Temporal fluctuations of myocardial high-energy phosphate metabolites withthe cardiac cycle

This review describes the temporal changes of high-energy phosphate metabol ites during the cardiac cycle. Under baseline condition, the extent of cycl ical changes ("cycling") of ATP, phosphocreatine and inorganic phosphate va ries between 10-15 %. Such energy oscillations are not augmented under vari ous forms of metabolic stress including 1) inotropic stimulation, 2) acute hypoxia and 3) failing, chronically infarcted hearts. Thus, the concentrati ons of high-energy phosphates over the cardiac cycle are a tightly regulate d entity, even when energetic needs are substantially augmented.