This experiment was designed to determine the relative degree of cardiac functional recovery provided by various forms of resuscitative retrograde blood
cardioplegia after global ischemic injury. Twenty-four dogs were subjected to 20 minutes of normothermic global
myocardial ischemia followed by 60 minutes of cardioplegic arrest by one of three methods: group 1, standard cold blood
cardioplegia with a cold terminal dose (n = 8); group 2,
aspartate-
glutamate-enhanced blood
cardioplegia with warm induction and terminal enhancement (n = 8); and group 3, continuous warm blood
cardioplegia (n = 8). Sonomicrometry was used to analyze left ventricular function for maximal elastance and preload recruitable
stroke work area. Data were recorded at baseline and after 30 and 60 minutes of unloaded reperfusion. The results showed improved early recovery of preload recruitable
stroke work area, but not of maximal elastance, after reperfusion of ischemic hearts with warm resuscitative blood
cardioplegic solution enhanced with
amino acids. The functional improvement provided by this technique was transient, however, and no significant differences were detectable among the groups after 60 minutes of unloaded reperfusion. Neither
amino acid enhancement nor continuous warm
cardioplegia offered a significant advantage in functional recovery over the standard method of cold blood
cardioplegia reperfusion.