An image of an electro-anatomical map of a body structure having cyclical motion is overlaid on a 3D ultrasonic image of the structure. The electro-anatomical data and anatomic image data are synchronized by gating both electro-anatomical data acquisition and an anatomic image at a specific point in the motion cycle. Transfer of image data includes identification of a point in the motion cycle at which the 3-dimensional image was captured or is to be displayed.