the pathogenesis of early-onset atrial flutter (EOAFL) is unclear.

METHODS AND RESULTS

In this cross-sectional study, participants were enrolled prospectively from 2015 to 2021 in multiple academic centers with a diagnosis of atrial flutter (AFL) confirmed by ECG. EOAFL was defined as a diagnosis of AFL before age 66 years with no concomitant or previous diagnosis of atrial tachyarrhythmias. Family history was adjudicated through baseline questionnaires and direct family interviews about the diagnosis of atrial tachyarrhythmias, stroke, and cardiomyopathy. The primary exposure was a positive family history in first-degree relatives, and the primary outcome was the odds of EOAFL versus late-onset AFL. A total of 909 patients were enrolled. Participants with a positive family history of atrial tachyarrhythmias were younger, less likely to be of Black race, and more likely to have EOAFL. The adjusted odds ratio (OR) for EOAFL in those with a positive family history was 1.8 (95% CI, 1.1-3.0). There was an increased odds of EOAFL in those of Black race (OR, 2.1 [95% CI, 1.4-3.2]), alcohol use (OR, 1.6 [95% CI, 1.0-2.6]), and obstructive sleep apnea (OR, 1.9 [95% CI, 1.0-3.4]). Use of cardioselective β blockers or calcium channel blockers before the diagnosis of AFL were associated with a lower odds of EOAFL (OR, 0.5 [95% CI, 0.2-0.9]).

CONCLUSIONS

These findings suggest a potentially hereditary predisposition to EOAFL across race and ethnicity, warranting further study of the genetic contributions to AFL.

Atrial fibrillation: pathophysiology, genetic and epigenetic mechanisms

Atrial fibrillation (AF) is the most common supraventricular arrhythmia affecting up to 1% of the general population. Its prevalence dramatically increases with age and could reach up to ∼10% in the elderly. The management of AF is a complex issue that is object of extensive ongoing basic and clinical research, it depends on its genetic and epigenetic causes, and it varies considerably geographically and also according to the ethnicity. Mechanistically, over the last decade, Genome Wide Association Studies have uncovered over 100 genetic loci associated with AF, and have shown that European ancestry is associated with elevated risk of AF. These AF-associated loci revolve around different types of disturbances, including inflammation, electrical abnormalities, and structural remodeling. Moreover, the discovery of epigenetic regulatory mechanisms, involving non-coding RNAs, DNA methylation and histone modification, has allowed unravelling what modifications reshape the processes leading to arrhythmias. Our review provides a current state of the field regarding the identification and functional characterization of AF-related genetic and epigenetic regulatory networks, including ethnic differences. We discuss clear and emerging connections between genetic regulation and pathophysiological mechanisms of AF.

Addressing racial differences in the management of atrial fibrillation: Focus on black patients

Atrial fibrillation (AF) is the most common sustained arrhythmia, affecting between 3 and 6 million people in the United States. It is associated with a reduced quality of life and increased risk of stroke, cognitive decline, heart failure and death. Black patients have a lower prevalence of AF than White patients but are more likely to suffer worse outcomes with the disease. It is important that stakeholders understand the disproportionate burden of disease and management gaps that exists among Black patients living with AF. Appropriate treatments, including aggressive risk factor control, early referral to cardiovascular specialists and improving healthcare access may bridge some of the gaps in management and improve outcomes.

Genome and atrial fibrillation

Atrial fibrillation (AF), the most common type of arrhythmia, can cause several adverse effects, such as stroke, heart failure, and cognitive dysfunction, also in addition to reducing quality of life and increasing mortality. Evidence suggests that AF is caused by a combination of genetic and clinical predispositions. In line with this, genetic studies on AF have progressed significantly through linkage studies, genome-wide association studies, use of polygenic risk scores, and studies on rare coding variations, gradually elucidating the relationship between genes and the pathogenesis and prognosis of AF. This article will review current trends in genetic analysis concerning AF.

Machine learning for atrial fibrillation risk prediction in patients with sleep apnea and coronary artery disease

Background

Patients with sleep apnea (SA) and coronary artery disease (CAD) are at higher risk of atrial fibrillation (AF) than the general population. Our objectives were: to evaluate the role of CAD and SA in determining AF risk through cluster and survival analysis, and to develop a risk model for predicting AF.

