Determinants of left ventricular shear strain
Peter H M Bovendeerd1, Wilco Kroon, Tammo Delhaas
1Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven 5600 MB, The Netherlands. p.h.m.bovendeerd@tue.nl
Summary
Accurately modeling cardiac mechanics requires accounting for myofiber crossover. This study shows transmural myofiber crossover is essential for realistic left ventricular (LV) mechanics simulations, improving predictions of cardiac deformation.
Area of Science:
- Cardiovascular mechanics
- Computational biology
- Biomedical engineering
Background:
- Mathematical models of cardiac mechanics aim to link abnormal heart deformation to pathology.
- Current models struggle to accurately predict wall shear strain, even in healthy hearts.
- Discrepancies are attributed to passive tissue behavior, active stress, or myofiber crossover.
Purpose of the Study:
- Investigate the sensitivity of midwall circumferential-radial shear strain (E(cr)) in left ventricular (LV) mechanics.
- Evaluate the impact of passive shear stiffness, cross-fiber active stress, and myofiber crossover on E(cr).
Main Methods:
- Utilized a finite-element model of LV mechanics.
- Simulated E(cr) and compared it to measurements from three healthy volunteers using magnetic resonance tagging (MRT).
- Assessed the influence of key parameters on simulated E(cr) time courses.
Main Results:
- Realistic E(cr) amplitude was achievable by adjusting passive stiffness, active stress, or myofiber crossover.
- A realistic E(cr) time course, including minimal change during isovolumetric contraction and correct base-to-apex gradient during ejection, required including transmural myofiber crossover.
- Simulated E(cr) was compared to MRT data from healthy volunteers.
Conclusions:
- Transmural myofiber crossover is crucial for accurate LV mechanics modeling.
- Accounting for myofiber crossover is essential for realistic simulations of cardiac deformation.
- Improved models can enhance the understanding of cardiac pathology through noninvasive imaging.
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