RESUSCITATION OF CARDIAC ENERGY-METABOLISM IN THE RABBIT HEART BY BRIEF HYPOTHERMIC REPERFUSION AFTER PRESERVATION STUDIED BY P-31 NMR-SPECTROSCOPY

Rabbit hearts were subjected to 24-h cold ischaemic storage (at 0 degr ees-2 degrees C in melting ice) after initial flushing with either St Thomas' cardioplegic solution (STS) or modified lactobionate/raffinose solution (LR), and the status of phosphorylated energy metabolites wa s measured by (31)phosphorus nuclear magnetic resonance (P NMR) spectr oscopy. In both groups signals for ATP and phosphocreatine (PCr) were still detectable by P-31 NMR after 24 h, and there was significantly m ore ATP in the LR group (P < 0.01). The hearts were then subjected to coronary reperfusion via an aortic cannula using the same storage solu tion (either STS or LR) at 6 degrees-8 degrees C, which was oxygenated . In both groups PCr recovered within 30 min of cold reperfusion, and by 60 min PCr was significantly higher in the LR group (P < 0.001). Al so, levels of ATP were maintained at higher values during cold reperfu sion in the LR group. These studies suggest two important points: (1) the general supply of phosphorylated high-energy intermediates of hear ts during cold ischaemic storage is better preserved using LR and (2) brief cold reperfusion may be used to restore energy metabolism in hea rts before re-implantation.