The Golden Proportion in the scallop geometry of normal mitral valves. When nature plays with jigsaw puzzles.

Abstract

The Golden Proportion is a particular geometric ratio between two segments. It results in an irrational number, commonly rounded to 1.618, or 0.618, and showing unique geometrical/mathematical properties. Its presence has been documented in a huge amount of natural settings, as well as the human body and the heart. In light of a previous research of ours, about its presence in the Coaptation Triangle, we investigated the dimensions of both mitral leaflets in healthy mitral valves and then compared our results to literature data, in order to search whether this proportional pattern could be extended to other valve aspects. Forty-one adults, with healthy mitral valves, underwent 2D echocardiography. Adequate long-axis three-chamber view images were chosen, at mid-diastole, where the central scallop of both the anterior and posterior leaflets (A2 and P2, respectively) could be well identified and measured. We then investigated these measurements, calculating their ratio and comparing our findings to literature data on normal mitral anatomy. The ratio between the two scallop heights appeared very close to the Golden Ratio. Literature data supported our results and, apparently, showed the mitral leaflets to be like a jigsaw puzzle of components highly interconnected each other with an extremely simple geometry, based on the Golden Proportion. The Golden Proportion looks to determine the geometry of normal mitral scallops. Studying such a pattern of anatomical proportions could improve surgical techniques for conservative surgery, as well as innovate the design of mitral repair rings and valve prostheses.