Treatment of Non-ST Segment Elevation Myocardial Infarction

Patients with a non-Q wave myocardial infarction in general do not have total occlusion of the infarct-related coronary artery. Thrombolytic therapy has not been shown to be of benefit in these patients and in several studies has been associated with a higher mortality. Medical management is otherwise similar to that with Q wave infarctions and involves aspirin, B blockers, nitrates, oxygen, and analgesia. Oral diltiazem may decrease the risk of reinfarction in patients with preserved ventricular function, but as with AMIs with ST segment elevation, the routine use of calcium channel blocking agents in patients with depressed ventricular function is not recommended. Angiotensin-converting enzyme in hibitors are indicated in patients with depressed ventricular function.

Intravenous heparin had been shown in the prethrombolytic era to decrease the mortality of AMI and should be administered to patients who are not candidates for reperfusion therapy, as well as to patients who are at a high risk of thromboembolic complications(e.g., patients with atrial fibrillation, intraven- tricular thrombus, or large anterior infarctions). Patients with non-Q wave myocardial infarction have smaller infarctions and lower in-hospital mortality rates than do patients with Q wave myocardial infarction. Despite this, the mortality at 1 year after infarction is no different and relates to a higher rate of recurrent infarction in the non-Q ve group.

Non Q-wave events may thus be viewed as an incomplete infarction. Because of the increased risk of recurrent infarction in frequently been applied with early catheterization and consideration of percutaneous or surgical revascularization.

Data from studies in the 1990s, however, suggest that a nore conservative approach with aggressive medical therapy and risk stratification with noninvasive modalities may be an equally effective, and perhaps safer, approach to these patients.