The tendinous chords, as functional extensions of the papillary muscles, perform the dual function of maintaining valvular competence by preventing leaflet prolapse and maintaining ventricular geometry by providing cross-ventricular support. The chords originate from the apical portions of the papillary muscles or directly from the posterior ventricular wall. They insert either into the free edge of the leaflets or on their ventricular surface. Chords have been characterized a number of ways. The most useful for repair purposes is to describe the first-degree chords as those inserting into the valve edge and the second-degree chords as those inserting into the underside.