Methods

Electronic medical record (EMR) database from 22,302 individuals including 10,202 individuals with AF, CAD, and SA, and 12,100 individuals without these diseases were analyzed using K-means clustering technique; k-nearest neighbor (kNN) algorithm and survival analysis. Age, sex, and diseases developed for each individual during 9 years were used for cluster and survival analysis.

Results

The risk models for AF, CAD, and SA were identified with high accuracy and sensitivity (0.98). Cluster analysis showed that CAD and high blood pressure (HBP) are the most prevalent diseases in the AF group, HBP is the most prevalent disease in CAD; and HBP and CAD are the most prevalent diseases in the SA group. Survival analysis demonstrated that individuals with HBP, CAD, and SA had a 1.5-fold increased risk of developing AF [hazard ratio (HR): 1.49, 95% CI: 1.18-1.87, p = 0.0041; HR: 1.46, 95% CI: 1.09-1.96, p = 0.01; HR: 1.54, 95% CI: 1.22-1.94, p = 0.0039, respectively] and individuals with chronic kidney disease (CKD) developed AF approximately 50% earlier than patients without these comorbidities in a period of 7 years (HR: 3.36, 95% CI: 1.46-7.73, p = 0.0023). Comorbidities that contributed to develop AF earlier in females compared to males in the group of 50-64 years were HBP (HR: 3.75 95% CI: 1.08-13, p = 0.04) CAD and SA in the group of 60-75 years were (HR: 2.4 95% CI: 1.18-4.86, p = 0.02; HR: 2.51, 95% CI: 1.14-5.52, p = 0.02, respectively).

Conclusion

Machine learning based algorithms demonstrated that CAD, SA, HBP, and CKD are significant risk factors for developing AF in a Latin-American population.

Transcriptomics-based network medicine approach identifies metformin as a repurposable drug for atrial fibrillation

Effective drugs for atrial fibrillation (AF) are lacking, resulting in significant morbidity and mortality. This study demonstrates that network proximity analysis of differentially expressed genes from atrial tissue to drug targets can help prioritize repurposed drugs for AF. Using enrichment analysis of drug-gene signatures and functional testing in human inducible pluripotent stem cell (iPSC)-derived atrial-like cardiomyocytes, we identify metformin as a top repurposed drug candidate for AF. Using the active compactor, a new design analysis of large-scale longitudinal electronic health record (EHR) data, we determine that metformin use is significantly associated with a reduced risk of AF (odds ratio = 0.48, 95%, confidence interval [CI] 0.36-0.64, p < 0.001) compared with standard treatments for diabetes. This study utilizes network medicine methodologies to identify repurposed drugs for AF treatment and identifies metformin as a candidate drug.

Association between the rs2106261 polymorphism in the zinc finger homeobox 3 gene and risk of atrial fibrillation: Evidence from a PRISMA-compliant meta-analysis

INTRODUCTION

Previous genome-wide studies have identified an association between the rs2106261 single-nucleotide polymorphism (SNP) in the zinc finger homeobox 3 (ZFHX3) gene and an increased risk of atrial fibrillation (AF). However, this association remains controversial, since conflicting results have been reported in previous studies. We aimed to investigate the association between the ZFHX3 rs2106261 polymorphism and susceptibility to AF.

METHODS

A comprehensive literature search, of articles written in either English or Chinese, was conducted on various databases, including PubMed, Embase, Web of Science, the Cochrane library, Wan Fang, and CNKI, for studies performed up to August 1, 2020. Data were abstracted and pooled using Stata 14.0 software. A meta-analysis was performed on all selected studies based on ZFHX3 rs2106261 polymorphism genotypes.

RESULTS

Nine studies, including 10,107 cases and 58,663 controls, were analyzed in the meta-analysis. In the overall population, a significant association was found between AF and the T-allelic ZFHX 3 rs2106261 SNP (odds ratio [OR] = 1.32, 95% confidence interval [CI] 1.19-1.46). In subgroup analysis, a significant association between the T-allele of rs7193343 and risk of AF in Caucasian (OR = 1.23, 95% CI 1.10-1.37) and Asian subgroups (OR = 1.58, 95% CI 1.32-1.89) was observed. However, no statistically significant association was found in African populations (OR = 1.06, 95% CI 0.95-1.19).

