DK2985_C000 1..28 - AlSharqia Echo Club

192 Transesophageal EchocardiographyTable 9.1 Summary of the Doppler Indices in the Evaluationof HypovolemiaDecreasein fillingpressureIncreasein fillingpressureMV inflow PW DopplerE velocity # "A velocity " #E/A ratio # "Deceleration time " #Pulmonary veins PW DopplerS velocity " #D velocity # "AR velocity # "AR duration # "S/D TVI ratio " #Respiratory variations " #MV annulus tissue Dopplere velocity " #Color M-modeVelocity of propagation (V p ) " #of the E-waveDerived indicesDifference A wave duration # "(MV–PV)E/e # "E/V p # "Figure 9.10 Dynamic left ventricular outflow tract obstruction:mid-esophageal long-axis view in a 38-year-old man withseptic shock and hemodynamic instability. (A, B) Part of theanterior mitral valve is obstructing the left ventricular outflowtract. (C, D) This was associated with mitral regurgitation(MR). His hemodynamic condition improved with fluid andb-blockade (Ao, aorta; AoV, aortic valve; LA, left atrium;LV, left ventricle; SAM, systolic anterior motion).contractility after the surgical procedure (Fig. 9.11) (25).In clinical practice, elastance is rarely obtained becauseartificial preload alteration is required to calculate theslope of the pressure–volume relationship.The most commonly used echocardiographic evaluationof ventricular performance includes measurementsof FAC, ejection fraction and CO. Fractional areachange provides an estimation of ejection fraction and iscommonly obtained from a transgastric view (Fig. 9.5).Ejection fraction calculation can be obtained through themeasurement of ventricular volumes from the four- andtwo-chamber views using one of several formulas availablefor volume measurements (see Chapter 5) (2).Stroke volume and secondly CO can be calculated fromeither 2D volume end-diastolic and end-systolic measurements,or from volumetric Doppler-derived results(see Chapter 5). Other indirect echocardiographic signsuseful in the identification of reduced left ventricular systolicfunction include the presence of intracavitary spontaneousecho contrast, increased anterior MV leafletseptal distance (see Fig. 10.22) reduced mitral annular displacement(26) and an abnormal myocardial performanceindex (27). The latter (see Fig. 9.12) is altered by abnormalitiesin either systolic and/or diastolic function and it canbe used in the evaluation of both left and right ventricularfunction (28,29).III. ABNORMAL LEFT VENTRICULARFUNCTIONA. Acute vs Chronic EtiologyAcute left ventricular dysfunction can be either systolic ordiastolic in origin. It is typically associated with bothincreased wall motion score index (see Chapter 8) andmoderate to severe diastolic dysfunction. Severe leftventricular systolic dysfunction will sometimes beaccompanied by pulsus alternans, where the left ventricularstroke volume and systolic blood pressure will bedecreased on every alternate beat (Fig. 9.13). Left ventriculardiastolic dysfunction is commonly seen in unstablepatients after cardiac surgery, even in patients withnormal systolic function (30). Chronic left ventricularsystolic dysfunction will be associated with ventriculardilatation and diastolic dysfunction which severity canrange from mild delayed relaxation to restrictive fillingpattern (see following text). Atrial dilatation is morecommon in chronic condition but can be observed alsoin the acute setting and often correlates with the degreeof diastolic dysfunction. This can be associated withmitral annular dilatation, mitral regurgitation (MR), andatrial fibrillation.