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

点击翻译按钮获取中文摘要

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 studies 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 noninvasive 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.