Abstract: This research report presents a new 3D electromechanical model of the two cardiac ventricles designed both for the simulation of their electrical and mechanical activity, and for the quantitative analysis of time series of medical images. First, we present a method to build volumetric biomechanical models based on different information sources. Then the action potential propagation is simulated using FitzHugh-Nagumo reaction-diffusion equations. The myocardium contraction is modelled through a rheologic law including an electromechanical coupling. Simulation of a cardiac cycle, with boundary conditions representing blood pressure and volume constraints, leads to the correct estimation of global and local parameters of the cardiac function. This model enables the introduction of pathologies and the simulation of electrophysiology interventions. Then a new pro-active deformable model of the heart is introduced to track the two ventricles in time series of cardiac images. Preliminary results indicate that this pro-active model, which integrates a priori knowledge on the cardiac anatomy and on its dynamical behaviour, can improve the accuracy and robustness of the extraction of functional parameters from cardiac images even in the presence of noisy or sparse data. Such a model also allows the simulation of cardiovascular pathologies in order to test therapy strategies and to plan interventions.