We describe an approach that we propose to model the electromechanical 
behavior of the heart, and to use the model in a data assimilation 
procedure in order to perform an identification of the parameters and 
state, based on image (MRI or ultrasound) measurements in particular. 
This procedure is intended to give access to quantities of interest for 
diagnosis purposes on individual patients. We report on numerical 
simulations and on validations of our approach.