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Prognostic significance of ST-T segment alterations in patients with non-Q wave myocardial infarction
J A Ramires1, C V Serrano, M C Solimene
1Heart Institute, University of São Paulo, Brazil.
Insights
Electrocardiogram ST-T shifts in non-Q wave myocardial infarction can predict outcomes. ST segment depression indicates more severe coronary artery disease and higher cardiac event rates compared to T wave inversion.
Area of Science:
- Cardiology
- Clinical Medicine
- Diagnostic Electrocardiography
Background:
- Non-Q wave myocardial infarction (MI) requires accurate prognostic indicators.
- Electrocardiogram (ECG) findings, specifically ST-T wave changes, may offer prognostic value.
- Identifying patients at higher risk is crucial for timely intervention.
Purpose of the Study:
- To evaluate if ST-T wave characteristics on diagnostic ECGs in non-Q wave MI patients can identify severe coronary artery disease (CAD).
- To determine if these ECG findings predict poor clinical outcomes.
- To compare the prognostic significance of ST segment depression versus T wave inversion in non-Q wave MI.
Main Methods:
- Prospective controlled clinical trial conducted at a primary referral medical center.
- Studied 93 patients with non-Q wave MI, categorized by ECG findings: 41 with T wave inversion and 52 with ST segment depression.
- Assessed cardiac events and mortality rates over a 42-month follow-up period.
Main Results:
- Patients with ST segment depression showed significantly higher rates of total occlusion in the infarct-related artery (26.7%) compared to those with T wave inversion (94.6%) (P < 0.05).
- ST segment depression was associated with higher short-term (9.6% vs. 0%, P < 0.01) and long-term (30.8% vs. 9.8%, P < 0.02) cardiac event rates.
- Mortality rates were comparable between the two groups in the short and long term.
Conclusions:
- ST segment depression in non-Q wave MI is linked to a higher incidence of short and long-term cardiac events compared to T wave inversion.
- This association may be attributed to a higher prevalence of residual stenosis in the infarct-related artery.
- ECG ST-T wave characteristics are valuable in stratifying risk in non-Q wave MI patients.
Objective:
To determine whether, among patients with non-Q wave myocardial infarction, the characteristics of the segment ST-T shifts at presentation in the diagnostic electrocardiogram can identify those with more severe coronary artery disease and predict a poor clinical outcome.
Design:
Prospective controlled clinical trial.
Setting:
Primary referral medical centre.
Patients:
93 patients (mean (SD) 62.0 (7.5) years) were studied: 41 with non-Q wave myocardial infarction and T wave inversion and 52 with ST segment depression. Cardiac events and mortality rates were assessed over 42 months. Age, sex, risk factors, creatinine kinase MB isoenzyme peak, and left ventricular function were comparable.
Results:
31 patients with T wave inversion myocardial infarction (94.6%) had total occlusion of the infarct related artery, compared with 12 patients with ST segment depression myocardial infarction (26.7%) (P < 0.05). When compared with patients with T wave inversion, patients with ST segment depression had a higher incidence of cardiac events during the first month and in the 41 subsequent months: 9.6% and 30.8% v 0% (P < 0.01) and 9.8% (P < 0.02), respectively. For the same observation periods, the mortality rates in patients with T wave inversion were 4.9% and 7.3%, and in patients with ST segment depression they were 5.8% and 9.6%, respectively.
Conclusion:
These data suggest that during a non-Q wave myocardial infarction the presence of ST segment depression is related to higher rates of short and long term cardiac events when compared with T wave inversion--possibly because of a higher incidence of residual stenosis of the infarct related artery.