The behavior of three types of large sinus node arteries with regard to the blood supply of the atrial myocardium.

Abstract

We describe angiographic findings of sinus node arteries (SNAs), focusing in the large sinus node artery (LSNA) variants, regarding the blood supply of the SN and atrial myocardium. We examined the SN arteries via postmortem angiographic visualization in six hundred hearts derived from victims of various accidents. The main stem or a branch of the SNA supplied the right atrium (RA) and part of the interatrial septum (IS) in 32% of cases (Group A), one atrium, the IS and a small part of the other atrium (Group B) in 39% and the entire atrial myocardium (LSNAs) (Group C) in 29%. Forty-two percent (42%) of LSNAs were arising from the anterior part of the right coronary artery (RCA) (type 1), 9% from its intermediate part (type 2) and 49% from the posterolateral portion of the left circumflex artery (LCx) (type 3). Type 2 can be injured by surgical procedures, type 3 by interventional ones, while type 1 is not affected by any. The SN area was supplied in Groups A and B by the main stem of SN arteries in 370 cases (62%) and by branches (Br) in 55 (9%). The 175 cases of group C (29%) were supplied only by branches. The clockwise (40% of cases) and counterclockwise rotations (60%) of the SNA around the superior vena cava, concern surgical procedures. The above findings are essential for every day surgical and interventional procedures.