Fields of velocities in the atrial cavity   Measured by a multidoor ultrasound Doppler velocimeter (Signal Processing), fields of velocities in the auricle constitute a very original result. As a matter of fact, no author had ever realized such fields of velocity. The maps displayed below were realized for an average flow of 3l/mn at 72 beats per minute. The plan of measurement lays in the axis of the mitral valve, considering the viewing plan represented besides the first field of velocities.   Beginning of the filling Atrial contraction Closing of the mitral valve The flow passes from the pulmonary veins to the mitral valve, the auricle acts as a "duct". The flow comes from the area located close to the atrial appendix. The ebb-flow which goes with the closing of the mitral valve gets visible. It should be noticed that the flow in the vicinity of the atrial appendix has a significant value only during the atrial contraction. This leads us into thinking that in case of atrial fibrillation, this area of the auricle might not be "washed" by the flow, creating therefore a zone of stasis propitious to the initiation of the thrombus.