Differential impact of race and risk factors on incidence of atrial fibrillation

The Impact of Weight Categories on the Association Between Atrial Fibrillation/Flutter and Known Risk Factors: A Nationwide Inpatient Data Analysis

Background/Objectives: Atrial fibrillation and atrial flutter (Afib/Aflut) are the most common arrhythmias presenting to the emergency department. The goal of this study was to evaluate any predictor of Afib/flut with cardiovascular risk factors and demographics based on weight categories. Methods: Using ICD-10 codes from the large Nationwide Inpatient Sample (NIS) database in the years 2016-2020, we evaluate any association between the presence of Afib/Aflut with risk factors and demographics in different weight categories in adults over the age of 18. Results: A total of 23,037,013 afib/flut patients were found in the NIS database. Obesity and morbid obesity were independently associated with the presence of Afib/Aflut (for multivariate OR obesity: 1.28, CI 1.27-1.28, p < 0.001; for morbid obesity: OR 1.9, CI 1.89-1.91, p < 0.001). Regardless of weight categories such as cachexia, overweight, obese, or morbidly obese, traditional risk factors remained independently associated with Afib/Aflut. Furthermore, male gender and Caucasians were independently associated with the presence of Afib/Aflut regardless of any weight categories. (For example, in the overweight categories, the multivariate OR for females was 0.69, CI: 0.69-0.69, p < 0.001, and for African Americans, OR 0.62, CI 0.61-0.62, p < 0.001). Conclusions: Traditional risk factors were persistently associated with the occurrence of atrial fibrillation regardless of weight categories. Furthermore, the Caucasian race and male gender were also strong independent predictors of Afib/Aflut.

National Trends in Mortality Due to Ischemic Stroke Among Older Adults With Atrial Fibrillation in the USA, 1999-2020

BACKGROUND

Atrial fibrillation (AF) is a significant contributor to ischemic stroke risk and mortality, particularly in aging populations. This study examines mortality trends from ischemic stroke secondary to AF in the U.S. from 1999 to 2020, focusing on demographic and regional disparities.

METHODS

Using data from the CDC WONDER database, this cross-sectional analysis included individuals aged ≥ 65 years with death certificates indicating ischemic stroke (ICD I63) and AF (ICD I48) as contributing causes. Age-adjusted mortality rates (AAMR) were calculated, and temporal trends were analyzed using join-point regression to estimate annual percentage changes (APC). Data were stratified by age, sex, race/ethnicity, urbanization, and geographic regions.

RESULTS

From 1999 to 2020, ischemic stroke with AF caused 62,443 deaths (AAMR: 6.75/100,000; 95% CI: 6.70-6.80). Mortality rates increased significantly after 2010, peaking between 2014 and 2017 (APC: 31.3 for females, 28.1 for males). Older adults (≥ 85 years) exhibited the highest AAMR (43.2/100,000; 95% CI: 41.6-44.8). Nonmetropolitan areas consistently showed higher mortality compared to metropolitan regions. Demographic disparities were evident, with higher AAMRs in females, Whites, and the Western U.S., though Hispanics had the sharpest APC increase during 2014-2017.

CONCLUSION

Mortality rates from ischemic stroke with AF are rising in older adults, with significant demographic and regional disparities. The findings underscore the need for targeted public health strategies to mitigate AF-related stroke risks and improve healthcare equity.

Atrial fibrillation in Black American patients: A review of genetics, risk factors, and outcomes

Atrial fibrillation (AF), the most common arrhythmia in the United States, affects 6 million Americans, with numbers projected to increase to 12 million by 2030. A racial paradox difference in the incidence and prevalence of AF exists between Black and White Americans. Black Americans are less prone than White Americans to development of AF, but they display a higher burden of modifiable risk factors for cardiovascular disease and higher rates of ischemic stroke. Data pertaining to the American Heart Association Life's Simple 7 (LS7) health metrics show that Black Americans have suboptimal LS7 scores compared with White Americans on average despite lower genetic predisposition to AF. This trend suggests the impact of cardiovascular health on the development and progression of AF. Social, genetic, and lifestyle risk factors have been shown to play a role in the racial paradox and AF outcomes in Black Americans. This review summarizes factors contributing to the racial paradox and discusses suggestions for improved health outcomes in Black Americans with AF.

Assessing ascertainment bias in atrial fibrillation across US minority groups

The aim of this study is to define atrial fibrillation (AF) prevalence and incidence rates across minority groups in the United States (US), to aid in diversity enrollment target setting for randomized controlled trials. In AF, US minority groups have lower clinically detected prevalence compared to the non-Hispanic or Latino White (NHW) population. We assess the impact of ascertainment bias on AF prevalence estimates. We analyzed data from adults in Optum's de-identified Clinformatics® Data Mart Database from 2017-2020 in a cohort study. Presence of AF at baseline was identified from inpatient and/or outpatient encounters claims using validated ICD-10-CM diagnosis algorithms. AF incidence and prevalence rates were determined both in the overall population, as well as in a population with a recent stroke event, where monitoring for AF is assumed. Differences in prevalence across cohorts were assessed to determine if ascertainment bias contributes to the variation in AF prevalence across US minority groups. The period prevalence was respectively 4.9%, 3.2%, 2.1% and 5.9% in the Black or African American, Asian, Hispanic or Latino, and NHW population. In patients with recent ischemic stroke, the proportion with AF was 32.2%, 24.3%, 25%, and 24.5%, respectively. The prevalence of AF among the stroke population was approximately 7 to 10 times higher than the prevalence among the overall population for the Asian and Hispanic or Latino population, compared to approximately 5 times higher for NHW patients. The relative AF prevalence difference of the Asian and Hispanic or Latino population with the NHW population narrowed from respectively, -46% and -65%, to -22% and -24%. The study findings align with previous observational studies, revealing lower incidence and prevalence rates of AF in US minority groups. Prevalence estimates of the adult population, when routine clinical practice is assumed, exhibit higher prevalence differences compared to settings in which monitoring for AF is assumed, particularly among Asian and Hispanic or Latino subgroups.

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.

