Interest in left ventricular (LV) mechanics has recently focused on detailed 3D analysis of LV deformations. Our goal is to investigate transmural strain variability within the normal ventricle and during the early stages of ischemia using sonomicrometric crystals implanted into canine LV wall. In this study 3 open chest dog models were implanted in a two-tetrahedron configuration with three crystals on the epicardial surface, three on the endocardial surface and one in the LV midwall. Our algorithm numerically reconstructs local ventricular 3D geometry and mechanics including radial, longitudinal and circumferential strain. Along with EKG, pressure-volume signals were acquired using a catheter introduced to LV from the femoral artery. Results obtained clearly illustrate a difference in strain across the myocardium. This study shows that the method can disclose important information regarding transmural variability in animal model and further investigation with different pacing and conditions could enhance understating of LV Mechanics.