A histological study of the atrioventricular junction in hearts with normal and prolapsed leaflets of the mitral valve.

Abstract

SUMMARY The mitral annulus is the point at which the atrial and ventricular walls meet the base of the mitral valve cusps. The suggestion that a variant of this arrangement termed "disjunction" was associated with prolapse of the leaflets prompted examination of the mitral atrioventricular junctions in seven normal hearts and six with prolapse owing to floppy mitral valves. A complete cord-like ring of connective tissue that encircled the atrioventricular junction and into which the three components were inserted at the same point was found in only one heart. The remaining hearts all showed a mixture of segments in which either the three components were inserted into a cord or simply met. Disjunction, defined as a separation of the atrial wall-mitral valve junction from the other component, the left ventricular wall, can occur both with and without a cord-like annulus. There was no significant difference in the number of segments around the left atrioventricular junction which showed disjunction in hearts with normal or prolapsing leaflets.The feature termed disjunction is an anatomical variation of the normal morphological characteristics of the left atrioventricular junction. atrial wall-mitral valve junction and the left ventricular attachment.9 They argued that this anomalous feature, through a process of hypermobility of the tension apparatus, could lead to floppiness of the leaflets. This group, however, studied only limited histological sections from a large number of hearts to demonstrate the significant association between so-called "disjunction" and floppy and prolapsed leaflets.It seemed to us that it was important to test their hypothesis by examining in detail the entire atrioventricular junction in a smaller number of hearts. This report describes our findings. Patients and methodsWe examined 13 hearts obtained an necropsy. The mitral valve was normal in seven (from 3 men and 4 women) and floppy in six (from 4 men and 2 women). The specimens of normal hearts came from a group aged 66-80 years (mean 71-9) and those with floppy valves came from a group aged 56-89 years (mean 69-5).

Plastia da valva mitral com a técnica do "Duplo Teflon": resultados de 10 anos

“…However, as we demonstrated in this series, the survival freedom of reoperation at 10 years was 99.2% ± 0.8, which corroborates the durability of the mitral valve repair with this technique. Furthermore, there were no histological differences between the mitral ring of patients with myxomatous degeneration and that of normal patients [16].…”

The clinical anatomy of the mitral valve

“…Following different landmarks, the annulus appears either more planar or saddleshaped. Anatomically, at the level of the atrioventricular junction, fibro-elastic tissue extends from the left and right fibrous trigones posteriorly describing however an incomplete ring, otherwise completed by myocardium (Angelini et al, 1988). The annulus is deficient towards the aorta, the mitral-aortic curtain extending between the two trigones (McAlpine, 1975).…”

Assessment of Atrioventricular Valve Anatomy and Function in Congenital Heart Diseases Using Three-Dimensional Echocardiography

“…Although the annulus is recognized as the hinge line of the leaflet on an echocardiogram, from the pathological point of view, the distinctive ringlike fibrous cord that supports the base of the leaflets does not always surround the entire area of the leaflet base. Moreover, a well-formed fibrous cord is frequently absent at the annulus opposite to the fibrous continuity [3,4]. The posterior leaflet (also called the mural leaflet) occupies two thirds of the annulus and has three or more scallops, which are referred to as the anterolateral (P1), middle (P2), and posteromedial sections (P3).…”