CONCLUSION

The genetic variant rs2106261 SNP is associated with susceptibility to AF in Caucasian and Asian individuals, with Asian samples showing a stronger association. However, based on the current evidence, no association was found in African samples. Future studies, with larger sample sizes and multiple ethnicities, are still necessary.

Racial and Ethnic Differences in the Management of Atrial Fibrillation

Atrial fibrillation (AF) is the most common clinical arrhythmia, and it results in adverse outcomes and increased healthcare costs. Racial and ethnic differences in AF management, although recognized, are poorly understood. This review summarizes racial differences in AF epidemiology, genetics, clinical presentation, and management. In addition, it highlights the underrepresentation of racial and ethnic populations in AF clinical trials, especially trials focused on stroke prevention. Specific strategies are proposed for future research and initiatives that have potential to eliminate racial and ethnic differences in the care of patients with AF. Addressing racial and ethnic disparities in healthcare access, enrollment in clinical trials, resource allocation, prevention, and management will likely narrow the gaps in the care and outcomes of racial and ethnic minorities suffering from AF.

Differences in Left Atrial Size and Function and Supraventricular Ectopy Between Black and White Participants in the ARIC Study

Background Black Americans have more atrial fibrillation risk factors but lower atrial fibrillation risk than White Americans. Left atrial (LA) enlargement and/or dysfunction, frequent atrial tachycardia (AT), and premature atrial contractions (PAC) are associated with increased atrial fibrillation risk. Racial differences in these factors may exist that could explain the difference in atrial fibrillation risk. Methods and Results We included 2133 ARIC (Atherosclerosis Risk in Communities) study participants (aged 74±4.5 years[mean±SD], 59% women, 27% Black participants) who had echocardiograms in 2011 to 2013 and wore the Zio XT Patch (a 2-week continuous heart monitor) in 2016 to 2017. Linear regression was used to analyze (1) differences in AT/day or PAC/hour between Black and White participants, (2) differences in LA measures between Black and White participants, and (3) racial differences in the association of LA measures with AT or PAC frequency. Compared with White participants, Black participants had a higher prevalence of cardiovascular risk factors and disease, lower AT frequency, greater LA size, and lower LA function. After multivariable adjustments, Black participants had 37% (95% CI, 24%-47%) fewer AT runs/day than White participants. No difference in PAC between races was noted. Greater LA size and reduced LA function are associated with more AT and PAC runs; however, no race interaction was present. Conclusions Differences in LA measures are unlikely to explain the difference in atrial fibrillation risk between Black and White individuals. Despite more cardiovascular risk factors and greater atrial remodeling, Black participants have lower AT frequency than White participants. Future research is needed to elucidate the protective mechanisms that confer resilience to atrial arrhythmias in Black individuals.

A study of the clinical application value of ultrasound and electrocardiogram in the differential diagnosis of cardiomyopathy

OBJECTIVE

To investigate the clinical application values of electrocardiogram (ECG) combined with ultrasound cardiogram (UCG) in the differential diagnosis of cardiomyopathy.

METHODS

A total of 120 patients with cardiomyopathy who were admitted to our hospital were randomly divided into the dilated cardiomyopathy (DCM) group (60 cases) and the ischemic cardiomyopathy (ICM) group (60 cases). Both groups were examined using ECG combined with UCG. The ultrasonic values (aorta, LADI, LVDd, LVESD, RVID, SV, LVEF, LVET, EPSS, E/A, RV6, RV6/RMAX), morphological changes (thin and round left ventricular apex, spherical left ventricle, arch-shaped left ventricle, segmental wall-motion abnormalities (SWMAs), diffuse wall motion abnormalities (DWMAs), paradoxical ventricular wall motion) and heart valve regurgitation (aortic valve, mitral valve, tricuspid valve, pulmonary valve) were compared and analyzed.

