HEART RATE VARIABILITY VIRTUAL SENSOR APPLICATION IN BLOOD PRESSURE ASSESSMENT SYSTEM

摘要

In order to obtain information about a person's cardiovascular condition, the estimation of heart rate variability (HRV), a parameter that provides detailed knowledge on hemodynamics and autonomic regulation, represents an important challenge. The usual form of measure HRV is based on beat-to-beat time interval extracted from the electrocardiogram (ECG) and analysed by different methods. Other biological signals can be also used for an accurate HRV estimation. In the present work the HRV estimation system uses photoplethysmography (PPG) to acquire the finger pulse waveform, and maintains the cuff pressure approximately constant, near the mean arterial pressure, to capture the blood pressure (BP) oscillations. Since BP and pulse transit time (PTT) variabilities are correlated, the ECG and PPG signals were used to calculate the pulse transit time and thus estimate BP variability. The three available independent estimations of HRV were tested with a group of healthy subjects, confirming the correspondence between the methods. The PTT variations and its dispersion were also computed.