BIAXIAL MECHANICAL-PROPERTIES OF PASSIVE RIGHT-VENTRICULAR FREE WALL MYOCARDIUM

The biaxial mechanical properties of right ventricular free wall (RVFW ) myocardium were studied. Tissue specimens were obtained from the sub -epicardium of potassium-arrested hearts and different stretch protoco ls were used to characterize the myocardium's mechanical response. To assess regional differences, we excised tissue specimens from the conu s and sinus regions. The RVFW myocardium was found to be consistently anisotropic, with a greater stiffness along the preferred (or averaged ) fiber direction. The anisotropy in the conus region was more pronoun ced than in the sinus region. A comparison with studies of left ventri cle (LV) midwall myocardium revealed that, 1) the fiber direction stif fnesses are greater in the RVFW than in the LV, 2) the degree of aniso tropy is greater in the RVFW than in the LV.