الفهرس 
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Abstract
It has been reported that acute myocardial infarction is responsible for a decrease in left ventricular function. The myocardium is composed of multiple oriented myocardial fibers and layers, and may cause different myocardial rotational changes with different regional mechanical disturbances.
The early identification of patients who are prone to develop remodeling post infarction has been the center of intense research in recent years, spearheaded by the introduction of new techniques in the field of cardiac imaging.
The role of conventional and speckle tracking echocardiography in predicting left ventricular remodeling and left ventricular twist after acute myocardial infarction is important for diagnosis and prognosis of left ventricular dysfunction.
In this study we tried to evaluate the impact of thrombolytic therapy on left ventricular rotation and twisting by comparing the alteration in apical and basal rotation between patients with anterior and inferior myocardial infarction.
29 patients with anterior and 9 patients with inferior myocardial infarction who were received thrombolytic therapy in acute stage were analyzed .19 healthy age and gender matched subjects were included for controls.
The apical and basal rotations were obtained and left ventricular twist and torsion were measured by 2D speckle tracking imaging.
Compared with normal, left ventricular twist was reduced in all AMI patients. Basal rotation was larger in anterior AMI than in inferior AMI and normal (-6.78±1.55 vs. -3.31±0.89) (p=0.01) respectively, although the apical was lower in anterior AMI .
As a result, left ventricular twist and torsion were not different between anterior and inferior AMI (8.59±0.91 vs. 8.17±0.87) (p=NS) respectively, although left ventricular ejection fraction was lower in anterior AMI. Early thrombolytic therapy after AMI may help left ventricular recovery in patients with anterior and inferior AMI.
The regional wall motion abnormalities in AMI altered left ventricular rotational mechanics either by reducing apical and basal rotations. Left ventricular twist and torsion were similarly reduced between anterior AMI and inferior AMI even through the left ventricular ejection fraction was worse in anterior AMI, which might be due to increased basal rotation as a compensatory mechanism. Basal rotation has often been ignored, however these study suggest that the basal rotation may have an important role in left ventricular function.
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Early revascularization maybe helpful for maintaining compensatory mechanism for early left ventricular recovery.
2D speckle tracking analysis cannot track the 3D motion of the heart and thus cannot eliminate the errors introduced by through plane motion, specially in the basal plane.
Most of our patients averaged six decades age, and the result may be different from younger or older subjects because it is known that left ventricular rotational characteristic differ with age.
Speckle tracking ECHO (STE) is simple non invasive technique for assessing LV strain, rotation and twist in humans. We recommend this technique in patients who are not recovered after early revascularization who may need further aggressive therapy to prevent LV remodeling, heart failure and poor outcome.
Early evaluation of LV apical rotation after AMI by STE may be able to identify patients with reduced apical rotation, who could benefit with reduced apical rotation, who could benefit from aggressive medical treatment, revascularization and stem cell therapy, in order to avoid LV remodeling and cardiac failure