Many cardiac diseases are strongly correlated to cardiac dynamic mechanics and its functional parameters. Understanding the heart’s mechanics is crucial for clinical investigation, diagnosis and patient care. This paper presents a novel Point Distribution Model based approach to analyze the left ventricle motion, and defines a new parameter named movement extents of myocardium to describe the local motion. The algorithm discovers the motion path of key point in a cardiac cycle via spline interpolation, and then the results were used to estimate the velocity and acceleration of key point. By comparison, we find that the results closely fit the physical motion mechanism of the heart. Meanwhile, by comparing these parameters with those of adjacent area, the normal and pathological heart will be distinguished. More important is that the abnormal ones in early stage of disease can be tracked from complex deformation of the cardiac muscles.