The Race-Specific Prevalence of Atrial Fibrillation Measured by 48-Hour Holter

描述（由申请人提供）：房颤（AF）是全球最常见的持续性心律失常，是卒中的已知风险因素。尽管与白人相比，非洲裔美国人的卒中患病率要高得多，但非洲裔美国人的AF患病率较低。非洲裔美国人还经历了与AF相关的高风险因素，包括高血压、肥胖和糖尿病。理论上，非裔美国人AF发生率意外低的矛盾可能是由于不同种族的AF检测差异（确认偏倚）。大多数之前的研究都通过自我报告、住院、索赔数据和/或12导联心电图来定义AF，所有这些都可能错过亚临床和间歇性AF。AF的检测可能具有挑战性，因为它可能是阵发性和无症状的，需要动态心电图（霍尔特）来确定。美国国家心肺和血液研究所（NHLBI）呼吁通过在纵向研究中增加对AF的监测，特别是在非白人群体中，来促进AF流行病学的发展。我们建议在正在进行的社区双种族动脉粥样硬化风险（ARIC）研究中进行的一项信息性研究中测量AF的种族特异性患病率。为了估计不同种族AF的患病率和特征，我们计划利用正在进行的第5次ARIC队列检查（2011年6月至2013年5月），包括最先进的超声心动图（ECHO），作为一种有效识别霍尔特监测信息亚组的方法。这项研究有四个主要目的。目的1：估计年龄在70岁及以上的非裔美国人和白人中AF的种族特异性患病率。目的2：根据霍尔特监测时间，通过量化房颤检测中的不确定性来校准房颤的患病率。目标3：通过在霍尔特监测附近进行的心电图、超声心动图、肺量测定和生物标志物测量，评价非裔美国人AF的近端风险因素和触发因素。目标4：确定中年时的代谢、行为和共病因素，以及它们在随后的四次队列检查过程中的变化，与非裔美国人的AF发病率相关。我们将对来自2个研究中心的ARIC队列的825名非洲裔美国人和400名白色成员进行AF指标的阶段性验证，并对未证实AF的受试者进行48小时连续霍尔特监测。分层随机抽样将基于人种、中心、性别和增加AF发生率的特征（左心房尺寸增大或超声心动图显示射血分数低或临床心力衰竭）。根据ARIC队列的5次检查和超过25年的事件全面随访的先前特征，我们将能够有效地检查AF的种族特异性患病率和特征，并防止已发表报告中无法获得的不确定性。本研究将调查非洲裔美国人中低房颤的种族矛盾，这对非洲裔美国人房颤的预防和临床管理具有意义。

DESCRIPTION (provided by applicant): Atrial fibrillation (AF) is the most common sustained arrhythmia worldwide and it is a known risk factor for stroke. Despite a much higher prevalence of stroke in African-Americans compared to Whites, African Americans have a lower prevalence of AF. African-Americans also experience high rates of risk factors associated with AF including hypertension, obesity and diabetes. It has been theorized that this paradox of unexpected low rates of AF in African Americans may be due to differential detection of AF by race (ascertainment bias). Most prior studies have defined AF by self-report, hospitalizations, claims data, and/or 12-lead electrocardiography, all of which may miss subclinical and intermittent AF. The detection of AF can be challenging as it can be paroxysmal and asymptomatic requiring ambulatory electrocardiography (Holter) for ascertainment. The National Heart Lung and Blood Institute (NHLBI) has called for advancements in AF epidemiology through increased surveillance of AF in longitudinal studies, especially among non-White ethnic groups. We propose to measure the race-specific prevalence of AF, in an informative study nested in the ongoing, bi-ethnic Atherosclerosis Risk in Communities (ARIC) Study. With the goal of estimating the prevalence and characteristics of AF by race, we plan to take advantage of the ongoing 5th ARIC cohort examination (June 2011-May 2013) inclusive of state-of-the-art echocardiograms (ECHOs) as a way to efficiently identify an informative subgroup for Holter monitoring. This study has four main aims. Aim 1: Estimate the race-specific prevalence of AF in African-Americans and Whites aged 70 years and older. Aim 2: Calibrate the prevalence of AF by quantifying under-ascertainment in the detection of AF according to length of Holter monitoring. Aim 3: Evaluate the proximal risk factors and triggering factors of AF in African Americans from the electrocardiographic, echocardiographic, spirometry, and biomarker measures performed proximal to Holter monitoring. Aim 4: Identify the metabolic, behavioral and comorbid factors in middle age, and their change over the course of the subsequent four cohort examinations, associated with the incidence of AF in African Americans. We will perform a staged validation of indicators of AF, and 48-hour continuous Holter monitoring on participants without substantiated AF, for 825 African American and 400 White members of the ARIC cohort from 2 study sites. Stratified random sampling will be based on race, center, gender, and characteristics that increase yield of AF(enlarged left atrial size or low ejection fraction on echocardiogram, or clinical heart failure). From the prior characterization of the ARIC cohort's 5 examinations and over 25 years of comprehensive follow-up for events, we will be able to efficiently examine the race-specific prevalence and characteristics of AF, with safeguards against under-ascertainment not available in published reports. This study will investigate the racial paradox of low atrial fibrillation in African Americans which has implications for the prevention and clinical management of AF in African Americans.