Calculation of Pulse Wave Velocity. Distance (white line, left panel, Δx) was calculated between A (green line, ascending aorta) and B (red line, abdominal aorta). Corresponding Aortic flow/time curves used to calculate the arrival times of aortic pulse waveform are shown in the right panel. Δt represents the time (ms) between the intercepts of the tangents to the flow in the ascending aorta (a, green line) and the abdominal aorta (b, red line). Pulse wave velocity is then calculated as Δx/Δt.