Diagnostics of ischemic heart disease: Influence of myocardial ischemia on AMP catabolite release and hemodynamics

The purpose of this study was to answer the questions: What is the correlation between adenosine monophosphate (AMP) breakdown and hemodynamic changes caused by myocardial ischemia? Can AMP catabolites released by the heart be used to diagnose ischemic heart disease? We studied changes in metabolism and hemodynamics in the intact ischemic pig heart and the isolated, perfused rat heart made hypoxic or ischemic. We measured the AMP catabolites adenosine, inosine, and hypoxanthine, which were released by the oxygen-deprived heart. Inosine is a sensitive (and early) indicator of wall-thickness changes in the ischemic pig heart. In addition to a change in lactate metabolism, myocardial inosine production is a good marker for myocardial ischemia because it correlates well with carbohydrate extraction and ventricular function, and because these occlusion-induced changes are relatively large. We tried unsuccessfully to develop a model to study interventions during myocardial ischemia in which the pig served as its own control.