Incidence and Prevalence of Atrial Fibrillation in Latinos: What's New Since the Study in Latinos (SOL)?

PURPOSE OF REVIEW: To assess contemporary epidemiological trends in AF incidence and prevalence in the LatinX population after the Hispanic Community Health Study/Study of Latinos. RECENT FINDINGS: Atrial fibrillation (AF) remains the most abnormal heart rhythm condition globally and disproportionately impacts morbidity and mortality of communities that have been historically disadvantaged. The incidence and prevalence of AF is lower in the LatinX population compared to White individuals despite a higher burden of classic risk factors associated with AF. Since the Hispanic Community Health Study/Study of Latinos study on AF, recent data continues to demonstrate a similar lower burden of AF in the LatinX population compared to White individuals. However, the rates of incident AF may be accelerating faster in the LatinX population compared to their White counterparts. Furthermore, studies have found environmental and genetic risk factors that are associated with the development of AF within LatinX individuals, which may help explain the rising development of AF among the LatinX community. Recent research continues to show that LatinX populations are less likely to be treated with stroke reduction and rhythm control strategies and have a disproportionately higher burden of poor outcomes associated with AF compared to White patients. Our review illuminates that further inclusion of LatinX individuals in AF randomized control trials and observational studies is imperative to understand the incidence and prevalence of AF in the LatinX community and improve overall morbidity and mortality.

Racial Differences in Atrial Fibrillation Management Between White Patients and Black Patients in Transthyretin Cardiac Amyloid.

Black patients have higher rates of stroke than White patients. Paradoxically, atrial fibrillation (AF) affects twice as many White patients compared with Black patients. Transthyretin cardiac amyloidosis (ATTR-CA) is associated with both AF and strokes. We hypothesized that although Black patients with ATTR-CA have a lower incidence of AF, when diagnosed with AF, they have increased thromboembolic events. Patients with ATTR-CA (n = 558) at 3 international centers were retrospectively identified. We compared baseline characteristics, presence of AF, outcomes of thromboembolism (stroke, transient ischemic attack, and peripheral embolism), major bleed, and mortality by race. Of all patients, 367 of 488 White patients (75%) were diagnosed with AF compared with 39 of 70 Black patients (56%) (p = 0.001). Black patients with AF had a hazard ratio of 5.78 (95% confidence interval 2.30 to 14.50) for time to first thromboembolic event compared with White patients. There were no racial differences in major bleeding. Black patients with AF more often lacked anticoagulation (p = 0.038) and had higher incidence of labile international normalized ratio (p <0.001). In conclusion, these data suggest that although Black patients with ATTR-CA have lower incidence of AF, they have increased thromboembolic events compared with White patients. These findings may be related to treatment discrepancies, time in therapeutic range for warfarin, and disparities in healthcare.

Racial and Ethnic Considerations in Patients With Atrial Fibrillation: JACC Focus Seminar 5/9.

Atrial fibrillation (AF) affects at least 60 million individuals globally and is associated with substantial impacts on morbidity, mortality, and health care expenditures. This review focuses on how race and ethnicity influence AF epidemiology, risk prediction, treatment, and outcomes; knowledge gaps in these areas are identified. Most AF studies have predominantly included White populations, with an underrepresentation of racial and ethnic groups, including but not limited to Black, Hispanic, and Indigenous individuals. Enhancement and implementation of AF risk prediction, prevention, and management call for studies that will gather accurate race-based epidemiologic data and evaluate social determinants and genetic factors in the context of multiple races and ethnicities. Available studies highlight inequities in access to treatment as well as outcomes between White individuals and persons of other races/ethnicities. These inequities will need to be addressed by a renewed emphasis on structural and social determinants of health that contribute to AF.

Underweight is a major risk factor for atrial fibrillation in Asian people with type 2 diabetes mellitus.

