High-risk ECG patterns in ACS--need for guideline revision.

The current guidelines advocate distinct approaches (urgent reperfusion therapy) to patients with suspected acute coronary syndromes (ACS) presenting with ST elevation (STE) versus patients without STE on their electrocardiogram (ECG). This is based on the paradigm that STE represents ongoing transmural ischemia due to an acute occlusion of an epicardial coronary artery whereas the significance of other ECG findings is more contentious. The role of urgent coronary angiography in patients without STE is less clear and initial stabilization with conservative treatment is recommended. However, in some cases the distinction between STEMI and non-STE-ACS is difficult. Acute occlusion of a coronary artery may cause less than the current recommended threshold STE. On the other hand, many patients may have STE secondary to nonischemic etiology. In many patients with non-STE-ACS the coronary artery is not completely occluded at the time of presentation and there are rapid fluctuations in the severity of ischemia and hence, dynamic changes are observed in the ECG. Several ECG patterns associated with particular coronary anatomy and high-risk prognosis have been identified. Patients with ACS presenting with these high-risk patterns should probably be referred for coronary angiography with the possibility of urgent intervention with the goal of prevention of ischemic complications, rather than for immediate myocardial salvage, as in classic STEMI.