RESULTS

The degree of chamber enlargement in the DCM group was remarkably higher than that in the ICM group, but the degree of LVEF and aortic enlargement were significantly lower than those in the ICM group (P<0.05). The detection rates of spherical left ventricle and DWMAs in the DCM group were 60.00% and 100.00% respectively, which was significantly higher than those (6.66% and 40.00%) of the ICM group (P<0.05), but the detection rates of thin and round left ventricular apex, arch-shaped left ventricle, SWMAs, and paradoxical ventricular wall motion were 53.33%, 66.66%, 46.66% and 20.00% respectively in the ICM group, which were markedly higher than those in the DCM group. The incidence rates of aortic valve, mitral valve, tricuspid valve and pulmonary valve in the DCM group were 66.66%, 100.00%, 46.66% and 76.66%, which were notably higher than those (36.66%, 93.33%, 26.66% and 40.00%) in the ICM group (P<0.05).

CONCLUSION

ECG combined with UCG examination can effectively improve the judgment rate and diagnosis accuracy of cardiomyopathy. Due to its high safety, ECG combined with UCG examination is worthy of clinical promotion and application.

Racial differences in the incidence of atrial fibrillation after cryptogenic stroke

BACKGROUND

The incidence of atrial fibrillation (AF) is lower in nonwhites than in whites despite a higher burden of AF risk factors. However, the incidence of new AF after cryptogenic stroke in minorities is unknown.

OBJECTIVE

The purpose of this study was to determine the incidence of AF after cryptogenic stroke in different racial/ethnic groups.

METHODS

We retrospectively analyzed 416 consecutive patients undergoing insertable cardiac monitor implantation at our hospital from 2014 through 2019. Incidence of AF was identified through the review of device monitoring, including adjudication of AF episodes for accuracy, and compared by race.

RESULTS

The mean follow-up time was 1.5 ± 1.1 years. The predominantly nonwhite cohort included 244 (59%) blacks and 109 (26%) Hispanics, and 45% (n=189) were male. The mean age was 62 ± 12 years; Blacks and Hispanics had more hypertension, diabetes, and chronic kidney disease and higher body mass index than did whites. In blacks and Hispanics, the cumulative incidences of AF at 1, 2, and 3 years were 14.1%, 19.9%, and 24% and 12.9%, 18.3%, and 20.9%, respectively. By comparison, the incidence in whites was significantly higher: 20.8%, 34.3%, and 40.3%. In a Cox proportional hazards model adjusting for common AF risk factors, blacks (hazard ratio 0.49; confidence interval 0.26-0.82; P = .03) and Hispanics (hazard ratio 0.39; confidence interval 0.18-0.83; P = .01) were less likely to have incident AF than whites.

CONCLUSION

In patients with an insertable cardiac monitor after cryptogenic stroke, the incidence of newly detected AF is approximately double in whites compared with both blacks and Hispanics. This has important implications for the investigation and treatment of nonwhites with cryptogenic stroke.

Comparison of Frequency of Atrial Fibrillation in Blacks Versus Whites and the Utilization of Race in a Novel Risk Score

Blacks have a lower prevalence of atrial fibrillation (AF) compared with Whites. We sought to confirm previously reported ethnic trends in AF in Blacks and Whites in a large database, and develop a prediction score for AF. Over 330 million hospital discharges between the years 2003 to 2013 from the National Inpatient Sample database were analyzed. All hospitalizations with a diagnosis of AF formed the study cohort. Traditional risk factors for the development of AF were compared between Blacks and Whites. Univariate and multiple logistic regression analyses were used to formulate a risk score to predict AF-CHADSAVES (Congestive heart failure, Hypertension, Age>65 years, Diabetes Mellitus, prior Stroke, Age>75 years, Vascular disease, White Ethnicity, and previous cardiothoracic Surgery). AF prevalence in Whites was 11.3% vs 4.6% in Blacks (p < 0.001). Blacks were younger (33.8% vs 14.4% patients <65 years, p < 0.01) and had less males (46.3% vs 49.4%, p < 0.01). Blacks had more hypertension (71.3% vs 64.1%, p < 0.01), congestive heart failure (24.8% vs 22.6%, p < 0.01), diabetes mellitus with (7.5% vs 4.7%, p < 0.01) or without complications (30.3% vs 23.1%, p < 0.01), renal failure (29.7% vs 17.1%, p < 0.01), and obesity (13.1% vs 8.7%, p < 0.01). CHADSAVES predicted AF in the study population (NIS 2003 to 2013) with an AUC of 0.82 and verified in a validation cohort (NIS 2014) with an AUC of 0.85. In conclusion, our data confirm a significant AF ethnicity paradox. Despite a higher prevalence of traditional risk factors for AF, Blacks had >2-fold lower prevalence of AF compared with Whites. CHADSAVES can be used effectively to predict AF in inpatients.

