Atrial fibrillation burden, vascular disease of the brain and cardiac MRI in MESA

 说明(申请人提供)：房颤(AF)是一种常见的心律失常，与中风、认知能力下降、痴呆、动脉血栓、心力衰竭和心血管死亡的风险显著增加有关。现有的房颤研究依赖于患者出现症状时对房颤的临床识别，但对植入起搏器或除颤器等监测设备的患者的研究表明，很大比例的房颤发作根本不会产生任何症状(亚临床房颤)。因此，依靠患者症状来识别房颤严重低估了房颤负荷，即监测到的心律为房颤的时间比例。方便的新型外部心电贴片监护仪现在使得以合理的价格进行扩展的动态监测成为可能，并允许识别亚临床房颤和估计房颤负荷。然而，关于亚临床房颤或房颤负荷的分布或预测因素；它们与脑结构和功能的关系或与临床心血管事件的关系；或左房或左室功能或结构与亚临床房颤和房颤负荷的关系，几乎没有信息。对植入装置的患者进行的研究几乎没有证据表明，无论患者是否有房颤症状，房颤并发症都会发生。我们建议在动脉粥样硬化的多种族研究(MESA)中进行一项关于房颤和房颤负荷与脑和心脏结构和功能以及心血管事件的关系的研究。我们将从所有6个野战中心招募总共1500名MESA参与者，采用队列设计：1)300名临床公认的房颤参与者 之前的MESA随访：2)450名基于2010-2012年绘制的NT-proBNP水平和公布的房颤风险评分的房颤高危参与者，以及3)750名参与者的随机样本。这1500名参与者将在2016-2017年间进行两次为期14天的心电监测，而同意的参与者(估计n=1350人)将在一到两年后进行脑部核磁共振检查。我们将检查动态心电监测中房颤和房颤负荷的存在，与心电监测一至两年后进行的脑MRI测量相关，以及与MESA事件随访期间的心血管事件相关。我们还将检查2010-2012年心脏MRI的测量方法，以及与监护仪上存在的房颤和房颤负荷相关的参与者特征和生物标记物。我们的研究信息将帮助医生和研究人员决定测量亚临床房颤和房颤负荷作为量化房颤的新方法的实用性。了解与房颤负荷谱相关的心脏和脑异常以及心血管事件可能对临床护理有影响，包括关于降低中风和心力衰竭风险的治疗决策，以及是否有必要对只有一次房颤首发的患者进行后续监测。

 DESCRIPTION (provided by applicant): Atrial fibrillation (AF), a common arrhythmia, is associated with substantially elevated risks of stroke, cognitive decline, dementia, arterial emboli, heart failure, and cardiovascular death. Existing studies of AF rely on clinical recognitio of AF when a patient presents with symptoms, but studies in patients with implanted monitoring devices such as pacemakers or defibrillators indicate that a large proportion of AF episodes produce no symptoms at all (subclinical AF). Therefore, relying on patient symptoms to identify AF seriously underestimates AF burden, defined as the proportion of monitored time that the cardiac rhythm is AF. Convenient new external ECG patch monitors now make possible extended ambulatory monitoring at reasonable cost, and permit identification of subclinical AF and estimation of AF burden. However, there is little information about the distribution or predictors of subclinical AF or AF burden; their associations with brain structure and function or with clinical cardiovascular events; or the association of left atrial or ventricular function or structure with subclinical AF and AF burden. What little evidence is available from studies in patients with implanted devices suggests that AF complications occur whether or not patients are experiencing symptoms with their AF. We propose to conduct a study of AF and AF burden in relation to cerebral and cardiac structure and function and cardiovascular events in the Multi-Ethnic Study of Atherosclerosis (MESA). We will recruit a total of 1500 MESA participants from all 6 Field Centers using a cohort design: 1) 300 participants with clinically-recognized AF during previous MESA follow-up; 2) 450 participants at high risk for AF based on NT-proBNP level drawn in 2010-2012 and a published AF risk score, and 3) a random sample of 750 participants. The 1500 participants will have two 14-day ECG monitoring episodes in 2016-2017, and consenting participants (estimated n=1350) will have a brain MRI one to two years later. We will examine the presence of AF and AF burden from the ambulatory ECG monitoring in relation to measures from the brain MRI done one to two years after ECG monitoring, and in relation to cardiovascular events during MESA events follow-up. We will also examine measures from the 2010-2012 cardiac MRI, as well as participant characteristics and biomarkers, in relation to the presence of AF and AF burden on the monitor. Information from our study will help physicians and researchers decide on the utility of measuring subclinical AF and AF burden as new ways of quantifying AF. Knowledge about cardiac and brain abnormalities and cardiovascular events associated with the spectrum of AF burden may have implications for clinical care, including decisions about therapy to reduce the risk of stroke and heart failure and whether follow-up monitoring is warranted for patients who have had a single first episode of AF.