Role of Serum Troponin-I in Identifying Left Ventricular Ejection Fraction of ≤40% in Patients with Acute Anterior ST Elevation Myocardial Infarction

Objective: To determine the serum levels of troponin-I in identifying left ventricular ejection fraction (LVEF) of <= 40% in patients with first anterior ST Elevation Myocardial Infarction (STEMI). Study Design: Case series. Place and Duration of Study: At the Tabba Heart Institute, Karachi, from May to November 2008. Methodology: Consecutive patients presenting with first anterior STEMI were studied. Troponin-I concentration was measured by MEIA (microparticle enzyme immunoassay) method and LVEF was visually assessed. Analysis of relation between troponin-I levels and LVEF by the Receiver-Operator Characteristic (ROC) curve was performed to determine the cut off values of troponin-I in identifying LVEF of <= 40% in patients, who had received streptokinase or undergone primary Percutaneous Coronary Intervention (PCI). Results: Out of the 90 patients studied, 50 patients received streptokinase and the remaining 40 patients underwent primary PCI. Mean age was 54.6 +/- 9 years and 82% were male. Troponin-I levels of > 63.5 ng/ml predicted LVEF of <= 40% with a sensitivity of 94% and specificity of 97% in patients receiving streptokinase, whereas in patients undergoing primary PCI, troponin-I levels of > 87.5 ng/ml predicted LVEF < 40% with a sensitivity of 86% and specificity of 100%. Conclusion: Troponin-I concentration of > 63.5 ng/ml and > 87.5 ng/ml can predict LVEF <= 40% in patients treated with either streptokinase or primary PCI respectively for first anterior STEMI. Troponin-I can be used as a non-imaging tool to identify patients with LVEF <= 40% who need early aggressive therapy.