Myocardial infarction size: measurement and modification.

The majority of in-hospital deaths from acute myocardial infarction occur as a result of the "power failure" syndrome (severe congestive heart failure and cardiogenic shock), which results from extensive loss of myocardium. The death of myocardial cells is sequential over many hours. Surrounding the central zone of necrosis in an acute myocardial infarction is a zone of ischemic myocardium whose fate might be altered by interventions during the early phase of the infarction. ST-segment mapping, serial measurement of the serum concentration of creatine phosphokinase and myocardial imaging by means of radionuclides are being developed for the noninvasive assessment of infarct size in animals and humans. A number of interventions appear to limit infarct size in animals. There have been relatively few studies in humans to date, but preliminary results suggest that infarct size might be limited by certain interventions. The research has provided important practical benefits in terms of understanding the course of acute myocardial infarction and the potential effects of conventional therapies. For the present, interventions designed to limit infarct size remain in the realm of clinical research; routine clinical use would be inappropriate.