BACKGROUND: Atrial fibrillation (AF) is prevalent in patients with type 2 diabetes mellitus (T2DM). Obesity commonly accompanies T2DM, and increases the risk of AF. However, the dose-relationship between body mass index (BMI) and AF risk has seldom been studied in patients with diabetes. METHODS: This cohort study utilized a database from National Taiwan University Hospital, a tertiary medical center in Taiwan. Between 2014 and 2019, 64,339 adult patients with T2DM were enrolled for analysis. BMI was measured and categorized as underweight (BMI < 18.5), normal (18.5 ≤ BMI < 24), overweight (24 ≤ BMI < 27), obesity class 1 (27 ≤ BMI < 30), obesity class 2 (30 ≤ BMI < 35), or obesity class 3 (BMI ≥ 35). Multivariate Cox regression and spline regression models were employed to estimate the relationship between BMI and the risk of AF in patients with T2DM. RESULTS: The incidence of AF was 1.97 per 1000 person-years (median follow-up, 70.7 months). In multivariate Cox regression, using normal BMI as the reference group, underweight (HR 1.52, 95% CI 1.25-1.87, p < 0.001) was associated with a significantly higher risk of AF, while overweight was associated with significantly reduced risk of AF (HR 0.82, 95% CI 0.73-0.89, p < 0.001). Kaplan-Meier analysis showed AF risk was highest in the underweight group, followed by obesity class 3, while the overweight group had the lowest incidence of AF (log-rank test, p < 0.001). The cubic restrictive spline model revealed a "J-shaped" or "L-shaped" relationship between BMI and AF risk. CONCLUSIONS: Underweight status confers the highest AF risk in Asian patients with T2DM.

Adhesion pathway proteins and risk of atrial fibrillation in the Multi-Ethnic Study of Atherosclerosis.

BACKGROUND: The cellular adhesion pathway has been suggested as playing an important role in the pathogenesis of atrial fibrillation (AF). However, prior studies that have investigated the role of adhesion pathway proteins in risk of AF have been limited in the number of proteins that were studied and in the ethnic and racial diversity of the study population. Therefore we aimed to study the associations of fifteen adhesion pathway proteins with incident AF in a large, diverse population. METHODS: Multi-Ethnic Study of Atherosclerosis participants from four races/ethnicities (n = 2504) with protein levels measured were followed for incident AF (n = 253). HGF protein was measured on Exam 1 samples (N = 6669; AF n = 851). Cox proportional hazards regression was used to assess the association of AF with 15 adhesion pathway proteins. Bonferroni correction was applied to account for multiple comparisons. RESULTS: After adjusting for potential confounding variables (age, sex, race/ethnicity, height, body mass index, systolic blood pressure, antihypertension therapy, diabetes status, current smoker, current alcohol use, and total and HDL cholesterol), and accounting for multiple testing (P < 0.05/15 = 0.0033), circulating levels of the following proteins were positively associated with a higher risk of AF: MMP-2 (HR per standard deviation increment, 1.27; 95% CI 1.11‒1.45), TIMP-2 (HR 1.28; 95% CI 1.12‒1.46), VCAM-1 (HR 1.32; 95% CI 1.16‒1.50), and SLPI (HR 1.22; 95% CI 1.07‒1.38). The association between proteins and AF did not differ by race/ethnicity. CONCLUSIONS: Circulating levels of MMP-2, TIMP-2, VCAM-1, and SLPI were positively associated with an increased risk of incident AF in a diverse population. Our findings suggest that adhesion pathway proteins may be important risk predictors of AF.

Association between human immunodeficiency virus serostatus and the prevalence of atrial fibrillation.

ABSTRACT: Atrial fibrillation (AF) leads to increased risk for stroke. Human immunodeficiency virus (HIV) is associated with cardiovascular disease (CVD), although it is unclear if HIV is associated with AF. The purpose of this study was to evaluate the association between HIV serostatus and the prevalence of AF in the Multicenter AIDS Cohort Study.A cross sectional study was conducted among 1674 HIV-infected (HIV+) and uninfected (HIV-) men who completed resting 12-lead electrocardiograms, and/or ambulatory electrocardiogram monitoring. Multivariable logistic regression was used to evaluate the association between AF, defined as the presence of either AF or atrial flutter, and HIV+ serostatus. Associations were adjusted for demographic variables, and then also for CVD risk factors.HIV+ men were younger than HIV- men (median 55.5 vs 61.7 years, P < .001) and were more frequently African-American (30.5% vs 17.8%, P < .001). Most HIV+ men (81%) had undetectable viral load. The age and race adjusted prevalence of AF was 3.0% in HIV+ and 3.3% in HIV- men. There was only 1 case of AF among African-American men. There were no associations between AF and HIV serostatus after adjusting for demographic factors (odds ratio 0.76; 95% CI 0.37 to -1.58; P = .47) or after further adjustment for CVD risk factors (odds ratio 0.84; 95% CI 0.39 to -1.81; P = .66).We found no association between HIV and AF in this cohort in which viral replication among the HIV+ men is generally suppressed. The overall prevalence of AF was low and was rare in African-American men.

