Adaptation of passive rat left ventricle in diastolic dysfunction

This article deals with providing a theoretical explanation for quantitativ e changes in the geometry, the opening angle and the deformation parameters of the rat ventricular wall during adaptation of the passive left ventricl e in diastolic dysfunction. A large deformation theory is applied to analys e transmural stress and strain distribution in the left ventricular wall co nsidering it to be made of homogeneous, incompressible, transversely isotro pic, non-linear elastic material. The basic assumptions made for computing stress distributions are that the average circumferential stress and strain for the adaptive ventricle is equal to the average circumferential stress and strain in the normotensive ventricle, respectively. All the relevant parameters, such as opening angle, twist per unit length, axial extension, internal and external radii and others, in the stress-free , unloaded and loaded states of normotensive, hypertensive and adaptive lef t ventricle are determined. The circumferential stress and strain distribut ion through the ventricular wall are also computed. Our analysis predicts t hat during adaptation, wall thickness and wall mass of the ventricle increa se. These results are consistent with experimental findings and are the ind ications of initiation of congestive heart failure. (C) 1999 Academic Press .