The Journal of Thoracic and Cardiovascular Surgery, Vol 83, 117-121, Copyright © 1982 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
The temperature dependence of recovery of metabolic function following hypothermic potassium cardioplegic arrest
JH Rousou, WA Dobbs, MK Meeran and RM Engelman
A study was performed to define the influence of reperfusate temperature on
the recovery of high-energy phosphate compounds following hypothermic
ischemic cardioplegic arrest. Two groups, each consisting of six pigs, were
subjected to 1 hour of hypothermic potassium cardioplegic arrest
(myocardial temperature 10 degrees to 15 degrees C). In one group, the
arrest period was followed by a 30 minute period of normothermic
reperfusion (37 degrees C) followed by a second hour of hypothermic
cardioplegic arrest and a second 30 minute normothermic reperfusion period.
The second group of pigs was reperfused after the first hour of arrest for
30 minutes with a cold blood (10 degrees to 14 degrees C) followed by an
additional hour of hypothermic cardioplegic arrest and a second 30 minute
hypothermic reperfusion period. Myocardial biopsy specimens for adenosine
triphosphate (ATP) and creatine phosphate (CP) were obtained at the
beginning of perfusion (control studies), at the end of each hour of the
arrest interval, and at the end of each 30 minutes of reperfusion. The ATP
and CP levels were significantly higher after normothermic reperfusion than
after hypothermic reperfusion. After normothermic reperfusion the CP level
exceeded control; following hypothermic reperfusion CP remained less than
70% of the control level. On the basis of these results, it is proposed
that hypothermic reperfusion does not permit the same level of high-energy
phosphorylation that is provided with normothermic reperfusion and may
therefore adversely affect hemodynamic recovery of the heart after
cardioplegic arrest.
