EFFECT OF GLUTAMATE-ASPARTATE REPERFUSION ON POSTISCHEMIC NEONATAL MYOCARDIUM

Objective: We postulated that L-glutamate- and L-aspartate-enriched pe rfusate would improve functional recovery of postischemic neonatal rab bit hearts. Methods: Isolated working neonatal rabbit hearts were perf used with Krebs-Henseleit buffer and then subjected to 1 hour of hlvpo thermic cardioplegic arrest with St. Thomas' Hospital solution. Hearts were then reperfused with L-glutamate- and L-aspartate-enriched (20 m mol/L) Krebs-Henseleit buffer (AA-enriched Krebs-Henseleit buffer). He arts reperfused with Krebs-Henseleit buffer alone acted as controls (e xperiment A). Another group of hearts underwent a similar protocol but were reperfused with the AA-enriched Krebs-Henseleit buffer with corr ection of the sodium content (experiment B). Results: Hearts reperfuse d with AA-enriched Krebs-Henseleit buffer showed a significant decreas e in aortic flow at both 15 (p = 0.04) and 30 (p = 0.025) minutes comp ared with controls. Arrhythmias were frequent. Sodium content of the A A-enriched Krebs-Henseleit buffer was 174 +/- 0.5 mmol/L. In experimen t B, hearts reperfused with the AA-enriched Krebs-Henseleit buffer wit h correction of the sodium content exhibited no difference in aortic f low and cardiac output at either 15 or 30 minutes (p = 0.95 and 0.5 an d 0.48 and 0.78, respectively) compared with controls. No arrhythmias were observed. The sodium content of the AA-enriched Krebs-Henseleit b uffer was 136 +/- 0.7 mmol/L. Conclusions: A beneficial effect on func tional recovery of neonatal hearts reperfused with AA-enriched Krebs-H enseleit bu[fer was not demonstrated.