Electrical alternans of the ST segment in non-Prinzmetal's angina.

Elevated electrical alternans of the elevated ST segment (STEA) was documented in a patient with non-Prinzmetal's or classical angina and severe atherosclerotic coronary artery disease. STEA was precipitated during graded exercise testing. The disappearance of this phenomenon after aortocoronary bypass surgery suggests that the coronary obstructions were the etiologic factors. These findings emphasize that the STEA may occur in myocardial ischemia caused by conditions other than Prinzmetal's angina.