Introduction: Acute anterior wall myocardial infarction (AWMI), when presenting with ST-segment elevation on an electrocardiogram (ECG), represents a form of ST-elevation myocardial infarction (STEMI) caused by a significant reduction in coronary blood flow to the heart muscle. The shape of the ST-segment elevation, whether it is concave, convex, or straight, has been associated with different levels of left ventricular ejection fraction (LVEF), which is an important indicator of cardiac function and prognosis.
Objective: To investigate the relationship between the type of ST-segment elevation on ECG and LVEF measured 48 hours after the onset of myocardial infarction in patients with AWMI.
Methodology: A retrospective observational study was conducted on 317 patients with acute anterior wall myocardial infarction at Shalamar Hospital, Lahore, Pakistan, from January 2023 to December 2023. Patients' electrocardiograms were analyzed for ST-segment elevation morphology, and left ventricular ejection fraction was assessed using echocardiography. Long-term echocardiography was performed at 30 days and 90 days post-infarction to evaluate the long-term effects on LVEF and to assess for stunned or hibernating myocardium. Statistical analysis was performed in IBM Corp. Released 2015. IBM SPSS Statistics for Windows, Version 23.0. Armonk, NY: IBM Corp. to determine the association between ST-segment types and left ventricular ejection fraction.
Results: The mean age was 58.3 ± 12.4 years, with a majority being male (67.5%). Key findings included that 33.1% of patients had left ventricular ejection fraction (LVEF) < 40%, while the mean LVEF was 45.2 ± 9.8%. Primary percutaneous coronary intervention (PCI) was performed in 45.7% of patients, and no deaths occurred during hospitalization. A significant association was observed between the type of ST-segment elevation and LVEF, with convex ST elevation linked to a 2.7-fold increased likelihood of severe LV dysfunction (LVEF < 40%) and a hazard ratio of 2.3 for adverse outcomes (p = 0.005). In contrast, concave ST elevation did not show significant predictive value for LV dysfunction. Older age and smoking were also identified as strong predictors of LV dysfunction, highlighting the impact of these factors on patient outcomes post-AWMI.
Conclusion: The study demonstrates a significant correlation between convex ST-segment elevation and lower LVEF, suggesting that ST-segment morphology can serve as an important prognostic indicator in AWMI patients.
Keywords: acute anterior wall myocardial infarction; cardiac prognosis; electrocardiogram; left ventricular ejection fraction; st-segment elevation.
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