A nationwide analysis of the outcomes in hospitalized patients with atrial fibrillation and temperature-related illnesses

OBJECTIVES

The authors evaluated mortality and indices of cost of care among inpatients with Atrial Fibrillation (AF) and a diagnosis of a Temperature-Related Illness (TRI). The authors also assessed trends in the prevalence of TRIs among AF hospitalizations.

METHODS

In this cross-sectional study, the authors used discharge data from the Nationwide Inpatient Sample (NIS) collected between January 2005 and September 2015 to identify patients with a diagnosis of AF and TRI. Outcomes of interest included in-hospital mortality, invasive mechanical ventilation, hospital length of stay, and cost of hospitalization.

RESULTS

A total of 37,933 encounters were included. The median age was 79 years. Males were slightly overrepresented relative to females (54.2% vs. 45.8%, respectively). Although Blacks were only 6.6% of the cohort, they represented 12.2% of the TRI cases. Compared to non-TRI-related hospitalizations, a diagnosis of a TRI was associated with an increased likelihood of invasive mechanical ventilation (16.5% vs. 4.1%, p < 0.001), longer length-of-stay (5 vs. 4 days, p < 0.001), higher cost of care (10,082 vs. 8,607, in US dollars p < 0.001), and increased mortality (18.6% vs. 5.1%, p < 0.001). Compared to non-TRI, cold-related illness portends higher odds of mortality 4.68, 95% Confidence Interval (4.35-5.04), p < 0.001, and heat-related illness was associated with less odds of mortality, but this was not statistically significant 0.77 (0.57-1.03), p = 0.88.

CONCLUSION

The occurrence of TRI among hospitalized AF patients is small but there is an increasing trend in the prevalence, which more than doubled over the decade in this study. Individuals with AF who are admitted with a TRI face significantly poorer outcomes than those admitted without a TRI including higher mortality. Cold-related illness is associated with higher odds of mortality. Further research is required to elucidate the pathogenic mechanisms underlying these findings and identify strategies to prevent TRIs in AF patients.

Effect of atrial fibrillation on mortality in SARS-CoV-2 patients: A propensity score-matched analysis of nationwide hospitalizations in the United States

Background

Atrial fibrillation (AF) is one of the most common arrhythmias encountered in patients with SARS-CoV-2 infection. There are racial disparities in the incidence of AF and COVID-19. Several studies have reported an association between AF and mortality. However, it remains to be determined if AF represents an independent risk factor for COVID-19-related mortality.

Methods

A propensity score-matched (PSM) analysis was performed using data from the National Inpatient Sample to assess the risk of mortality among patients hospitalized with SARS-CoV-2 infection and incident AF from March 2020 through December 2020.

Results

AF was less common among patients who tested positive for SARS-CoV-2 as compared to those who tested negative (6.8% vs 7.4%, p < 0.001). White individuals with the virus had an increased incidence of AF but had lower mortality rates relative to Black and Hispanic patients. After PSM analysis, AF retained a significantly increased odds of mortality among patients with SARS-CoV-2 (OR: 1.35, CI: 1.29-1.41, p < 0.001).

Conclusion

This PSM analysis shows that AF is an independent risk factor for inpatient mortality in those with SARS-CoV-2 infection and that White patients, while having a higher burden of SARS-CoV-2 and AF, demonstrate a significantly lower mortality rate as compared to their Black and Hispanic counterparts.

Racial disparity in sleep apnea-related mortality in the United States

BACKGROUND

Sleep apnea is one of the most common sleep disorders in the United States (US). Although the prevalence, risk factors, and clinical presentations of sleep apnea vary by racial groups, the racial disparity in sleep apnea-related mortality remains unclear.

METHODS

Sleep apnea-related mortality for 1999-2019 was obtained from the National Center for Health Statistics provided by the Centers for Disease Control and Prevention. We examined the mortality trends for sleep apnea using Joinpoint regression analysis and compared the associated outcomes and multiple causes of death between Blacks and Whites.

RESULTS

For 1999-2019, sleep apnea was documented as the underlying cause of death in 17,053 decedents, with 2593 Blacks and 14,127 Whites. The overall age-adjusted mortality rates in all population, Blacks, and Whites were 2.5, 3.5, and 2.4 per 1,000,000 population, respectively (P < 0.001). Both Blacks and Whites had the highest mortality rates in the Midwest and the lowest in the Northeast. Despite the flattened mortality trend in the last decade overall, Black males had a continuous mortality increase over the study period (Annual Percentage Change 2.7%, 95% CI: 1.2-4.2). For both genders of sleep apnea decedents, Blacks were more likely to have multiple cause of death of Cardiac Arrest, Hypertension, Obesity, and Chronic Renal Failure, but Arrhythmia was more common in Whites (P < 0.05).

CONCLUSIONS

There is a significant racial disparity in sleep apnea-related mortality in the US. The uptrend in mortality in Black males and associated outcomes related to cardiovascular disease should raise concerns specifically in Blacks with sleep apnea.

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.

No Racial Disparity in Outcome Measures After Endovascular Treatment for Stroke in the Elderly

BACKGROUND AND PURPOSE

Despite the lower rates of good outcomes and higher mortality in elderly patients, age does not modify the treatment effect of mechanical thrombectomy for large vessel occlusion strokes. We aimed to study whether racial background influences the outcome after mechanical thrombectomy in the elderly population.

METHODS

We reviewed a prospectively maintained database of patients with acute ischemic stroke treated with mechanical thrombectomy from October 2010 through June 2020 to identify all consecutive patients with age ≥80 years and anterior circulation large vessel occlusion strokes. The patients were categorized according to their race as Black and White. Univariable and multivariable analyses were performed to define the predictors of 90-day modified Rankin Scale and mortality in the overall population and in each race separately.

