The Annals of Thoracic Surgery, Vol 31, 233-239, Copyright © 1981 by The Society of Thoracic Surgeons
Correlation of patterns of subendocardial reperfusion and left ventricular performance after ischemia
HR Kay, FH Levine, JT Fallon, GJ Grotte, J Newell, T McEnany, WG Austen and MJ Buckley
Ninety-three dogs were studied with normothermic or hypothermic ischemia
for 60 or 90 minutes, with or without potassium cardioplegia.
Radioactive-labeled microspheres (9 +/- 1) were injected into the aortic
perfusion cannula just prior to aortic cross-clamping and at 2, 6, and 10
minutes after the clamp was released. Left ventricular (LV) function was
analyzed with a right heart bypass model before and 45 minutes after the
ischemia period. Changes in LV function were defined as the arithmetic
difference in the center of mass between preischemia and postischemia
computer-drawn Sarnoff curves. Regardless of technique of myocardial
protection, increased subendocardial flow 2 minutes after ischemia
correlated strongly with preservation of LV function (p less than 0.01).
Well-preserved hearts showed a rapid return to normal levels of coronary
blood flow (p less than 0.01). In contrast, a delay in the peaking of
subendocardial flow to 10 minutes was associated with poor function (p less
than 0.01). There was a high correlation between ultrastructural morphology
and LV function. While well-preserved hearts showed early preferential
subendocardial perfusion, the poorly protected myocardium is unable to
restore adequate subendocardial flow early in the reperfusion period.
