Characteristics and Outcomes in Patients With Acute MI
Background: Acute myocardial infarction (AMI) with nonreciprocal ST-segment depression is said to have a poor prognosis, and early diagnosis and treatment are problematic. The aim of this study was to determine the proportion of unselected consecutive patients admitted to a university center with AMI with nonreciprocal ST-segment depression and to characterize these patients in terms of clinical features, treatment, and short- and long-term prognoses.
Methods and Results: Admission electrocardiographic data on 852 consecutive admissions with AMI were analyzed. Nonreciprocal ST-depression was an admitting feature in 95 (11%) patients, the majority of whom had ST depression >3 mm. These were older (70.3 vs 66.8 years, P < .05), more likely to have had myocardial infarction (40% vs 25%, P < .01), and to have left ventricular failure (56% vs 42%, P < .5), cardiogenic shock (15% vs 9% P = .06), and atrial fibrillation (34% vs 19%, P < .01). Hospital mortality rate was significantly higher (31% vs 17%, P < .01). Patients were less likely to undergo thrombolysis (17% vs 31%, P < .01), angiography (22% vs 35%, P < .05), or percutaneous revascularization (5% vs 9%, P < .01). Patients with ST depression undergoing coronary angiography were more likely to have 3-vessel disease (71% vs 47%, P < .05). Mortality rate at follow-up (median 36 months) was significantly higher in patients with ST depression (56% vs 32%, P < .001). Analysis by individual electrocardiography demonstrated ST-segment depression to be the third most frequent presentation after ST elevation (n = 327) and T-wave changes (n = 258), in whom hospital mortality rates were 24% and 9%, respectively. In multivariate analysis, previous myocardial infarction was an independent predictor of nonreciprocal ST depression at initial examination (odds ratio 2.04 [1.25 to 3.34], P < .005). No electrocardiographic presentation was an independent predictor of death in the hospital after AMI.
Conclusions: In unselected cases of AMI, patients with ST-segment depression make up a significant minority (11%), who are likely to be older with a high prevalence of previous myocardial infarction and multivessel disease, and who have a poor prognosis.

Patients with acute myocardial infarction (AMI) with ST-segment depression without associated ST-segment elevation constitute up to 50% of the initial examinations of non-Q-wave AMI and have a worse prognosis than patients without this ST elevation. Diagnosis before the detection of cardiac enzymes is problematic, and optimal treatment has not been defined. Such patients have largely been excluded from randomized trials of thrombolysis, and the prevalence of this presentation among unselected patients with AMI is unknown.

The aim of this study was to identify the frequency of nonreciprocal ST-segment depression, defined by the presence of ST-segment depression of >=1 mm at or after 0.08 seconds from the J point of the QRS complex in any 2 contiguous leads in the absence of ST-segment elevation in any lead occurring in the admission electrocardiograms of unselected patients with AMI, to determine the clinical characteristics of such patients and to determine the short- and long-term prognoses of AMI in this population.