standardized data acquisition in transoesophageal echocardiography 25 Fig. 1.29 The mid-oesophageal 4-chamber view during systole (a) and diastole (b), the midoesophageal 2-chamber view during systole (c) and diastole (d), the mid-oesophageal long-axis view during systole (e) and diastole (f) and the simultaneous triplane views during systole (g) and diastole (h) to document that angle differences between mid-oesophageal standardized views with the left ventricular apex near the centreline of the sector are about 60° like the transthoracic views. Additional comments in the text. The aortic short-axis view is also obtained by further flexion of the tip of the probe taking the 2-chamber view as the starting view. In addition to the morphological analysis of the aortic valve, the aortic short-axis view ( Figs 1.31d and 1.32a) also shows the region of the oval fossa to detect a patent foramen ovale, which is located at the connection of the inter-atrial septum with the aortic valve annulus. With rotation from 50°–75° to 120°–135° the longitudinal intersected channel of the patent foramen ovale can be visualized ( Fig. 1.31d–f). In addition, colour-coded Doppler can be used or contrast can be administrated to document a communication defect. An additional long-axis view of the aortic valve (120°–135°) should be documented from the most upper oesophageal approach to display the best possible view of the ascending aorta ( Fig. 1.32b). The perpendicular short-axis view of the ascending aorta (again 60°–75°) displays the cross-sected ascending aorta, as well as the bifurcation and origin of the right pulmonary artery ( Fig. 1.32c–d). With a clockwise rotation of the probe shaft, the cross-sected superior caval vein is behind the right upper pulmonary vein ( Fig. 1.32e–f). This view is necessary for the detection of upper sinus venosus atrial defects. By rotating the shaft of the transoesophageal probe clockwise from the aortic long-axis view, the bicaval view can be achieved ( Fig. 1.33a–b). The bicaval view of the right atrium displays the left atrium at the top followed by the inter-atrial septum, which is longitudinally intersected and is seen as a nearly horizontal structure. Distal to the inter-atrial septum the right atrium is displayed. Located on the right side of the sector the orifice of the superior caval vein and the right atrial appendage can be documented, on the left side of the sector the orifice of the inferior caval vein enters the right atrium. The transgastric views will be achieved after positioning the tip of the probe in the upper stomach. For the transgastric approach harmonic imaging is often superior to fundamental imaging due to the larger near field and the longer distance between the transducer and the cardiac structures. The investigation starts with a short-axis view of the left ventricle at the
26 chapter 1 conventional echocardiography—basic principles Fig. 1.30 Oblique mid oesophageal 2-chamber view (a) for visualization of the left atrial appendage (LAA) and the upper left pulmonary vein. The upper left pulmonary vein is displayed at the right side of the sector by positioning of the left atrial appendage in the centre of the sector (b). Colour-coded imaging of the pulmonary vein (c) facilitates the positioning of the sample volume for flow measurements. In the middle of the figure the pulsed wave Doppler spectra of the flow in the left atrial appendage with sinus rhythm (e) and in the upper left pulmonary vein (e) are displayed. Additional comments in the text. Fig. 1.31 Biplane documentation of a normal left atrial appendage (a, b) and the corresponding pulsed wave Doppler spectrum during atrial fibrillation (c). Documentation of the oval fossa in a short-axis view at the aortic root level (d). By rotation of the plane to 90° (e) and 107° (f) the channel between the septum primum and secundum is displayed. Additional comments in the text.