The Annals of Thoracic Surgery, Vol 35, 621-625, Copyright © 1983 by The Society of Thoracic Surgeons
The effect of nitroglycerin cardioplegia on myocardial cooling in patients undergoing myocardial revascularization
R Landymore, S Colvin, W Isom and A Culliford
The effect of intracoronary administration of nitroglycerin on the
distribution of cardioplegia and myocardial cooling was assessed in 45
patients undergoing elective myocardial revascularization. The patients
were divided into three groups. Myocardial temperature was measured over
the right and left coronary artery distributions in Group 1 after the
infusion of 1 liter of potassium blood cardioplegic solution (20 mEq of
potassium per liter). Similar temperature measurements were made in Group 2
after the addition of 300 micrograms of nitroglycerin to the cardioplegic
solution and in Group 3 after the addition of 1,000 micrograms of
nitroglycerin. Nitroglycerin did not affect myocardial cooling, and large
temperature gradients persisted after delivery of cardioplegia in patients
with occlusive coronary artery disease. Unexpectedly, however, the rate of
cardioplegia delivery increased by 134%, within the same range of infusion
pressures, in patients receiving nitroglycerin. Although nitroglycerin
cardioplegia does not affect the regional disparity in the distribution of
cardioplegia in patients with severe coronary artery disease, intracoronary
administration of nitroglycerin reduces the time required for
administration of cardioplegia and thereby decreases the total ischemia
time.
