Preface

The autonomic nervous system (ANS) plays a vital role not only for homeostasis of the organism but also for reaction rate and extent to stimuli. Thus, monitoring ANS is crucial for understanding disease progress. There are many methods for monitoring ANS, including heart rate variability (HRV), hormonal biomarkers (epinephrine, cortisol, norepinephrine), infrared digital pupillometry, salivary α-amylase, electrodermal activity recording, and functional nervous system imaging.

Every ANS marker is considered a complex reflection of the sympathetic parasympathetic system balance activation (autonomic outflow), neuroendocrine influences, and the ability of the human system network to respond to the former factors (autonomic responsiveness). They are probably more than an indicator for probable disturbances in the autonomous system. They can serve as a surrogate indexes both for the objective well-being (homeostasis and health status) and for subjective well-being (emotional and psychological health). Increasing data support in its use of ANS for monitoring for both somatic and psychological disorders and diseases. Moreover, newer studies provide us an insight into the physiology of consciousness and raise our understanding of several psychological and physiological processes, like neuroendocrine habituation or emotional regulation.

This book focuses on HRV, which refers to the interval between R waves in the electrocardiogram (i.e., variability in beat-by-beat heart period). The first section of the book is dedicated to technical themes related to both modes of monitoring and the variables recorded. The second section highlights special aspect use of heart rate variability HRV in relation to hypothermia. Finally, the third section of the book covers general aspects of its HRV application. Throughout the book, the authors offer us not only a "vigorous" review of the current literature but also a research road path for further advancement.

**II**

**Section 3**

System Monitoring

Special Focus **87**

**Chapter 6 89**

**Chapter 7 103**

**Chapter 8 113**

Heart Rate Variability as Biomarker for Prognostic of Metabolic Disease

*Benjamín López-Silva, Martha Lucía Ita-Amador and Julián Torres-Jácome*

The Role of Magnetic Resonance Imaging (MRI) in Autonomic Nervous

Evolution of Parasympathetic Modulation throughout the Life Cycle

*by Alondra Albarado-Ibañez, Rosa Elena Arroyo-Carmona, Daniela Alexandra Bernabé-Sánchez, Marissa Limón-Cantú,* 

*by Moacir Fernandes de Godoy and Michele Lima Gregório*

*by Yousif Mohamed Y. Abdallah and Nouf H. Abuhadi*

#### **Theodoros Aslanidis, MD, PhD**

Consultant/Researcher, Anaesthesiology - Critical Care, Pre-hospital Emergency Medicine, Intensive Care Unit, St. Paul General Hospital, Thessaloniki, Greece

**1**

Section 1

Technical Themes
