[Prolonged preservation due to acceleration of anaerobic glycolysis with histidine buffered cardioplegia in canine heart].

Myocardial preservation has centered around the deep hypothermia with metabolic arrest to save energy loss. We evaluated the efficacy of histidine buffered cardioplegia containing 100 mM histidine formulated to promote anaeraboic energy production in a blood perfused canine heart subjected to 24 hours or 30 hours ischemia. The hearts were flushed with 100 mM histidine containing buffered solution (HBS) in one group and a second group and University Wisconsin solution (UWS) in a third group. The hearts were preserved at 4 degrees C for 24 hours in one and third group, and for 30 hours in a second group, then reperfused with autologous blood in an isolated heart perfusion apparatus. Standardized stroke volume, ejection fraction, developed pressure and end-systolic elastance were measured at 2 hours after reperfusion and compared with control non-preserved hearts. Better recovery of cardiac performance was attained in the hearts preserved with histidine containing cardioplegia for 24 hours or 30 hours than that in UW group. Although cardiac performances in the hearts preserved with histidine cardioplegia for 30 hours was worse than that in 24 hours preserved heart for 24 hour, those were comparable if low dose or high dose cathecolamine was given. We concluded that the histidine containing cardioplegia provides effective preservation of the canine heart with superior recovery of pump performance after 24 hours or 30 hours of preservation by buffering proton and lactate to promote anaerobic glycolysis.