Comparison of Left Ventricular Ejection Fraction and Left Ventricular Global Strain as Determinants of Infarct Size in Patients with Acute Myocardial Infarction

Background: The aim was to compare left ventricular ejection fraction (LVEF) and left ventricular (LV) global strain by speckle tracking as predictors of final infarct size. Methods: LV global strain and LVEF by echocardiography were assessed in the acute phase and after revascularization in 39 patients with ST-elevation myocardial infarction treated with thrombolysis. Results: After revascularization, global strain and LVEF correlated well with infarct size measured by contrast-enhanced cardiac magnetic resonance. A cutoff value of -15.0% for global strain had a sensitivity of 90% and a specificity of 86% to identify myocardial infarcts larger than 20%. Interobserver variability, expressed by intraclass correlation coefficients, for global strain and LVEF was 0.91 and 0.72, respectively. Conclusions: LV global strain is a more precise diagnostic predictor of large infarcts compared with LVEF and is more reproducible. Global strain measured after revascularization demonstrates advantages over LVEF in the evaluation of LV injury in patients with ST-elevation myocardial infarction. (J Am Soc Echocardiogr 2009;22:1232-8.)