Modelling passive diastolic mechanics with quantitative MRI of cardiac structure and function

Area of Science:

• Cardiovascular Physiology
• Biomedical Engineering
• Medical Imaging Analysis

Background:

• Diastolic heart failure, common in patients with normal systolic function, is characterized by impaired passive left ventricular (LV) mechanics.
• LV remodeling alters geometry and loading conditions, impacting passive ventricular function.
• Understanding passive mechanics is crucial for diagnosing and treating diastolic heart failure.

Purpose of the Study:

• To develop and validate a finite element (FE) model of the left ventricle (LV) to analyze passive diastolic mechanics.
• To estimate myocardial stiffness in the LV using in vivo and ex vivo imaging data.
• To improve the understanding of the structural basis of mechanical dysfunction in diastolic heart failure.

Main Methods:

• A LV finite element (FE) model was created using tagged MRI for geometry and diffusion tensor MRI (DTMRI) for myofiber orientation.
• Myofiber orientations were mapped to the FE model using host mesh fitting.
• Diastolic LV deformation was simulated using synchronized pressure recordings as loading constraints.

Main Results:

• The FE model successfully simulated diastolic LV mechanics.
• Myocardial stiffness was estimated from kinematic data derived from tagged MRI.
• The study provides a method for individualized physiological modeling of LV mechanics.

Conclusions:

• Integrated physiological modeling enhances insights into LV mechanics on an individual basis.
• This approach improves understanding of the structural basis of mechanical dysfunction in pathological conditions like diastolic heart failure.
• The developed model aids in evaluating passive ventricular mechanics and myocardial stiffness.