Interrelation between the rs2200733 polymorphism of the ATFB5 gene and atrial fibrillation in Uzbek patients.

OBJECTIVE: Atrial fibrillation (AF) is one of the most common cardiac arrhythmias and a major predictor of morbidity and mortality. AF is a polygenic and polyetiological disease. In various ethnic groups, the strongest and most independent relationship with the development of AF was found with the 4q25 locus, where the ATFB5 gene is located. An analysis of the literature data showed that the carriage of the TT genotype of the rs2200733 ATFB5 gene polymorphism is the most unfavorable genotype for the development of AF. The purpose of the study was to identify the prevalence of genotypes and alleles of the rs2200733 polymorphism of the ATFB5 gene in Uzbek patients with AF. METHODS: The study included 69 Uzbek patients with paroxysmal (n=20) and persistent AF (n=49). The control group (n=30) was composed of Uzbek patients without AF. Genotyping for the carriage of allelic variants of the rs2200733 polymorphism of the ATFB5 gene was performed using the Polymerase Chain Reaction-Restriction Length Polymorphism (PCR-RFLP) method. The distribution of the C and T alleles and the CC, CT, and TT genotypes of the rs2200733 polymorphism of the ATFB5 gene in patients with AF and controls were compared. RESULTS: After genotyping 69 patients with AF, the following distribution of the ATFB5 gene polymorphism rs2200733 was revealed: the CC genotype was detected in 35 (50.72%) patients, the CT genotype in 25 (36.23%) patients, and the TT genotype in 9 (13.05%) patients (p<0.001, χ²=22.435). Moreover, the C allele was detected in 95 (68.8%) patients, and the T allele was detected in 43 (31.2%) patients (p<0.001, χ²=37.696). The distribution of genotypes in the control group was as follows: the CC genotype was detected in 17 individuals (56.7%), the CT genotype was detected in 12 individuals (40%), and the TT genotype was detected in 1 individual (3.3%) (p<0.001, χ²=20.100). Moreover, the C allele was detected in 46 (76.7%) patients, and the T allele was detected in 14 (23.3%) patients (p<0.001, χ²=32.033). The TT genotype of the ATFB5 gene was found to be significantly more prevalent in patients with AF than in controls (13.1% vs 3.3%, p=0.0001). CONCLUSION: The TT genotype of the rs2200733 polymorphism of the ATFB5 gene was found to be significantly more prevalent in Uzbek patients with AF than in controls.

Multiple Blood Biomarkers and Stroke Risk in Atrial Fibrillation: The REGARDS Study.

Background Atrial fibrillation is associated with increased stroke risk; available risk prediction tools have modest accuracy. We hypothesized that circulating stroke risk biomarkers may improve stroke risk prediction in atrial fibrillation. Methods and Results The REGARDS (Reasons for Geographic and Racial Differences in Stroke) study is a prospective cohort study of 30 239 Black and White adults age ≥45 years. A nested study of stroke cases and a random sample of the cohort included 175 participants (63% women, 37% Black adults) with baseline atrial fibrillation and available blood biomarker data. There were 81 ischemic strokes over 5.2 years in these participants. Adjusted for demographics, stroke risk factors, and warfarin use, the following biomarkers were associated with stroke risk (hazard ratio [HR]; 95% CI for upper versus lower tertile): cystatin C (3.16; 1.04-9.58), factor VIII antigen (2.77; 1.03-7.48), interleukin-6 (9.35; 1.95-44.78), and NT-proBNP (N-terminal B-type natriuretic peptide) (4.21; 1.24-14.29). A multimarker risk score based on the number of blood biomarkers in the highest tertile was developed; adjusted HRs of stroke for 1, 2, and 3+ elevated blood biomarkers, compared with none, were 1.75 (0.57-5.40), 4.97 (1.20-20.5), and 9.51 (2.22-40.8), respectively. Incorporating the multimarker risk score to the CHA2DS2VASc score resulted in a net reclassification improvement of 0.34 (95% CI, 0.04-0.65). Conclusions Findings in this biracial cohort suggested the possibility of substantial improvement in stroke risk prediction in atrial fibrillation using blood biomarkers or a multimarker risk score.