RESULTS

Among 2241 mechanical thrombectomy, a total of 344 patients (median [interquartile range]; age 85 [82-88] years, baseline National Institutes of Health Stroke Scale score of 19 [15-23], Alberta Stroke Program Early CT Score 9 [7-9], 69.5% females) were eligible for the analysis. White patients (n=251; 73%) had significantly lower median body mass index (25.37 versus 26.89, P=0.04) and less frequent hypertension (78.9% versus 90.3%, P=0.01) but more atrial fibrillation (64.5% versus 44.1%, P=0.001) compared with African Americans (n=93; 27%). Other clinical, imaging, and procedural characteristics were comparable between groups. The rates of symptomatic intracerebral hemorrhage, 90-day modified Rankin Scale score of 0 to 2, and mortality were comparable among both groups. On multivariable analysis, race was neither a predictor of 90-day modified Rankin Scale score of 0 to 2 (White race: odds ratio, 0.899 [95% CI, 0.409-1.974], P=0.79) nor 90-day mortality (White race: odds ratio, 1.368; [95% CI, 0.715-2.618], P=0.34).

CONCLUSIONS

In elderly patients undergoing mechanical thrombectomy for acute ischemic stroke, there was no racial difference in terms of outcome.

Association of Rare Genetic Variants and Early-Onset Atrial Fibrillation in Ethnic Minority Individuals

Importance

Although rare variants in cardiac ion channels, transcription factors, and myocardial structural proteins are associated with early-onset atrial fibrillation (AF) in White individuals of European descent, it remains unclear whether genetic variation also contributes to the cause of AF in those of minority ethnicity.

Objectives

To assess the prevalence of rare and novel pathogenic variants in candidate genes in ethnic minority probands with early-onset AF and determine genotype-phenotype associations.

Design, Setting, and Participants

In this cohort, family-based study, probands of African and Hispanic descent with early-onset AF (defined as AF occurring in individuals aged ≤66 years) prospectively enrolled in a clinical and genetic biorepository underwent sequencing of 60 candidate genes. Recruitment took place from July 1, 2015, to June 30, 2019. Data were analyzed from February 1 to February 28, 2020.

Exposures

Rare and novel variants categorized as pathogenic or likely pathogenic.

Main Outcomes and Measures

The prevalence of rare and novel pathogenic variants in African American and Hispanic/Latinx probands with early-onset AF and genotype-phenotype associations.

Results

Among 227 probands with early-onset AF, mean (SD) age at onset of AF was 51.0 (9.9) years, 132 probands (58.1%) were men, 148 (65.2%) were African American, and 79 (34.8%) were Hispanic/Latinx. A family history of AF was verified in 24 probands with early-onset AF (10.6%). Sequencing 60 candidate genes identified 53 (23 rare and 30 novel) variants with 16 of the 227 (7.0%) probands harboring likely pathogenic (43.8%) or pathogenic (56.2%) variants, with most loss-of-function variants in TTN, the gene encoding the sarcomeric protein titin (46.7%). In 6 families with more than 2 affected members, variants of unknown significance in sodium channel (SCN10A), potassium channel (KCNE5), sarcomeric proteins (MYH6 and TTN), and atrial natriuretic peptide (NPPA) cosegregated with AF.

Conclusions and Relevance

In this study, likely pathogenic and pathogenic variants were identified, with most loss-of-function variants in TTN, that increase susceptibility to early-onset AF in African American and Hispanic/Latinx individuals. These findings provide further understanding toward molecular phenotyping of AF and suggest novel mechanism-based therapeutic approaches for this common arrhythmia in ethnic minority groups.

A survey on a rural in-hospital population diagnosed with Atrial Fibrillation in west Shewa region, Ethiopia

BACKGROUND

Atrial fibrillation (AF) is the most common sustained arrhythmia seen in clinical practice. It has been extensively studied in Western countries but less is known about developing countries.

METHODS

We collected data on a rural population afferent to Wolisso hospital in Ethiopia, analysing epidemiology, clinical and cardiac ultrasound profile.We enrolled 54 patients with first diagnosis of AF who undertook cardiac ultrasound and a questionnaire about personal and clinical profile.

RESULTS

Enrolled patients were younger than reported in the African urban population (mean age 51 years) and females were symptomatic at a younger age than males (61.8% of females were <50 years old versus 30% of males) and had complicated disease (100% of females had CHF). Rheumatic heart disease (RHD) was found in 38.9% of patients, especially in females (41.1%) and young patients, whereas hypertension (HTN) and degenerative valvular disease were predisposing to AF in old patients.

CONCLUSION

Low socio-economic level may explain findings we observed, particularly male to female ratio, more relevant than in urban subsets. RHD and HTN are many etiological factors of AF in our small population, so low-cost strategies to prevent their complications are surely cost-effective in rural catchment area of Wolisso hospital.

Atrial Fibrillation in Middle Eastern Arabs and South Asians: Summary of Published Articles in the Arabian Gulf

Seven studies are summarized herein focusing on different aspects of Atrial fibrillation (AF) in two unique ethnicities for which there is very limited literature published before; Middle Eastern Arabs and South Asians, using data from a national registry of cardiovascular diseases in Qatar over a 20-years period (1991-2010). These studies shed light upon important aspects of AF presentations and outcomes in these two ethnicities, thereby enriching the world literature on AF. In the process, several novel observations were reported and new questions were raised that warrant further investigations.

Detecting cerebrovascular changes in the brain caused by hypertension in atrial fibrillation group using acoustocerebrography

Acoustocerebrography is a novel, non-invasive, transcranial ultrasonic diagnostic method based on the transmission of multispectral ultrasound signals propagating through the brain tissue. Dedicated signal processing enables the estimation of absorption coefficient, frequency-dependent attenuation, speed of sound and tissue elasticity. Hypertension and atrial fibrillation are well known factors correlated with white matter lesions, intracerebral hemorrhage and cryptogenic stroke numbers. The aim of this study was to compare the acoustocerebrography signal in the brains of asymptomatic atrial fibrillation patients with and without hypertension. The study included 97 asymptomatic patients (40 female and 57 male, age 66.26 ± 6.54 years) who were clinically monitored for atrial fibrillation. The patients were divided into two groups: group I (patients with hypertension) n = 75, and group II (patients without hypertension) n = 22. Phase and amplitude of all spectral components for the received signals from the brain path were extracted and compared to the phase and amplitude of the transmitted pulse. Next, the time of flight and the attenuation of each frequency component were calculated. Additionally, a fast Fourier transformation was performed and its features were extracted. After introducing a machine learning technique, the ROC plot of differentiations between group I and group II with an AUC of 0.958 (sensitivity 0.99 and specificity 0.968) was obtained. It can be assumed that the significant difference in the acoustocerebrography signals in patients with hypertension is due to changes in the brain tissue, and it allows for the differentiating of high-risk patients with asymptomatic atrial fibrillation and hypertension.

