DYNAMIC ANALYSIS OF THE HIGH ENERGY PHOSPHATES IN MYOCARDIUM USING THE GATED PHOSPHORUS NMR TECHNIQUE.

The gating technique of phosphorus NMR (P-NMR) spectroscopy was developed to investigate the dynamic changes of high energy phosphates during the cardiac cycle in a perfused rat heart. Left ventricular pressure (LVP) was measured by a catheter-tip manometer and the control pulse to trigger the P-NMR spectrometer was generated with programmed delay after the threshold point of LVP. Using this new system, the amounts of phosphocreatine (CP), inorganic phosphate (Pi) and ATP in the myocardium at different cardiac phases were obtained: The amount of CP was maximal at end-diastole and minimal at end-systole, whereas the amount Pi was changed inversely to CP during the cardiac cycle. This system is useful for the simultaneous analysis of cardiac function and the energy metabolism in the perfused heart.