Mapping and measuring regional changes of energy substrate metabolism, in vivo, can be considered as a new frontier of cardiac physiology. We are currently testing a highly innovative and sensitive method based on ¹³C hyperpolarization combined with magnetic resonance imaging (MRI). ¹³C-labeled pyruvate is exposed to a high magnetic field (hyperpolarization) and then rapidly infused in the experimental animal placed in a 3 tesla MRI scanner. The process of hyperpolarization increases the MRI signal to noise ratio by >10.000 and the subsequent spectroscopic image acquisitions provide semiquantitative information relative to pyruvate metabolism in well-defined ventricular regions. If pyruvate is labeled in position 1 ([1-¹³C]pyruvate), the detectable metabolites are [1-¹³C]lactate, [1-¹³C]alanine and [¹³C]bicarbonate. If pyruvate is labeled in position 2, MRI detects an array of intermediate metabolites of the Krebs cycle. In addition to metabolic mapping, cardiac MRI provides detailed morphological and functional information, therefore allows physiological evaluations with a level of completeness never achieved before. Despite these promising results, some major limitations of hyperpolarization/MRI must still be overcome, for instance the high dose of ¹³C-pyruvate necessary to obtain a readable signal and the lack of fully quantitative information. Nevertheless, we believe that this imaging technique will tremendously contribute to the advancement of cardiac physiology.