In patients admitted to the hospital because of unstable angina, a subgroup can be recognized that is at high risk for the development of an extensive anterior wall myocardial infarction. These patients, who show characteristic ST-T segment changes in the precordial leads on or shortly after admission, have a critical stenosis high in the left anterior descending coronary artery. Of 145 patients consecutively admitted because of unstable angina, 26 (18%) showing this ECG pattern, suggesting that this finding is not rare. In spite of symptom control by nitroglycerin and beta blockade, 12 of 16 patients (75%) who were not operated on developed a usually extensive anterior wall infarction within a few weeks after admission. In view of these observations, urgent coronary angiography and, when possible, coronary revascularization should be done in patients with unstable angina who show this ECG pattern.