Estimation of Regional Cardiac Wall Stress From Biplane Coronary Cineangiograms

The regional changes of cardiac wall deformation and the wall stress are important for evaluation of the myocardial functions. However, their application for clinical diagnosis has been limited, because it is difficult to measure these regional myocardial parameters in the intact heart. Meier et a1. (1980) and Walley et a1. (1982) used the radiographic images of the implanted radiopaque markers in the beating heart to estimate the local twist and segmental shortening of small epicardial segment. After elimination of the effects of the timevarying displacements of the overall cardiac motion using kinematic approaches, the local deformation was represented by the regional rotation tensor and the muscle wall stretch tensor. Also , the changes of wall thickness could be computed from the stretch tensor under the assumption of the isochoric deformation