Stress relaxation behavior of left ventricular myocardium in mice.

Myocardial tissue viscoelasticity is an important behavior contributing to both diastolic and systolic cardiac function, which remains understudied, especially in case of structural heart diseases associated with impaired relaxation in the LV. Our study suggests that stress relaxation behavior is prominent in the LV myocardium and may exhibit different relaxation behavior depending on strain magnitudes and strain ratios along different directions. The level of anisotropy in stress relaxation was found to be similar to the level of anisotropy in the tissue quasi-static behavior. These results serve to motivate further studies to fully characterize the viscoelastic behavior of LV myocardium and its contribution to the LV relaxation and filling in murine models of LV diseases.