Heart failure due to ischemic coronary artery disease is a leading cause of morbidity and mortality. Metabolic assessment of myocardium could be important for assessing myocardial ischemia in patients. This study evaluated in vivo metabolism of hyperpolarized 13C-pyruvate in ischemia rat hearts under normal and elevated workload by dobutamine stimulation. Decreased production of bicarbonate was observed in hearts with ischemic myocardium compared to control hearts. Dobutamine stimulation lowered bicarbonate production in control hearts but did not change the appearance of bicarbonate signals in ischemic group.