The mitral valve controls the flow of blood into the ventricle during diastole and prevents backflow into the atrium in systole. The two mitral valve leaflets have significantly different geometries. The dynamics of the leaflets and their influence on the transmitral and intraventricular flow is a controversial topic. In this paper we report results from work in progress on fluid structure interaction simulations of the mitral leaflets during left ventricular filling. The aim of the present study was to assess the impact of left ventricular initial pressures and vortices on the mitral leaflet dynamics. An explicitly coupled fluid structure interaction scheme was utilized for the numerical simulations. A 2D transient representation of the left ventricular wall movement was imposed as boundary conditions for the simulations. The left ventricular wall was rendered by ultrasound recordings, and speckle tracking was used for transient tracking of the wall movement during diastole. Thus, the structural calculations are simplified and involve only the mitral valves. The ultrasound measurements were used both for validation/comparison with the simulated mitral valve dynamics as well as for imposition of the left ventricular wall movement. Our simulations show that the initial pressure configuration in the left heart is significant for the mitral valve dynamics. The simulations also indicate that the mitral valve flutter has important bearings on the vortex formation in the vicinity of the mitral valves.