Transducer Position: The patient is placed flat on their back. Sometimes it helps for the head to be slightly elevated or if the patient takes in a deep breath. It may also be helpful if the patient bends their legs.
Scan under the subxyphoid process until a standard 4 chamber view is obtained with the indicator at 3 o'clock. Increasing the depth is usually needed depending on how high up the heart is located.
The heart is now in the far field, and the ultrasound beam has to go through the liver first, before slicing through the right ventricle and then left ventricle.
The structures seen are roughly similar to the apical four chamber however now the ultrasound beam is more perpendicular to the atrial and ventricular septum.
RV - right ventricle, LV - left ventricle, RA - right atrium, LA - left atrium, MV - mitral valve, TV - tricuspid valve
A ideal subcostal 4 chamber
This view is excellent for looking at the anterior RV free wall, to assess for RV thickness, and for the evaluation of pericardial effusions. It is also one of the most useful views for evaluating flow across the intra-atrial septum for the presence of a PFO or ASD. In this view we are seeing the septum and lateral wall of the LV similar to a 4 chamber apical view. RV- right ventricle, LV - left ventricle, LA - left atrium, RA - right atrium, TV - tricuspid valve, and MV - mitral valve.
Color Doppler across the interatrial septum
This is also a good view to assess for an atrial septal defects or patent foramen ovale as the color Doppler window is now perpendicular to the intra-atrial septum.
View of the SVC from the Subcostal Window
On occasion, from the 4 chamber view the SVC can be seen with some additional angulation toward the head. It is shown here as a color flow toward moving upward on this image into the right atrium.