DK2985_C000 1..28 - AlSharqia Echo Club

Normal Anatomy and Flow 61Figure 4.6 (A, B) Mid-esophageal long-axis view of the left ventricle (LV). (C) Three-dimensional echocardiogram. (D) Anatomicalcorrelation (Ao, aorta; LA, left atrium; LVOT, left ventricular outflow tract; RV, right ventricle).from 08 to 1358 to obtain a comprehensive assessment ofthe AoV cusps and exclude aortic regurgitation (AR). Animportant orientation plane is at about 458 (+158) whenthe imaging sector is most parallel to the AoV ring andthere is optimal visualization of all three AoV cusps(Fig. 4.3h). Another is at 908 when, with slight leftwardrotation, the imaging plane is parallel to the ascendingaorta. It is this view which is most useful in excludingascending aortic aneurysm as well as type A dissection(Fig. 4.3q). However, it is important to remember that asmall portion of the distal ascending aorta is never wellvisualized by TEE due to interposition of the air-containingtrachea and left mainstem bronchus. Finally, the viewat approximatively 1358, which corresponds to the transthoracicleft parasternal long-axis view, is important toget the best measurements of the LVOT diameter (Fig. 4.3i).Tip 4: The aortic cusp facing the interatrial septum isalways the noncoronary cusp, and the one that is anterioris always the right coronary cusp in the absence of majorcongenital heart disease. This principle assists withaortic cusp identification independent of the imagingmodality [transthoracic echocardiography (TTE) or TEE]being used.4. Four-Chamber View (0–208, Retroflexion)This view depicts the left and right ventricles, left and rightatria, atrial septum and mitral and tricuspid valves(Figs. 4.3a and 4.7). However, the true apex of the left ventricle(LV) is often not optimally seen due to foreshortening.This can be corrected by more retroflexion, but loss ofesophageal mucosal contact and image degradation isusually the limiting factor.5. Transgastric Views (08, 908, and 1358)The probe is advanced from the mid-esophageal positionthrough the lower esophageal sphincter into the stomach.At 08 with anteflexion of the probe tip and gentle advancementor withdrawal, a short-axis view of the LV at papillarymuscle level can be obtained (Figs. 4.3d and 4.8). From thisposition, withdrawal or anteflexion of the probe tip oftenallows a short-axis view of the mitral valve (Fig. 4.3f), while