Usually only severe (not mild or moderate) MR leads to nega- Favorable loading conditions in MR increase LVEF but do not affect the extent of shortening. Thus, a normal LVEF in MR is approximately 70%. The onset of LV dysfunction is inferred when LVEF declines toward 60% or when the LV is unable to contract to a diameter <40 mm at end systole.16 18 Although chamber volumes may give more information about car- 2D volume accuracy is variable in clinical practice. Determination of MR severity is made by integrating all available data. These data include measurements of the effective ori- fice area, regurgitant volume, regurgitant frac- tion (obtained by using the proximal isovelocity surface area or quantitative Doppler flow mea- color jet area, vena contracta, continuous-wave Doppler intensity, and the trans- mitral jet velocity curve. In mitral valve prolapse, MR may be non-holosystolic (mid-late systole). Thus, careful attention in assessing its severity is needed as conventional color Doppler parameter may overestimate its severity on a single image frame. Volumetric measurements provide a better assessment in this situation.9 2. TEE provides excellent imaging of the mitral valve and should be performed when TTE images are inadequate to fulfill the goals of TTE noted pre- viously. TEE is especially useful in cases of MR attributable to IE because TEE can provide infor- mation about other potentially infected struc- tures. TEE may allow more precise quantitation of regurgitant severity and provide a better esti- mate of the likelihood of a successful surgical valve repair than does TTE. Three-dimensional TEE may be helpful in further visualizing the abnormal mitral valve anatomy, offering a sur- gical view of the valve. Mitral valve repair is preferable to valve replacement because of a lower operative mortality rate and avoidance of the complications inherent to prosthetic valves. 