Fig. 1.

(a) Intraoperative antero-lateral commissurotomy being performed, and (b) a schematic illustration of how commissurotomy is performed at our institution. The blue arrows depict symmetrical traction, applied by using nerve hooks around the major chordae on the left and right side of the anterior mitral leaflet perpendicular to the inter-trigonal line; this will create areas of dimpling, depicted by the blue markings, subsequently identifying the trigones (orange zones). The red dotted line represents the ideal point up to which commissurotomy should be performed, determined by stopping 3 to 5 mm from the annulus and 2 to 3 mm laterally from the trigone, as represented by the red bars. The commissural leaflets (C1 and C2) are outlined in grey to highlight the importance of preserving the commissural chords.