Electromechanical mapping with MRI tagging and epicardial sock electrodes.

Methods currently exist for the precise measurement of local three-dimensional myocardial motion noninvasivly with magnetic resonace imaging tagging. From these motion estimates, strain images representing the local deformation of the myocardium can be formed to show local myocardial contraction. These images clearly show the sequence of mechanical events during the activation and relaxation of the heart, making them ideal to visualize abnormalities caused by asynchronous electrical activation or ischemia. Coupled with the near simultaneous mapping of electrical depolarization with a sock electrode array, we can investigate the relationship between electical activity and mechanical function on a local level in the in vivo heart. Registered fiber angle maps can be also be obtained in the same heart with diffusion magnetic resonance imaging to assist in the construction of the electromechanical model of the whole heart.