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)