European Journal of Cardio-Thoracic Surgery, Vol 1, 91-97, Copyright © 1987 by European Association for Cardio-thoracic Surgery
Coronary blood flow and myocardial metabolism during reperfusion after hypothermic cardioplegia in the dog
FL Rosenfeldt, M Rabinov and M Newman
Baker Medical Research Institute, Melbourne, Australia.
There have been many studies of reperfusion injury after normothermic
ischemia. However, there have been few clinically relevant studies on the
nature and time course of recovery of the myocardium during reperfusion
after hypothermic cardioplegia. We studied reperfusion in the isolated dog
heart supported by another dog. After 2 h of cardioplegic arrest at 20
degrees C, 11 normal hearts were reperfused for 30 min at optimal coronary
pressures (60-100 mm Hg mean). The following events occurred: rapid
rewarming, a transient hyperemia followed by a rapid return of both
coronary blood flow and myocardial oxygen consumption to normal, washout of
lactate, recovery of contractility and a slight decline in ATP. Most of
these events occurred during the first 15 min of reperfusion. We concluded
that, in normal hearts which are well protected during hypothermic
cardioplegia, reperfusion at optimal coronary pressure results in recovery
of the myocardium within 15 min, with the exception of recovery of ATP
levels.
