Heart disease is the leading cause of death worldwide. To determine the factors contributing to the development of cardiac disease, computational fluid dynamics (CFD) and in vivo data, such as MRI of blood flow, are being compared and validated to better understand the hemodynamics of the heart in detail. The cardiac conduction system, which transmits electrical signals and controls the heart’s beating, is also being studied. However, no studies have examined the relationship between the cardiac conduction system and left ventricular hemodynamics. In this study, we focused on the Purkinje fibers located in the left ventricle within the cardiac conduction system. The simulation results of left ventricular models with and without Purkinje fibers were compared. The results showed differences in blood flow within the left ventricle. Thus, changes in contraction caused by the Purkinje fibers affect the hemodynamics of the left ventricle and can contribute to the development of heart disease.