Lifetime Risk of Atrial Fibrillation by Race and Socioeconomic Status: ARIC Study (Atherosclerosis Risk in Communities)

BACKGROUND

Limited information exists on the lifetime risk of atrial fibrillation (AF) in African Americans and by socioeconomic status.

METHODS

We studied 15 343 participants without AF at baseline from the ARIC (Atherosclerosis Risk in Communities) cohort recruited in 1987 to 1989 from 4 communities in the United States when they were 45 to 64 years of age. Participants have been followed through 2014. Incidence rates of AF were calculated dividing the number of new cases by person-years of follow-up. Lifetime risk of AF was estimated by a modified Kaplan-Meier method considering death as a competing risk. Participants' family income and education were obtained at baseline.

RESULTS

We identified 2760 AF cases during a mean follow-up of 21 years. Lifetime risk of AF was 36% (95% confidence interval, 32%-38%) in white men, 30% (95% confidence interval, 26%-32%) in white women, 21% (95% confidence interval, 13%-24%) in African American men, and 22% (95% confidence interval, 16%-25%) in African American women. Regardless of race and sex, incidence rates of AF decreased from the lowest to the highest categories of income and education. In contrast, lifetime risk of AF increased in individuals with higher income and education in most sex-race groups. Cumulative incidence of AF was lower in those with higher income and education compared with their low socioeconomic status counterparts through earlier life but was reversed after age 80.

CONCLUSIONS

Lifetime risk of AF in the ARIC cohort was ≈1 in 3 among whites and 1 in 5 among African Americans. Socioeconomic status was inversely associated with cumulative incidence of AF before the last decades of life.

Genetic modulation of atrial fibrillation risk in a Hispanic/Latino cohort

Atrial fibrillation (AF) is the most prevalent cardiac rhythm disorder worldwide but the underlying genetic and molecular mechanisms and the response to therapies is not fully understood. Despite a greater burden of AF risk factors in Hispanics/Latinos the prevalence of AF remains low. Over the last decade, genome-wide association studies have identified numerous AF susceptibility loci in mostly whites of European descent. The goal of this study was to determine if the top 9 single nucleotide polymorphisms (SNPs) associated with AF in patients of European descent also increase susceptibility to AF in Hispanics/Latinos. AF cases were prospectively enrolled in the University of Illinois at Chicago (UIC) AF Registry and control subjects were identified from the UIC Cohort of Patients, Family and Friends. AF cases and controls were genotyped for 9 AF risk SNPs at chromosome 1q21: rs13376333, rs6666258; chr1q24: rs3903239; chr4q25: rs2200733; rs10033464; chr10q22: rs10824026; chr14q23: rs1152591; chr16q22: rs2106261 and rs7193343. The study sample consisted of 713 Hispanic/Latino subjects including 103 AF cases and 610 controls. Among the 8 AF risk SNPs genotyped, only rs10033464 SNP at chromosome (chr) 4q25 (near PITX2) was significantly associated with development of AF after multiple risk factor adjustment and multiple testing (adj. odds ratio [OR] 2.27, 95% confidence interval [CI] 1.31–3.94; P = 3.3 x 10⁻³). Furthermore, the association remained significant when the analysis was restricted to Hispanics of Mexican descent (adj. OR 2.32, 95% CI 1.35–3.99; P = 0.002. We confirm for the first time the association between a chromosome 4q25 SNP and increased susceptibility to AF in Hispanics/Latinos. While the underlying molecular mechanisms by which the chr4q25 SNP modulates AF risk remains unclear, this study supports a genetic basis for non-familial AF in patients of Hispanic descent.

Evidence for reduced susceptibility to cardiac bradycardias in South Asians compared with Caucasians

Objectives

To investigate ethnic differences in susceptibility to bradycardias in South Asian and white European patients in the UK by determining rates of permanent pacemaker (PPM) implantation for sinus node dysfunction (SND) and atrioventricular block (AVB) in each ethnic group.

Methods

We carried out a retrospective cohort study into new PPM implantation during the period from 1 May 2006 to 31 March 2014, in patients of South Asian and Caucasian ethnicity resident in Leicestershire, UK. Numbers of individuals at risk in each ethnic group were derived from UK National Census data of 2011. Crude, and age-standardised incidence rates and risk ratios per 1000 population of PPM implantation were calculated for Caucasians and South Asians.

Results

During the study period, 4883 individuals from the Leicestershire population of 980 328 underwent PPM implantation, a cumulative implantation rate of 4.98/1000 population. The population cumulative PPM implantation rate for SND was 1.74/1000, AVB 2.83/1000 and other indications 0.38/1000 population. The crude incidence in Caucasians (6.15/1000 population) was higher than in South Asians (1.07/1000 population) and remained higher after age standardisation (5.60/1000 vs 2.03/1000, P<0.001). The age-standardised cumulative PPM implantation rates were lower in South Asians for both SND (0.53/1000 in South Asians; 1.97/1000 in Caucasians, P<0.001) and AVB (1.30/1000 in South Asians; 3.17/1000 in Caucasians, P<0.001). Standardised risk ratios (95% CI) for PPM implantation in South Asians compared with Caucasians for all pacing indications, SND and AVB were 0.36 (95% CI 0.36 to 0.37), 0.27 (95% CI 0.27 to 0.28) and 0.41 (95% CI 0.41 to 0.42), respectively.

Conclusions

Rates of PPM implantation are lower in South Asians residing in the UK, compared with Caucasians. This observation raises the possibility of lower inherent susceptibility to bradycardias in South Asians compared with Caucasians. Studies aimed at identifying underlying mechanisms, including possible genetic differences, are warranted.

Effect of Digoxin Use Among Medicaid Enrollees With Atrial Fibrillation

BACKGROUND

Recently published analysis of contemporary atrial fibrillation (AF) cohorts showed an association between digoxin and increased mortality and hospitalizations; however, other studies have demonstrated conflicting results. Many AF cohort studies did not or were unable to examine racial differences. Our goal was to examine risk factors for hospitalizations and mortality with digoxin use in a diverse real-world AF patient population and evaluate racial differences.

