HEART RATE VARIABILITY IN SLEEP-DISORDERED BREATHING

描述（由申请人提供）：该项目的长期目标是确定轻度至中度睡眠呼吸障碍（SDB）是否会导致心脏自主控制的改变，这可以通过夜间心率变异性（HRV）和呼吸测量来检测。由于传统的HRV频谱分析可能会被SDB期间通气和通气模式的主体间差异或个体内变化严重混淆，因此将使用最近开发的算法来计算HRV的“呼吸调节”频谱指数。该算法将应用于由睡眠心脏健康研究收集的无人值守的家庭多导睡眠图中获得的大量心肺数据样本。本研究的具体目的是确定：(1)重度SDB患者安静清醒时HRV的常规和“呼吸调节”谱指数是否与呼吸暂停低通气指数相关；(2)慢性SDB暴露改变了HRV“呼吸调节”谱指数对睡眠状态的依赖性；(3) SDB严重程度的增加导致HRV“呼吸调节”频谱测量值的超振幅和时间过程发生变化。将这种形式的HRV分析应用于大型多导睡眠图数据数据库，可能有助于更好地了解SDB与心脑血管疾病之间的因果关系。此外，提高对内在自主神经活动波动的夜间节律性的认识，以及慢性暴露于SDB时这种变化的方式，也可以为急性心血管事件（如心肌梗死和中风）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.