Among the new echocardiographic techniques, two dimensional Speckle Tracking Imaging or 2D Strain allows a dynamic study of regionalized and global ventricular contraction. With software for the spatial and temporal processing of a standard 2D image, this technique measures the displacement of natural markers present on the myocardial wall.~Used in adult cardiology since 2000, it could be eligible to pediatric population because of many potential applications. In Duchenne muscular dystrophy, myocardial disease leads to death in the third decade. Early diagnosis and preventive therapy remain a challenge. No clinic, biologic or radiologic markers can predict myocardial disease before advanced and irreversible heart failure.~Recent animals and human studies suggest that 2D strain anomalies could predict left ventricular systolic dysfunction in Duchenne muscular dystrophy. If it is confirmed, 2D strain could be used as early marker of myocardial disease in routine patient follow-up and in future therapeutic studies.~Purpose : - To compare systolic function of left ventricle (LV) and right ventricle (RV) by 2D strain evaluation in Duchenne muscular dystrophy children versus a control group.~To correlate 2D Strain variables to conventional LV and RV echo variables.~To evaluate 2D strain feasibility in normal children and Duchenne muscular myopathy population
Compare systolic function of left ventricle (LV) and right ventricle (VD) by 2D strain evaluation in Duchenne muscular dystrophy children versus a control group.