The left ventricle is the most prone to diseases. Among these the dyssynchrony constitutes a pathology of considerable epidemiological relevance, it is caused by a disorder cardiac contraction. The purpose of the following study is to investigate blood flow during the systole phase within the left ventricle both in physiological conditions and in the presence of dyssynchrony. The three-dimensional reconstruction of the left ventricle is used to perform the numerical simulations through computational fluid dynamics (CFD) analysis. The fluid-structure interaction, with wall motion, was conducted on the physiological left ventricle and in presence of dyssynchrony, to investigate the LVflow in terms of volume, pressure, and deformation. The results show the comparison between the ejection curve of the physiological ventricle and that in the presence of pathology. The result of this study indicates that the dyssynchrony causes incomplete left ventricular filling with reduced ejected volume and reduced output pressure in the aorta.