HEART RATE VARIABILITY IN SLEEP-DISORDERED BREATHING

描述(申请人提供)：该项目的长期目标是确定轻度到中度睡眠障碍呼吸(SDB)是否会导致心脏自主神经控制的改变，这些改变可以通过夜间心率变异性(HRV)和呼吸的测量来检测到。由于常规的心率变异性频谱分析可能会受到受试者之间的差异或个体内在SDB期间换气和换气模式的变化的严重混淆，因此将使用最近开发的一种算法来计算“呼吸调整”的HRV频谱指数。该算法将应用于从睡眠心脏健康研究收集的无人看管的家庭多导睡眠图中获得的心肺数据的大样本。这项研究的具体目标是确定：(1)在SDB严重的个体中，安静清醒时的常规HRV谱指数和呼吸调节的HRV谱指数是否与呼吸暂停-低呼吸指数相关；(2)长期暴露于SDB改变了HRV的呼吸调节谱指数对睡眠状态的依赖性；(3)SDB的严重性增加导致派生的呼吸调节的HRV谱测量的超传统振荡的幅度和时间进程的改变。将这种形式的心率变异性分析应用于多导睡眠图数据的大型数据库，可能会更好地理解SDB与心脑血管疾病之间的因果联系。此外，更好地了解内在自主活动波动的夜间节律性以及这种节律性是如何随着长期接触SDB而变化的，也可以为急性心血管事件(如心肌梗塞和中风)的发生时间提供重要的见解。

DESCRIPTION (provided by applicant): The long-term objective of this project is to determine whether mild-to-moderate sleep-disordered breathing (SDB) leads to alterations in cardiac autonomic control that are detectable from nocturnal measurements of heart rate variability (HRV) and respiration. Since conventional spectral analysis of HRV can be seriously confounded by inter-subject differences or intra-individual changes in ventilation and ventilatory pattern during SDB, a recently developed algorithm will be used to compute "respiration-adjusted" spectral indices of HRV. This algorithm will be applied to a large sample of cardiorespiratory data derived from unattended home-based polysomnograms collected by the Sleep Heart Health Study. The specific goals of this study are to determine whether: (1) the conventional and "respiration-adjusted" spectral indices of HRV in quiet wakefulness are correlated with apnea-hypopnea index in individuals with severity of SDB; (2) chronic exposure to SDB alters the dependencies of the "respiration-adjusted" spectral indices of HRV on sleep state; (3) increasing severity of SDB leads to alterations in the amplitude and time-course of ultradian oscillations in the derived "respiration-adjusted" spectral measures of HRV. The application of this form of HRV analysis to a large database of polysomnographic data is likely to lead to a better understanding of the causal links that relate SDB to cardiovascular or cerebrovascular disease. As well, improved knowledge of the nocturnal rhythmicity of fluctuations in intrinsic autonomic activity and how this changes with chronic exposure to SDB could also provide important insights into the timing of acute cardiovascular events, such as myocardial infarction and stroke.