Simultaneous determination of aortic valve area by the Gorlin formula and by transesophageal echocardiography under different transvalvular flow conditions. Evidence that anatomic aortic valve area does not change with variations in flow in aortic stenosis. - Tardif,J.C.; Rodrigues,A.G.; Hardy,J.F.; Leclerc,Y.; Petitclerc,R.; Mongrain,R.; Mercier,L.A. (J Am Coll Cardiol, 1997)