Abstract: Abstract Objective: To assess the left ventricular twist and untwist in patients with acute infarcted myocardial ( AMI ) by two-dimensional speckle tracking imaging ( STI) .Method: Two-dimensional images of left ventricule (LV) at basal and apical short-axis views were acquired in 60 patients with AMI and 30 healthy subjects to evaluate LV rotation1．Patients with AMI were divided into two groups according to global LV systolic function: normal LV ejection fraction (LVEF) group, (LVEF≥50% , n=36) and abnormal LVEF gruop (LVEF <50% , n = 24 ) .Rotation were measured in the left ventricular short-axis views using 2D-strain software. LV twist were defined as rate of apical LV rotation (PAR)to the basal Peak rotation (PBR) and the time to Prot in basal and apical short axis views were measured separately, Peak twist(Ptw), twist at aortic valve closure(AVCtw), twist at mitral valve opening (MVO tw), untwisting rate(Untw R), and half time of untwisting (HTU )were calculated. Results: Compared with the control group , the value of Ptw、PAR、PBR、AVCtw and MVOtw significantly decreased in abnormal LVEF group；the value of Ptw、PAR、AVCtw and MVOtw decreased in normal LVEF group . Compared with normal LVEF group ,the value of Ptw、AVCtw and MVOtw significantly decreased in abnormal LVEF group.Significant correlation was found between LV twist and LVEF. Conclusion: Left ventricular twist and untwist can be measured using speckle tracking echocardiography. Apical rotation and global twist decrease significantly in patients with myocardial infarction.

Key words: Echocardiography , Speckle tracking imaging, Acute infarcted myocardial , Twist, untwist