Improved LV septal function and RV remodeling:
Chronic MR is frequently associated with impaired ventricular septal
motion. The contribution of septal contraction to RV systolic function
ranges from 24% in a normal RV to 35% in RV dysfunction [22, 23].
Interventricular septal contraction is able to maintain RV function and
cardiac output despite RV free-wall impairment [3, 22-24]. In this
study, LV radial and circumferential strain remained steady at 3-months
despite an overall decline in other measurements of LV contractile
performance including EF and GLS (Table 5). This observation might
suggest a redistribution of LV contractile load from the apex to the
base of the heart, possibly related to the mechanical effect of the
tether and its fixation to an apical pad. Similarly, more modest changes
in RV longitudinal and annular function relative to RVFAC are observed
in our study. This suggests that in addition to improvement in intrinsic
myocardial contractility of the RV free wall, it is the exaggerated
movement of the septum, possibly induced by the tether and apical pad,
that contributes to an immediate improvement in overall RV function and
warrants future evaluation.