Calculation of the Aortic Valve Area by the continuity equation, patient in atrial fibrillation. Aortic jet velocity, left ventricular outflow velocity and diameter of the left ventricular outflow tract. Male patient aged 77 with severe aortic stenosis, matched to the patient in Figure 3. Aortic valve area (0.80 cm2). Ejection fraction (31%). Cardiac Index (1.80 l/m2). Stroke volume (50 ml).