The importance of the sinus node artery in the blood supply of the atrial myocardium. An anatomical study of 360 cases.

The sinus node artery (SNA) and its contribution to the blood supply of the atrial myocardium (AM) were studied using X-rays and corrosion casting in a series of 360 human hearts. In 68 cases (19%) the SNA supplied the right atrium and part of the atrial septum (group A), in 211 cases (59%) it supplied the myocardium of one atrium (right or left), the atrial septum and part of the other atrium (group B), and in 81 cases (22%) the SNA supplied almost the entire AM (group C). In 133 cases (37%) the vessel supplying the sinus node (SN) was not the main continuation of the SNA, contrary to what is generally accepted. The SNA has many intercoronary and intracoronary anastomoses which comprise an important anastomosing net between the right coronary (RC) and left circumflex (LCir) arteries. These findings suggest that the SNA plays a major role in the blood supply of the AM apart from the SN.