“…Therefore, it is extremely important to record the LAA flow velocity in AF patients. Recent advancement in echocardiography, i.e., tissue harmonic imaging, enables us to visualize the LAA structure more clearly than fundamental imaging and to measure the LAA flow velocity to some extent by TTE [8,16,17]. However, the rate of detecting the LAA flow velocity by TTE is not necessarily a satisfactory value in clinical practice.…”