METHODS AND RESULTS

We performed a retrospective cohort analysis of claims data for Medicaid beneficiaries, aged 18 to 64 years, with incident diagnosis of AF in 2008 with follow-up until December 31, 2009. We created Kaplan-Meier curves and constructed multivariable Cox proportional hazard models for mortality and hospitalization. We identified 11 297 patients with an incident diagnosis of AF in 2008, of those, 1401 (12.4%) were on digoxin. Kaplan-Meier analysis demonstrated an increased risk of hospitalization with digoxin use overall and within race and heart failure groups. In adjusted models, digoxin was associated with an increased risk of hospitalization (adjusted hazard ratio, 1.54; 95% confidence interval, 1.39-1.70) and mortality (adjusted hazard ratio, 1.50; 95% confidence interval, 1.05-2.13). Overall, blacks had a higher risk of hospitalization but similar mortality when compared with whites regardless of digoxin use. We found no significant interaction between race and digoxin use for mortality (P=0.4437) and hospitalization (P=0.7122).

CONCLUSIONS

Our study demonstrates an overall increased risk of hospitalizations and mortality with digoxin use but no racial/ethnic differences in outcomes were observed. Further studies including minority populations are needed to critically evaluate these associations.

Atrial fibrillation in immigrant groups: a cohort study of all adults 45 years of age and older in Sweden

To study the association between country of birth and incident atrial fibrillation (AF) in several immigrant groups in Sweden. The study population included all adults (n = 3,226,752) aged 45 years and older in Sweden. AF was defined as having at least one registered diagnosis of AF in the National Patient Register. The incidence of AF in different immigrant groups, using Swedish-born as referents, was assessed by Cox regression, expressed in hazard ratios (HRs) and 95% confidence intervals (CI). All models were stratified by sex and adjusted for age, geographical residence in Sweden, educational level, marital status, and neighbourhood socioeconomic status. Compared to their Swedish-born counterparts, higher incidence of AF [HR (95% CI)] was observed among men from Bosnia 1.74 (1.56–1.94) and Latvia 1.29 (1.09–1.54), and among women from Iraq 1.96 (1.67–2.31), Bosnia 1.88 (1.61–1.94), Finland 1.14 (1.11–1.17), Estonia 1.14 (1.05–1.24) and Germany 1.08 (1.03–1.14). Lower incidence of AF was noted among men (HRs ≤ 0.60) from Iceland, Southern Europe (especially Greece, Italy and Spain), Latin America (especially Chile), Africa, Asia (including Iraq, Turkey, Lebanon and Iran), and among women from Nordic countries (except Finland), Southern Europe, Western Europe (except Germany), Africa, North America, Latin America, Iran, Lebanon and other Asian countries (except Turkey and Iraq). In conclusion, we observed substantial differences in incidence of AF between immigrant groups and the Swedish-born population. A greater awareness of the increased risk of AF development in some immigrant groups may enable for a timely diagnosis, treatment and prevention of its debilitating complications, such as stroke.

Global Burden of Thrombosis: Epidemiologic Aspects

Thromboembolic conditions were estimated to account for 1 in 4 deaths worldwide in 2010 and are the leading cause of mortality. Thromboembolic conditions are divided into arterial and venous thrombotic conditions. Ischemic heart disease and ischemic stroke comprise the major arterial thromboses and deep-vein thrombosis and pulmonary embolism comprise venous thromboembolism. Atrial fibrillation is a major risk factor for stroke and systemic arterial thromboembolism. Estimates of the global burden of disease were obtained from Global Burden of Disease Project reports, recent systematic reviews, and searching the published literature for recent studies reporting measures of incidence, burden, and disability-adjusted life-years. Estimates per 100 000 of the global incidence rate (IR) for each condition are ischemic heart disease, IR=1518.7; myocardial infarction, IR=139.3; ischemic stroke, IR=114.3; atrial fibrillation, IR=77.5 in males and 59.5 in females; and venous thromboembolism, IR=115 to 269. Mortality rates (MRs) for each condition are ischemic heart disease, MR=105.5; ischemic stroke, MR=42.3; atrial fibrillation, MR=1.7; and venous thromboembolism, MR=9.4 to 32.3. Global public awareness is substantially lower for pulmonary embolism (54%) and deep-vein thrombosis (44%) than heart attack (88%) and stroke (85%). Over time, the incidence and MRs of these conditions have improved in developed countries, but are increasing in developing countries. Public health efforts to measure disease burden and increase awareness of symptoms and risk factors need to improve, particularly in low- and middle-income regions to address this leading cause of morbidity and mortality.

Ethnicity and anticoagulation management of hospitalized patients with atrial fibrillation in northwest China

The therapeutic management and health challenges caused by atrial fibrillation (AF) differ between different groups. The purpose of this study was to investigate the clinical features of patients hospitalized with AF and to explore the use of anticoagulation treatments in Han and Uygur patients in Xinjiang, northwest China. Data were collected from a retrospective descriptive study involving patients hospitalized at 13 hospitals in Xinjiang, China from Jul 1, 2014 to Jun 31, 2015. Anticoagulation management was measured according to guideline-recommended risk scores. A total of 4,181 patients with AF were included (mean age 69.5 ± 11.7 years, 41.4% females; 71.5% Han, 28.5% Uygur). The prevalence of AF in Uygur individuals may occur earlier than in Han individuals (mean age 64.9 vs 71.3, P < 0.001). Most of the hospitalized patients with AF had a high risk of stroke (CHA₂DS₂-VASc score ≥2; 80.6% Han vs 73.7% Uygur, P < 0.05); this risk was especially high in elderly patients. In AF patients, the application of anticoagulants according to the guidelines is far from expected, and the underutilization of anticoagulants exists in both ethnic groups.

