How must the sonographer angle the transducer from the apical four-chamber view in order to...

To obtain the apical five-chamber view from the apical four-chamber, the transducer is angled anteriorly (towards the patient’s chest). This brings the left ventricular outflow tract and aortic valve into the imaging plane anterior to the left ventricle and mitral valve seen in the four-chamber view.

Posterior, medial, or lateral angulations do not adequately visualize the aortic valve in this context.

This technique is described in adult echocardiography imaging protocols and ASE chamber quantification guidelines【12:ASE Imaging Protocols†p.30-35】【16:Textbook of Clinical Echocardiography, 6e†p.70-75】.