Before performing the echo it is important to gain verbal consent from the patient and explain what you are going to do. It is good practice to attach the 3-lead ECG to the patient from the echo machine as it helps when evaluating systole and diastole.
There are 4x main views obtained with bedside echocardiography:
1. PLAX=Parasternal long axis
2. PSAX=Parasternal short axis
4. SC(+IVC)=Subcostal(+inferior vena cava)
5. Lung bases
Videos by Ultrasound Critical Care
Each view on echocardiography shows different cross sections of the heart. Here are labelled images seen within each window.
LA = Left Atrium
LV = Left Ventricle
RA = Right Atrium
RV = Right Ventricle
RVOT = Right Ventricular Outflow Tract
Ao = Aorta
AV = Aortic Valve
MV = Mitral Valve
TV = Tricuspid Valve
IVS = Intra-ventricular septum
IAS = Intra-atrial septum
IVC = Inferior vena cava
HV = Hepatic vein
Below are labelled images of the different FUSIC Heart views. Slide the middle cursor across to view either the labelled or unlabelled image ↔︎
SC IVC ↔︎
The left ventricle can be assessed from the:
Each view will give an impression of the size of the LV and the function of the LV.
The questions that FUSIC Heart tries to answer regarding the left ventricular are:
The most common way to measure LV dilatation is in the PLAX view where the LV internal dimension in diastole (LVIDd) is taken.
End diastole can be determined in a few ways, these are:
1. The frame where the LV is at its largest
2. The frame after MV closure
3. The start of the QRS complex
When determine LVIDd in the PLAX view it is important to get good image optimization as any foreshortening of the LV could lead to inaccuracies in the measurements.
Normal LV: This is a PLAX view of the LVIDd (measuring at 4.92cm)
The measurement is taken using calipers to measure from the endocardial border of the septal wall of the LV to the endocardial border of the posterior free wall of the LV. This is taken at the level of the tips of the MV in systole (when they are open).
For the purpose of FUSIC heart the LV is determined to be dilated if the LVIDd >6cm
BSE reference for LVIDd
Dilated LV: This is a PLAX view of the LVIDd (measuring at 6.22cm)
When assessing the function of the LV it is important to assess how the LV is contracting, but is also important to assess for any regional wall motion abnormalities (RWMAs), and any reduction in wall thickening and motion. This assessment is done by ‘eyeballing’ the LV to get a global picture of how well it is contracting and performing a mitral annular plane systolic excursion (MAPSE) as a quantitative analysis.
Formal assessment of ejection fraction is an advanced echo technique and beyond the scope of FUSIC heart. There are a couple simpler methods that are worth knowing about and the MAPSE is part of the FUSIC heart curriculum. These are:
This is taken in the A4Ch view. As the LV contracts in systole in shortens longitudinally, radially and circumferentially. The distance that the MV lateral annulus travels in systole towards the LV apex is measured and this is known as the MAPSE.
To get the MAPSE value the A4Ch view is obtained and the M-mode line is placed over the lateral annulus of the MV. When in the correct position record M-mode by pressing the button again and freeze the screen once a few cardiac cycles have been recorded by M-mode. Place the calipers on the M-mode image and measure the lowest and highest points of the line of the MV.
MAPSE >12mm predicts normal LV function
MAPSE < 6mm predicts severe LV systolic dysfunction
MAPSE is good for distinguishing between normal and significant impairment of the LV, but is harder to interpret when the value lies between 6-12mm.
MAPSE measurement taken in M-mode with the cursor over the lateral mitral valve annulus.
Measurements taken from lowest to highest point of the line on M-mode representing the mitral annulus.
Fractional shortening can be useful because it is not too dissimilar to measuring the LVIDd. Again it is taken in the PLAX and LVIDd is measured, but at the same time LV internal diameter in systole is measured along the same plane as the LVIDd.
Systole can be determined by a few different ways:
This is a PLAX view of the LVIDs (measuring at 2.60cm)
Fractional shortening is then calculated using these 2 values:
FS = [(LVIDd – LVIDs)/LVIDd] x 100
This is a normal value for fractional shortening
BSE reference for fractional shortening
In health the LV contracts and the walls thicken and they move equally towards the centre of the LV cavity. Whilst looking at the LV from the PLAX, PSAX and A4Ch it is important to assess how the LV is contracting in all the different areas of its walls.
