1. A physiology system, comprising: an ultrasound beamformer coupled to receive signals from an ultrasound probe configured to be located proximate a region of interest and, based thereon produce ultrasound data representative of a scan plane including the region of interest; an ultrasound (U/S) processor module for generating an ultrasound image, based on the ultrasound data, representative of an anatomical structure of a portion of the region of interest contained in the scan plane; a physiology signal processor module coupled to receive physiology signals from a physiology catheter configured to be located proximate the region of interest and, based thereon produce physiology data representative of physiology activity of the portion of the region of interest contained in the scan plane; a display processor module forming a display image superimposing an image representation of the physiology data on the ultrasound image; and a position tracking module configured to track positions of the ultrasound probe and the physiology catheter, and to generate position information denoting the position of the ultrasound probe and physiology catheter with respect to a common reference coordinate system, the display processor module forming the display image superimposing the image representation of the physiological data on the ultrasound image using the position information.