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
Introduction
The increased frequency of non-Q wave acute myocardial infarction (AMI) in the reperfusion era 1, 2, 3, 4, and the poor post discharge prognosis of this type of infarction 5, 6, make early risk stratification in this group of patients to be of great clinical importance.
ST segment depression in the electrocardiogram was previously reported to be an important predictor for mortality in patients with AMI 7, 8, 9. However, the importance of ST segment depression in patients with non-Q wave AMI is controversial. Several studies showed that ST segment depression was associated with increased mortality or other cardiac events compared to no ST segment depression 10, 11, 12, 13, 14. In one of these studies the univariate association between ST segment depression and mortality disappeared after adjustment for other confounding variables [10]. In another study this association was present for cardiac events but not for mortality [13]. Some of the studies included a large proportion of patients with previous infarction, more often associated with increased mortality 10, 11, 12. The aim of the present study was to compare the short- and long-term prognosis of patients with a first non-Q wave AMI presenting with ST segment depression versus those with ST elevation or no ST changes on the admission electrocardiogram.
Section snippets
Study population
The Secondary Prevention Reinfarction Israeli Nifedipine Trial (SPRINT) registry contains data on 5,839 consecutive patients with AMI hospitalized in 13 coronary care units in Israel between July 1981 and August 1983. Among 4808 hospital survivors, 2138 patients were enrolled in the SPRINT study. The detailed methods and results of this trial have been published [15]. Demographic and medical data from hospitalization and 1-year post discharge follow-up were collected for all the 5839 patients
Results
Among the 4,314 patients with a first AMI, 610 patients (14%) had a non-Q wave infarction. Sixty one patients lacking admission electrocardiograms were excluded from the present analysis (see Methods).
Among the remaining 549 patients, 236 (43%) had ST segment elevation, 186 patients (34%) had ST depression, and 127 patients (23%) displayed only T wave changes or no electrocardiographic abnormalities on the admission electrocardiogram. Among the 236 patients with ST segment elevation, 130 (55%)
Discussion
The most important findings of the present study are: 1) The presence of ST segment deviation (elevation or depression) on the admission electrocardiogram of patients with a first non-Q wave acute myocardial infarction, was associated with increased mortality risk during the index hospitalization, and after 5-years of follow-up, compared to patients with no ST changes. 2) After multivariate adjustment for possible confounders, the in-hospital and 1-year mortality risk were similar in patients
References (31)
- et al.
Myocardial infarction patients in the 1990s – their risk factors, stratification and survival in Canada: The Canadian Assessment of Myocardial Infarction (CAMI) study
J Am Coll Cardiol
(1996) - et al.
Non-Q wave myocardial infarction: recent changes in occurrence and prognosis – a community wide perspective
Am Heart J
(1987) - et al.
For the TIMI III Registry ECG Ancillary Study Investigators. The Electrocardiogram Predicts One-Year Outcome of Patients With Unstable Angina and Non-Q Wave Myocardial Infarction: Results of the TIMI III Registry ECG Ancillary Study
J Am Coll Cardiol
(1997) - et al.
Prognostic significance of precordial ST segment depression during inferior myocardial infarction in the thrombolytic era: Results in 16,521 patients
J Am Coll Cardiol
(1996) - et al.
Prognostic significance of precordial ST segment depression on admission electrocardiogram in patients with inferior wall myocardial infarction
J Am Coll Cardiol
(1996) - et al.
Emergent coronary angiographic findings of patients with ST depression in the inferior or lateral, or both, during anterior wall acute myocardial infarction
Am J Cardiol
(1995) - et al.
Implication of ST-segment depression in anterior acute myocardial infarction: electrocardiographic and angiographic correlation
Am Heart J
(1994) - et al.
Anterolateral ST segment depression in acute inferior myocardial infarction: angiographic and clinical implications
Am Heart J
(1984) - et al.
For the Secondary Prevention Reinfarction Israeli Nifedipine Trial (SPRINT) study group. Comparison of short- and long-term prognosis in patients with anterior versus inferior or lateral wall non-Q wave acute myocardial infarction
Am J Cardiol
(1997) - et al.
for the SPRINT study group. Frequency and prognostic significance of high- degree atrioventricular block in patients with a first non-Q wave acute myocardial infarction
Am J Cardiol
(1997)
For the LATE study investigators. Late assessment of thrombolytic efficacy (LATE) study: Prognosis in patients with non-Q wave myocardial infarction
J Am Coll Cardiol
Decline in the rate of hospital mortality from acute myocardial infarction: impact of changing management strategies
Am Heart J
Non-Q- and Q-wave infarction after thrombolytic therapy with intravenous streptokinase for chest pain and anterior ST segment elevation
Am J Cardiol
Prognosis after first myocardial infarction. Comparison of Q wave and non-Q wave myocardial infarction in the Framingham heart study
J Am Med Assoc
Long-term prognosis of patients after a Q wave versus non-Q wave first acute myocardial infarction
Eur Heart J
Cited by (15)
Characteristics and Outcome of Patients With Acute Myocardial Infarction According to Presenting Electrocardiogram (from the MONICA/KORA Augsburg Myocardial Infarction - Registry)
2007, American Journal of CardiologyCitation Excerpt :Patients with STE were younger and were more likely to be smokers compared with those in the other groups. This also has been observed in other trials.17,20,21 It has been speculated that smoking has prothrombotic effects that exaggerate the thrombotic response to plaque rupture and increase the risk for total rather than partial coronary occlusion.22
The greatest benefit of enoxaparin over unfractionated heparin in acute coronary syndromes is achieved in patients presenting with ST-segment changes: The Enoxaparin in Non-Q-Wave Coronary Events (ESSENCE) Electrocardiogram Core Laboratory Substudy
2006, American Heart JournalCitation Excerpt :Furthermore, the highest risk ECG subgroup of patients (those with ST-segment depression), experienced significantly greater clinical benefit from enoxaparin, as compared with UFH. The observation that patients presenting with ST depression are at increased risk for adverse outcome is consistent with previous studies examining clinical trial6-13 and other populations.5,14-20 Together with clinical features, cardiac marker status,20-24 or both,25-27 the initial ECG can identify not only those patients at higher risk for adverse outcome, but those who will potentially derive the greatest absolute benefit of more potent antithrombotic/platelet therapy and/or an invasive treatment strategy.
Cardiac markers protocols in a chest pain observation unit
2001, Emergency Medicine Clinics of North AmericaCitation Excerpt :In comparison, for patients with first-time non–Q-wave AMI who demonstrate ST depression on their admission ECG, the hospital, 1-year and 5-year mortality rates in those patients are 17%, 27% and 51% respectively.76 These rates differ little from patients with ST elevation with hospital 1-year and 5-year mortality rates of 15%, 21%, and 34%, respectively.33 During the last decade of improved AMI therapy, “the reperfusion era,” the 1-year mortality has decreased from 19% to 15% in first-time non–Q-wave AMI patients.34
- 1
For the SPRINT Study Group: see appendix Eur Heart J 1988;9:354–64.