Compared the empty beating herat and and aortic cros-clamp aplication,the metabolic rate of the empty fibrilating heart, at 37c, is greater, while potassium arrest incurse a furter major reduction in MVO2 by removing electric work.Temperature reductions deminish metabolic rate for all electromechanical states of the myocardium.Interestengly, the empty fibrilating heart in particular gains significant furter reductions in matabolic rate with the aditional aplication of hypotermia.