The effects of pre-ejection period on post-exercise systolic blood pressure estimation using the pulse arrival time technique

Pulse arrival time (PAT) is comprised of the vascular transit time (TT) through the arterial system and the pre-ejection period (PEP) in the heart. It has been used to predict arterial blood pressure (BP) without using a cuff. The aim of this study was to investigate the effects of including the PEP on the accuracy of cuffless systolic BP (SBP) estimation using the PAT technique in post-exercise recovery. Experiments were conducted on 22 normotensive participants. PAT, TT and PEP were determined from simultaneous measurements of the electrocardiogram, photoplethysmogram and impedance cardiogram. Moderate exercise induced significant (p < 0.05) increases in SBP and heart rate and significant (p < 0.05) decreases in PEP and PAT. Diastolic blood pressure and TT only varied insignificantly (p > 0.05). SBP was moderately correlated with PEP (r = -0.61) and PAT (r = -0.81). PAT and PEP were moderately correlated (r = 0.67). When SBP was estimated using least-squares methods, the differences between the measured and predicted SBP using PEP, PAT and TT were 0.0 ± 6.6, 0.0 ± 4.9 and 0.0 ± 9.3 mmHg, respectively. The findings suggested that PAT gives the best SBP prediction and PEP has some potential to predict blood pressure. The inclusion of PEP in the PAT measurement is necessary to facilitate accurate cuffless blood pressure prediction after exercise.