Annotation of susceptibility SNPs associated with atrial fibrillation

OBJECTIVE

Genome-wide association studies (GWAS) and the candidate gene based association studies have identified a panel of variants associated with atrial fibrillation (AF), however, most of the identified single nucleotide polymorphisms (SNPs) were found located within intergenic or intronic genomic regions, and whether the positive SNPs have a real biological function is unknown, and the real disease causing gene need to be studied.

RESULTS

The current results of the genetic studies including common variants identified by GWAS (338 index SNPs) and candidate gene based association studies (40 SNPs) were summarized.

CONCLUSION

Our study suggests the relationship between genetic variants and possible targeted genes, and provides insight into potential genetic pathways underlying AF incidence and development. The results may provide an encyclopedia of AF susceptibility SNPs and shed light on the functional mechanisms of AF variants identified through genetic studies.

METHODS

We summarized AF susceptibility SNPs identified by GWAS and candidate gene based association studies, and give a comprehensive functional annotation of all these AF susceptibility loci. by genomic annotation, microRNA binding prediction, promoter activity analysis, enhancer activity analysis, transcription factors binding activity prediction, expression quantitative trait loci (eQTL) analysis, long-range transcriptional regulatory function analysis, gene ontology and pathway enrichment analysis.

Epidemiology of Atrial Fibrillation in the 21st Century: Novel Methods and New Insights

Accompanying the aging of populations worldwide, and increased survival with chronic diseases, the incidence and prevalence of atrial fibrillation (AF) are rising, justifying the term global epidemic. This multifactorial arrhythmia is intertwined with common concomitant cardiovascular diseases, which share classical cardiovascular risk factors. Targeted prevention programs are largely missing. Prevention needs to start at an early age with primordial interventions at the population level. The public health dimension of AF motivates research in modifiable AF risk factors and improved precision in AF prediction and management. In this review, we summarize current knowledge in an attempt to untangle these multifaceted associations from an epidemiological perspective. We discuss disease trends, preventive opportunities offered by underlying risk factors and concomitant disorders, current developments in diagnosis and risk prediction, and prognostic implications of AF and its complications. Finally, we review current technological (eg, eHealth) and methodological (artificial intelligence) advances and their relevance for future prevention and disease management.

The prevalence of atrial fibrillation on 48-hour ambulatory electrocardiography in African Americans compared to Whites: The Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND

A lower prevalence of atrial fibrillation (AF), but paradoxically higher burden of cardiovascular disease risk factors, has been observed among African Americans compared to Whites in studies of AF identified by mostly 12-lead electrocardiograms (ECGs) and clinically.

METHODS

We performed 48-hour ambulatory electrocardiography (aECG) in a biracial sample of 1,193 participants in the Atherosclerosis Risk in Communities (ARIC) (mean age = 78 years, 62% African Americans, 64% female). Atrial fibrillation was identified from aECG, study visit ECGs, and discharge codes from cohort hospitalizations. We used covariate-adjusted logistic regression to estimate prevalence odds ratios (ORs) for AF in African Americans versus Whites, with adjustment for sampling and nonresponse.

RESULTS

African Americans were more likely than Whites to have hypertension and diabetes but less likely to have coronary heart disease. The prevalence of AF detected by aECG or ARIC study ECG (adjusted for age and coronary heart disease) was lower in African Americans than Whites (2.7% vs 5.0%). White men had a higher (although not significant) AF prevalence of 7.8% compared to the other race and gender groups at 2.3%-2.8%. The adjusted OR for AF was 0.49 (0.24-0.99) comparing African Americans to Whites. Findings were similar when AF was defined to include prior AF hospitalizations (OR = 0.42, 0.25-0.72). There were no significant differences by race for asymptomatic or paroxysmal AF.

CONCLUSIONS

Atrial fibrillation was less prevalent in African American than white older adults, regardless of detection method. Although overall detection of new AF cases with aECG was low, future studies should consider longer-term monitoring to characterize AF by race.

