Accurate quantification of mitral regurgitation (MR) plays a critical role in clinical decision making for mitral valve disease. Doppler echocardiography has emerged as the primary method used to quantitate mitral regurgitation in clinical practice but remains challenging. Current recommendations integrate multiple Doppler-derived parameters to determine MR degree,1 mainly colour-flow jet area, vena contracta (VC) width and effective regurgitant orifice area (EROA). As is well known, each colour Doppler parameter has limitations based on technical issues or inaccurate geometric assumptions. Colour-flow jet area is semi-quantitative, while VC width reflects orifice size, not MR regurgitant volume. There are well-known limitations of these variables including sensitivity to load, gain settings (jet area) and narrow measurement range (VC). EROA is a quantitative measure that is calculated using geometric assumptions based on the proximal isovelocity surface area (PISA) method. The MR regurgitant volume is calculated by multiplying the EROA by the time velocity integral. Although in theory EROA calculated using the PISA method provides an accurate quantification of MR flow and volume, in practice EROA is technically challenging with varying reproducibility, which has limited widespread adoption in clinical practice. Importantly, none of these …