A retrospective analysis of high sensitivity cardiac troponin-T ranges in non-myocardial infarction emergency department visits.

INTRODUCTION: Current evidence suggests that high sensitivity cardiac troponin-T (hs-cTnT) values differ based on sex, race, age, and kidney function. However, most studies examining the relationship of hs-cTnT and these individual factors are in healthy participants, leading to difficulty in interpreting hs-cTnT values in the Emergency Department (ED) setting. We seek to examine the relationship between hs-cTnT values and sex, race, age, and kidney function in a contemporary, urban academic setting. METHODS: ED visits from June 2018 through April 2019 with at least 1 hs-cTnT and no diagnosis of acute myocardial infarction (AMI) at an academic medical center in the south side of Chicago were retrospectively analyzed. Median hs-cTnT values were stratified by sex (male or female), race (African American or Caucasian), age, estimated glomerular filtration rate (eGFR), and stage of chronic kidney disease. RESULTS: 9679 encounters, representing 7989 distinct patients, were included for analysis (age 58 ± 18 years, 59% female, 85% black). Males had significantly higher median hs-cTnT values than females (16 [8-34] vs. 9 [6-22] ng/L, p < 0.001), African Americans had a significantly lower median value than Caucasians (10 [6-24] vs. 15 [6-29] ng/L, p < 0.001), and those with atrial fibrillation (27 [16-48] vs. 9 [6-19] ng/L, p < 0.001) and heart failure (28 [14-48] vs. 8 [6-15] ng/L, p < 0.001) had higher median values than those without. Median hs-cTnT values increased significantly with increased age and decreased eGFR. All relationships continued to be significant even after multivariable regression of sex, age, race, eGFR, presence of atrial fibrillation, and presence of heart failure (p < 0.01). CONCLUSIONS: Analysis of hs-cTnT in non-AMI patients during ED encounters showed that males have higher values than females, African Americans have lower values than Caucasians, those with atrial fibrillation and heart failure have higher values than those without, and that older age and lower eGFR were associated with higher median values.

Association Between Omega-3 Fatty Acid Levels and Risk for Incident Major Bleeding Events and Atrial Fibrillation: MESA.

Background Randomized trials of pharmacologic strength omega-3 fatty acid (n3-FA)-based therapies suggest a dose-dependent cardiovascular benefit. Whether blood n3-FA levels also mediate safety signals observed in these trials, such as increased bleeding and atrial fibrillation (AF), remains uncertain. We hypothesized that higher baseline n3-FA levels would be associated with incident bleeding and AF events in MESA (Multi-Ethnic Study of Atherosclerosis), which included a population free of clinical cardiovascular disease at baseline. Methods and Results We examined the association between baseline plasma n3-FA levels (expressed as percent mass of total fatty acid) with incident bleeding and AF in MESA, an ongoing prospective cohort study. Bleeding events were identified from review of hospitalization International Classification of Diseases, Ninth Revision (ICD-9), and International Classification of Diseases, Tenth Revision (ICD-10), codes, and AF from participant report, discharge diagnoses, Medicare claims data, and study ECGs performed at MESA visit 5. Separate multivariable Cox proportional hazard modeling was used to estimate hazard ratios of the association of continuous n3-FA (log eicosapentaenoic acid [EPA], log docosahexaenoic acid [DHA], log [EPA+DHA]) and incident hospitalized bleeding events and AF. Among 6546 participants, the mean age was 62.1 years and 53% were women. For incident bleeding, consistent statistically significant associations with lower rates were seen with increasing levels of EPA and EPA+DHA in unadjusted and adjusted models including medications that modulate bleeding risk (aspirin, NSAIDS, corticosteroids, and proton pump inhibitors). For incident AF, a significant association with lower rates was seen with increasing levels of DHA, but not for EPA or EPA+DHA. Conclusions In MESA, higher plasma levels of n3-FA (EPA and EPA+DHA, but not DHA) were associated with significantly fewer hospitalized bleeding events, and higher DHA levels (but not EPA or EPA+DHA) with fewer incident AF events.

