Journal of Bioengineering & Biomedical Science

Orthostatic Stress Induced Changes in Heart Rate Variability, Pulse Transit Time and QRS Duration

Abstract

Zaidi SN and Collins SM

Studies have shown the application of non-invasive cardiovascular parameters like heart rate variability (HRV), pulse transit time (PTT) and QRS duration. However no information is available about effects of orthostatic stress on these parameters. Our objective was to study the changes in HRV, PTT and QRS duration caused by orthostatic stress. Electrocardiogram (ECG) and photoplethysmogram (PPG) data was collected from 22 subjects in supine and upright positions. Comparison of parameters in supine and upright positions revealed that every parameter was effected by orthostatic stress. High frequency power of HRV showed the largest response (75%), while QRS duration had the smallest response of (7%). We found that gender played a significant role in PTT, R-R interval and QRS duration values, with male subjects showing higher values of all three parameters. Subject height also played a distinguishing role, with taller subjects showing higher values of R-R interval and PTT. The results allow us to better understand the interaction between various parameters and how they reflect the hemodynamic changes caused by orthostatic stress.