The Annals of Thoracic Surgery, Vol 54, 712-716, Copyright © 1992 by The Society of Thoracic Surgeons
Nicardipine: myocardial protection in isolated working hearts
ME Mitchell, DA DeBoer, MD Crittenden and RE Clark
Surgery Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland.
The effectiveness of the calcium antagonist nicardipine in protecting the
ischemic myocardium was evaluated using the hemodynamic recovery of
isolated working rat hearts subjected to hyperkalemic cardiac arrest
followed by ischemia at 37.5 degrees C and 10 degrees C. Rat hearts (n =
51) received 20 mL of cardioplegia and were subjected to 27 minutes of
ischemia at 37.5 degrees C. Group A (control) did not receive nicardipine.
Groups B through F received nicardipine in the cardioplegia with total
doses ranging from 2 micrograms to 6 micrograms. Group A had 46% survival
of ischemia, whereas groups C (3 micrograms) and D (4 micrograms) had
survival rates of 88% and 100%, respectively (p less than 0.05). The
recovery of aortic flow after ischemia was 35% in group A, compared with
76% in group B (2 micrograms) and 81% in group D (p less than 0.05). Group
A had 49% postischemic recovery of cardiac output, whereas groups B and D
had 82% and 85% recovery (p less than 0.05). The postischemic recovery of
stroke volume was 48% in group A compared with 84% in group B, 87% in group
D, and 73% in group E (5 micrograms) (p less than 0.05). Additional rats
were exposed to 210 minutes of ischemia (n = 41) or 240 minutes of ischemia
(n = 56) at 10 degrees C. Control groups did not receive nicardipine,
whereas treatment groups received nicardipine in the cardioplegia with
total doses ranging from 1.4 micrograms to 6.4 micrograms. There were no
significant differences in the survival of ischemia or the recovery of
function after ischemia at 10 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)
