Anatomical features of right atrium

Abstract

The anatomy of the inside surface of the right atrium became more interesting with the development of ablation techniques for treatment of atrioventricular nodal reentry tachycardia (AVNRT). The aim of this study was to present the dimensions of the ostium of the coronary sinus, the tricuspid valve anulus and the triangle of Koch, and to describe the arrangement of the superficial atrial muscle fibers in and around the area of the triangle of Koch. The examination was made on 100 human hearts obtained after autopsies of patients who died from no cardiac reasons. The diameter of the orifice of the coronary sinus, the circumference of the tricuspid valve anulus and the dimensions of the triangle of Koch (sides a, b, c and the area) were measured and the arrangement of the superficial, subendocardial muscle fibers was analyzed. The mean values of the lenght of the side a was 26.1 + 3.0 mm, side b 20.2 + 3.6 mm and side c 24.5 + 2.5 mm. The mean value of the area of the triangle of Koch was 256, 2 + 6.7 mm2.The mean value of the diameter of the ostium of the coronary sinus was 9.3 + 1.8 mm.The mean value of the length of the tricuspid leaflet was 107.8 + 10.3 mm. We presented the usual pattern and the variations of atrial subendocardial muscle fibers orientation.