The chordae tendinae connect the papillary muscles to the mitral valve.
While the first-order chordae serve to secure the leaflets to maintain
valve closure and prevent mitral valve prolapse, the second-order
chordae are believed that they play a role in maintaining normal LV size
and geometry. The papillary muscles, from where the chordae tendinae
originate, function as shock absorbers that compensate for the geometric
changes of the left ventricular wall. The second-order chordae connect
the PMs to both trigons under tension. The tension distributed towards
the second-order chordae has been demonstrate to be more than three-fold
that in the first-order counterpart. Cutting the second-order chordae
puts all the tension on the first-order chordae, that can go closer to
their rupture point. However, it has been experimentally demonstrated
that the tension where the first-order chordae break is 6.8 N, by far
higher than the maximal tension reached, that is 0.4 N. Even if the
clinical reports have been favorable, the importance of cutting the
second-order chordae to recover curvature of the anterior leaflet and
increasing the coaptation length between the mitral leaflet has been
slowly absorbed by the surgical world. Nevertheless, there are
progressive demonstrations that chordal tethering affects the anterior
leaflet not only in secondary, but also in primary mitral regurgitation,
having a not negligeable role in the long-term outcome of mitral repair.