Left ventricle size
From Echocardiography in ICU
The objective of this chapter is to determine if the left ventricle is:
-dilated: mildly, moderately or severely
The left ventricle diameter is measured in parasternal long axis, at the tip of the mitral leaflets, at the interface blood-internall wall.
LVED: left ventricle end-diastolic diameter, is the most important measurement. It is measured at end diastole, on the frame after mitral closure. It normally corresponds to the largest cardiac dimension.
LVES: left ventricle end-systolic diameter, is measured at end systole, on the frame preceding mitral valve opening. It corresponds to the smallest cardiac dimension.
The LV dimensions can be measured in M-mode. This imaging modality allows the visualization of each structure depending on the time and gives a better image resolution than 2D imaging. However you must be sure that the imaging beam is cutting perpendicularly the long axis of the left ventricle or you will overestimate the LV size.
Normal and abnormal values
|LVED (mm)||Normal||Mildly dilated||Moderately dilated||Severely dilated|
Pitfalls of LV diameter measurement
- Be careful to exclude the chordae and papillary muscle from the measurement
- Measure perpendicularly to the long axis of the left ventricle
- Your PSL view must be parallel to the long axis of the LV: the septum and posterior wall should be parallel, and you should not visualize the LV apex
Left ventricle shortening fraction
With the left ventricle end-diastolic and end-systolic diameters, you will be able to calculate the shortening fraction. The shortening fraction reflects the left ventricle systolic function, but is valid only if the left ventricle geometry is normal and in the absence of wall motion abnormality.
Shortening fraction = -------------------------- x 100