A fast computational model for circulatory dynamics: effects of left ventricle-aorta coupling

Area of Science:

• Cardiovascular physiology
• Biomedical engineering
• Computational modeling

Background:

• Interactions between the left ventricle (LV) and vasculature influence cardiovascular diseases like hypertension and heart failure.
• Understanding these complex interactions is crucial for developing effective treatments.

Purpose of the Study:

• To develop a computationally efficient, biophysically based mathematical model of the circulatory system.
• To investigate the effects of aging-related aortic changes on LV function and mechanics.
• To examine the combined impact of aortic aging and reduced LV contractility in heart failure.

Main Methods:

• A four-chamber cardiac model incorporating LV torsion and wall motion, coupled with aortic wave propagation and lumped-parameter circulation models.
• Model parameters were fitted to experimental data for normal heart and aorta.
• Simulations were performed to assess changes in aortic properties (compliance, taper) and their effects on LV pressure-volume loops, fiber stress, and sarcomere shortening.

Main Results:

• Aging-induced changes in aortic compliance and taper alter pulse wave reflections, impacting LV pressure-volume loops and mechanics.
• In a failing heart model, aortic aging affects stroke volume and sarcomere shortening without significantly increasing aortic pressure.
• The reflected pressure wave plays an increasingly significant role in overall aortic pressure in aging and failing hearts.

Conclusions:

• The developed model provides a valuable tool for studying cardiovascular mechanics and the impact of aging on heart function.
• Aortic stiffening and altered wave reflections significantly influence LV performance, particularly in the context of heart failure.
• Computational modeling can elucidate complex cardiovascular dynamics and predict disease progression.