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Prognosis

ST-segment depression and mortality after myocardial infarction

ACP J Club. 1994 Jan-Feb;120:19. doi:10.7326/ACPJC-1994-120-1-019


Source Citation

Gheorghiade M, Shivkumar K, Schultz L, et al. Prognostic significance of electrocardiographic persistent ST depression in patients with their first myocardial infarction in the placebo arm of the Beta-Blocker Heart Attack Trial. Am Heart J. 1993 Aug;126:271-8.


Abstract

Objective

To ascertain if ST-segment depression found during electrocardiography (ECG) is predictive of long-term mortality in patients who have had a first myocardial infarction (MI).

Design

Inception cohort followed for a median of 26 months (placebo arm of the Beta-Blocker Heart Attack Trial [BHAT]).

Setting

Hospitals in the United States.

Patients

1444 patients (mean age, 55 y; 89% white; 85% men) with a proven MI (according to the Minnesota criteria). Exclusion criteria were previous MI, left bundle-branch block, or the Wolff-Parkinson-White syndrome.

Assessment of Prognostic Factors

Patients were divided into 3 groups (no ST depression, transient ST depression, and persistent ST depression). 392 patients had no ST depression (337 with Q-wave MI and 55 with non-Q-wave MI) soon after admission or at time of randomization to the BHAT study; 713 patients had transient ST depression ≥ 1 mm in ≥ 2 contiguous leads (585 with Q-wave MI and 128 with non-Q-wave MI) transiently soon after admission or at the time of randomization; and 339 patients had persistent ST depression soon after admission and at the time of randomization (264 with Q-wave MI and 75 with non-Q-wave MI).

Main Outcome Measures

Total mortality and sudden death, congestive heart failure (CHF), MI, and coronary bypass grafting.

Main Results

Cox regression analysis adjusting for baseline variables showed that the relative risk (RR) for mortality was 1.77 (95% CI, 1.02 to 3.09) for patients with transient ST depression and was 2.59 (CI, 1.41 to 4.76) for patients with persistent ST depression. In addition, sudden death (RR, 3.26; CI, 1.52 to 7.01), non-fatal or fatal MI (RR, 2.07; CI, 1.27 to 3.36), and CHF (RR, 2.08; CI, 1.25 to 3.49) occurred more frequently in patients with persistent ST depression than in patients with transient or no ST depression. Patients with persistent ST abnormalities included more women and were older; were more often hypertensive; and had less persistent angina but more frequent cardiomegaly, digitalis, and diuretic use (P ≤ 0.02 for each). Patients with transient and no ST depression did not differ for fatal and nonfatal MI, CHF, or sudden death.

Conclusions

Transient and persistent ST-segment depression during electrocardiographic evaluation was associated with increased mortality in patients who had a first myocardial infarction compared with patients who did not have ST-segment depression.

Source of funding: Not stated.

For article reprint: Dr. M. Gheorghiade, Division of Cardiology, Northwestern Memorial Hospital, 250 East Superior, Wesley Pavilion 524, Chicago, IL 60611. FAX 312-908-5774.


Commentary

This natural history evaluation of the 1981 BHAT study from the National Heart, Lung, and Blood Institute archives predates, by definition, the availability of β-blockers, calcium channel blockers, intravenous thrombolytic agents, and acute coronary angioplasty for first MI. Despite this limitation, the study by Gheorghiade and colleagues reports that in the absence of persistent ST-segment depression, 2-year survival after discharge was 95% (mortality and infarction rate of 8%) compared with only 87% (mortality and infarction rate of 18%) when persistent ST-segment depression was noted. The patients at higher risk were more often female, were older, had more cardiomegaly, had more frequent atrial fibrillation, and had less preexisting angina.

This study supports literature suggesting that clinicians can predict long-term risk from standard, inexpensive, and readily available observations. The low-risk group can expect a 2-year survival of more than 97% by using β-blockers and aspirin with only an occasional crossover to higher risk. These patients may receive little benefit from early aggressive therapy. Patients identified to be at higher risk by age, sex, socioeconomic status, previous history, ST-segment depression, heart size, estrogen status, and clinical course (including functional evaluation and noninvasive testing) (1-3) are more likely to benefit from more expensive and intensive testing after MI. Progress in risk assessment may enable us to cost-effectively tailor the management of patients using appropriate patient subgroupings based on scientific principles rather than on prejudices (4).

Larry A. Weinrauch, MD
Mount Auburn Hospital Cambridge, Massachusetts, USA