Racial, ethnic and socioeconomic disparities in patients undergoing left atrial appendage closure.

OBJECTIVE: This manuscript aims to explore the impact of race/ethnicity and socioeconomic status on in-hospital complication rates after left atrial appendage closure (LAAC). METHODS: The US National Inpatient Sample was used to identify hospitalisations for LAAC between 1 October 2015 to 31 December 2018. These patients were stratified by race/ethnicity and quartiles of median neighbourhood income. The primary outcome was the occurrence of in-hospital major adverse events, defined as a composite of postprocedural bleeding, cardiac and vascular complications, acute kidney injury and ischaemic stroke. RESULTS: Of 6478 unweighted hospitalisations for LAAC, 58% were male and patients of black, Hispanic and 'other' race/ethnicity each comprised approximately 5% of the cohort. Adjusted by the older Americans population, the estimated number of LAAC procedures was 69.2/100 000 for white individuals, as compared with 29.5/100 000 for blacks, 47.2/100 000 for Hispanics and 40.7/100 000 for individuals of 'other' race/ethnicity. Black patients were ~5 years younger but had a higher comorbidity burden. The primary outcome occurred in 5% of patients and differed significantly between racial/ethnic groups (p<0.001) but not across neighbourhood income quartiles (p=0.88). After multilevel modelling, the overall rate of in-hospital major adverse events was higher in black patients as compared with whites (OR: 1.60, 95% CI 1.22 to 2.10, p<0.001); however, the incidence of acute kidney injury was higher in Hispanics (OR: 2.19, 95% CI 1.52 to 3.17, p<0.001). No significant differences were found in adjusted overall in-hospital complication rates between income quartiles. CONCLUSION: In this study assessing racial/ethnic disparities in patients undergoing LAAC, minorities are under-represented, specifically patients of black race/ethnicity. Compared with whites, black patients had higher comorbidity burden and higher rates of in-hospital complications. Lower socioeconomic status was not associated with complication rates.

Racial Disparities in In-Hospital Adverse Events Among Patients With Atrial Fibrillation Implanted With a Watchman Left Atrial Appendage Occlusion Device: A US National Perspective.

[Figure: see text].

Screening for Atrial Fibrillation in American Indian Adults in a Tribal Primary Care Clinic.

Background American Indian adults have a higher risk of atrial fibrillation (AF) compared with other racial groups. We implemented opportunistic screening to detect silent AF in American Indian adults attending a tribal health system using a mobile, single-lead ECG device. Methods and Results American Indian patients aged ≥50 years followed in a tribal primary care clinic with no history of AF underwent a 30-second ECG. A cardiologist overread all tracings to confirm the diagnosis of AF. After AF was confirmed, patients were referred to their primary care physician for initiation of anticoagulation. Patients seen over the same time period, who were not undergoing screening, served as controls. A total of 1019 patients received AF screening (mean age, 61.5±8.9 years, 62% women). Age and sex distribution of those screened was similar to the overall clinic population. New AF was diagnosed in 15 of 1019 (1.5%) patients screened versus 4 of 1267 (0.3%) patients who were not screened (mean difference, 1.2%; 95% CI, 0.3%-2.2%, P=0.002). Eight of 15 with new screen-detected AF were aged <65 years. Those with screen-detected AF were slightly older and had a higher CHA2DS2-VASc score than those without AF. Fourteen of 15 patients diagnosed with new AF had a CHA2DS2-VASc score ≥1 and initiated anticoagulation. Conclusions Opportunistic, mobile single-lead ECG screening for AF is feasible in tribal clinics, and detects more AF than usual care, leading to appropriate initiation of anticoagulation. AF develops at a younger age in American Indian adults who would likely benefit from earlier AF screening. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT03740477.

