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

Abstract

In normal hearts, the annulo-papillary muscle distances of the mitral apparatus are similar in 2-, 4-, 8-, and 10-o'clock positions and correlate with the mitral annular diameter.

Three-Dimensional Echocardiographic Measurements of Distance Between Papillary Muscles and Mitral Annulus: Assessment With Three-Dimensional Quantification Software System

“…However, it is difficult to determine the precise mitral annular plane because of the unique non-planar (saddle shaped) configuration of the mitral annulus [17][18][19][20]. Although Sakai et al reported the distances between mitral annulus and the tips of papillary muscles in normal cadaveric hearts [16], it had been difficult to measure these distances in the clinical setting. 3D computer software REAL VIEW ® has made it possible to visualize and quantify the geometry of the mitral annulus and leaflets with the use of transthoracic real-time 3D echocardiography in humans [9][10][11][12].…”

“…Further investigation is needed in this issue. 3) Although we labeled anatomic regions according to the previous study in human hearts at autopsy [16], we have no exact data regarding how much error occurred by making this assumption. However, it is reasonable to suppose that we use these labeling as reference points on measurement of papillary muscle to mitral annulus distances in vivo, in clinical setting.…”

“…The 3D measurements of the distance between the papillary muscle tips and the 5 points on the mitral annulus performed as follows, from the 3D datasets. First, we defined the midpoint of anterior mitral annulus, determined as the furthest point from the apex on the anterior-posterior axis [15][16][17], as 0 o'clock, which is relatively fixed and had been used for a reference point to evaluate the papillary muscle location in previous study [14,15]. Then, we defined the other 4 points on the annulus corresponding to 2, 4, 8, and 10 o'clock.…”

“…The point of 2 o'clock was considered as the position of the right fibrous trigone, and the point of 10 o'clock as the position of the left fibrous trigone. The point of 4 o'clock was considered as the point between the posterior and middle scallop leaflets of the mural leaflets, and the point of 8 o'clock as the point between the anterior and the middle scallops of the mural leaflet [16]. We measured 6 distances from the tip of each papillary muscle to corresponding points of annulus (PM-MA distance a to f ) as follows: the distances between the points of 0 o'clock and the tips of the posteromedial and anterolateral papillary muscles were defined as PM-MA distance a and b; the distances between the tip of the posteromedial papillary muscle and the points of 2 and 4 o'clock as PM-MA distances c and d; and the distances between the tip of the anterolateral papillary muscle and the points of 8 and 10 o'clock as PM-MA distances e and f. The distance between two tips of papillary muscle (inter-PM distance) was measured from 3D data as well (Figure 2).…”

The clinical anatomy of the mitral valve

“…Different from the tricuspid valve, there is no direct attachment of the mitral valve to the ventricular septum, although the papillary muscles are frequently connected to the septum or to the right fibrous trigone by false cords (Loukas et al, 2007). The length and the reciprocal ratio between papillary muscles and cords show individual variations, but some studies demonstrated similar annular-to-papillary muscle tip distances in the 2-, 4-, 8-, and 10-o'clock positions that also correlate with mitral annular diameter (Sakai et al, 1999) and which are relevant for the proper choice of cordal length during reparative surgery.…”