Evaluating the benefits of home-based management of atrial fibrillation: current perspectives

Atrial fibrillation (AF) is the most common arrhythmia worldwide, leading to an extensive public health and economic burden. The increasing incidence and prevalence of AF is due to the advancing age of the population, structural heart disease, hypertension, diabetes, and thyroid disease. The majority of costs associated with AF have been attributed to the cost of hospitalization. In order to minimize costs and decrease hospitalizations, counseling on modifiable risk factors contributing to AF has been strongly emphasized. With the release of novel oral anticoagulants bypassing the need for anticoagulant bridging or laboratory monitoring, post-discharge nurse-led home intervention, and novel methods of heart rate monitoring, home-based AF management has reached a new level of ease and sophistication. In this review, we aimed to review modifiable risk factors for AF and various methods of home-based management of AF, along with their benefits.

Atrial fibrillation in the Indigenous populations of Australia, Canada, New Zealand, and the United States: a systematic scoping review

BACKGROUND

The epidemiology of atrial fibrillation (AF) among Indigenous minorities in affluent countries is poorly delineated, despite the high cardiovascular disease burden in these populations. We undertook a systematic scoping review examining the epidemiology of AF in the Indigenous populations of Australia, Canada, New Zealand (NZ) and the United States (US).

METHODS

PubMed, Scopus, EMBASE and CINAHL-Plus databases were systematically searched in May 2014. Supplementary full-text searches of Google Scholar and government website searches were also undertaken.

RESULTS

Key findings from 27 publications with diverse aims and methods were included. Small studies from Canada and NZ suggest higher AF prevalence in Indigenous than other populations. However, this was not reflected in a large sample of US male military veterans. No data were identified on community-based incidence rates of AF in Indigenous populations. Australian and Canadian studies indicate higher first-ever and overall AF hospitalisation rates among Indigenous than other populations, at younger ages and with more comorbidity. Studies in stroke, heart failure and other clinical groups demonstrate AF as a common comorbidity, with AF possibly more prevalent at younger ages in Indigenous people. Indigenous patients have similar early post-hospitalisation adjusted mortality but higher 1-year risk-adjusted mortality than non-Indigenous patients.

CONCLUSIONS

No clear epidemiological pattern of AF frequency across the considered Indigenous populations emerges from the limited available evidence. AF should be included in key conditions reported in national surveillance reports, although Indigenous identifiers are required in administrative data from Canada and the US. Sufficiently powered, community-based studies of AF epidemiology in diverse Indigenous populations are needed.

Association of Sleep Apnea and Snoring With Incident Atrial Fibrillation in the Multi-Ethnic Study of Atherosclerosis

The association between sleep apnea and atrial fibrillation (AF) has not been examined in a multiethnic adult population in prospective community-based studies. We prospectively (2000-2011) investigated the associations of physician-diagnosed sleep apnea (PDSA), which is considered more severe sleep apnea, and self-reported habitual snoring without PDSA (HS), a surrogate for mild sleep apnea, with incident AF in white, black, and Hispanic participants in the Multi-Ethnic Study of Atherosclerosis (MESA) who were free of clinical cardiovascular disease at baseline (2000-2002). Cox proportional hazards models were used to assess the associations, with adjustment for socioeconomic status, traditional vascular disease risk factors, race/ethnicity, body mass index, diabetes, chronic kidney disease, alcohol intake, and lipid-lowering therapy. Out of 4,395 respondents to a sleep questionnaire administered in MESA, 181 reported PDSA, 1,086 reported HS, and 3,128 reported neither HS nor PDSA (unaffected). Over an average 8.5-year follow-up period, 212 AF events were identified. As compared with unaffected participants, PDSA was associated with incident AF in the multivariable analysis, but HS was not (PDSA: hazard ratio = 1.76, 95% confidence interval: 1.03, 3.02; HS: hazard ratio = 1.02, 95% confidence interval: 0.72, 1.44). PDSA, a marker of more severe sleep apnea, was associated with higher risk of incident AF in this analysis of MESA data.

Genetic variants of potassium voltage-gated channel genes (KCNQ1, KCNH2, and KCNE1) affected the risk of atrial fibrillation in elderly patients

BACKGROUND

Atrial fibrillation (AF) is a common type of cardiac arrhythmia and is a major healthcare burden. Around 20% of patients show no obvious clinical manifestations; this can lead to a delay of AF diagnosis and prevention. Genetic mutations are one of the important risk factors for AF. This study aimed to assess the associations between polymorphisms on KCNE1, KCNQ1, and KCNH2 with the risk of AF in a Chinese population.

MATERIALS AND METHODS

A case-control study comprised of 438 AF patients and 450 controls. The tag single-nucleotide polymorphisms (SNPs) were retrieved in the International HapMap database and Haploview software was used to capture all the polymorphisms on KCNE1, KCNQ1, and KCNH2. DNA was extracted from blood and polymerase chain reaction-based assays were used to genotype polymorphisms of the KCNE1, KCNQ1, and KCNH2 genes. Chi-square test and student t-tests were used to evaluate the differences in the clinical characteristics between AF cases and controls. Odds ratios (OR) and corresponding 95% confidence intervals (CIs) were calculated to assess the association between genetic variants of KCNQ1, KCNH2, KCNE1, and AF risk.

RESULTS

Among the nine tag SNPs, three were significantly associated with the risk of AF: the rs1805127*G allele on KCNE1, and the rs2283228*C and rs1057128*A alleles on KCNQ1. In contrast, rs1805120*T variant was correlated with lower risk of AF. However, the other five genetic variants (rs2237892, rs2237895, rs2237897, rs2070357, and rs2070356) showed no significant association with AF risk (all p>0.05).

CONCLUSIONS

Our study suggested that the rs1805127*G allele of KCNE1, and the rs2283228*C and rs1057128*A alleles on KCNQ1 are risk factors for AF, while the rs1805120*T allele on KCNH2 may serve as a protective factor for AF.

Atrial fibrillation in Indigenous and non-Indigenous Australians: a cross-sectional study

OBJECTIVE

To examine the prevalence of atrial fibrillation (AF) and cardiac structural characteristics in Indigenous and non-Indigenous Australians.

DESIGN

Retrospective cross-sectional study linking clinical, echocardiography and administrative databases over a 10-year period.

SETTING

A tertiary, university teaching hospital in Adelaide, Australia.

