Prevalence and predictors of asymptomatic atrial fibrillation in the community

描述（由申请人提供）：房颤是缺血性卒中的一个强风险因素，在老年人中尤其常见。目前的知识是基于临床确诊的病例;短暂的、通常无症状的房颤发作（通常发生在持续性房颤发作之前）的频率尚不清楚，其相关的中风风险也不清楚。此外，其他常见房性和室性心律失常的频率及其与卒中风险的潜在关联仅部分已知。本研究拟对1200名65岁以上的无脑卒中志愿者进行前瞻性社区研究，主要目的如下：1.评估多种族老年人群中未诊断的房颤的患病率，并描述其按性别和种族-种族的分布; 2.探讨心脏亚临床疾病、心血管危险因素和选择的生物标志物作为未诊断房颤的潜在预测因子的作用;评估可能与卒中相关的其他房性心律失常（室上性心动过速、频发房性早搏）和室性心律失常（频发室性早搏）的患病率;在校正传统血管危险因素后，确定多种族老年队列中与未诊断的房颤和其他心律失常相关的卒中、心肌梗死和血管性死亡的风险。 研究队列将来自 先前资助的心血管异常和脑病变（CABL）研究，基于正在进行的北方曼哈顿研究（NOMAS）和NOMAS本身。将通过使用新型、经验证的贴片式心脏记录仪连续记录14天心律来评价未诊断的房颤和其他心律失常。除了左心室质量和几何形状外，还将评价左心室收缩（LV应变）和舒张功能（通过组织多普勒）的新超声心动图指标。将通过3D回波图像（LA容积和排空分数）并使用电重构的ECG指标（P波持续时间和离散度）评估左心房形态和功能。将测量生物标志物作为房颤的预测因子，探索不同的致病途径：心房扩张和 亚临床心功能不全（N-T proBNP）、炎症（高敏CRP、IL-6）、亚临床心肌损伤/缺血（肌钙蛋白I）、血栓形成（D-二聚体）、心房纤维化（TGF β 1）。将对受试者进行年度电话随访，以确定卒中、心肌梗死（在阳性应答的情况下进行亲自评估）和死亡。将通过逻辑回归计算推定预测因素和未诊断房颤的比值比。将通过考克斯比例风险模型计算房颤/其他心律失常和CV事件的风险比，并调整血管风险因素。 本提案将填补我们在老年人房颤/其他心律失常的全球负担及其与卒中和其他血管事件的关系方面的知识空白，并将确定发生这些心律失常的风险较高的受试者，可对其进行预防性干预。

DESCRIPTION (provided by applicant): Atrial fibrillation is a strong risk factor for ischemic stroke, and is especially frequent in the elderly. The current knowledge is based on clinically established cases; the frequency of short, often asymptomatic episodes of atrial fibrillation, which often precede the onset of sustained atrial fibrillation, is not known, and neither is their associated stroke risk. Also, the frequency of other common atrial and ventricular arrhythmias, and their potential association with stroke risk, is only partially known. A prospective community-based study is proposed on 1200 stroke-free volunteers over the age of 65 years with the following primary aims: 1. To evaluate the prevalence of undiagnosed atrial fibrillation in a multiethnic elderly cohort and describe its distribution by sex and race-ethnicity; 2. To investigate the role of cardiac subclinical disease, cardiovascular risk factors and selected biomarkers as potential predictors of undiagnosed atrial fibrillation; 3. To evaluate the prevalence of other atrial arrhythmias (supraventricular tachycardia, frequent atrial premature contractions) and ventricular arrhythmias (frequent ventricular premature contractions) possibly related to stroke; 4. To determine the risk of stroke, myocardial infarction and vascular death associated with undiagnosed atrial fibrillation and other arrhythmias in a multiethnic elderly cohort after adjusting for conventional vascular risk factors. The study cohort will be drawn from the previously funded Cardiovascular Abnormalities and Brain Lesions (CABL) study, based on the ongoing Northern Manhattan Study (NOMAS), and from NOMAS itself. Undiagnosed atrial fibrillation and other arrhythmias will be evaluated by means of 14-day continuous recording of cardiac rhythm using a novel, validated patch-based cardiac recorder. Novel echocardiographic indicators of left ventricular systolic (LV strain) and diastolic function (by tissue Doppler) willbe evaluated, in addition to LV mass and geometry. Left atrial morphology and function will be assessed on 3D echo images (LA volumes and emptying fraction) and using ECG indicators of electrical remodeling (P wave duration and dispersion). Biomarkers will be measured as predictors of atrial fibrillation that explore different pathogenic pathways: atrial distention and subclinical cardiac dysfunction (N-T pro BNP), inflammation (high-sensitivity CRP, IL-6), subclinical myocardial damage/ischemia (troponin I), thrombosis (D-dimer), atrial fibrosis (TGF beta1). Subjects will be followed by annual telephone interviews to ascertain stroke, myocardial infarction (with in- person evaluation in case of positive responses) and death. Odds ratio for putative predictors and undiagnosed atrial fibrillation will be calculated by logistic regression. Hazard ratios for atrial fibrillation/other arrhythmias and CV events will be calculated by Cox proportional hazards model, adjusting for vascular risk factors. The present proposal will fill gaps in our knowledge on the global burden of atrial fibrillation/other arrhythmias in the elderly and their relationship with stroke and other vascular events, and will identify subjects at higher risk of developing these arrhythmias to whom preventative interventions could be addressed.