Background and aim of the study: The study aim was to understand the role of different mitral valve chordae tendineae, and how damage to them affects valve competence.
Methods: A test apparatus was used to apply pressure to porcine mitral heart valves that were intact and have had selected chords severed. Anterior leaflet strut and marginal chords were selectively severed, as were posterior leaflet basal and marginal chords. Commissural chords were also severed.
Results: Severing anterior leaflet marginal chords (p = 0.018) and commissural chords (p = 0.018) significantly reduced mitral valve competence.

Severing posterior leaflet marginal and basal chords, and anterior leaflet strut chords, had no significant effect in reducing the pressures that the valves could withstand. Severing a mixture of posterior leaflet basal and marginal chords significantly reduced the pressure withstood by the valves (p = 0.004).
Conclusion: The study results confirmed that anterior leaflet marginal chords, but not strut chords, are vital for valve competence. Commissural chords were also shown to be vital for mitral valve competence. Several posterior leaflet chords had to be severed to affect mitral valve competence.
The Journal of Heart Valve Disease 2005;14:603-609