Transmural metabolic gradients of the canine left ventricle in coronary constriction, systemic hypoxia, hemorrhagic shock, and isoproterenol infusion.

In the left ventricle of the dog, a transmural difference is present in the normal state for various metabolites and persists in the experimental conditions studied. ATP stores are maintained both in the endo-as well as epicardium at the expense of PC. This is true for systemic hypoxia, hemorrhagic shock, and isoproterenol infusion. In severe ischemia, however, endocardial ATP is lower, while the transmural gradient for PC is increased due to a marked decrease in endocardial PC content. Our studies underline the importance of nonhomogeneity of the left ventricular wall and demonstrate that the subendocardium is more subject to anaerobic metabolism, especially when coronary perfusion pressure is decreased.