Analysis of Heart Rate Variability Linked with Autonomic Nervous System

The electrocardiogram (ECG) is a time-varying signal reflecting the ionic current flow which causes the cardiac fibres to contract and subsequently relax. The mammalian brain guides the body by regulating heart and other organs through autonomic nervous system. This physiological variation of heart rate, supervised by autonomic nervous system, is called Heart Rate Variability (also commonly known as HRV). The heart rate can be estimated from ECG and it has the greater significance in risk stratification in cardiovascular system. HRV can be analyzed by time domain, frequency domain and nonlinear methods. HRV can be used as a template to investigate the sympathetic and parasympathetic function of the ANS. The modulation of LF/HF ratio in frequency domain, short term and long term variability in nonlinear method constitute a novel technique to determine the status of human body.