Electromechanical endocardial mapping of the heart using a nonfluoroscopic catheter-based system is a new imaging modality that has been studied recently in the experimental setting as well as in patients. Besides its original application in the diagnosis and treatment of various cardiac arrhythmias, it has also been used as an investigational tool for assessing left ventricular function and viability. Finally, the mapping system may be a valuable platform for direct myocardial revascularization using either laser treatment or injection of pharmacologic agents.