Relationship between epicardial ST-segment elevation, regional myocardial blood flow, and extent of myocardial infarction in awake dogs.

This study was designed to examine the relationship between epicardial ST change (EpST) and regional myocardial blood flow (RMBF) following coronary occlusion and extent of myocardial infarction (MI) in awake dogs. Fifteen min and two hr after coronary occlusion simultaneous measurements of EpST and RMBF were made. Six days later histologic MI and RMBF were determined in transmural myocardial samples from each electrode site. Greatest ST elevation occurred at sites of greatest ischemia and MI. However, 15 min after occlusion 29% of sites with greater than 50% MI and 39% of sites with greater than 50% reduction in RMBF did not demonstrate ST elevation greater than 2 mV. There were poor correlations between EpST and MI (r = 0.59) and RMBF (r = 0.57). Comparable relationships were observed two hr after occlusion. In the present study, there were not close quantitative or qualitative relationships between EpST and MI or RMBF. A good correlation was observed between RMBF at two hr and MI (r = 0.89).