Evidence of heterogeneity by race/ethnicity in genetic determinants of QT interval.

Background: QT interval (QT) prolongation is an established risk factor for ventricular tachyarrhythmia and sudden cardiac death. Previous genome-wide association studies in populations of the European descent have identified multiple genetic loci that influence QT, but few have examined these loci in ethnically diverse populations.

Methods: Here, we examine the direction, magnitude, and precision of effect sizes for 21 previously reported SNPs from 12 QT loci, in populations of European (n = 16,398), African (n = 5,437), American Indian (n = 5,032), Hispanic (n = 1,143), and Asian (n = 932) descent as part of the Population Architecture using Genomics and Epidemiology (PAGE) study.

Impact of intensive glycemic control on the incidence of atrial fibrillation and associated cardiovascular outcomes in patients with type 2 diabetes mellitus (from the Action to Control Cardiovascular Risk in Diabetes Study).

Atrial fibrillation (AF) is prevalent in patients with type 2 diabetes mellitus (DM) and is associated with markers of poor glycemic control; however, the impact of glycemic control on incident AF and outcomes is unknown. The aims of this study were to prospectively evaluate if intensive glycemic control in patients with DM affects incident AF and to evaluate morbidity and mortality in patients with DM and incident AF. A total of 10,082 patients with DM from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) cohort were studied in a randomized, double-blind fashion.

Socioeconomic status and the incidence of atrial fibrillation in whites and blacks: the Atherosclerosis Risk in Communities (ARIC) study.

Background: No previous studies have examined the interplay among socioeconomic status, sex, and race with the risk of atrial fibrillation (AF).

Methods And Results: We prospectively followed 14 352 persons (25% black, 75% white, 55% women, mean age 54 years) who were free of AF and participating in the Atherosclerosis Risk in Communities (ARIC) study. Socioeconomic status was assessed at baseline (1987-1989) through educational level and total family income.

Subclinical myocardial injury identified by cardiac infarction/injury score and the risk of mortality in men and women free of cardiovascular disease.

Previous studies have explored the ability of the Cardiac Infarction/Injury Score (CIIS) to identify individuals who are high risk for cardiovascular disease (CVD) mortality. However, its prognostic significance among those without CVD in the United States general population has not been established. This analysis included 6,298 participants (mean age 59±13 years, 53% women, 51% nonwhites) from the Third National Health and Nutrition Examination Survey, excluding participants with a history of CVD or electrocardiographic evidence of old myocardial infarction or ischemic ST depression at baseline.

The paradox of atrial fibrillation in African Americans.

The reported lower prevalence and incidence of atrial fibrillation (AF) despite the higher prevalence of AF risk factors in African Americans compared to Caucasian whites has been referred to as the paradox of AF in African Americans. In this report we highlight this paradox and address potential explanations using data from several US populations studies. These possible explanations include limited methodology to detect AF patterns that are harder to detect (e.

Electrocardiographic repolarization-related variables as predictors of coronary heart disease death in the women's health initiative study.

Background: We evaluated 25 repolarization-related ECG variables for the risk of coronary heart disease (CHD) death in 52 994 postmenopausal women from the Women's Health Initiative study.

Methods And Results: Hazard ratios from Cox regression were computed for subgroups of women with and without cardiovascular disease (CVD). During the average follow-up of 16.

A common SCN5A variant is associated with PR interval and atrial fibrillation among African Americans.

Objective: We examined the association of rs7626962 (S1103Y) or rs7629265, a variant in high linkage disequilibrium with S1103Y (r(2) = 0.87 - 1), with sudden cardiac death (SCD) and atrial fibrillation (AF) among African Americans.

Background: The SCN5A missense variant S1103Y has been associated with SCD among African Americans in small case-control studies, but larger population-based studies are needed to validate these findings.

P-wave morphology and the risk of incident ischemic stroke in the Multi-Ethnic Study of Atherosclerosis.

Background And Purpose: Emerging data suggest that left atrial disease may cause ischemic stroke in the absence of atrial fibrillation or flutter (AF). If true, this condition may provide a cause for many strokes currently classified as cryptogenic.

Methods: Among 6741 participants in the Multi-Ethnic Study of Atherosclerosis who were free of clinically apparent cerebrovascular or cardiovascular disease (including AF) at baseline, we examined the association between markers of left atrial abnormality on a standard 12-lead ECG-specifically P-wave area, duration, and terminal force in lead V1-and the subsequent risk of ischemic stroke while accounting for incident AF.

