HEART-RATE-VARIABILITY IN INTENSIVE-CARE

Clinicians have long been aware that the normal oscillations in a hear t beat are lost during fetal distress, during the early stages of hear t failure, with advanced aging, and with critical illness and injury H owever, these oscillations, or variability in heart rate and other car diovascular signals, have largely been ignored or discounted as varian ces from the mean or avenge values. It is becoming increasingly clear that these oscillations reflect the dynamic interactions of many physi ologic processes, including neuroautonomic regulation of heart rate an d blood pressure. We present a synthesis and review of the current lit erature concerning heart rate variability with special reference to in tensive care. This article describes the background of time series ana lysis of heart rate variability including time and frequency domain an d nonlinear measurements. The implications and potential for time seri es analysis of variability in cardiovascular signals in clinical diagn osis and management of critically ill and injured patients are discuss ed.