Structural basis of myocardial stunning after coronary artery bypass surgery

Acute heart failure is the main cause of death in early postoperative perio d after coronary artery bypass surgery but mechanism of its development rem ains poorly understood. Morphological study of myocardium of patients who d ied during first 2 days after surgery revealed diffuse changes of cardiomyo cytes consisting of contractural alterations and intracellular insoluble de posits of calcium phosphate. Pronounced disturbances of microcirculation ap pearing as foci of extravasated blood and stasis of leukocytes were also pr esent. Meanwhile no cellular or enzymatic reactions indicative of foci of l ocal ischemia were found. The observed morphological changes are supposed t o constitute structural basis of stunning of ischemic myocardium during res toration of coronary blood flow. These structural changes are presumably ca used by disturbed calcium ion transport and abundance of various metabolite s in the reperfused zone.