Purpose: The goals of this study were to determine if very early revascularization might ameliorate the adverse prognosis associated with ST-segment depression in patients with unstable angina/non-ST-segment elevation myocardial infarction.
Methods: In this prospective cohort study, 1450 consecutive patients with unstable angina/non-ST-segment elevation myocardial infarction were stratified by the presence of ST-segment depression, T-wave inversion, or no changes on the admission electrocardiogram (ECG). All patients underwent coronary angiography and, if appropriate, revascularization within 24 hours after admission. The primary endpoint was all-cause mortality.
Results: During up to 59 months of follow-up, the in-hospital mortality rate was 2.1% (19/895) in patients with no ECG changes, 4% (6/136) in those with ST-segment depression, and 0.2% (1/419) in those with T-wave inversion. The cumulative death rate at 36 months was 8.0% (n = 49) in patients with no ECG changes, 19.9% (n = 18) in patients with ST-segment depression, and 5.1% (n = 13) in patients with T-wave inversion (P = 0.0001 by log-rank). After adjustment for potential cofounders, ST-segment depression (hazard ratio [HR] = 2.2; 95% confidence interval [CI]: 1.1 to 4.6) and T-wave inversion (HR = 0.44; 95% CI: 0.20 to 0.96) were associated with long-term mortality.
Conclusion: ST-segment depression and T-wave inversion on the admission ECG were important predictors of outcome in patients with unstable angina/non-ST-segment elevation myocardial infarction undergoing very early revascularization. In contrast to the considerable mortality seen in patients with ST-segment depression, T-wave inversion was associated with a more favorable outcome.