Mechanisms of Acute Myocardial Ischemia

Summary Myocardial ischemia results from a decline in the oxygen supply-and-demand ratio. The consequences of ischemia range from metabolic disturbances, detectable only by research techniques, to sudden death. The heart is unique in that it must generate pressure for its own perfusion. This results in complex interrelationships between the factors determining myocardial oxygen supply and demand. In the presence of a coronary stenosis, the effects of hemodynamic changes become even more difficult to predict. An understanding of the physiology of the normal and diseased coronary circulation helps the anesthesiologist protect the patient with coronary artery disease from cardiac morbidity.