Potential Improvements in Means of Evaluation of Acute Myocardial Infarction
Studies on Effective Capillary Blood Flow of the Human and Canine Heart after Acute Myocardial Infarction
Effective capillary blood flow (ECF) through the myocardium was studied after experimentally produced myocardial infarction in 33 dogs, and after clinical acute myocardial infarction in nine human subjects. In dogs, ECF as measured by Rubidium-86, was compared to terminal vascular capacity (TVC) as measured by I-131 albumin in infarcted and noninfarcted portions of the myocardium. In man, ECF was determined from the myocardial uptake of Rubidium-84 by the double coincidence counting system. A discrepancy between ECF and TVC in animals became apparent by the tenth day after infarction, at which time TVC had attained control levels, whereas ECF had not; 2 months later, ECF was still 24% less than control. Studies in man demonstrated a significant decrease in ECF within 4 days of infarction; the low flow persisted in one patient 6 weeks after the initial injury. Low ECF in patients was present despite the insignificant changes in cardiac and stroke indices, and in mean aortic pressure. It is thought that the low values for ECF after acute myocardial infarction might reflect alterations in cellular metabolism leading to interference with tissue uptake of rubidium.
The discussion that followed this paper appears after the paper by Dr. Richard Gorlin.
- © 1969 American Heart Association, Inc.