Evidence that ischemic cell death begins in the subendocardium independent of variations in collateral flow or wall tension

Abstract

Irreversible ischemic injury occurs after coronary artery occlusion in vivo, first in the subendocardium and progressing toward the subepicardium over time, presumably due to transmural variations in collateral flow or wall tension. In this study, 10 left ventricular globally ischemic slabs were created that were free of wall tension and collateral flow. The onset and completion of ischemic contracture were identified by means of a new tissue compressibility gauge designed for these studies. Transmural samples were obtained at 15 min intervals for determination of high-energy nucleotide levels and for ultrastructural analysis. The results show that there is a statistically significant gradient of ATP depletion, with the subendocardium consistently accelerated energy utilization compared with the subepicardium (p