HEART RATE RECOVERY AND CARDIAC REHABILITATION

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。以运动为基础的心脏康复已被证明可以降低冠状动脉疾病患者的死亡率和随后的心脏事件。尽管运动降低死亡率的确切机制尚不清楚，但有一种假说援引了运动对自主神经张力的影响。最近，运动后立即心率恢复（定义为心率从运动峰值下降到恢复后一分钟）被证明是全因死亡率的有力预测指标。低于每分钟12次的心率与死亡风险显著增加有关。心率恢复是评估自主神经张力的一个容易测量的参数。虽然运动训练已被证明可以改变交感迷走神经对心率的控制，从而增加副交感神经张力，但之前没有对心脏康复对心率恢复的影响进行评估。本研究旨在前瞻性评价心脏康复对冠心病患者随访运动试验心率恢复的影响。本研究还旨在评估运动试验中使用副交感神经阻滞所观察到的这些患者心率恢复变化的机制。如果在有组织的运动训练计划后心率恢复确实有所改善，那么这个参数可能是有用的，作为门诊心脏康复机构的结果测量指标，也许有助于识别后续心脏事件风险增加的患者。

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. Exercise-based cardiac rehabilitation has been shown to reduce mortality and subsequent cardiac events in patients with coronary artery disease. Although the exact mechanism by which exercise reduces mortality is unclear, one hypothesis invokes the effect of exercise on autonomic tone. Recently, heart rate recovery immediately after exercise (defined as the decrease in heart rate from peak exercise to one minute into recovery) was shown to be a powerful predictor of all cause mortality. Values below twelve beats per minute were associated with a marked increase in the risk of death. Heart rate recovery is an easily measured parameter to assess autonomic tone. Although exercise training has been shown to modify the sympathovagal control of heart rate towards an increase in parasympathetic tone, no evaluation of the effect of cardiac rehabilitation on heart rate recovery has been demonstrated previously. This study aims to prospectively evaluate the effect of cardiac rehabilitation on heart rate recovery on follow-up exercise testing in patients with coronary artery disease. It also aims to evaluate the mechanism for the observed change in heart rate recovery in these patients by using parasympathetic blockade during the exercise test. If heart rate recovery does improve following a structured exercise training program, then this parameter may be useful as an outcome measure in an outpatient cardiac rehabilitation facility, and perhaps help to identify patients with increased risk for subsequent cardiac events.