Representative images of the left atrial appendage, and time-volume curve and time-strain curves constructed by velocity vector imaging in patients with atrial fibrillation. (A) Left atrial appendage (LAA) of a patient without thrombus. (B) LAA of a patient with thrombus. (C) Time-volume curve is shown as an orange line. Time-dv/dt curve is shown as a blue line. *thrombus. Bar=1 cm.