Electrocardiographic ST-segment changes during acute myocardial ischemia.

The recognition and management of patients with acute coronary syndromes has relied to a large extent on the standard 12-lead electrocardiogram (ECG) for assessing ST-segment changes associated with ischemia. The purpose of this review is to show both the capabilities and the limitations of the 12-lead ECG in recognizing ischemia, and to seek alternative electrocardiographic leads, optimized for detection of ischemia originating in different regions of the ventricular myocardium. Three such leads are proposed-based on the results obtained by electrocardiographic body-surface mapping performed during ischemia induced by balloon-inflation coronary angioplasty. A survey of recent clinical studies shows that the electrocardiographic manifestations of acute myocardial ischemia observed during coronary angioplasty are in agreement with the ST-segment measurements in admission ECGs of patients with acute myocardial infarction.