Anatomy

The tricuspid valve (TV) is a right-sided heart valve between the right atrium and the right ventricle. The TV complex consists of 3 leaflets: anterior, posterior, and septal; the chordae tendinae; 2 identifiable papillary muscles; the fibrous tricuspid annulus (TA); and the right atrial and right ventricular myocardium (Figure 1). In order for the TV to function competently, all of these components must be coordinated. With respect to leaflet size, the anterior leaflet is the largest, and the septal leaflet is the smallest. The posterior leaflet is unique due to the presence of multiple scallops. Because the septal leaflet is the smallest and fixed, it is standardly spared from annular dilatation, and the base of this leaflet is utilized as a reference for sizing tricuspid annuloplasty rings. The 2 papillary muscles are identified as anterior and posterior. The anterior papillary muscle supplies chordae tendinae to the anterior and posterior leaflets, whereas the posterior papillary muscle supplies chordae to the septal and posterior leaflets. Accessory chordal attachments may be appreciated to the right ventricular free wall or the moderator band. These accessory chordal attachments may play a role in tricuspid regurgitation (TR), as they can impair proper leaflet coaptation in the setting of right ventricular dysfunction. The TV complex is intimately associated with the conduction system, as the atrioventricular node (AV) lies within the triangle of Koch, an anatomic confine demarcated by the tendon of Todaro, the septal leaflet of the TV, and the origin of the coronary sinus. Great care must be taken when performing surgical maneuvers on the TV in order to avoid injury to the conduction system.

Figure 1

The surgeon’s view of the tricuspid valve complex.