Prognostic Significance of Electrocardiography, Echocardiography, and Troponin in Patients Admitted With Non-ST Elevation Myocardial Infarction.

Background: Non-ST segment elevation myocardial infarction (NSTEMI) is a clinical condition characterized by typical symptoms of myocardial ischemia along with electrocardiographic changes and a positive value of troponin. After presentation in the emergency department, these patients have their troponin I value and electrocardiography done. Echocardiography (echo) should also be performed on these patients. This study was conducted to determine the prognostic significance of ECG, echo, and troponin.

Methods: This observational study was conducted at a tertiary care cardiac hospital on 221 diagnosed patients of NSTEMI. Electrocardiography was performed to see any particular resting ECG findings and the peak values of cardiospecific troponin were analyzed for associations with major adverse events after a six-month period of follow-up. On echo, the left ventricular ejection fraction was divided into two categories: left ventricular ejection fraction (LVEF) <40% and LVEF >40%.

Results:  The most frequent finding on presenting ECG was ST depression in anterior leads (V1-V6) in 27.6%. Median troponin I at presentation was 3.2 ng/dl and the median ejection fraction was 45%. The overall all-cause mortality rate at six months was observed to be 8.6%; re-infarction in 5%, re-hospitalization in 16.3%, and heart failure in 25.3% were observed. However, mortality was higher for patients with baseline ECG findings of A-fib, generalized ST-depression, poor R-wave progression, Wellens sign, and T-wave inversion in inferior; the mortality rate was also relatively higher among patients with poor LVEF (<30%).

Conclusion: ECG and echo were prognostically significant and with the combined incidence of adverse events. However, troponin lacks prognostic significance at six months.