PARTICIPANTS

Indigenous and non-Indigenous Australians.

MAIN OUTCOME MEASURES

AF prevalence and echocardiographic characteristics.

RESULTS

Indigenous Australians with AF were significantly younger compared to non-Indigenous Australians (55±13 vs 75±13 years, p<0.001). As a result, racial differences in AF prevalence and left atrial diameter varied according to age. In those under 60 years of age, Indigenous Australians had a significantly greater AF prevalence (2.57 vs1.73%, p<0.001) and left atrial diameters (39±7 vs 37±7 mm, p<0.001) compared to non-Indigenous Australians. In those aged 60 years and above, however, non-Indigenous Australians had significantly greater AF prevalence (9.26 vs 4.61%, p<0.001) and left atrial diameters (39±7 vs 37±7 mm, p<0.001). Left ventricular ejection fractions were less in Indigenous Australians under 60 years of age (49±14 vs 55±11%, p<0.001) and not statistically different in those aged 60 years and above (47±11 vs 52±13, p=0.074) compared to non-Indigenous Australians. Despite their younger age, Indigenous Australians with AF had similar or greater rates of cardiovascular comorbidities than non-Indigenous Australians with AF.

CONCLUSIONS

Young Indigenous Australians have a significantly greater prevalence of AF than their non-Indigenous counterparts. In contrast, older non-Indigenous Australians have a greater prevalence of AF compared to their Indigenous counterparts. These observations may be mediated by age-based differences in comorbid cardiovascular conditions, left atrial diameter and left ventricular ejection fraction. Our findings suggest that AF is likely to be contributing to the greater burden of morbidity and mortality experienced by young Indigenous Australians. Further study is required to elucidate whether strategies to prevent and better manage AF in Indigenous Australians may reduce this burden.

Prevalence of cardiac arrhythmias in a community based chiropractic practice

INTRODUCTION

The prevalence of arrhythmias in chiropractic practice (the proportion of current patients who currently have arrhythmias) is unknown, but thought to be increasing. As arrhythmias influence management of chiropractic patients, the objective of this study was to determine the feasibility of screening for cardiac arrhythmias in a chiropractic clinic.

METHODS

With a convenience sample from one clinic, ECG data were recorded and analyzed to identify arrhythmias.

RESULTS

Seventy-six of ninety contacted patients participated in this study. Only 8 (∼26%) of 31 patients with known or suspected cardiovascular abnormalities demonstrated arrhythmias versus 7 (∼16%) of 45 subjects who were not previously aware of having an arrhythmia.

CONCLUSION

The screening of patients for cardiac arrhythmias in a community based chiropractic clinic is feasible. A 3-minute recording of ECG activity at rest is not a highly sensitive method of identifying patients with previously recognized arrhythmias, but is capable of identifying previously undiagnosed arrhythmias.

Endovascular ablation of atrial fibrillation

Atrial fibrillation is the most common arrhythmia. The anesthetic considerations of endovascular ablation for the treatment of atrial fibrillation are reviewed.

Monoamine oxidase is a major determinant of redox balance in human atrial myocardium and is associated with postoperative atrial fibrillation

Background

Onset of postoperative atrial fibrillation (POAF) is a common and costly complication of heart surgery despite major improvements in surgical technique and quality of patient care. The etiology of POAF, and the ability of clinicians to identify and therapeutically target high‐risk patients, remains elusive.

Methods and Results

Myocardial tissue dissected from right atrial appendage (RAA) was obtained from 244 patients undergoing cardiac surgery. Reactive oxygen species (ROS) generation from multiple sources was assessed in this tissue, along with total glutathione (GSHt) and its related enzymes GSH‐peroxidase (GPx) and GSH‐reductase (GR). Monoamine oxidase (MAO) and NADPH oxidase were observed to generate ROS at rates 10‐fold greater than intact, coupled mitochondria. POAF risk was significantly associated with MAO activity (Quartile 1 [Q1]: adjusted relative risk [ARR]=1.0; Q2: ARR=1.8, 95% confidence interval [CI]=0.84 to 4.0; Q3: ARR=2.1, 95% CI=0.99 to 4.3; Q4: ARR=3.8, 95% CI=1.9 to 7.5; adjusted P_trend=0.009). In contrast, myocardial GSHt was inversely associated with POAF (Quartile 1 [Q1]: adjusted relative risk [ARR]=1.0; Q2: ARR=0.93, 95% confidence interval [CI]=0.60 to 1.4; Q3: ARR=0.62, 95% CI=0.36 to 1.1; Q4: ARR=0.56, 95% CI=0.34 to 0.93; adjusted P_trend=0.014). GPx also was significantly associated with POAF; however, a linear trend for risk was not observed across increasing levels of the enzyme. GR was not associated with POAF risk.

Conclusions

Our results show that MAO is an important determinant of redox balance in human atrial myocardium, and that this enzyme, in addition to GSHt and GPx, is associated with an increased risk for POAF. Further investigation is needed to validate MAO as a predictive biomarker for POAF, and to explore this enzyme's potential role in arrhythmogenesis.

Atrial fibrillation in the 21st century: a current understanding of risk factors and primary prevention strategies

Atrial fibrillation (AF) is the most common arrhythmia worldwide, and it has a significant effect on morbidity and mortality. It is a significant risk factor for stroke and peripheral embolization, and it has an effect on cardiac function. Despite widespread interest and extensive research on this topic, our understanding of the etiology and pathogenesis of this disease process is still incomplete. As a result, there are no set primary preventive strategies in place apart from general cardiology risk factor prevention goals. It seems intuitive that a better understanding of the risk factors for AF would better prepare medical professionals to initially prevent or subsequently treat these patients. In this article, we discuss widely established risk factors for AF and explore newer risk factors currently being investigated that may have implications in the primary prevention of AF. For this review, we conducted a search of PubMed and used the following search terms (or a combination of terms): atrial fibrillation, metabolic syndrome, obesity, dyslipidemia, hypertension, type 2 diabetes mellitus, omega-3 fatty acids, vitamin D, exercise toxicity, alcohol abuse, and treatment. We also used additional articles that were identified from the bibliographies of the retrieved articles to examine the published evidence for the risk factors of AF.

