Left ventricle systolic function
From Echocardiography in ICU
"Eye ball" estimation of left ventricle systolic function
Visual estimation of left ventricle systolic function, even after a limited training, has been proven to be reasonably accurate (ref 1)
A semi-quantitative scaling can be proposed:
-normal LV function
-mild-moderately decreased LV function
-severely impaired LV function
It is possible to assess the LV function from all echocardiographic windows. However, for increased accuracy, confrontation of two different views at least is recommended (apical 4 chamber and parasternal short axis for example).
Parasternal long axis, moderately reduced EF:
Parasternal short axis, moderately reduced EF:
Apical 4 chamber, moderately reduced EF:
Subcostal 4 chamber, normal EF:
To see examples of LV function and dysfunction from all views, please go to the image library.
Left ventricle ejection fraction
The systolic performance of the left heart depends upon the left ventricle contractility, pre-load, after-load and heart rate. Though dependant on loading conditions, the left ventricle ejection fraction (EF) is the best indice of left ventricle systolic function. The ejection fraction is calculated from the difference between end-diastolic and end-systolic LV volume, divided by the end-diastolic LV volume:
End-diastolic volume - end-systolic volume
EF = --------------------------------------------
These methods require many geometric assumptions (no regional dysfunction, normal LV geometry, cubing of dimensions measurement) to convert a linear measurement to a 3D volume and can not be considered as reliable, therefore Teichholz or Quinones are not recommended for clinic practice.
The most commonly used 2D measurement for volume measurements is the biplane method of disks (modified Simpson’s rule). The principle underlying this method is that the total LV volume is calculated from the summation of a stack of elliptical disks.
You will measure the LV volumes from apical 4 and/or apical 2 chamber views, tracing the endocardial border of the LV. The echocardiography machine will automatically give you the volume of the cavity.
If there is no wall motion abnormality, the EF can be estimated from one view only, apical 4 chamber or apical 2 chamber view. It is no longer reliable if there are some wall motion abnormalities, you will need to measure the LV volumes in both views (apical 4 + apical 2 chamber).
- You must be careful to have a true "apical 4 chamber view":
- -LV not fore-shortened
- -visualization of mitral and tricuspid leaflets and whole atria
- You must trace the endocardial border, for which you need to have a good image quality
- You must measure the diastolic and systolic volumes from the same cardiac cycle. It should not be a PVC neither the beat post-PVC. If the heart rythm is irregular (atrial fibrillation), you will need to average the measurements over several cardiac cycles.
||Hyperdynamic LV function||Normal LV function||Mild LV dysfunction||Moderate LV dysfunction||Severe LV dysfunction|
Click on the links to see an example of LV function:
1. Melamed R et al. Assessment of Left Ventricular Function by Intensivists Using Hand-Held Echocardiography. Chest. 2009 Feb 18
2. Lang RM, Bierig M, Devereux RB. Recommendations for chamber quantification. J Am Soc Echocardiogr. 2005 Dec;18(12):1440-63.
Ciampi and Villari. Cardiovascular Ultrasound. 2007 5:34 doi:10.1186/1476-7120-5-34