A system and method of treating tachycardias and similar syndromes by the use of catheter ablation of tissue is described. A computed tomography (CT)-like image of the heart is obtained and processed to segment the various types of tissue. Papillary muscle areas are identified and displayed differently from the other nearby tissues so that the muscles can be avoided during treatment to avoid or minimize damage to the muscles during ablation treatment. Electrophysical data and scar tissue may also be identified in the image, which may be of the endoscopic type. The position of the catheter may be displayed as a synthetic image on the endoscopic view.