Visualization of the location and magnitude of kinetic energy (KE) in the heart of one representative volunteer at three time points during the cardiac cycle: at peak systole (top), at peak early diastolic filling (middle) and during atrial contraction (bottom). Three imaging planes are shown: three-chamber view (3CH, left), four-chamber view (4CH, middle), and a mid-atrial short-axis view (SAX, right). During systole, atrial KE is more prominent in the RA than in the LA, where KE is mainly located near the pulmonary vein inlets. Left atrial KE increases sharply during early diastolic filling, which is seen as a streak from the middle of the LA into the center of the LV. Meanwhile, RA KE also increases, but not as much. This increase in KE is likely caused by ventricular recoil. The KE during atrial contraction has a similar location as during early diastolic filling, but the magnitude is smaller.