Temporal fluctuations of myocardial high-energy phosphate metabolites with the cardiac cycle.

This review describes the temporal changes of high-energy phosphate metabolites during the cardiac cycle. Under baseline condition, the extent of cyclical changes (“cycling”) of ATP, phosphocreatine and inorganic phosphate varies between 10–15 %. Such energy oscillations are not augmented under various forms of metabolic stress including 1) inotropic stimulation, 2) acute hypoxia and 3) failing, chronically infarcted hearts. Thus, the concentrations of high-energy phosphates over the cardiac cycle are a tightly regulated entity, even when energetic needs are substantially augmented. [ABSTRACT FROM AUTHOR]