HEART RATE VARIABILITY--ROLE AS A HEMODYNAMIC MODULATOR

心率持续变化，以响应心脏的波动。 自主活动 近年来，心率控制异常 与多种病理生理状态有关。 虽然 对这一领域的兴趣和实验迅速增长， 心率逐搏变化的生理作用， 心血管血流动力学尚未得到严格的检验。 到 整合调节心脏生理学的学科， 心室力学，系统研究 心率、心室和血管功能的短暂变化， 必要 这些调查的结果将产生重大的新成果， 对心脏疾病的常见病理生理学的见解 心率控制和心室功能。 在本申请中， 的训练和一系列的实验动物和人类提出 来解决这些问题。 在实验的第一阶段， 结合已建立的心室研究方法， 功能和新的信号处理技术将用于急性和 慢性动物模型。 将建立一套参数， 描述：）心率逐搏变化对 心室前负荷、后负荷和收缩力的独立测量 在各种生理条件下，以及2）结果如何变化 影响血压的变化。 自发性 呼吸慢性模型，这项研究将扩大到包括一个 胸内压与容积关系的检查 和心室负荷条件，以及它们与呼吸的相互作用， 窦性心律失常。 在实验的第二阶段， 研究者将利用在急性手术和 自发呼吸慢性动物正常人，使用 建立了无创超声心动图技术来测量负荷- 心室力学的独立指标。 在这些数据中获得的 最后的研究将用于指导一系列的发展， 研究心脏病理生理学的协议， 一组新出现的临床重要性-姑息性先天性 心脏病

Heart rate varies continuously in response to fluctuations of cardiac autonomic activity. In recent years, abnormalities of heart rate control have been associated with a variety of pathophysiologic states. Although interest and experimentation in this field have grown rapidly, the physiologic role of beat-to-beat changes in heart rate as a modulator of cardiovascular hemodynamics has not been critically examined. To integrate the disciplines of regulatory cardiac physiology and ventricular mechanics, systematic investigation of the relations between transient changes in heart rate and ventricular and vascular function is necessary. The results of such investigations will yield significant new insights into the often-associated pathophysiology of disordered heart rate control and ventricular function. In this application, a program of training and a series of experiments in animals and humans is proposed to address these questions. In the first phase of experimentation, a combination of established methodologies for the study of ventricular function and novel signal processing techniques will be used in acute and chronic animal models. A set of parameters will be established which describe:) the effect of beat-to-beat changes in heart rate on independent measures of ventricular preload, afterload and contractility under a variety of physiologic conditions, and 2) how resultant changes in cardiac output effect changes in blood pressure. In spontaneously breathing chronic models, this study will be extended to include an examination of the relations between intrathoracic pressure and volume and ventricular loading conditions, and their interplay with respiratory sinus arrhythmia. In the second phase of experimentation, the investigator will utilize the results obtained in acute surgical and spontaneously breathing chronic animals to normal humans, using established noninvasive echocardiographic techniques to measure load- independent indices of ventricular mechanics. Data obtained in these final studies will be used to guide to the development of a series of protocols for the study of cardiac pathophysiology in a poorly-understood group of emerging clinical importance-patients with palliated congenital heart disease.