The Mechanics of Apical Rotation in Patients with Myocardial Infarction and Reduced Left Ventricular Function

Abstract

Background: Traditionally the use of Left ventricular ejection fraction (LVEF) for assessment of left ventricular (LV) systolic. Function is the most widely used method. However, this method is inaccurate after acute MI, this attributed to the development of wall-motion abnormalities after acute MI; Inaddition, the biplane Simpson method calculation is inaccurate, because it relys on geometric assumptions. Recently, the use of two-dimensional speckle-tracking imaging has facilitated noninvasive measurement of LV torsion. Objective: The aim of this study was to use speckle-tracking echocardiography to assess apical rotation in patients with anterior and inferior myocardial infarction (MI). Patients and methods: The present study enrolled 54 patients with anterior or inferior MI, in addition to 20 healthy volunteers (matched for age and sex) as the control group. Using commercially available two-dimensional strain software, apical, basal rotation, and LV torsion were calculated. Basal and apical LV short-axis images were acquired for further off-line analysis. Results: Apical rotation was significantly reduced in the patient group compared with the control group (P<0.001). Consequently, torsion degree (P<0.001), torsion rate, and untwisting rate (P=0.007) were significantly reduced. There was a significant correlation between ejection fraction and apex rotation (r=0.466, P=0.044), torsion degree (r=0.499, P=0.03), and untwisting rate (r=−0.543, P<0.001). Correlation with basal rotation was nonsignificant, and thus measurement of apical rotation alone (rather than calculation of LV torsion) might provide a simple and accurate alternative for assessment of LV contractility. Conclusion: Apical rotation and torsion were decreased in ST-elevation MI, and this was statistically significant in patients with LV dysfunction.