Impact of Simulated Vascular Aging and Heart Rate on Myocardial Efficiency: A Tale of Two Paradigms from In Silico Modelling

Introduction: Vascular aging is associated with a loss of aortic compliance (C<sub>A</sub>), which results in increased left ventricular pressure–volume area (PVA), stroke work (SW) and myocardial oxygen consumption (MVO<sub>2</sub>). Myocardial efficiency (MyoEff) is derived...

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Bibliographic Details
Main Authors: Lawrence J. Mulligan, Julian Thrash, Ludmil Mitrev, Daniel Ewert, Jeffrey C. Hill
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Journal of Cardiovascular Development and Disease
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Online Access:https://www.mdpi.com/2308-3425/12/5/163
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Summary:Introduction: Vascular aging is associated with a loss of aortic compliance (C<sub>A</sub>), which results in increased left ventricular pressure–volume area (PVA), stroke work (SW) and myocardial oxygen consumption (MVO<sub>2</sub>). Myocardial efficiency (MyoEff) is derived from the PVA and MVO<sub>2</sub> construct, which includes potential energy (PE). However, the SW/MVO<sub>2</sub> ratio does not include PE and provides a more accurate physiologic measure. Methods: We used a modified computational model (CM) to assess PVA and SW and calculate MVO<sub>2</sub> using a pressure-work index (e MVO<sub>2</sub>), to derive MyoEff–PVA and MyoEff–SW metrics. Phase I evaluated five levels of human C<sub>A</sub> from normal (N) to stiff (S) at 80 bpm, and Phase II evaluated two levels of C<sub>A</sub> (N and S) at three heart rates (60, 100, and 140 bpm). Results: During Phase I, MyoEff–PVA increased from 20.7 to 31.2%, and MyoEff–SW increased from 14.8 to 18.9%. In Phase II, during the N setting coupled with increases in the heart rate, the MyoEff–PVA decreased from 29.4 to 14.8 to 9.5%; the MyoEff–SW also decreased from 22.5 to 10.3 to 5.9%. As expected, during the S setting, MyoEff–PVA decreased from 45.5 to 22.9 to 14.8; a similar effect occurred with the MyoEff–SW, demonstrating a decrease from 29.9 to 13.9 to 7.9%, respectively. Conclusions: The CM provided insights into a simple and clinically relevant calculation for assessing MyoEff. The agreement on the CM metrics aligns with studies conducted previously in the clinical setting.
ISSN:2308-3425