The pre-ejection period is a highly stress dependent parameter of paramount importance for pulse-wave-velocity based applications

Abstract

PurposeThe pulse-wave-velocity, is used for indirect, cuff-less, continuous blood pressure estimation. It is commonly detected by measuring the time delay between a defined point in an ECG and the arrival of the peripheral pulse wave (e.g., oxygen saturation sensor). The period between electrical stimulation of the heart (ECG) and actual blood ejection from the heart is called the pre-ejection period (PEP). This study aims at characterizing the PEP under mental and physical stress with focus on its relations to other cardiovascular parameters such as heart rate and importance for blood pressure (BP) estimation.MethodsWe measured the PEP in 71 young adults at rest, under mental (TSST) and physical stress (ergometer) via impedance-cardiography.ResultsThe PEP is highly dependent on mental and physical load. It is strongly correlated with indicators of sympathetic strain (p < 0.001). At rest (mean 104.5 ms), the PEP shows a high interindividual variability but small intraindividual variability. Mental stress decreases the PEP by 16% (mean 90.0 ms) while physical stress halves PEP (mean 53.9 ms). The PEP does correlate differently with heart rate under differing circumstances (rest: R2 0.06, mental stress: R2 0.29, physical stress: R2 0.65). Subsequently, using PEP and heart rate enables the discrimination of rest, mental and physical strain with a positive predictive value of 93%.ConclusionThe PEP is a cardiovascular parameter with large interindividual variability at rest and subject-depended dynamic under load which is of great importance for ECG-based pulse-wave-velocity (PWV) determination. Considering its variability and large impact on the pulse arrival time, PEP is a crucial factor in PWV based BP estimation.

Intraoperative Beat-to-Beat Pulse Transit Time (PTT) Monitoring via Non-Invasive Piezoelectric/Piezocapacitive Peripheral Sensors Can Predict Changes in Invasively Acquired Blood Pressure in High-Risk Surgical Patients

“…However, the use of PTT as a surrogate BP marker may be complicated by the PEP component, as PEP is strongly influenced by mechanical and electrical cardiac factors, which may negate BP correlations [ 23 ]. Additionally, PEP is highly inter-individual dependent and is strongly influenced by sympathetic tone during mental stress, which may have implications when used in a general perioperative setting [ 24 ]. Previous work by Finnegan et al found that during vasoactive administration, PTT showed greater correlations with BP than PAT [ 18 ], a finding highly relevant to the use of PTT in the perioperative setting, where the use of vasoactive medications is quite common.…”

“…All three signals indicate distinct characteristics of the PW. PEP is strongly influenced by sympathetic tone [ 24 ], and the use of PEP may have altered the correlation results presented here. For the purpose of this proof-of-concept study, we chose to use the R-wave of the ECG as a starting point.…”

Bridging the gap: The dichotomy between measurement and reality in physiological research

“…The spectrum of physiological models is vast: ranging from proteomics 1 to animal models 2 and extending into the realm of laboratory 3 and applied human physiology. 4 They assist in deconstructing complex biological phenomena into constituent parts.…”

“…This, in consequence, enables motivated and bright scientists to devise pragmatic methods of seeking answers to these unresolved mysteries. The spectrum of physiological models is vast: ranging from proteomics 1 to animal models 2 and extending into the realm of laboratory 3 and applied human physiology 4 . They assist in deconstructing complex biological phenomena into constituent parts.…”

Relativistic aspects of physiology: Expanding our understanding of conventional control loops

“…Extremes in temperature, variations in gravity, physical exertion, organ system pathologies, or psychological stressors change what our regulatory systems consider as normal 6,7 . These circumstances necessitate adaptations in our physiology, which can be temporary, lead to a new hemostatic balance, or progressively alter and possibly harm our long‐term functionality 8,9 …”