The invention relates to an electrocardiographic imaging system (100) for providing electrocardiographic image data indicative of an electrical activity map of a heart (101) suitable for real time applications, and that comprises an ultrasound imaging unit (102) for generating a three dimensional cardiac anatomical model, an electrocardiographic sensing unit (108) comprising a set of between three and twenty electrocardiographic electrodes (110) for providing body surface signals indicative of an electrical activity of the heart, a camera unit (114) for determining positions of the electrocardiographic electrodes , a transducer position determination unit (116), for determining a position of the ultrasound transducer, a torso-heart geometry determination unit (118) for determining a position and orientation of the three dimensional shape of the heart within a predetermined three dimensional coordinate space and an electrical activity determination unit (120) for generating an electrical activity map of the heart, suitable for real time applications.