Elsevier

American Heart Journal

Volume 164, Issue 2, August 2012, Pages 163-176
American Heart Journal

Curriculum in Cardiology
Anatomy, mechanics, and pathophysiology of the mitral annulus

https://doi.org/10.1016/j.ahj.2012.05.014Get rights and content

The mitral annulus plays an important role in leaflet coaptation, in unloading mitral valve closing forces, and in promoting left atrial and left ventricular filling and emptying. Perturbations of annular mechanics figure prominently in a number of disorders including functional and ischemic mitral regurgitation, mitral valve prolapse, atrial fibrillation, mitral annular calcification, and annular submitral aneurysm. This review discusses the role of annular dysfunction in the pathogenesis of these disorders.

Section snippets

Mitral annulus anatomy

The mitral annulus separates the left atrium (LA) from the left ventricle (LV). It is conventionally divided into anterior and posterior portions. The anterior annulus spans between the left and the right fibrous trigones and is anatomically coupled to the aortic annulus. This confluence is called the aortomitral curtain (Figure 1).1 The posterior annulus encompasses the remainder of the annular perimeter and is composed of a discontinuous rim of fibrous tissue periodically interrupted by fat,2

Disorders of mitral annular structure and function

The mitral annulus plays an important role in leaflet coaptation, in unloading mitral valve closing forces, and in promoting LA and LV filling and emptying. Perturbations of annular geometry and mechanics figure prominently in a number of disorders including functional and ischemic mitral regurgitation (MR), mitral valve prolapse (MVP), atrial fibrillation (AF), mitral annular calcification (MAC), and annular submitral aneurysm, all of which are discussed below.

Conclusion

Although many questions remain, recent research has significantly enhanced our understanding of the role of annular dysfunction in mitral valve disease. Application of new insights will undoubtedly lead to increasingly individualized and less invasive therapies with improved patient outcomes.

Disclosures

Conflicts of interest: none.

Funding sources: none.

Acknowledgements

No extramural funding was used to support this work. The author is solely responsible for the drafting and editing of this paper and its final contents.

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