Coronary Circulation and Cardiac Function

Summary

In this article, the close link between coronary circulation and cardiac function is reviewed from several points of view. Cardiac function is greatly determined by the loading condition, and on the contrary, the latter definitely regulates coronary blood supply through myocardial oxygen demand. Since many other variables also affect both coronary circulation and cardiac function simultaneously, it is difficult to establish in the in situ heart how the relation between the two factors is modified by loading change alone. From the clinical point of view, this problem is serious in respect to how to change loading in order to manage myocardial ischemic injury with coronary stenosis. In that matter, our experimental model using an excised, perfused heart preparation has given some valuable insight. Although many questions remain unanswered and controversies remain, our results support the concept that preload elevation leads to aggravation of ischemic injury while alleviating it in afterload elevation. Effects of loading on coronary circulation are, in particular, discussed. We stress the important role of the pericardium and also of the surrounding heart pressure on determining Pf = 0.