There are multiple levels of short axis images depending on how you tilt the probe. The slices show the LV from the base to apex and all four valves.
RVOT - right ventricular outflow tract, PV - pulmonic valve, TV - tricuspid valve, PA - pulmonary artery, RA - right atrium, LA - left atrium, AV - aortic valve, AML - anterior mitral leaflet, PML - posterior mitral leaflet, ALPM - anterolateral papillary muscle, PMPM - posteromedial papillary muscle, RV - right ventricle, LV - left ventricle.
We will review each level
Short Axis: Aortic, Tricuspid and Pulmonic Valve Level
This is the most basal short axis view that lays out the 2 atria, 3 valves and the RV outflow tract. Repeat PW and CW across the tricuspid valve is usually done here. TV - tricuspid valve, RA - right atrium, LA - left atrium, AV - aortic valve, PV - pulmonary valve, RVOT - right ventricular outflow tract, PA - pulmonary artery.
Short Axis: Zoom in on the Aortic Valve
It is quite useful to zoom in on the aortic valve to try to assess whether it is trileaflet. Color Doppler here can also help tell the origin of a regurgitant jet. The cusps can always be identified as follows, whether in this view, the subcostal view or via TEE: the intra-atrial septum always intersects the non coronary cusp; the right coronary cusp is the most anterior and abuts the right ventricular outflow tract. The left coronary cusp is therefore the one that is left. Sometimes slight angulation will allow visualization of the left main and right coronary arteries. RCC - right coronary cusp, LCC - left coronary cusp, NCC - non coronary cusp.
Pulmonary Artery View
Slight angulation superiorly will show the pulmonary artery and sometimes past the bifurcation. This is the view that is useful for seeing a PDA with color Doppler (usually a jet seen along the left PA). Also note the geometry of the pulmonary valve and artery, more anterior and almost perpendicular to the aortic valve plane. It is important to use PW Doppler above and below the pulmonic valve. Sometimes PW Doppler can be done separately in each pulmonary artery branch if stenosis or a mass is seen. Note that this individual is in atrial flutter during the echocardiogram. PA - pulmonary artery, PV - pulmonic valve
Short Axis: Mitral Valve Level
Tilting the probe tip downward the view of the base of the LV and mitral valve can be seen. The ventricle in this view should be round and not oval when done properly. In this view and the next two, many of the 17 different segments of the LV wall can be assessed individually. Note it is the RV insertion site anteriorly which separates septum from anterior wall and the RV insertion site inferiorly which separates septum from the inferior wall. Simply assuming the the 12 o’clock position on the LV identifies the anterior wall will not always be correct, especially in hearts that are rotated. AML - anterior mitral leaflet, PML - posterior mitral leaflet
Short Axis: Mid Ventricle Level
The mid ventricle level is identified by the presence of the two papillary muscles, which should not be confused for masses or thrombi. ALPM - anterolateral papillary muscle. PMPM - posteromedial papillary muscle.
Short Axis: Left Ventricular Apex
Tilting the probe even more inferiorly allows one to see the very apical segment which has no clear papillary muscle structures.