B-type natriuretic peptide and C-reactive protein in the prediction of atrial fibrillation risk: the CHARGE-AF Consortium of community-based cohort studies.

Aims: B-type natriuretic peptide (BNP) and C-reactive protein (CRP) predict atrial fibrillation (AF) risk. However, their risk stratification abilities in the broad community remain uncertain. We sought to improve risk stratification for AF using biomarker information.

Electrocardiographic left ventricular hypertrophy and the risk of adverse cardiovascular events: a critical appraisal.

This review covers selected electrocardiographic left ventricular hypertrophy (ECG-LVH) studies which have evaluated their prognostic value for adverse cardiovascular (CVD) events. Most ECG-LVH studies have used echocardiographic left ventricular mass (Echo-LVM) as the gold standard for evaluating ECG-LVH criteria. More recently, LVM from magnetic resonance imaging (MRI-LVM) has evolved as the new gold standard.

Relation of systolic, diastolic, and pulse pressures and aortic distensibility with atrial fibrillation (from the Multi-Ethnic Study of Atherosclerosis).

Previous research suggests that elevated pulse pressure (PP) is a risk factor for atrial fibrillation (AF) independently of mean arterial pressure (MAP). PP may serve as an indirect measure of aortic stiffness (reduced distensibility), but whether directly measured aortic distensibility is related to risk for AF has not yet been studied. This analysis included 6,630 participants aged 45 to 84 years from the Multi-Ethnic Study of Atherosclerosis.

Sequencing of SCN5A identifies rare and common variants associated with cardiac conduction: Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Consortium.

Background: The cardiac sodium channel SCN5A regulates atrioventricular and ventricular conduction. Genetic variants in this gene are associated with PR and QRS intervals. We sought to characterize further the contribution of rare and common coding variation in SCN5A to cardiac conduction.

Abnormal electrocardiographic QRS transition zone and risk of mortality in individuals free of cardiovascular disease.

Aims: We examined the prognostic significance of abnormal electrocardiographic QRS transition zone (clockwise and counterclockwise horizontal rotations) in individuals free of cardiovascular disease (CVD).

Methods And Results: A total of 5541 adults (age 53 ± 10.4 years, 54% women, 24% non-Hispanic black, 25% Hispanic) without CVD or any major electrocardiogram (ECG) abnormalities from the US Third National Health and Nutrition Examination Survey were included in this analysis.

Usefulness of electrocardiographic QRS/T angles with versus without bundle branch blocks to predict heart failure (from the Atherosclerosis Risk in Communities Study).

Repolarization abnormalities in the setting of bundle branch blocks (BBB) are generally ignored. We used Cox regression models to determine hazard ratios (HRs) with 95% confidence intervals (CIs) for incident heart failure (HF) associated with wide spatial and frontal QRS/T angle (upper twenty-fifth percentile of each) in men and women with and without BBB. This analysis included 14,478 participants (54.

Circulating levels of liver enzymes and incidence of atrial fibrillation: the Atherosclerosis Risk in Communities cohort.

Background: Elevated levels of circulating liver enzymes have been associated with increased risk of cardiovascular disease. Their possible association with atrial fibrillation (AF) has received little attention.

Methods: We studied 9333 men and women, aged 53-75 years, free of AF, participating in the Atherosclerosis Risk in Communities Study followed-up from 1996 to 2010.

Physical activity, obesity, weight change, and risk of atrial fibrillation: the Atherosclerosis Risk in Communities study.

Background: Physical activity (PA) has previously been suggested to attenuate the risk of atrial fibrillation (AF) conferred by excess body weight and weight gain. We prospectively examined the relationship between body size, weight change, and level of PA in a biracial cohort of middle-aged men and women.

Methods And Results: Baseline characteristics on risk factor levels were obtained on 14 219 participants from the Atherosclerosis Risk in Communities Study.

Birth weight and the risk of atrial fibrillation in whites and African Americans: the Atherosclerosis Risk In Communities (ARIC) study.

Background: Low birth weight (LBW) has been associated with an increased risk of cardiovascular disease (CVD). A previous study, however, found higher risk of atrial fibrillation (AF) in individuals with higher birth weight (BW). To further understand this apparent paradox, we examined the relationship between AF and BW in the Atherosclerosis Risk in Communities (ARIC) cohort.

