PHYSIOLOGY OF HEART RATE RECOVERY AFTER SUBMAXIMAL EXERCISE IN SUBJECTS WITH CAD

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 在运动过程中和之后，猝死的风险会增加。静息副交感神经张力减弱也与死亡率增加有关。最近，运动后心率恢复减慢被证明可以预测死亡率，但关于运动和副交感神经张力在心脏电生理学上的相互作用尚无相关信息。 本研究的目的是验证以下假设：a)在冠心病和左心功能不全患者中，副交感神经重新激活对心率和QT间期恢复的影响减弱。这将通过使用和不使用副交感神经阻断的顺序运动试验对患有和不伴有中度至严重左心功能不全的冠心病患者进行评估；b)恢复期间心率变异性的新的非侵入性指标与重新激活副交感神经对心率和QT间期恢复的影响相关。 这项研究将为副交感神经张力减弱和猝死风险之间的病理生理学联系提供重要的见解。这一结果可能支持使用运动和/或恢复期间副交感神经张力的特定指数作为预后指标，而不是静息状态下得出的指数。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The risk of sudden death is increased during and following exercise. Diminished resting parasympathetic tone is also associated with increased mortality. Recently, attenuated heart rate recovery after exercise has been shown to predict mortality yet, no information is available regarding the interaction between exercise and parasympathetic tone on cardiac electrophysiology. The aim of the proposed study is to test the following hypotheses: a) there is diminished effect of parasympathetic reactivation on recovery of heart rate and QT interval in subjects with coronary artery disease and left ventricular dysfunction. This will be assessed by sequential exercise testing with and without parasympathetic blockade in subjects with coronary artery disease with and without moderate to severe left ventricular dysfunction; b) new non-invasive indices of heart rate variability during recovery are correlated with the effects of parasympathetic reactivation on recovery of heart rate and QT interval. This study will provide important insight into the pathophysiologic link between diminished parasympathetic tone and the risk of sudden death. The results may support the use of specific indices of parasympathetic tone during exercise and/or recovery as prognostic markers rather than indices derived at rest.