Anatomy, mechanics, and pathophysiology of the mitral annulus.

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.