Speckle-Tracking Echocardiography Enables Model-Based Identification of Regional Stiffness Indices in the Left Ventricular Myocardium.

Introduction: Left ventricular (LV) remodeling is a critical process underlying heart failure (HF) development and progression. While LV global longitudinal strain determined by speckle-tracking echocardiography (STE) provides a promising basis to monitor LV remodeling, reported strain measures are limited by the masking of regional differences and a dependency on hemodynamic load.

Objectives: Our goal is to extend two-dimensional STE to enhance regional mechanical assessment of the LV myocardium-providing clinically accessible and load-independent response variables that directly reflect the LV remodeling process.

Methods: An inverse finite element analysis was employed with a pattern search optimization algorithm to identify regional indices of LV myocardial stiffness based on STE-derived regional LV longitudinal strains and wall geometries. Our framework was applied in two distinct porcine models of early LV remodeling, specifically following myocardial infarction and onset of LV pressure overload.

Results: Regional and temporal changes in computed indices of LV myocardial stiffness over diastolic pressures correlate with conventional indices of LV remodeling and show enhanced early sensitivity as compared to LV global longitudinal strain.

Conclusion: Our findings suggest that STE-integrated computational modeling can be used to track indices of LV myocardial stiffness and, thus, is a potential tool for HF diagnosis and prognosis.