Our current ability to accurately measure ventricular global contractile behavior remains unsatisfactory due to the lack of quantitative diagnostic indexes that can assess the mechanical properties of myocardial tissue. The general objective of this project is to develop a better understanding of ventricular global mechanical properties in healthy intact hearts and in dysfunctional hearts. The current paper suggests a mathematical model that can estimate viscoelastic characteristics of the myocardium. Based on this hypothesis, a local injury and/or a global change adversely affect the viscoelastic characteristics of the myocardium and these changes are reflected in harmonic motions of the long axis (1-D) and the short axes (2-D) of LV during a cardiac cycle. This paper estimates the viscoelastic components of the long axis of left ventricle in sheep based on harmonic motion of the cardiac base toward the cardiac apex.