Sex and racial differences in cardiovascular disease risk in patients with atrial fibrillation

Background

Outcomes among atrial fibrillation (AF) patients may differ according to race/ethnicity and sex due to differences in biology, the prevalence of cardiovascular risk factors, and the use and effectiveness of AF treatments. We aimed to characterize patterns of cardiovascular risk across subgroups of AF patients by sex and race/ethnicity, since doing so may provide opportunities to identify interventions. We also evaluated whether these patterns changed over time.

Methods

We utilized administrative claims data from the Optum Clinformatics® Datamart database from 2009 to 2015. Patients with AF with ≥6 months of enrollment prior to the first non-valvular AF diagnosis were included in the analysis. Final analysis utilized Cox proportional hazard models to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for cardiovascular outcomes stratified by sex and race/ethnicity. An additional analysis stratified outcomes by calendar year of AF diagnosis to evaluate changes in outcomes over time.

Results

In a cohort of 380,636 AF patients, women had a higher risk of ischemic stroke [HR (95% CI): 1.25 (1.19, 1.31)] and lower risk of heart failure and myocardial infarction [HR (95% CI): 0.91 (0.88, 0.94) and 0.81 (0.77, 0.86), respectively)] compared to men. Black patients had elevated risk across all endpoints compared to whites, while Hispanics and Asian Americans showed no significant differences in any outcome compared to white patients. These sex and race/ethnic differences did not change over time.

Conclusions

We found sex and race/ethnic differences in risk of cardiovascular outcomes among AF patients, without evidence of improvement over time.

Racial and ethnic differences in the prevalence, management, and outcomes in patients with atrial fibrillation: A systematic review

Atrial fibrillation (AF) is the most common cardiac arrhythmia in the United States and is associated with increased morbidity, mortality, and health care expenditures. In this review, our aim was to assess the racial and ethnic differences in the epidemiology, management, and outcomes of patients with AF. A search of relevant studies from January 1, 2007, to December 30, 2017, was conducted in PubMed, EMBASE, and Web of Science and supplemented by manual searches of the bibliographies of retrieved articles. We identified 152 studies of which 64 were subsequently included. We found that underrepresented racial and ethnic groups have a higher prevalence of established risk factors associated with the development of AF but an overall lower incidence and prevalence of AF as compared with non-Hispanic whites. Moreover, racial and ethnic differences exist in detection, awareness, and AF-associated symptoms. Nonwhite populations also experience decreased use of rhythm control modalities and anticoagulation for stroke prevention. Lastly, among those with AF, underrepresented racial and ethnic groups had increased morbidity and mortality relative to white groups. Racial and ethnic differences exist in the prevalence, quality of life, management, and outcomes of individuals with AF; however, the mechanisms for these differences have yet to be fully elucidated. Racial and ethnic differences in AF warrant further analysis to understand the factors contributing to the differences in prevalence and management to ensure the delivery of high quality care that prevents stroke, reduces deaths, and decreases expenses associated with caring for underrepresented populations with AF.

Validation of a genetic risk score for atrial fibrillation: A prospective multicenter cohort study

BACKGROUND

Atrial fibrillation (AF) is the most commonly encountered arrhythmia and is associated with an elevated risk of stroke. Improving the identification of patients with the highest risk for AF to enable appropriate surveillance and treatment, if necessary, is critical to reducing AF-associated morbidity and mortality. Multiple common single nucleotide polymorphisms (SNPs) are unequivocally associated with the lifetime risk of AF. In the current study we aimed to prospectively validate an AF genetic risk score (GRS) in previously undiagnosed patients at risk for AF.

METHODS AND FINDINGS

Individuals 40 years of age or older with 1 clinical risk factor for AF, presenting with symptoms of AF, or with a first diagnosis of AF, were enrolled for genetic testing and ambulatory cardiac rhythm monitoring with an adhesive patch monitor or a long-term Holter monitor (mean wear time 10 days 21 hours and 13 days 18 hours, respectively). An AF event was the first diagnosis of AF by ECG, patch monitor, or long-term Holter monitor. The AF GRS was determined for each participant based on the weighted contribution of 12 genetic risk loci. Of 904 participants, 85 manifested AF. Their mean age was 66.2 (SD 11.8) years; 38% of participants were male. Participants in the highest quintile of AF GRS were more likely (odds ratio 3.11; 95% CI 1.27-7.58; p = 0.01) to have had an AF event than participants in the lowest quintile after adjusting for age, sex, smoking status, BMI, hypertension, diabetes mellitus, heart failure, and prior myocardial infarction. Study limitations included an ethnically homogenous population, a restricted rhythm monitoring period, and the evolving discovery of SNPs associated with AF.

