Effects and early perioperative diagnosis of graded reductions in regional coronary perfusion

The effects of graded reductions and total occlusion of the flow in a small branch of the coronary circulation on regional myocardial function and metabolism and routinely monitored determinants of myocardial function, such as body surface electocardiogram, pressure tracings and dP/dt, are evaluated in mongrel dogs. Normal regional myocardial function and pH remain preserved until coronary blood flow is reduced to about one half its normal initial value. Then, important and dramatic changes in systolic regional myocardial function occur together with a significant decrease in regional pH. There were no significant changes in the global determinants of myocardial function. This study proves the inadequacy of the body surface electrocardiogram and the other routinely monitored hemodynamic determinants to detect limited regional ischemia. In addition, it stresses the importance to evaluate the sensitivity of new monitoring techniques in the detection of regional myocardial malfunctioning and the importance of research on the effects of anesthetic agents on regional myocardial function.