Cardiac contraction originates at a subcellular – molecular, indeed – scale, within specific components of the cardiomyocytes (i.e. cardiac cells) called sarcomeres. This contractile behaviour then needs to be integrated at the organ level, namely, with a specific structure and shape. Furthermore, this organ crucially interacts with other physiological systems, the first of which being blood circulation via the cardiac function itself, and also the nervous system that controls the heart via various regulation mechanisms, and these interactions must be adequately represented in order to obtain accurate and predictive model simulations. This presentation will provide an overview of the recent advances on cardiac modeling achieved in the M3DISIM group, with a particular focus on the key multiscale, multi-physics and integrated system modeling aspects that need to be addressed, with many associated challenges pertaining to numerical methods and model validation, in particular.