Differential Tension between Secondary and Primary Mitral Chordae in an Acute In-Vivo Porcine Model
Mads Lomholt MD, Sten Lyager Nielsen MD, Søren Berndt Hansen MD, Niels Trolle Andersen PhD, J. Michael Hasenkam MD

Leading edge (primary) chordae are considered essential to mitral leaflet coaptation, while the leaflet belly (secondary) chordae are claimed to be important to left valvular-ventricular interaction. In postulating that secondary chordae carry more load than their primary counterparts, anterior mitral leaflet chordal tension forces were measured in beating porcine hearts. Primary chordal tension was found to oscillate between 0 and 0.2 N, while secondary chordal tension was between 0 and 0.7 N. The magnitude of both chordal tensions forces fluctuated in line with left ventricular pressure (LVP); chordal tension reached a maximum when LVP was maximal during, or in some cases just prior to, early systole. Likewise, during early diastole the minimal tension was reached coincident with minimal LVP.