DK2985_C000 1..28 - AlSharqia Echo Club

412 Transesophageal Echocardiography(A)(B)LAAoLVRV(C) LVOT(D) TMFFigure 17.34 Calculation of the mitral valve area (MVA) using the continuity equation. (A, B) The left ventricular outflow tract(LVOT) diameter is measured from the mid-esophageal long-axis view at 1358. (C) To complete the calculation of the strokevolume, the LVOT time velocity integral (TVI) is obtained by pulsed-wave Doppler (PWD) examination from a deep transgastricview at 08 (or alternatively from a basal transgastric view at 1108). (D) The MVA is calculated by dividing the stroke volume bythe TVI of the mitral valve, which is given by continuous-wave Doppler (CWD) examination through the mitral valve from the mid-esophagealview (Ao, aorta; LA, left atrium; LV, left ventricle; RV, right ventricle; TMF, transmitral flow).stenotic MVA. The angle between the two mitral leafletsmust also be measured for the necessary correctionfactor a/180 in MS.The PISA method appears to provide valve area estimateswhich are at least as accurate as the traditionalechocardiographic methods with accuracy preserved inatrial fibrillation (55). Because this method applies thecontinuity equation with flow parameters measured on asingle valve, the presence of other valve disease such asAR should not affect its accuracy (56).