The Journal of Thoracic and Cardiovascular Surgery, Vol 75, 555-563, Copyright © 1978 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
The significance of multidose cardioplegia and hypothermia in myocardial preservation during ischemic arrest
RM Engelman, J Auvil, MJ O'Donoghue and S Levitsky
A standard experimental protocol was developed to explore the optimal
technique for myocardial preservation during 120 minutes of ischemic arrest
followed by 30 minutes of reperfusion. Eight different experimental groups
were evaluated with the use of an in vivo pig heart preparation. The
parameters measured included myocardial contractility and compliance,
myocardial blood flow, and endocardial/epicardial blood flow ratio.
Myocardial preservation was inadequate after hypothermic arrest alone,
cardioplegic arrest alone (at normothermia), and single- dose cardioplegia
plus hypothermia. Adequate myocardial preservation was found only after
hypothermia and multidose cardioplegia with either potassium (35 mEq. per
liter) or magnesium-procaine solutions. Continuous cardioplegia and
hypothermia, while providing a moderate degree of myocardial preservation,
was not as satisfactory as multidose cardioplegia and hypothermia. No
difference in myocardial preservation was apparent when potassium-induced
cardioplegia was compared with magnesium-procaine-induced cardioplegia.