Q. Determine ST-Segment Elevation?
Ans.
Exercise induced ST-segment elevation is common in subjects with post MI stress tests in leads where Q-waves are present. It has been correlated with abnormal wall motion in the area of infarction. However, approximately 50 per cent of the ST-segment elevation observed initially with pre discharge stress tests will be absent on retesting at 6 weeks, which may reflect improvement of abnormal wall motion with fibrosis and scarring or it may be due to recovery of hibernating myocardium. It rarely occurs with inferior infarction, and the ejection fraction is significantly lower in patients demonstrating ST-segment elevation. Thus, when the ST-segment elevation is noted on post MI stress testing that becomes more marked with exercise it may indicate viable myocardium in the region of the infarct.