The outcome of patients with a first non-Q wave acute myocardial infarction presenting with ST segment depression, ST segment elevation, or no ST deviations on the admission electrocardiogram.

Unlabelled: We evaluated the prognosis of patients with a first non-Q wave myocardial infarction according to their admission electrocardiogram. Hospital and 1-year mortality rates in patients with ST elevation (15%, and 21% respectively) and ST depression (17%, and 27% respectively) were similar and significantly higher than in patients with no ST changes (3%, and 10% respectively). Likewise, the adjusted hospital and 1-year mortality risks of patients with ST elevation or depression were comparable but higher than the corresponding mortality risk of patients with no ST deviations. The cumulative 5-year mortality rate was highest among patients with ST segment depression (51%) compared to patients with ST elevation (34%) or no ST deviation (21%), (p<0.001 for both comparisons). The adjusted 5-year mortality risk of patients with ST depression was higher (HR: 1.83, 95% C.I., 1.17-2.83) compared to patients with baseline ST elevation (HR-1.33, 95% C.I., 0.83-2.12) or patients with no ST changes (reference group). Patients with baseline ST segment elevation and coexistent ST segment depression in other electrocardiogram leads, had a higher in-hospital mortality rate (19%) compared to counterparts without concomitant ST depression (10%) and a tendency for higher in-hospital mortality risk but not for subsequent 1- and 5-year mortality risks.

Conclusions: Patients with a first non-Q wave MI with ST elevation or depression on admission have similar hospital and 1-year mortality risk, but the long-term mortality risk is higher among patients with ST segment depression. Patients with ST elevation and concomitant ST segment depression are at increased risk for mortality during the index hospitalization.