Assessment and description of left ventricular function comprises usually its systolic or diastolic, global or
regional aspects. Myocardial function during the whole cardiac cycle is more complex, due to myocardial
architecture. Radial left ventricular function predominates certainly, but longitudinal and torsional
function also play a role. Global strain (e.g. 2D-strain), as well as other parameters, can give an
insight in the longitudinal left ventricular function. Radial LV function can be assessed with
the methods presented below.
Qualitative assessment of systolic LV function
– multiple cross-sectional views
– endocardial movement and myocardial thinckening
– Assessment:
"descriptive"
| Ejection fraction, %*
normal
|
≥ 55 %
mild impairment
|
45 - 54 %
moderate impairment
|
30 - 44 %
severe impairment
|
< 30 %
*Current reference limits after the new recommendations of
American Society of Echocardiography
(ASE), 2005.
Quantitative assessment of systolic LV function
– Calculation of left ventricular ejection fraction, LV-EF
– Formula: [(EDV - ESV) / EDV] x 100 = EF (%)
– Assessment of LV volumina with the method of discs (modified Simpson's rule, biplane)
Regional wall motion assessment
18-segment model: left ventricular wall segments
There are several models to depict left ventricular wall segments, and correspondingly, some
confusion. The 16-segment model, suggested by the American Society of Echocardiography in 1989
has proven its practicability in clinical work. Three-chamber view, used regularly in echocardiography
examinations in Europe since decades introduced two more apical segments: anteroseptal apical and
posterior apical. In American models, apical segments remained only 4: apical anterior, apical lateral,
apical inferior and apical septal. A new model was recently proposed, in order to equalize standards in echocardiographic,
thallium-scintigraphy, NMR and PET examinations. The document can be downloaded directly from
the ASE:
Recommendations for
Chamber Quantification, 2005.
Typical distribution of coronary perfusion and the new 17-segment model from the ASE shown here as an overlay to
the old model - onMouseover (enable JavaScript in your browser).
Examples of wall motion abnormalities
|
Overview