Electrocardiographic deep terminal negativity of the P wave in V1 and risk of mortality: the National Health and Nutrition Examination Survey III.

Introduction: Deep terminal negativity of P wave in V1 (DTNPV1), defined as negative P prime larger than one small box (1 mm, or 0.1 mV), could be easily detected by simple visual inspection of the resting 12-lead ECG. The objective of this study was to determine the relationship between DTNPV1 and all-cause-, cardiovascular disease (CVD), and ischemic heart disease (IHD) mortality in the National Health and Nutrition Examination Survey III (NHANES III).

Long-term mortality risk in individuals with atrial or ventricular premature complexes (results from the Third National Health and Nutrition Examination Survey).

Premature ectopic beats are frequently detected on routine 12-lead screening electrocardiograms (ECGs). However, their prognostic importance in subjects without known cardiovascular disease (CVD) is not well established. We evaluated prognostic value of atrial premature complexes (APCs) and ventricular premature complexes (VPCs) detected by a single 12-lead electrocardiography.

Short-term repeatability of electrocardiographic Tpeak-Tend and QT intervals.

Background: The electrocardiographic (ECG) Tpeak-Tend interval (TpTe) is associated with arrhythmias and sudden cardiac death. TpTe offers a supplementary measure for the QT interval (QT), yet its repeatability has not been established.

Purpose: Evaluate short-term repeatability of TpTe and QT.

Inter-relationship between electrocardiographic left ventricular hypertrophy and QT prolongation as predictors of increased risk of mortality in the general population.

Background: Prolonged-QT commonly coexists in the ECG with left ventricular hypertrophy (ECG-LVH). However, it is unclear whether to what extent QT prolongation coexisting with ECG-LVH can explain the prognostic significance of ECG-LVH, and whether prolonged-QT coexisting with ECG-LVH should be considered as an innocent consequence of ECG-LVH.

Methods And Results: The study population consisted of 7506 participants (mean age, 59.

Clinical characteristics and outcomes associated with the natural history of early repolarization in a young, biracial cohort followed to middle age: the Coronary Artery Risk Development in Young Adults (CARDIA) study.

Background: Early repolarization (ER), a common electrocardiographic phenotype, has been associated with increased mortality risk in middle-aged adults. Data are sparse on long-term follow-up and outcomes associated with ER in younger adults.

Methods And Results: We prospectively examined 5039 participants (mean age, 25 years at baseline, 40% black) from the Coronary Artery Disease Risk in Adults (CARDIA) cohort for 23 years.

Serum aldosterone and death, end-stage renal disease, and cardiovascular events in blacks and whites: findings from the Chronic Renal Insufficiency Cohort (CRIC) Study.

Prior studies have demonstrated that elevated aldosterone concentrations are an independent risk factor for death in patients with cardiovascular disease. Limited studies, however, have evaluated systematically the association between serum aldosterone and adverse events in the setting of chronic kidney disease. We investigated the association between serum aldosterone and death and end-stage renal disease in 3866 participants from the Chronic Renal Insufficiency Cohort.

Assessing the performance of the Framingham Stroke Risk Score in the reasons for geographic and racial differences in stroke cohort.

Background And Purpose: The most well-known stroke risk score is the Framingham Stroke Risk Score (FSRS), which was developed during the higher stroke risk period of the 1990s and has not been validated for blacks. We assessed the performance of the FSRS among participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study to determine whether it is useful in both blacks and whites.

Methods: Expected annualized stroke rates from the FSRS were compared with observed stroke rates overall and within strata defined by FSRS risk factors (age, sex, systolic blood pressure, use of antihypertensive medications, diabetes mellitus, smoking, atrial fibrillation, left ventricular hypertrophy, and prevalent coronary heart disease).

Association of electrocardiographic and imaging surrogates of left ventricular hypertrophy with incident atrial fibrillation: MESA (Multi-Ethnic Study of Atherosclerosis).

Objectives: This study sought to examine the association between left ventricular hypertrophy (LVH), defined by cardiac magnetic resonance (CMR) and electrocardiography (ECG), with incident atrial fibrillation (AF).

Background: Previous studies of the association between AF and LVH were based primarily on echocardiographic measures of LVH.

Methods: The MESA (Multi-Ethnic Study of Atherosclerosis) enrolled 4,942 participants free of clinically recognized cardiovascular disease.