الفهرس 
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Abstract
Complex architecture of left ventricular (LV) myocardial fibers is a vital contributor to normal LV performance.(1) Contraction of obliquely oriented myocardial fibers leads to a systolic wringing motion of the LV as a result of the opposing rotation of apex and base.
Myocardial fiber orientation in the LV wall changes from a left-handed helix in the subepicardium to a right-handed helix in the subendocardium.(2-5) Contraction of these obliquely oriented fibers creates a wringing or twisting motion of the LV. Torsional deformation is determined by the net effect of positive torsional deformation forces developing in the subepicardium and negative torsional deformation forces generated in the subendocardial fibers.(3-5) The loss of torsion results from the diminution of counterclockwise apical rotation. These severe impairments of apical strain cannot generate sufficient apical rotational movement, which is the main determinant of LV systolic twist. This is a result of the reduction of circumferential strain in the apex, which may affect LV twist behavior.
Speckle tracking (STE) is a simple echocardiographic method for assessing LV strain, rotation and torsion.
MI is accompanied with regional wall-motion abnormalities in the LV apex. Because LV torsion is predominantly generated from apical rotation, so that apical rotation and LV torsion might be depressed in patients with MI.
74 individuals were enrolled, divided into two groups; Group I (patients group): 54 myocardial infarction patients included 19 patients with LV dysfunction (EF<50%) and 35 patients with normal LV function also included 38 patients with anterior MI and 16 patients with inferior
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MI. Group II: included 20 healthy ages and sex matched volunteers free from cardiovascular risk factors.
Participants in the study were subjected to full history taking, thorough clinical examination, 12 leads ECG. 2D echocardiography, M-mode and Doppler examination were performed; LV dimensions were measured including LVEDD, LVESD, IVSd, LVPWd, and left ventricular ejection fraction. Pulsed wave Doppler echocardiography was performed for measuring mitral inflow velocities.
Global longitudinal peak systolic strain values were measured by 2D STE.apical rotation,basal rotation ,torsion degree, apical rotation rate,basal rotation rate,torsion rate,untwisting rate and time to peak untwisting velocity
Results of the current study showed that:
Regarding conventional echocardiographic parameters:
Significant difference between myocardial infarction group and control regarding FS& EF& LA& LVIDs& IVSd& ESV However, No significant difference was recorded regardingAO& LVIDd& IVSs.
Regarding the left ventricular diastolic function as measured by pulsed wave Doppler E/A ratio
The findings of this study indicated that significant LV diastolic impairment was common in patients groups compared with control group.
Regarding LV Deformation Data
Bull’s eye projections of peak longitudinal strain of 17 myocardial segments in patients group showed marked reduction of peak systolic strain
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Apical rotation was high significantly reduced in patient group compared to control group(p<0.001),consequently torsion degree (p<0.001)and torsion rate & untwisting rate(p=0.007).
Apical rotation was reduced in abnormal LVEF group compared with normal LVEF group (P =0.669),also torsion degree (P =0.573) mainly because of reduced apical rotation consequently torsion rate and untwisting rate(p<0.001 ).
Significant correlation between EF and apex rotation (r=0.466, p=0.044), and torsion degree (r=0.499,p=0.03) and untwisting rate (r=-0.543,p=<0.001).
Correlation with basal rotation was non significant so measurement of apical rotation alone (rather than calculation of LV twist) might provide a simple and accurate alternative for assessment of LV contractility.
No difference between anterior and inferior MI as regard to apical rotation which is affected by size rather than site of infarction (p=0.426)