Relation between infarct size and myocardial stiffeness: effects of ischemic preconditioning

pp. 630-635

Abstract

It has been shown that ischemic preconditioning decrease the size of the infarction. On the other hand, myocardial infarction increases diastolic stiffness, and this increase is proportional to the size of the infarction. Based on theses findings, it could be expected that preconditioning diminishes the increase of diastolic stiffness. Therefor, the objetive of the present paper was to determine if ischemic preconditioning -by decreasing the size of the infarction- is able to diminish the increase of myocardial stiffness. 

Isolated, isovolumic rabbit hearts that were perfused according to Langerdorff modified technique, and were studied after 30 minutes of ischemia followed by 30 minutes of reperfusion. Another group of hearts were submitted o a prolonged ischemia. A latex balloon was placed inside left ventricles and connected to a pressure transducer, allowing the register of left ventricular end dyastolic pressures (myocardial stiffness). Besides, the size of the infarction was measured using 2, 3, 5-tripheniltetrazolium chloride. Ischemic preconditioning significantly decreased the size of the infarction caused by 30 minutes of global ischemia, but did not attenuate the increase of myocardial stiffness, probably due to the persistence of stunned areas, adjacent to the infarction area.