Sternal pulse rate variability compared with heart rate variability on healthy subjects

Area of Science:

• Physiology
• Biomedical Engineering
• Cardiovascular Research

Background:

• Heart rate variability (HRV) quantifies autonomic nervous system modulation using electrocardiograms (ECG).
• Photo-plethysmography (PPG) is an emerging non-invasive technology for assessing autonomic tone.
• Investigating PPG-based pulse rate variability (PRV) as an alternative to HRV is crucial for accessible cardiovascular monitoring.

Purpose of the Study:

• To evaluate the feasibility of deriving PRV from PPG signals recorded on the sternum.
• To compare PRV metrics with traditional HRV parameters.
• To assess the agreement between PRV and HRV under resting and forced respiration conditions.

Main Methods:

• Reflectance PPG sensors were used to record signals from the sternum of 9 healthy subjects.
• HRV and PRV parameters (meanNN, SDNN, RMSSD, pNN50, LF/HF ratio) were calculated from R-R and P-P intervals.
• Pearson correlation and Bland-Altman analysis were employed for comparison.

Main Results:

• All calculated HRV and PRV parameters showed significant correlations (r > 0.95, p < 0.001).
• Bland-Altman analysis indicated close agreement between sternal PPG-derived PRV and ECG-derived HRV.
• These findings held true for both resting and forced respiration conditions.

Conclusions:

• Pulse rate variability (PRV) derived from sternal PPG is a feasible and accurate alternative to HRV analysis.
• This non-invasive method offers a promising approach for monitoring autonomic function in healthy individuals.
• Sternal PPG presents a practical option for widespread cardiovascular health assessment.