The subcostal view profiling the atrial septum is a very important view in patients with transposition of the great vessels. This view can be used to assess the size and location of an atrial septal defect which is critical to have in these patients as they rely on this communication for proper mixing of the parallel circulations. If the degree of mixing at the atrial septum is inadequate, often a procedure called a balloon atrial septostomy is required to enlarge/create an atrial communication to improve intracardiac mixing.
Transducer located in the abdomen just below xyphoid process
Notch at 3 o'clock
Transducer tilted anteriorly (tail down)
Assess size and degree of mixing in patients with transposition
A small ASD with inadequate mixing may require a balloon atrial septostomy