[unreadable] The advent of cardiac resynchronization therapy (CRT) as an effectual treatment of congestive heart failure has been a revolutionary step in cardiac rhythm management. This treatment has been proven to significantly improve the morbidity and mortality of this very sick patient population of over 5 million in the US. Research indicates that the timing sequence between and within each cardiac chamber and stimulation site location are critical factors for the restoration of synchrony and proper hemodynamics. Another evident conclusion is that the inter-patient variation in heart failure condition and etiology requires therapy specialized to the individual. The consistent and disappointing portion (20-30%) of the subject population that do not respond to CRT may be due in part to suboptimal patient therapy. Current endovascular pacing of the left ventricle (LV) has several limitations, especially the restriction of pacing site options within the constraints of the coronary venous branches. The evolution of this therapy must now focus on maximizing the outcome of every CRT patient, however clinical practice has not made use of pacing location to realize the maximum benefit available with CRT. The proposed work outlines the design, development, and testing of a system for optimizing the site of left ventricular epicardial stimulation associated with CRT. The device will be capable of recording and analyzing the electromechanical response of the LV during intrinsic sinus rhythm in order to identify the pacing site that provides the maximum hemodynamic improvement. This much needed optimization device will take advantage of the unconstrained location potential of epicardial pacing and the minimally invasive access to the epicardial surface of the heart. A feasibility study will demonstrate that an optimum LV site of stimulation exists and if the prototype device can accurately locate that site. The proposed pacing site optimization study will also add valuable insights to the scientific understanding of CRT. [unreadable] [unreadable]