DK2985_C000 1..28 - AlSharqia Echo Club

Native Aortic Valve 343(A)(B)SAMLAIVSAoLVRV(C)(D)Blood VelocityASHOCMFigure 15.19 Hypertrophic obstructive cardiomyopathy (HOCM). (A, B) Mid-esophageal long-axis view. Note the systolic anteriormotion (SAM) and the septal contact of the anterior mitral leaflet in a patient with severe basal septal hypertrophy. The SAM is oftenassociated with a posteriorly directed jet of mitral regurgitation and may be associated with significant left ventricular outflow tract(LVOT) obstruction and flow acceleration. (C) Continuous-wave Doppler interrogation of a patient with HOCM. (D) Compared withaortic stenosis (AS), dynamic LVOT obstruction is characterized by late-peaking flow velocity and dagger-shaped velocity profile(Ao, aorta; IVS, interventricular septum; LA, left atrium; LV, left ventricle; RV, right ventricle).isosceles triangle can easily be calculated by measuringthe distance between two commissures (L) and applyingthe following formula:Area ¼ 0:433 L 2 (15:4)Doppler-derived Measurement of AoV Area:The Continuity EquationDoppler-derived measurements of the AVA are usuallyperformed using the continuity equation. The continuityequation is based on the principle that flow across theLVOT must equal flow across the AoV. The ASE taskforce on Doppler quantification recommends that themeasurement of blood flow velocity in the LVOT shouldbe performed with the PW Doppler sample volume positioned5 mm beneath the AoV (7). The peak velocitymeasured with CW Doppler represents the maximalblood flow velocity across the AoV.Measurement of the AVA using the continuityequation and peak velocities is obtained through thefollowing formula:Flow ¼ area(cm 2 )velocity(cm=sec) ¼ cm 3 =sec (15:5)Flow LVOT ¼ Flow AoV (15:6)Area LVOT Velocity LVOT (PW)¼ AVAVelocity AoV (CW)AVA ¼ Area LVOT Velocity LVOTVelocity AoV¼ pR2 Velocity LVOTVelocity AoV¼ pD2 =4Velocity LVOTVelocity AoVAVA ¼ 0:785D2 Velocity LVOT (PW)V max (CW)(15:7)Measurement of the AVA can also be performed usingthe volumetric principle in the continuity equation bysubstituting the velocity measurement (cm/sec) with the