Distance between mitral anulus and papillary muscles: Anatomic study in normal human hearts

Background: Preservation of the annulo-papillary muscle continuity in mitra l valve replacement is important, Even in patients who require excision of the mitral apparatus, the continuity can be restored. However, there is no guide to the proper length for the resuspension, Methods: In 57 normal cada veric hearts, the distance from the tip of the papillary muscle to its corr esponding mitral anulus was directly measured. Results: The distance from t he tip of the anterolateral papillary muscle to the left trigone (10-o'cloc k position: D10) and to the point between the anterior and the middle scall ops of the mural leaflet (8-o'clock position: D8) was 23.5 +/- 3.7 mm and 2 3.2 +/- 3.6 mm, respectively. The distance from the tip of the posteromedia l papillary muscle to the right trigone (2-o'clock position: D2) and to the point between the middle and the posterior scallops of the mural leaflet ( 4-o'clock position: D4) was 23.5 +/- 4.0 mm and 23.5 +/- 3.9 mm, respective ly. There was no statistically significant difference among the 4 distances (P = .96), Each distance was significantly longer than the corresponding c hordae tendineae (D10 vs the anterior main chorda: 17.2 +/- 3.9 mm. D8 vs t he anterior cleft chorda: 14.5 +/- 3.2 mm, D2 vs the posterior main chorda: 17.9 +/- 4.3 mm, and D4 vs the posterior cleft chorda: 14.9 +/- 3.2 mm, re spectively; P = .0001), The mean distance had a significant correlation wit h the mitral annular diameter (r = 0.31, P = .019), Conclusions: In normal hearts, the annulo-papillary muscle distances of the mitral apparatus are s imilar in 2-, 4-, 8-, and 10-o'clock positions and correlate with the mitra l annular diameter.