An Investigation of the Relationship between Heart Rate Variability and Pulse Transit Time under Cold Stimulus

Abstract

Heart rate variability (HRV) is an important quantitative index to investigate the autonomic dysfunction, and pulse transit time (PTT) is a non-invasive measurement to estimate the blood pressure. However, the relationships of HRV to PTT have not been well depicted. In the present study, 55 adult subjects were specified to complete the experiment with cold stimulus in laboratory. The electrocardiogram (ECG) and photoplethysmographic (PPG) signals were simultaneously measured before and during the cold stimulus. Then the peaks of R wave in ECG and the feet of PPG waveform were detected to calculate the HRV and PTT, and in the meantime the changes of mean HRV and PTT (ΔHRV and ΔPTT) caused by cold stimulus were examined to investigate the correlations between HRV and PTT by the correlation analysis and regression method. The results indicate the change trends of HRV and PTT were the same in the case of cold stimulus, and ΔHRV showed positive correlation with ΔPTT (r=0.57, p=0.0002). This study might be helpful to understand the relationship among regulatory mechanisms of different cardiovascular risk factors.