ALPM, anterior-lateral/posterior-medial diameter index; AP, anterior–posterior diameter index; THi, tenting height index; PHi, prolapse volume index; TVi, tenting volume index; PVi, prolapse volume index; ACi, annular circumference index; AML, anterior mitral leaflet; PML, posterior mitral leaflet

Figure 1 3D parametric models (D) of patient’s mitral valve by MVN analysis. Three orthogonal mitral annulus images, including two-chamber view (A), long-axis view (B) and short-axis view (C)were displayed and subsequently used to model the entire annulus and mitral valve.

Figure 2 A: Scatterplots demonstrating the distribution of tenting volume index among healthy controls and MVP patients and the cutoff value of 0.7 mL/m² (horizontal dashed line) to distinguish the occurrence of secondary leaflet tethering in MVP patients. B to E: Histograms comparing the tenting volume index (B), annular area index, prolapse volume index and AHCWR between the healthy controls, MVPt- and MVP+ group.

Figure 3 Correlations of tenting volume index with NT-proBNP and 3D VCA. The scatterplot demonstrates a mild correlation between tenting volume index and NT-proBNP (A) and 3D VCA (B). C: ROC curve for 3D VCA to predict the occurrence of secondary leaflet tethering.

Figure 4 Illustrative examples of mitral valve prolapse patients without and with secondary leaflet tethering. A mitral valve prolapse patients without secondary leaflet tethering (PVi = 0.69 mL/m², tenting volume index = 0.19 mL/m², VCA = 0.32 cm²) B and C mitral valve prolapse patients with secondary leaflet tethering and larger regurgitant orifices. Case B PVi =0.02 mL/m², tenting volume index = 1.46 mL/m², VCA = 0.95 cm²; Case C PVi = 0.25 mL/m², tenting volume index = 2.2 mL/m², VCA = 1.48 cm²)