The Assessment of Autonomic Influences on the Heart Using Impedance Cardiography and Heart Rate Variability

Abstract

The autonomic nervous system (ANS) is critically important in both physiological and psychological health and well-being. However, the noninvasive assessment of the ANS is not trivial and requires special care. The advent of modern, turnkey systems for the measurement of impedance cardiography and heart rate variability (HRV) has greatly enhanced our ability to capture indices of ANS function but has also opened the field up to less than fully informed use of these measures. It is now currently possible to measure both central and peripheral cardiovascular functions in an ambulatory setting. This has expanded the opportunities as well as the challenges associated with ANS measurement. The present chapter seeks to briefly summarize major aspects of the assessment of ANS function using impedance cardiography and HRV.We start with an overview of the ANS and one of its most important aspects, the baroreflex. We then describe the use of impedance cardiography with special care taken to highlight important findings since the publication of the Society for Psychophysiological Research guidelines.We next describe the assessment of HRV and again hope to highlight important research since the publication of several seminal guideline papers. It is hoped that this chapter will provide a ready resource for researchers and others interested in the noninvasive assessment of the autonomic nervous system in health and disease.