Figure 6: Mitral valve area by continuity equation (a) parasternal long-axis view to measure the left ventricular outflow tract diameter (b) A4C view to measure mitral stenosis velocity time integral (c) A5C view to measure left ventricular outflow tract velocity time integral. Left ventricular outflow tract diameter = 1.96 cm, left ventricular outflow tract velocity time integral = 17.4 cm, mitral stenosis velocity time integral = 74.9 cm, mitral valve area = 1.96 × 1.96 × 0.785 × 17.4/74.9 = 0.7 cm²