Non-Invasive Assessment of the Autonomic Nervous System

Autonomic dysfunction is associated with worse outcome in many disease states. Invasive assessment is time consuming and rarely used in the clinical setting. However, autonomic data can also be derived non-invasively from beat to beat analysis of heart rate and blood pressure. Computer based software (power spectral analysis) permits real time analysis of heart rate variability in the frequency domain. This article explores the principles and practice of non-invasive autonomic function assessment and the consequences of changes in autonomic tone seen in disease states associated with increased cardiovascular disease morbidity and mortality.