Risk of major bleeding by ethnicity and socioeconomic deprivation among 488,107 people in primary care: a cohort study.

BACKGROUND: Antithrombotic medications (antiplatelets and anticoagulants) reduce the risk of cardiovascular disease (CVD), but with the disadvantage of increasing bleeding risk. Ethnicity and socioeconomic deprivation are independent predictors of major bleeds among patients without CVD, but it is unclear whether they are also predictors of major bleeds among patients with CVD or atrial fibrillation (AF) after adjustment for clinical variables. METHODS: Prospective cohort study of 488,107 people in New Zealand Primary Care (including 64,420 Maori, the indigenous people of New Zealand) aged 30-79 years who had their CVD risk assessed between 2007 and 2016. Participants were divided into three mutually exclusive subgroups: (1) AF with or without CVD (n = 15,212), (2) CVD and no AF (n = 43,790), (3) no CVD or AF (n = 429,105). Adjusted hazards ratios (adjHRs) were estimated from Cox proportional hazards models predicting major bleeding risk for each of the three subgroups to determine whether ethnicity and socioeconomic deprivation are independent predictors of major bleeds in different cardiovascular risk groups. RESULTS: In all three subgroups (AF, CVD, no CVD/AF), Maori (adjHR 1.63 [1.39-1.91], 1.24 [1.09-1.42], 1.57 [95% CI 1.45-1.70], respectively), Pacific people (adjHR 1.90 [1.58-2.28], 1.30 [1.12-1.51], 1.62 [95% CI 1.49-1.75], respectively) and Chinese people (adjHR 1.53 [1.08-2.16], 1.15 [0.90-1.47], 1.13 [95% CI 1.01-1.26], respectively) were at increased risk of a major bleed compared to Europeans, although for Chinese people the effect did not reach statistical significance in the CVD subgroup. Compared to Europeans, Maori and Pacific peoples were generally at increased risk of all bleed types (gastrointestinal, intracranial and other bleeds). An increased risk of intracranial bleeds was observed among Chinese and Other Asian people and, in the CVD and no CVD/AF subgroups, among Indian people. Increasing socioeconomic deprivation was also associated with increased risk of a major bleed in all three subgroups (adjHR 1.07 [1.02-1.12], 1.07 [1.03-1.10], 1.10 [95% CI 1.08-1.12], respectively, for each increase in socioeconomic deprivation quintile). CONCLUSION: Ethnicity and socioeconomic status should be considered in bleeding risk assessments to guide the use of antithrombotic medication for the management of AF and CVD.

Plasma ω-3 and ω-6 PUFA Concentrations and Risk of Atrial Fibrillation: The Multi-Ethnic Study of Atherosclerosis.

BACKGROUND: Current literature examining the prospective relation of circulating omega-3 (n-3) and omega-6 (n-6) PUFAs and atrial fibrillation (AF) is limited to predominantly white populations. OBJECTIVES: We investigated the association of circulating n-3 and n-6 PUFAs with incident AF in participants from the Multi-Ethnic Study of Atherosclerosis. METHODS: A total of 6229 participants (mean age = 62 y; 53% female; 39% white, 27% black, 22% Hispanic, and 12% Chinese) who were free of baseline AF and with plasma phospholipid PUFAs measured at baseline using GC were prospectively followed for the development of AF. Incident AF was ascertained using International Classification of Diseases-9 codes from hospital discharge records and Medicare claims data with follow-up through 2014. Multivariable Cox proportional hazards regression analysis was performed to determine the risk of incident AF. RESULTS: During a median follow-up of 12.9 y, 813 (13%) participants developed AF. Each higher SD increment in arachidonic acid (AA; 20:4n-6) concentrations was associated with an 11% decreased risk of incident AF (HR: 0.89; 95% CI: 0.82, 0.96). Similarly, higher overall n-6 PUFA concentrations were also associated with a reduced AF risk (HR per SD increment: 0.93; 95% CI: 0.87, 1.00). Although no significant overall associations were observed for any individual n-3 PUFAs, higher circulating concentrations of DHA (22:6n-3) and EPA (20:5n-3) were associated with a decreased AF risk in blacks and Hispanics (DHA only) but not whites or Chinese Americans. CONCLUSIONS: In a multiethnic cohort of individuals free of baseline cardiovascular disease, higher plasma concentrations of n-6 PUFAs, particularly AA, were associated with a reduced risk of incident AF. Important differences in AF risk were also noted across race/ethnicity for the n-3 PUFAs DHA and EPA.

