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Comparison of the two dimensional versus three dimensional transthoracic echocardiography in assessment of mitral regurgitation.

Kovitu Tyugo

The mitral valve is a complex structure1 .Mitral regurgitation is often referred to as organic, if there is an intrinsic valve disease, or functional, if the valve is structurally normal but leaks as a result of an extravalvular abnormality, such as an alteration in left ventricle chamber geometry and/or dilatation of the mitral annulus that adversely affects normal coaptation of the mitral valve leaflets during systole .Ischemic MR may be organic (ruptured or ischemic papillary muscle) and/or functional because of LV chamber dilatation. Nonischemic MR may be organic e.g., rheumatic or functional e.g., dilated cardiomyopathy. In contrast to conventional 2 dimensional echocardiography, which only displays the mitral valve leaflets en face from the left ventricle perspective, 3D echocardiography enables en face visualization from both left ventricle and left atrial perspectives. The latter view is also known as the ‘‘surgical view,’’ because it resembles the intraoperative image of the mitral valve after the surgeon, standing on the patient’s right side, opens the left atrium2. Two-dimensional echocardiography is not able to provide data about mitral annular shape, because mental reconstruction from separate 2D views cannot provide the same information as the volume-rendered 3D reconstruction. Instead, the oval shape of the mitral annulus is best appreciated from the 3DE surgical view of the mitral valve with the entire annular circumference captured in one data set. Moreover, the saddle shape of the mitral valve is best assessed by offline reconstructions, which depict the saddle shaped contour in three dimensions with high points that are anterior and posterior and low points that are lateral and medial . In addition, dynamic 3 dimensional rendering of the mitral valve can discriminate between normal leaflet mobility and tethered leaflets due to regional wall motion abnormalities or global left ventricular enlargement with increased sphericity (resulting in ischemic or functional mitral regurgitation). Despite proven superiority of three dimensional echocardiography over two-dimensional echocardiography no Indian studies are available comparing the two modalities. Considering above factors we decided to take up this study at our center to compare the assessment of mitral regurgitation by two dimensional versus three dimensional transthoracic echocardiography .