Fast Filling: Suction Phase.
It begins after the isovolumetric relaxation or decompression phase when
the decrease in pressure falls below the atrial pressure and is
associated with a rapid additional accentuation of the twisting of the
apex in a clockwise direction. (Figure 4: 3A-C) ,
(Figure 3: 4) At a basal level, it produces an
elongation due to the movement of the AS, which simultaneously produces
the final clockwise rotation of the ventricular base, in turn leading to
the detorsion of the entire ventricular
mass24,30(Figure 2: 3A-B). During this
phase, an active suction of blood from the atria is produced. It has
been argued that the continuous unwinding process is caused by elastic
recoils of compressed titin within the AS, however the active and
unopposed shortening due to subepicardial contraction is responsible for
the suction during the rapid filling, the straightening of the LV during
the “relaxation” isovolumetric, is a very important component which,
if altered, would trigger phenomena such as diastolic
dysfunction7.(Figure 4: Note the
prevalence of the subepicardium over the subendocardium, 3A-C)