The Trileaflet Mitral Valve

A rare case series of mitral valve clefts diagnosed by 3D echocardiography and mini‐review of the literature

“…23 and the gap between the superior and inferior bridging leaflets is not a true commissure and is called a cleft, which points to the inlet septum. 22 Also, the normal saddle-shaped mitral annulus becomes more circular and the mural leaflet is significantly smaller than that found in patients with isolated clefting of the mitral valve. 22,24…”

“…True clefts are considered congenital malformations while cleft‐like indentations may represent anatomic variants, acquired lesions, or adaptative mechanisms in certain pathologies . Trifoliate appearing left atrioventricular valve may represent different conditions such as (a) cleft mitral valve in the setting of an endocardial cushion defect with an intact septum, (b) isolated cleft of the posterior (mural) leaflet, (c) isolated cleft of the anterior (aortic) leaflet, (d) trileaflet left atrioventricular valve, and (e) cleft‐like indentation (pseudo‐cleft) . Accuracy in the morphologic description of the left atrioventricular valve and compliance with the correct use of terms “cleft” and “cleft‐like indentations” are necessary to avoid misclassification of valvular pathology.…”

“…The superior and inferior bridging leaflets may be linked by a rim of tissue as they bridge the inter‐ventricular septum, creating two separate left and right orifices. The left orifice appears as a trifoliate appearing valve which is constituted by the left part of the superior and inferior bridging leaflets and the left mural leaflet; it has 2 commissures located between the superior bridging leaflet and the mural leaflet and the inferior bridging leaflet and the mural leaflet; and the gap between the superior and inferior bridging leaflets is not a true commissure and is called a cleft, which points to the inlet septum . Also, the normal saddle‐shaped mitral annulus becomes more circular and the mural leaflet is significantly smaller than that found in patients with isolated clefting of the mitral valve …”

“…Its prevalence has been estimated in 0.11% in the population . The cleft is oriented away from the left ventricular outflow tract, similar to the cleft mitral valve in the setting of an endocardial cushion defect with an intact septum . It does not have any other feature of an endocardial cushion defect presenting fully developed septal structures and normal inlet–outlet proportion of the left ventricle …”

“…In recent years, there has been an increasing number of publications describing trifoliate appearing left atrioventricular valves and terms such as clefts and cleft-like indentations have been used with sometimes unclear meanings. 1,22 In most reports, true clefts are defined as gap appearing lesions reaching the anterior or posterior mitral annulus (atrioventricular junction). 23 On the other hand, cleft-like indentations represent deeper indentations between welldefined scallops of otherwise anatomically normal mitral valves.…”