Leonardo da Vinci described as early as 1478, that contracting hearts showed a movement from the base to the apex
during each cardiac systole. Ventricular torsion was first described by William Harvey in 1628. Recently, a new
dissection technique developed by
Francisco Torrent Guasp
and published in 1980, could show the complexity of myocardial architecture, explaining all types of
cardiac movement during the heart function.
The picture left shows a very simplified scheme of the helical ventricular myocardial band. To
the right, a superposition with the apical four-chamber view. (1) band insertion at the pulmonary
artery, (2) free RV wall, (3) basal loop, (4) apical loop and (5) insertion at the aorta.
From this architectonic structure of the heart can be perceived, that the right ventricle will have a predominantly
longitudinal and torsional, and the left ventricle a preponderant radial function.
Quantitative assessment of longitudinal venticular function
Longitudinal LV function can be quantitatively assessed with different methods. The degree of movement of
the atrioventricular plane can be determined with M-mode, its velocity with tissue Doppler imaging (TDI).
Longitudinal deformation examined with
strain/strain rate can be also very helpful.
Normal values of longitudinal function are still not confirmed in large population studies. The following
values could reflect the lower limits of longitudinal LV and RV function:
MAPSE (mitral annular plane systolic excursion)
1 cm
Obtained values can be influenced by at least 4 factors: age, angulation of examination beam (M-mode, TDI),
respiration and method-dependent (PW-TDI versus color TDI, the latter shows significant lower values).
Studies that define normal values in larger populations are still lacking.
Left:
MAPSE is assessed with M-mode in apical four-chamber view, placing the examination beam on the lateral
mitral annulus.
Right: measurement take place from the end of diastole, until maximal
expansion in systole.
Left:
pulsed TDI sample volume is placed on the lateral mitral annulus to assess systolic velocities.
Possible oscillation due to respiration, as well as by MAPSE, should also be avoided here.
Right:
here an example of TDI velocities of mitral annulus, with a important wave of isovolumetric
contraction. This wave should not be taken for the systolic wave.
Torsional ventricular function
Torsional ventricular LV function can be calculated with the formula: LVtor (degree/cm) = (apical LV rotation —
basal LV rotation)/longitudinal diastolic LV dimension.
Normal value = 3°/cm; it shows no variation with age (Kim HK et al. J Am Soc Echocardiogr 2007;20:45-53).
Left:
a counterclockwise rotation of the apex and a clockwise rotation of the base can be determined in normal physiology.
Right:
assessment of ventricular rotation is not easy, especially at the ventricular base. It can be
conducted with bidimensional strain, as in this example.
Overview