RWMAs can be due to ischaemia such as in an acute coronary syndrome and in this case the RWMA will be in the area supplied by the affected blood vessel. The RWMA will look like reduced excursion and thickening in this case. For FUSIC heart one of the ways to assess for RWMAs is to look in the PSAX at the papillary muscle level. The LV should be circular and all areas of the LV should be contracting and thickening equally towards the centre.
PSAX view showing antero-septal RWMA - note the reduced contractility in the upper left corner of the LV on this clip
PLAX view showing the areas of coronary blood supply to the LV
PSAX view showing the areas of coronary blood supply to the LV
A4Ch view showing the areas of coronary blood supply to the LV - the lateral free wall of the LV can sometimes be supplied by the LCx.
Using the knowledge of the assessments above and gaining experience in scanning the LV, over time, you will get better at using an ‘eyeball’ assessment of the LV and answer the questions:
The RV can be assessed from the:
If the patient has a dilated LV then this rule can lead to underestimating RV size, and if the image is foreshortened then this can lead to overestimating the RV size.
The main view for assessing the RV size and function is the A4Ch view but the other views can be helpful as well.
The main way to assess for RV dilatation is in the A4Ch view. This is done using an ‘eyeball’ assessment where the LV and RV are seen next to each other. The RV is determined to be normal size when the RV basal width is no more than 2/3 that of the LV.
RV is mildly dilated when it is >2/3 the basal width of the LV
RV is moderately dilated when it is equal to the size of the LV
RV is severely dilated when it is larger than the LV
The PSAX is not usually used to assess RV size but can give an indication of whether RV dilatation is present – see images below.
No RV dilatation - A4Ch view showing the RV roughly 2/3 the size of the LV and the LV is the apex forming ventricle
RV severely dilatation - A4Ch view showing RV basal diameter > LV basal diameter
PSAX view of a normal RV
PSAX view of dilated RV
RV systole is predominantly in the longitudinal plane with some inward motion of the RV free wall. This makes the tricuspid annular plane systolic excursion (TAPSE) reflects longitudinal function and equates well with RV ejection fraction – making it ideal for measuring systolic function of the RV. The technique is similar to the MAPSE but performed on the lateral annulus of the tricuspid valve.
To measure the TAPSE get an optimal view in the A4Ch and place the M-mode line through the lateral annulus of the tricuspid valve. Press M-mode again and freeze the image after a few cardiac cycles. Measure using callipers the distance from the highest to the lowest point of lateral annulus of the tricuspid valve.
BSE reference values for TAPSE:
TAPSE assessment using M-mode with a measurement of 2.05cm from the lowest to the highest point of the lateral annulus of the tricuspid valve. This is a normal TAPSE.
TAPSE assessment using M-mode with a measurement of 0.95cm from the lowest to the highest point of the lateral annulus of the tricuspid valve. This indicates the RV is severely impaired.
The methods used to assess for low preload within FUSIC heart are inferior vena cava (IVC) assessment, combined with LV/RV assessment.
In a low preload state, which can be either due to vasodilation (for example in sepsis), or hypovolaemia (for example in dehydration/blood loss), the LV and RV will appear on echo to be hyperdynamic to try and increase the cardiac output through increasing the heart rate or contractility. This can be assessed in all views but may be well visualized in the A4Ch view.
In severe hypovolaemia there may be evidence of papillary muscle apposition in systole in the PSAX view. This gives the impression that most of the LV is emptying during systole and is evidence that there is low preload and the LV is underfilled.
The IVC assessment is also used to assess preload, however, it will differ depending on whether the patient is spontaneously breathing or is mechanically ventilated – which is not ideal for the ITU population for which FUSIC heart is used.
The IVC is assessed using the subcostal view with the probe rotate through 90 degrees anticlockwise from the original view of the heart. This brings into view the IVC in its long axis passing through the diaphragm and draining into the right atrium. Using M-mode place the line through the IVC perpendicular to its walls 1-2cm before its junction with the RA. Measuring on the M-mode image the maximum and minimum distance using calipers, as the IVC diameter changes with respiration.
The IVC diameter changes with respiration due to a negative intrathoracic pressure during inspiration and a positive intrathoracic pressure during expiration. During inspiration the negative intrathoracic pressure draws blood from the IVC into RA and the diameter reduces. During expiration the opposite occurs. This is during spontaneous respiration.
Normal IVC diameter is 1.5-2.1cm – outside of these limits suggest hypovolaemia or well-filled fluid status.
