1. Method for delivering a medical device coupled with a catheter, to a selected position within a lumen of the body of a patient, the method comprising the procedures of: registering a three-dimensional coordinate system with a two-dimensional coordinate system, said three-dimensional coordinate system being associated with a medical positioning system (MPS), said two-dimensional coordinate system being associated with a two-dimensional image of said lumen, said two-dimensional image being further associated with an organ timing signal of an organ of said patient; acquiring MPS data respective of a plurality of points within said lumen, each of said points being associated with said three-dimensional coordinate system, each of said points being further associated with a respective activity state of said organ; determining a temporal three-dimensional trajectory representation for each said respective activity states from said acquired MPS data which is associated with said respective activity state; and superimposing said temporal three-dimensional trajectory representations on said two-dimensional image, according to said respective activity state; receiving position data respective of said selected position, by selecting at least one of said points along said oral three-dimensional trajectory representation; determining the coordinates of said selected position in said three-dimensional coordinate system, from said selected at least one point; producing a real-time navigation image of said lumen, said real-time navigation image being associated with said three-dimensional coordinate system, said real-time navigation image including a real-time medical device image of a medical device, located at the tip of a catheter, which is being maneuvered within said lumen; and superimposing a representation respective of said selected position, on said real-time navigation image, thereby enabling an operator to visually navigate said medical device toward said selected position.