ST depression in ECG at entry indicates severe coronary lesions and large benefits of an early invasive treatment strategy in unstable coronary artery disease. The FRISC II ECG substudy

BACKGROUND: In unstable coronary artery disease, ST-segment depression indicates a poor prognosis. We evaluated whether the effect of early revascularization and the extent of coronary lesions were related to ST-segment and T wave changes on admission. METHODS AND RESULTS: 2457 patients with unstable coronary artery disease were randomized to an early invasive strategy with coronary angiography/revascularization within 7 days or to a non-invasive strategy with coronary procedures only when symptoms or severe ischaemia recurred. ST depression was present in 1114 (45.5%) patients. In the invasive group, 45% of the patients with ST depression had three-vessel disease or left main stenosis compared with 22% if no ST-segment depression was present, PP=0.004 while mortality was changed from 5.8 to 3.3%, P=0.050. In patients without ST-segment depression the corresponding rates concerning death/myocardial infarction were 10.4 and 8.9, and for mortality 2.0 and 1.2% (non-significant). CONCLUSIONS: In unstable coronary artery disease, ST-segment depression is associated with a 100% increase in the occurrence of three-vessel/left main disease and to an increased risk of subsequent cardiac events. In these patients an early invasive strategy substantially decreases death/myocardial infarction.