Functional Relations to the Right Ventricle.
The RV is formed in its free wall by the circumferential sheath of
transverse fibers that make up the RS, however, the septum of this
cavity is formed by the continuity of the AS of the AL,
(Figure 1: 5) until its insertion in the fibrous trigone
and the recently described cardiac fulcrum17,50 the
failure of this ventricle is related to septal lesions such as
interdependence related to pulmonary hypertension, pulmonary
thromboembolism, or occlusion of posterior septal branches of the right
coronary artery51,52 so it is must take into account
the difference between transverse fibers that form an envelope and
helical ones.
The dynamics behind TAPSE (tricuspid annular plane systolic excursion)
is the longitudinal translation of the shortening that causes the
contraction of the subendocardial DS, this extension and speed of
base-apex shortening so that both cavities are interconnected by a
muscular unit the only one that during its torsion explains TAPSE in the
RV and MAPSE in the LV. In cases of increased afterload, as in pulmonary
hypertension, the force to be overcome would be increasing the torsion
phenomenon of the DS. Saleh et al. describe that in the RV the helical
fibers of the septum determine the highest ejection fraction; in
situations where there is septal damage, therefore, a deterioration in
torsion, the ejection fraction is compensated by the circumferential
constriction caused by the free wall of the RV with fibers of BL,
recognizing how septal dysfunction can be the cause of RV failure, this
phenomenon does not cause catastrophic LV dysfunction due to the
presence of compensation to a greater area of subendocardial fibers,
however, in the RV its free wall is predominantly transversal generating
low pressure before a high resistance circuit. (Figure 4:
Observe the participation of the septal subepicardial velocity vectors,
which belong to the AS and therefore to the RV septum).