CONCLUSIONS

Prospective assessment of a GRS for AF identified participants with elevated risk of AF beyond established clinical criteria. Accordingly, a GRS for AF could be incorporated into overall risk assessment to better identify patients at the highest risk of developing AF, although further testing in larger populations is needed to confirm these findings.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01970969.

Symptom challenges after atrial fibrillation ablation

BACKGROUND

It is unclear what symptom challenges occur during the recovery phase after atrial fibrillation (AF) ablation.

OBJECTIVES

This longitudinal pilot study explored the patient perspective of the first six months following an AF ablation.

METHODS

Telephone interviews and questionnaires were used with 20 patients at baseline, at 1, 3, and 6 months after AF ablation. Telephone interview data were analyzed using content analysis. Longitudinal outcomes were analyzed using repeated measures analysis of variance (ANOVA).

RESULTS

Mean age was 65 ± 7 years and the sample was 55% female. The severity and duration of fatigue was the most concerning symptom. Patient expectations differed from providers' expectations. Recovery was a much slower process than patients expected.

CONCLUSIONS

Patients struggled to manage symptoms after AF ablation. A more accurate understanding of the symptom challenges following AF ablation could lead to development of more realistic education to improve patient self-management.

Update about atrial fibrillation genetics

PURPOSE OF REVIEW

Atrial fibrillation is an important cause of morbidity in the aging population. The mechanisms responsible for the triggering and maintenance of the chaotic atrial rhythm are still poorly understood. In this review, we will focus on the genetic aspects of atrial fibrillation, to understand causality, with special emphasis on recent studies published in the field.

RECENT FINDINGS

Diseases such as hypertension, valvular heart disease, and heart failure may induce atrial fibrillation, which increases the risk of stroke and sudden cardiac death. Clinical studies published in these last two decades have provided evidence that genetics play a key role in atrial fibrillation. Thus, a family history of the disease has been identified in up to 30% of clinically diagnosed patients. In those genotyped families, most carry rare genetic variants in genes associated with ionic channels, calcium handling protein, or predisposing to fibrosis, conduction system disease, and inflammatory processes.

SUMMARY

Currently, atrial fibrillation is the most common sustained arrhythmia in clinical practice. The pathophysiological mechanisms of atrial fibrillation are complex. A better understanding of the molecular basis will help improve both current risk stratification and clinical management.

Atrial Fibrillation: Epidemiology, Pathophysiology, and Clinical Outcomes

The past 3 decades have been characterized by an exponential growth in knowledge and advances in the clinical treatment of atrial fibrillation (AF). It is now known that AF genesis requires a vulnerable atrial substrate and that the formation and composition of this substrate may vary depending on comorbid conditions, genetics, sex, and other factors. Population-based studies have identified numerous factors that modify the atrial substrate and increase AF susceptibility. To date, genetic studies have reported 17 independent signals for AF at 14 genomic regions. Studies have established that advanced age, male sex, and European ancestry are prominent AF risk factors. Other modifiable risk factors include sedentary lifestyle, smoking, obesity, diabetes mellitus, obstructive sleep apnea, and elevated blood pressure predispose to AF, and each factor has been shown to induce structural and electric remodeling of the atria. Both heart failure and myocardial infarction increase risk of AF and vice versa creating a feed-forward loop that increases mortality. Other cardiovascular outcomes attributed to AF, including stroke and thromboembolism, are well established, and epidemiology studies have championed therapeutics that mitigate these adverse outcomes. However, the role of anticoagulation for preventing dementia attributed to AF is less established. Our review is a comprehensive examination of the epidemiological data associating unmodifiable and modifiable risk factors for AF and of the pathophysiological evidence supporting the mechanistic link between each risk factor and AF genesis. Our review also critically examines the epidemiological data on clinical outcomes attributed to AF and summarizes current evidence linking each outcome with AF.