A low-order model for left ventricle dynamics throughout the cardiac cycle

Area of Science:

• Cardiovascular Physiology
• Computational Biology
• Biomedical Engineering

Background:

• The left ventricle (LV) is crucial for pumping blood, and its mechanical function is complex, involving myocardial contractility, preload, and afterload.
• Understanding these dynamics is vital for diagnosing and treating heart conditions.

Purpose of the Study:

• To develop and validate a theoretical model simulating LV dynamics across the cardiac cycle.
• To investigate the impact of myocardial properties and loading conditions on ventricular performance.

Main Methods:

• A cylindrical model of the ventricle with helical muscle fibers and non-linear material properties was developed.
• A system of differential algebraic equations was solved numerically to simulate cardiac cycle dynamics.
• The model incorporates interactions between contractility, pressure generation, preload, and afterload.

Main Results:

• The model accurately predicts time-dependent torsional, circumferential, and longitudinal strains in the LV, consistent with experimental data.
• Simulations demonstrate the influence of myocardial contractility, fiber orientation, stiffness, atrial pressure, and peripheral resistance on stroke work and ejection fraction.
• The model illustrates diastolic suction and its role in ventricular filling.

Conclusions:

• The developed theoretical model provides a robust simulation of left ventricular dynamics.
• This computational approach allows for rapid, faster-than-real-time simulations.
• The model holds potential for on-line, patient-specific assessment of ventricular performance using clinical data.