Left ventricle size

The objective of this chapter is to determine if the left ventricle is:

-small

-dilated: mildly, moderately or severely

-normal size

The left ventricle diameter is measured in parasternal long axis, at the tip of the mitral leaflets, at the interface blood-internall wall.

Contents

Diastolic diameter:

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.

Systolic diameter:

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.

M-mode measurements:

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 Men 42-59 60-63 64-68 >69 Women 39-53 54-57 58-61 >62

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.

(LVED-LVES)

Shortening fraction = -------------------------- x 100

LVED

 Shortening fraction % Normal 25-45 Mild 20-25 Moderate 15-20 Severe <15