1. A method of motion compensation for cardiac imaging of a patient, comprising the steps of: a. obtaining a pre-operative volumetric image dataset of a cardiac target site for the patient; b. obtaining an intra-operative image of the target site; c. performing a registration of the pre-operative volumetric dataset with the intra-operative image; d. incorporating a model of the respiratory motion made by the patient's heart into the registration to compensate for the respiratory motion; and e. adjusting the registrations for the intra-operative image and subsequent intra-operative images using the motion model.