Mechanical stimuli for left ventricular growth during pressure overload

Area of Science:

• Cardiovascular Physiology
• Biomechanical Engineering
• Cardiac Remodeling

Background:

• The mechanical stimuli driving left ventricular (LV) growth during pressure overload remain unclear.
• Understanding these stimuli is crucial for addressing pathological cardiac remodeling.

Purpose of the Study:

• To investigate the correlation between local mechanical stimuli and ventricular growth after inducing pressure overload via aortic banding.
• To identify the specific mechanical factors (stress or stretch) responsible for LV hypertrophy.

Main Methods:

• Utilized a swine model of aortic banding, acquiring 3D echocardiography data at baseline and 2 weeks.
• Developed and calibrated patient-specific finite element (FE) models to simulate LV mechanics.
• Quantified local changes in myocardial stress and stretch in orthogonal directions and correlated them with changes in wall thickness.

Main Results:

• LV free-wall thickness increased, while septal thickness decreased post-banding.
• Strong correlations were found between LV growth and changes in maximum fiber stress (PCN=0.5471, SCN=0.5111) and mean sheet-normal stress (PCN=0.5266, SCN=0.5256).
• Myocardial stretches showed poor correlation with observed ventricular growth.

Conclusions:

• Fiber stress is identified as the key mechanical stimulus for left ventricular growth in pressure-overload conditions.
• These findings advance our understanding of the mechanisms underlying cardiac remodeling and hypertrophy.