Insight into the dicrotic notch in photoplethysmographic pulses from the finger tip of young adults

Abstract

This study aims to investigate arterial stiffness in selected young adults by non-invasively determining the characteristics of the photoplethysmographic dicrotic notch. A total of 15 volunteers participated in this study, divided into four groups by age and gender. Contour analysis was applied to analyse the photoplethysmographic dicrotic notch, including time-related and height-related parameters. The height of reflected wave, mirrored by the notch relative amplitude (NRA), was found to be significantly larger in the older group compared to the younger group (p = 0.016). The timing of the reflected wave, measured by three parameters, i.e. notch index (NI), notch latency (NL) and peak-to-notch latency (PTNL), significantly increased in the female group compared to the male group (all p < 0.02). The results confirm that arterial stiffness occurs in young adults, and demonstrate that a difference of arterial stiffness exists between young male and female. This study indicates that examining the characteristic notch of the PPG pulse could help in identifying differences of vascular activities.

Keywords:

• Photoplethysmography (PPG)
• Dicrotic notch
• Contour analysis
• Arterial stiffness

Acknowledgements

We thank Professor Shanbao Tong (Med-X Research Institute, Shanghai Jiao Tong University, China) for supporting this study; Dr. Vincent Azorin-Peris (Department of Electronic and Electrical Engineering, Loughborough University, UK) for his language suggestions; the anonymous reviewers for their valuable comments; and the editors for their editorial contributions.