Point of Care Ultrasound (POCUS) has become commonplace in many hospitals. For Cardiac POCUS only limited views are obtained to assess four discrete things, often qualitatively. These are:
1. LV size and function
2. RV size and function
3. Presence of a significant pericardial effusion
4. Right sided filling pressures (using the IVC and sometimes PASP).
Often only 2D and color are used to make these assessments. More advanced users may also use doppler to assess additional information such as cardiac output which is described here.
Views for Cardiac POCUS
The basic views used for cardiac POCUS are 1. The Parasternal Long Axis; 2. The Parasternal Short Axis at the mid LV level. 3. The Apical 4 chamber; 4. The Subcostal 4 chamber; 5. The IVC. These are described in more detail below.
If you would like to review some practice cases for POCUS please look for these in the Assessment section.
Parasternal Long Axis
The most anterior structure is the right ventricular outflow tract (RVOT). The left ventricle (LV), left atrium (LA) and descending aorta are visible below. An ideal PLAX view doesn't show the LV apex and the LV wall are almost horizontal. Also seen are the anterior and posterior mitral valve leaflets (AML, PML), aortic valve (AV) and descending aorta (DA).
Parasternal Short Axis - Mid LV
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.
Apical 4 chamber view
In the appropriate orientation, the septum lines up vertically near the center of the screen. The LV and LV apex should be vertically oriented and the LV should be parabolic in shape as shown. If the LV apex appears round or is off center you are likely "off axis" which can affect interpretation. This view is also used to assess RV size and function, atrial size, abnormal intra-atrial and interventricular septal movement, as well as diastolic function. A few institutions have standardized this view in right-left reverse with the left ventricle on the left side of the screen and the right ventricle on the right of the screen. The majority of hospitals otherwise use the convention we show above. LV - left ventricle, RV - right ventricle, LA - left atrium, RA - right atrium, TV - tricuspid valve, and MV - mitral valve.
Subcostal 4 chamber view
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.
Inferior Vena Cava
To get this view, tilt the probe more right lateral from the abdominal aorta view. Alternatively from the subcostal four chamber, visualize the right atrium and turn the probe from the 9 o'clock position to the 12 o'clock position. This view is used to assess RA pressures based on inspiratory collapse of the IVC. Lack of collapse suggests high RA pressures where as complete collapse suggests low RA pressures. Note the change here in IVC diameter with respiration. Sometimes an M mode through the IVC as shown above on the right can better help show respiratory changes with time. This topic is covered further in the hemodynamics section.