Pressures in aortic stenosis

Simultaneously recorded pressures from the left ventricle (LV) and aorta (Ao) in a patient with aortic stenosis. There is a systolic pressure gradient (shaded area) in which the LV systolic pressure is greater than that in the aorta. The pressure gradient and systolic ejection period (SEP, in sec/beat) are used in the Gorlin formula to calculate the aortic valve area (aortic valve area = cardiac output ÷ [44.3 x SEP x HR x sq rt mean gradient]).