Fig. 2 Long-axis four-chamber views (RA, right atrium; LA, left atrium; RV, right ventricle; LV, left ventricle) at end-diastole (ED) and end-systole (ES) obtained by transesophageal echocardiography in two different patients. Left panel, a patient with some degree of hypertrophic cardiomyopathy and normal LV systolic function who was managed by mechanical ventilation for an acute pulmonary edema. Right panel, a patient, with previously normal cardiac status, who was managed for a septic shock with severe left ventricular systolic dysfunction and extremely low cardiac output resulting in spontaneous contrast (SC) in the left atrium.
Several anatomical structures (ascending aorta, main pulmonary artery, right and left atria, atrial appendages, pulmonary veins, and aortic and pulmonary valves) are readily accessible on these views (Fig 3). Pathological phenomena, such as small atrial thrombi (particularly in the left atrial appendage) and left atrium spontaneous echo contrast, both associated with an increased risk of thromboemboli, patent foramen ovale during mechanical ventilation with or without positive end-expiratory pressure, and central pulmonary artery thrombi in massive pulmonary embolism, are identified more clearly and more frequently by transesophageal echocardiography than by transthoracic echocardiography.
Fig. 3 Basal short-axis view, showing the interatrial septum (SIA) (left upper panel), with the foramen ovale (F). The left lower panel shows the kinetics of the SIA recorded in M-mode; the profile is the same as that of a left atrial pressure recording. The left atrial appendage (La) is shown in the right upper panel, and the pulmonary venous flow velocity from the left superior pulmonary vein is recorded, together with airway pressure, in the right lower panel. RA, right atrium; LA, left atrium; Ao, aorta.
Transesophageal echocardiography has become an established technique ( Fig...^) for the rapid and reliable detection of traumatic and medical abnormalities associated with the ascending and descending aorta, particularly aortic dissection. This technique compares favorably with other imaging methods such as aortography, CT scanning, and magnetic resonance imaging. When single-plane transesophageal echocardiography is used, the upper portion of the ascending aorta is masked by the trachea and the proximal bronchus. Dual-plane and multiplane transesophageal echocardiography, combined with color Doppler, partly overcome this limitation.
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Fig. 4 The thoracic aorta: (a) ascending part; (b) arch; (c) descending part.
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