FIG 19.16 Subcostal short-axis section, tilting more leftward and revealing the left ventricle (LV), showing the left ventricular outflow tract and the ascending aorta (Ao) The aortic valve is shown in a closed position The right ventricle (RV) and the ventricular septum are also seen Parasternal and Apical Views Parasternal imaging starts with obtaining a left parasternal long-axis view This reference section shows the left ventricular outflow tract, the aortic valve, the mitral valve, the left ventricle, and the left atrium (Fig 19.17) The fibrous continuity typically present between the leaflets of the mitral and aortic valves is easily demonstrated, and this view is useful for assessing mitral and aortic valvar motion and function When the transducer is tilted toward the right hip, the right ventricular inflow and the tricuspid valve can be visualized (Fig 19.18) The orifice of the coronary sinus can also be identified in this view With anterior tilting of the transducer, the right ventricular outflow tract, the pulmonary valve, and the pulmonary trunk can be visualized (Fig 19.19) When the transducer is rotated 90 degrees clockwise from the long-axis section, a parasternal short-axis view of the base of the heart is obtained This view can provide information on the structure of the aortic valvar leaflets (Fig 19.20), the right ventricular outflow tract, and the pulmonary valve (Fig 19.21) A short-axis sweep is then usually performed from base to apex, which shows the ventricular septum Short-axis sections are obtained at the level of the leaflets of the mitral valve (Fig 19.22), the papillary muscles, and the left ventricular apex The short-axis views show well the papillary muscles supporting the tendinous cords of the mitral valve (Fig 19.23) Although conventionally described as being posteroseptal and anterolateral, examination of short-axis sections when the heart is positioned as it lies in the body reveals that these muscles are positioned inferoanteriorly and superoposteriorly A short-axis sweep with color Doppler imaging positioned over the ventricular septum allows identification of ventricular septal defects The short-axis views also show the origins of coronary arteries Slight clockwise rotation from the section showing the short axis of the aorta will demonstrate the origin of the left coronary artery, whereas slight counterclockwise rotation will demonstrate the origin of the right coronary artery The arterial duct, if patent, can be demonstrated by using a high left parasternal window with the notch of the transducer at the 12 o'clock position From the apical window, the apical four-chamber, three-chamber long-axis, and two-chamber views can be obtained The apical views are presented in the anatomic orientation with the apex down The apical four-chamber view allows interrogation of the atrioventricular valves and the morphology of the ventricular apical components (Fig 19.24) This view is particularly valuable for assessing apical displacement of the hinges of the leaflets of the tricuspid valve, as well as the septal insertions of the tendinous cords supporting the septal leaflet Posterior tilting from the apical four-chamber view shows the coronary sinus extending through the inferior left atrioventricular groove Anterosuperior tilting provides the apical five-chamber view, which contains the left ventricular outflow tract, the aortic valve, and the ascending aorta (Fig 19.25) The apical long-axis view is obtained by a 60-degree counterclockwise rotation from the cut showing the apical four-chamber view (Fig 19.26) This allows visualization of the left ventricular outflow tract, as well as the mitral valve The two-chamber view is obtained by further counter-clockwise rotation and provides images of the walls necessary for assessment of left ventricular function (Fig 19.27) FIG 19.17 Parasternal long-axis view showing the left atrium (LA), left ventricle (LV) and aorta (AO) Note the fibrous continuity between the leaflets of the mitral and aortic valves The infundibulum of the right ventricle (RV) is seen anterosuperiorly FIG 19.18 Parasternal long-axis view showing the right ventricular inlet