Ethnic differences in atrial fibrillation identified using implanted cardiac devices

INTRODUCTION

Atrial fibrillation (AF) is suggested to be less common among black and Asian individuals, which could reflect bias in symptom reporting and access to care. In the Asymptomatic AF and Stroke Evaluation in Pacemaker Patients and the AF Reduction Atrial Pacing Trial (ASSERT), patients with hypertension but no history of AF had AF recorded via an implanted pacemaker or defibrillator, thus allowing both symptomatic and asymptomatic AF incidence to be determined without ascertainment bias.

METHODS AND RESULTS

The ASSERT enrolled 2,580 patients in 23 countries in North America, Europe, and Asia. AF was defined as device-recorded AF episodes >190/min, lasting either for >6 minutes or >6 hours in duration. All ethnic groups with >50 patients were enrolled. Ethnic groups studied include Europeans (n = 1900), black Africans (n = 73), Chinese (n = 89), and Japanese (n = 105) patients. Compared to Europeans, black Africans had more risk factors for AF such as heart failure (27.8 vs 14.6%) and diabetes (41.7 vs 26.3%). At 2.5 years follow-up, all 3 non-European races had a lower incidence of AF (8.3%, 10.1%, and 9.5% vs 18.0%, respectively, for AF>6 minutes, P < 0.006). When adjusted for baseline difference, Chinese had a lower incidence of AF > 6 minutes (P < 0.007), and Japanese and black Africans had a lower incidence of AF > 6 hours (P < 0.04 and P = 0.057, respectively).

CONCLUSIONS

Black Africans, Chinese, and Japanese had lower incidence of AF compared to Europeans. In the case of black Africans, this is despite an increased prevalence of AF risk factors.

Correlation of CHADS2 and CHA2DS2-VASc scores with transesophageal echocardiography risk factors for thromboembolism in a multiethnic United States population with nonvalvular atrial fibrillation

BACKGROUND

The aims of this study were to evaluate the relationship of the CHA(2)DS(2)-VASc score and risk categories with transesophageal echocardiographic (TEE) risk factors for thromboembolism and to compare the CHA(2)DS(2)-VASc and CHADS(2) risk stratification schemes with respect to their ability to predict these risk factors in a multiethnic US population with nonvalvular atrial fibrillation.

METHODS

Transesophageal echocardiograms of 167 patients (mean age, 66.3 ± 11.6 years; 146 men [87%]; 100 whites [60%]; 40 Hispanics [24%]; 27 blacks [16%]) with nonvalvular atrial fibrillation were retrospectively reviewed for smoke, sludge, thrombus, and left atrial appendage (LAA) emptying velocity ≤20 cm/sec. The patients' CHA(2)DS(2)-VASc and CHADS(2) risk scores and categories were also calculated.

RESULTS

Any LAA abnormality, smoke, sludge, thrombus, and abnormal LAA emptying velocity were present in 45%, 38%, 13%, 3%, and 22% of patients, respectively. Heart failure (P < .001), age (P < .001 for age ≥75 vs ≤64 years, P = .013 for age 65-74 vs ≤64 years), and diabetes (P = .019) were independent predictors of LAA abnormalities, while ethnicity was not. The prevalence of TEE risk factors for thromboembolism increased with increasing CHA(2)DS(2)-VASc score and risk category. The CHADS(2) risk categories of 35 patients (21%) were upgraded by the CHA(2)DS(2)-VASc scheme. Using the latter scheme, fewer patients were classified as at intermediate risk compared with the CHADS(2) system (21 [13%] vs 46 [28%]). Patients classified as at low risk by either scheme had almost no TEE risk factors. Of 30 intermediate-risk patients by CHADS(2) score upgraded to high risk using CHA(2)DS(2)-VASc score, eight (27%) had at least one TEE risk factor for thromboembolism. C-statistics, sensitivity, and specificity for predicting any LAA abnormality were 0.607 (95% confidence interval, 0.549-0.665), 92.0%, and 28.9% for CHA(2)DS(2)-VASc score and 0.685 (95% confidence interval, 0.615-0.755), 81.3%, and 54.2% for CHADS(2) score.

CONCLUSIONS

CHA(2)DS(2)-VASc score is associated with TEE risk factors for thromboembolism in a multiethnic US population. Compared with CHADS(2) score, it has increased sensitivity, decreased specificity, and lower ability for predicting TEE risk factors in this population.

Initiation and persistence with warfarin therapy in atrial fibrillation according to ethnicity

The aim of this study was to investigate initiation of and persistence with warfarin treatment in patients with atrial fibrillation (AF) according to ethnicity. Patients hospitalized with first-time AF from 1997 to 2009, prescription claims of warfarin and country of birth were identified by individual-level linkage of nationwide administrative agencies. Cox proportional hazards models were used to estimate the relationship between covariates affecting initiation and non-persistence with warfarin treatment. A total of 151,537 patients were included in the study and 5,061(3.3%) were of non-Danish origin. CHADS2 score distribution varied substantially according to ethnicity, the proportion of patients with CHADS2 score ≥1 being 79.2, 78.1, 65.9, and 46.0% for patients of Danish, Western, Eastern, and African origin, respectively. 79,239(52.4%) of all patients initiated treatment with warfarin at some point in time. Multivariable Cox proportional hazard analyses indicated patients of Eastern and African origin were less likely to initiate warfarin therapy (HR 0.75; 95% CI 0.69-0.82 and HR 0.58; 95% CI 0.44-0.76, respectively). Patients of Eastern origin were more likely to interrupt treatment (HR 1.23; 95% CI 1.02-1.47; for all patients; HR 1.62; 95% CI 1.22-2.16; for patients with CHADS2 score >1). African origin was associated with a trend to interrupt treatment (HR 1.44; 95% CI 0.46-4.47; for patients with CHADS2 score >1). Initiation of and persistence with warfarin in AF patients is lower among patients of Eastern and African origin compared to patients of Danish and Western origin, despite equal access to health care and medication. Future studies should address, beyond ethnicity, all possible driving factors of (non)initiation and persistence with treatment in general. This will be particularly interesting in light of the new generation of anticoagulants, which might render different adherence to treatment.