Fig. (1) Panel (a): schematic representation of the instantaneous flow pattern through the aortic valve. Notations are as follows: GOA: geometric orifice area, i.e. the area of the stenotic valve orifice; EOA: effective orifice area, i.e. the area of the jet at vena contracta section. Sections 1 and 2 are located in the left ventricular outflow tract and ascending aorta, respectively. Panel (b): instantaneous flow pattern as the GOA increases during the valve opening phase.