HEART RATE VARIABILITY--ROLE AS A HEMODYNAMIC MODULATOR

心率连续变化以响应心脏的波动 自主活动。近年来，心率控制的异常 与多种病理生理状态有关。虽然 对这一领域的兴趣和实验增长迅速， 心率节律变化作为心率调节器的生理学作用 心血管血流动力学还没有得到严格的检查。至 整合心脏生理学和心脏调节学的学科 心室力学，系统地研究了 心率、心脏和血管功能的一过性变化 这是必要的。这类调查的结果将产生重大的新的 对心脏紊乱的常见病理生理学的洞察 心率控制和心功能。在此应用程序中，一个程序 以及在动物和人类身上进行的一系列实验 来解决这些问题。在实验的第一阶段，一个 已建立的研究脑室的方法学组合 功能和新的信号处理技术将用于急性和 慢性动物模型。将建立一组参数，这些参数 描述：)心率逐次变化对 心室前负荷、后负荷和收缩能力的独立测量 在不同的生理条件下，以及2)结果如何变化 在心输出量影响血压的变化。不由自主地 呼吸慢性模型，这项研究将扩大到包括 胸内压与容量关系的探讨 和心脏负荷状况，以及它们与呼吸的相互作用 窦性心律不齐。在实验的第二阶段， 研究人员将利用在急性外科手术和 自发地将慢性动物呼吸给正常人类，使用 已建立的无创超声心动图技术可以测量负荷- 独立的心室力学指标。在这些项目中获得的数据 最后的研究将被用来指导一系列 一种知之甚少的心脏病理生理学研究方案 临床新出现的重要群体--姑息性先天性心脏病患者 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.