Figure 5Congenital MS with a combination of a connective tissue layer on the valve leaflets, short fused chords, multiple papillary muscles, and accessory chords tethering the posterior leaflet. To gain access to the subvalvar structures, detachment of the posterior leaflet close to the annulus facilitates access to the accessory chords and papillary muscles. The incision needs to extend from commissure to commissure. Aggressive delamination of the papillary muscles leaving only the apical-most attachments helps mobilize these structures for improved leaflet mobility. Inset, lower right: cross-sectional view of the leaflet incision and papillary muscle dissection. LA, left atrium; LV, left ventricle.