Methods for the precise measurement of three dimensional myocardial motion non-invasivley with MRI have recently been developed. These methods use a technique called "presaturation tagging" to mark the myocardium, and rapid MRI to track the motion of these markers. A unique capability of this method is the production of strain images representing the local deformation of the myocardium. These images clearly show the sequence of events during the activation of the heart, and can demonstrate abnormalities caused by asynchronous electrical activation or ischemia. Coupled with the near simultaneous mapping of electrical depolarization with an epicardial sock array, we can investigate the relationship between electical activity and mechanical function on a local level. Registered fiber angle maps can be obtained in the same heart with diffusion MRI to assist in the construction of the mechanoelectrical model of the whole heart.