The IVC size and reactivity can be affected by multiple factors, including:
An IVC diameter <2.1cm with collapsibility >50% with a sniff suggests right atrial pressure (RAP) 0-5mmHg
An IVC diameter ≥ 2.1cm with collapsibility <50% with a sniff suggests RAP of 15mmHg
Assume a RAP of 8mmHg for any other value that dies not meet the criteria above
SC IVC view in a spontaneously breathing patient with a sniff
SC IVC M-mode assessment of collapsibility with a sniff. Callipers can be used to measure between the largest and smallest diameter of the IVC.
During mechanical ventilation there is positive intrathoracic pressure during inspiration and reduced intrathoracic pressure relatively in expiration. So the phasic collapse of the IVC is reversed.
The assumption is made that a dilated IVC with low respiratory variability reflects a high RAP (high preload).
A small IVC with high respiratory variability reflects a low RAP (reduced preload).
IVC measurement in M-mode showing a dilated IVC (2.57cm) with very little respiratory variation indicating a raised RAP - this could be due to RV failure or fluid overload
In both severe pressure and volume overload RV dilatation is seen with a D-shaped septum on the PSAX view. In normal circumstances the LV is circular with the inter-ventricular septum bowed towards the RV. In conditions of pressure or volume overload the IVS can start to flatten and become D-shaped.
Depending on which phase of the cardiac cycle the IVS appears D-shaped will determine whether it is pressure or volume overload or a combination of the both.
Pressure overload – the IVS is D-shaped in systole
Volume overload – IVS is D-shaped in diastole, paradoxical septal motion may be present where hyperdynamic ventricles appear to move the septum anteriorly during systole.
Combination of both pressure and volume overload – IVS appears D-shaped throughout both systole and diastole.
In both pressure and volume overload the IVC will start to dilate >2cm and there will be minimal respiratory variability.
PSAX view with a normal circular LV ↔︎
PSAX view of a D-shaped septum in both systole and diastole - indicating both pressure and volume overload
PSAX view with a flattened inter-ventricular septum making the LV appear D-shaped ↔︎
Assessment for pericardial fluid should be made in all views of the heart. Fluid on echo appears anechoic (black) and for it to be pericardial fluid needs to be between the myocardium and the pericardium. It is normal to see very small amounts of pericardial fluid in some patients. In patients with high body fat content the epicardial fat pad can appear similar to pericardial fluid, however this has a much more granular appearance which can help distinguish it and it is usually small. The pericardial collection can either be concentric or localized and it is best seen in the PLAX and SC views.
To distinguish between pericardial and pleural fluid this is best done in the PLAX view. Pericardial fluid appears anterior to the descending thoracic aorta whereas pleural effusions are posterior to the descending thoracic aorta.
PLAX view showing a small amount of pericardial fluid below the infero-lateral wall of the LV. ↔︎
Note: The fluid is anterior to the descending thoracic aorta meaning it is pericardial and not pleural fluid
This is best distinguished in the deep PLAX view.
PLAX view showing a small amount of pericardial fluid below the infero-lateral wall of the LV.
The pericardial effusion size can be measured at end diastole perpendicular to the pericardium and myocardium.
Pericardial effusion size
Small < 0.5cm Moderate 0.5-2cm Large >2cm
Maximal measurements around each regional wall should be made.
The appearance of the effusion can help distinguish its cause:
Simple effusion – uniform, anechoic
Exudative/fibrinous – stranding/loculation
Old blood – echogenic & grainy
Acute blood – similar to simple serous effusion
Purulent effusion – echogenic
Deep PLAX view demonstrating fluid posterior to the descending thoracic aorta meaning that it is pleural fluid.
Early signs of pericardial tamponade are:
Very late sign:
SC view with evidence of pericardial fluid
Focused echo can be used during cardiac arrest and fits into the ALS algorithm at the pulse check. Usually the only place to assess the patient is via the subcostal view and limited to only 10 seconds.
Echo during cardiac arrest can help distinguish between true PEA (where coordinated electrical activity is seen on the monitor but there is no cardiac movement on echo and no palpable pulse) and pseudo PEA (where there is coordinated electrical activity on the monitor but there is cardiac activity on echo but with no palpable pulse).
Content created by Ben Stoney
Design by Max Broadbent
The ultrasound images and clips used on this website have be reproduced following the local clinical governance guidance.