The mechanism of elevated postrepair MV gradients is poorly understood, but is in our opinion related to fixation of the posterior annular perimeter length. Indeed, in an adult sheep model, Dagum et al. [9] have shown that cyclic changes in the MV annular area, reaching a maximum in late diastole, are correlated with length changes of the posterior annular perimeter. After implantation of a true-sized partial or complete flexible annuloplasty device, complete fixation of the MV annular area, posterior and anterior annular perimeters throughout the cardiac cycle was observed. Similarly, Bothe et al. [10] reported that MV annuloplasty results in a significant reduction of the maximal MV opening area, independent of the type of annuloplasty device used (partial or full ring; flexible, semi-rigid or rigid). Moreover, the Physio I ring (as well as the majority of other full rings implanted) did not impair posterior MV leaflet motion. Additionally, while the Physio I ring did increase the excursion of the annular and belly region of the anterior MV leaflet, it did not affect the excursion of the anterior leaflet at the leaflet edge. No effect on anterior leaflet motion was seen after the implantation of a partial Cosgrove-Edwards band (Edwards Lifesciences). Their results suggest that no diastolic flow obstruction due to changes in anterior leaflet motion is to be expected after implantation of the majority of annuloplasty devices tested.