DK2985_C000 1..28 - AlSharqia Echo Club

Global Ventricular Function and Hemodynamics 191REDUCTIONTPBASELINETPINCREASETP(A)TMFPRE INFUSIONTMFEAEAEA0PVFSDARSDFigure 9.8 Effect of changes in preload on the pulsed-waveDoppler interrogation of the transmitral valve flow (TMF) andthe pulmonary venous flow (PVF). With reduction in volume,both the early diastolic mitral valve inflow E-wave and the diastolicD-wave of the PVF are reduced. With increase in preload,the TMF E-wave and PVF D-wave are increased (AR, atrialreversal).ARSDAR80cm/sec(B)TMFMAP:86 mmHgMPAP:20 mmHgPra:13 mmHgPaop:9 mmHgSV:48 mlCO:3.2 L/minCI: 2.0 L/min/m 2POST INFUSIONelastance, that is, the ratio of LVESP over the LVESV (24)or by estimating the LVES wall stress which combinesM-mode or 2D measurements with pressure data (seeChapter 5). An often unrecognized important clinical scenarioleading to an increase in afterload is seen with the systolicanterior motion (SAM) of the MV and its associatedleft ventricular outflow tract (LVOT) obstruction whichresults in mosaic flow due to aliasing on color imagingof the LVOT (Fig. 9.10). Systolic anterior motion of theMV can occur during MV repair and several otherextreme physiologic situations during which left ventricularfilling is significantly reduced.3. Contractility and Ventricular PerformanceChanges in preload and afterload will displace thepressure–volume loops along a line called maximal elastance.Decreasing or increasing contractility will beassociated with a downward or upward shift of the elastanceand a displacement of the pressure volume relationshiptowards the right. In Fig. 9.4(C), for instance, thedecrease in contractility (dotted loop) results in a greaterLVESV for the same LVESP. The concept of elastanceis important to understand because this measure is consideredrelatively independent of changes in preload andafterload. Measurements such as ejection fraction andCO are not pure indices of contractility but rather markersof ventricular performance. Consequently, changes inpreload or afterload may affect the ejection fraction butno changes in elastance will be observed. A study with080cm/secMAP :78 mmHgMPAP :24 mmHgPra :16 mmHgPaop :20 mmHgSV :52 mlCO :3.4 L/minCI : 2.1 L/min/m 2Figure 9.9 Echocardiographic and hemodynamic effect ofvolume loading: a high baseline E/A ratio predicts limited responseto fluid infusion. (A) The transmitral flow (TMF) early diastolic E-wave is predominant compared with the atrial A-wave. (B) Followinga bolus of 500 mL of a colloid solution, the E/A ratio increased.This was associated with an increase in mean pulmonary arterypressure (MPAP), right atrial pressure (Pra), pulmonary arteryocclusion (Paop) or “wedge” pressure but no significant changein mean arterial pressure (MAP), stroke volume (SV), cardiacoutput (CO), and cardiac index (CI).patients undergoing coronary artery bypass also documentedthe fact that despite the absence of significant postoperativechange in SV, fractional area change (FAC)and CO, the elastance index suggested a reduction in