Left ventricular finite element model bounded by a systemic circulation model

Area of Science:

• Computational Biology
• Cardiovascular Physiology
• Biomedical Engineering

Background:

• Finite element (FE) models of the left ventricle (LV) require realistic boundary conditions.
• Existing LV models lack integrated circulatory system dynamics for comprehensive analysis.

Purpose of the Study:

• To develop and couple a circulatory system model with existing FE models of the LV.
• To investigate the impact of varying hypertension levels on LV stress and circulatory workload.

Main Methods:

• Developed a closed-loop circulatory model (systemic arterial, capillary, venous) integrated with a JSim-based LV FE model.
• Created three coupled models: normal, mild hypertension (137/89 mm Hg), and moderate hypertension (165/100 mm Hg).
• Optimized circulation to LV end-diastolic parameters and LV models to circulatory steady-state characteristics.

Main Results:

• Mild hypertension increased average LV fiber stress by 21%; moderate hypertension increased it by 36%.
• Circulatory work increased by 18% for mild hypertension and 43% for moderate hypertension compared to normal conditions.
• Coupled modeling provided realistic boundary conditions, enabling accurate stress and workload predictions.

Conclusions:

• Hypertension significantly elevates mechanical stress and workload within the left ventricle.
• The coupled FE and circulatory models offer a robust platform for studying cardiovascular disease mechanics.
• These findings highlight the detrimental effects of elevated blood pressure on cardiac performance.