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Quantitative grading of the severity of mitral regurgitation (MR) in same patient of Fig. 2, using PISA method. Effective Regurgitant Orifice Area (EROA) = 2 tc^X NL/Vmax which comes 0.44 cm2, compatible with severe MR. Regurgitant nvolume = EROA X VTI which is calculated as 71 ml/beat confirming severe MR. NL = Nyquist limit, r = radius of proximal isovelocity surface area (red arrow), Vmax = maximum velocity of MR jet, VTI = velocity time integral.
