| dc.description.abstract | Heart-rate variability (HRV) is a popular issue which has been widely discussed in academic heart studies. In the HRV, the changes of heart-rate information is continuously analyzed. Current HRV measurements analyze R-R intervals of electrocardiogram (ECG) and calculate the spectral density of very low-frequency, low-frequency, and high-frequency bands for estimating the sympathetic/parasympathetic activities. Indicators, such as RMSSD, SDNN, and SDANN, are proposed as indexes for risk factor estimations. Though ECG-based HRV has been widely studied, however, the ECG measurement requires the electrodes to be contacted on both hands which causes inconveniency and is not suitable to be designed for continuous measurement using wearable devices. Accordingly, in our study, we intend to test the feasibility of using photoplethysmogram (PPG) to replace ECG in HRV measurement. Both ECG and PPG signals were measured simultaneously and compared. The ratio between HRV low-frequency and high-frequency components (LF/HF) in each subject was calculated and compared with the value of ECG LF/HF. We found there was a high linear correlation between PPG and ECG -based HRV which demonstes its feasibitliy of replacing ECG by PPG. In addition, in our stud, the feasibility of time-domain parameter SDNN/RMSSD was also calculated for HRV study. | en_US |