Relationship between SCN5A gene H558R polymorphism and atrial fibrillation in Tibetan and Han nationalities at high altitude.

ABSTRACT: This study aimed to explore the relationship between H558R polymorphism of the SCN5A gene and atrial fibrillation (AF) in Tibetan and Han nationalities at high altitude.A total of 50 Tibetan and 50 Han patients with AF at the same altitude (2260 m) were included. Meanwhile, the general clinical data of patients without AF (50 Tibetan and 50 Han) matched with the data of patients with AF were included during the same period. The blood samples of patients were collected to extract DNA. The DNA sequencing was performed by Xi'an Zhenpin Biotechnology Co., Ltd. The mutation loci of the sequence were located and identified by DNA sequencing. The general information, laboratory examination, color Doppler echocardiography, and genotypes and alleles of each group were analyzed. The multivariate logistic regression analysis was used to determine the independent risk factors for AF.The genotype and allele frequencies of the H558R locus of the SCN5A gene in the AF groups of Tibetan and Han nationalities were significantly different from those in the non-AF groups (P < .05). The genotype and allele frequency of the H558R locus of the SCN5A gene in the AF group of Tibetan nationalities were not significantly different from those in the AF group of Han nationalities (P > .05). The logistic regression analysis of the total population revealed that coronary heart disease, age, total cholesterol (TC), left atrial diameter, and G allele were independent risk factors for AF occurrence.The occurrence of AF in Tibetan and Han nationalities at high altitude is associated with the polymorphism of H558R locus of the SCN5A gene. The G allele is an independent risk factor for the occurrence of AF in Tibetan and Han nationalities.

Incident Strokes Among American Indian Individuals With Atrial Fibrillation.

BACKGROUND American Indian individuals experience a relatively high risk for cardiovascular disease and have exhibited a higher risk of stroke compared with other racial and ethnic minorities. Although this population has the highest incidence of atrial fibrillation (AF) compared with other groups, the relationship between AF and nonhemorrhagic stroke among American Indian individuals compared with other groups has not been thoroughly studied. METHODS and RESULTS We used the Healthcare Cost and Utilization Project to evaluate risk of nonhemorrhagic stroke among American Indian individuals, with comparisons to White, Black, Hispanic, and Asian individuals, among all adult California residents receiving care in an emergency department, inpatient hospital unit, or ambulatory surgery setting from 2005 to 2011. Of 16 951 579 patients followed for a median 4.1 years, 105 822 (0.6%) were American Indian. After adjusting for age, sex, income level, insurance payer, hypertension, diabetes mellitus, coronary artery disease, congestive heart failure, cardiac surgery, valvular heart disease, chronic kidney disease, smoking, obstructive sleep apnea, pulmonary disease, and alcohol use, American Indian individuals with AF exhibited the highest risk of nonhemorrhagic stroke when compared with either non-American Indian individuals with AF (hazard ratio, 1.38; 95% CI, 1.23-1.55; P<0.0001) or to each race and ethnicity with AF. American Indian individuals also experienced the highest overall risk for stroke, with no evidence that AF disproportionately heightened that risk in interaction analyses. CONCLUSIONS American Indian individuals experienced the highest risk of nonhemorrhagic stroke, whether in the presence or absence of AF. Our findings likely suggest an opportunity to further study, if not immediately address, guideline-adherent anticoagulation prescribing patterns among American Indian individuals with AF.