Determinants of Delayed Preconditioning Against My

Authors: James A Fallavollita

Publish Date: 2008/12/02

Volume: 2, Issue: 1, Pages: 71-80

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Abstract

To test the hypothesis that a critical stenosis prevents delayed preconditioning against stunning studies were conducted in pigs chronically instrumented with occluders and segmentshortening crystals In the setting of a critical stenosis a preconditioning stimulus of repetitive brief occlusions resulted in infarction Thereafter a single 10min occlusion was used as the preconditioning stimulus Delayed preconditioning against stunning was documented on subsequent days by the deficitoffunction following brief repetitive occlusions In contrast to experiments in the naïve heart the deficitoffunction improved on the day after a single 10min occlusion from 60 ± 14 to 24 ± 6 arbitrary units p = 0003 and similar improvement occurred when reperfusion was performed through a critical stenosis 32 ± 6 units p = 002 vs naïve and p = 034 vs no stenosis Delayed preconditioning also reduced the frequency of ventricular fibrillation and produced a fourfold increase in both calciumdependent and calciumindependent NOS activity Thus a critical stenosis did not prevent delayed preconditioning against stunningI would like to thank Edward O McFalls MD PhD and Joseph Sikora for performing the myocardial NOS activity assays Elaine Granica for her expert technical assistance with conduct and analysis of these studies and Anne Coe for her assistance with the completion of this manuscript I would also like to thank John M Canty Jr MD for his helpful comments on the draft of this manuscript This study is supported by the Department of Veterans Affairs the American Heart Association and the National Heart Lung and Blood Institute

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