Atrioventricular nodal branch of right coronary artery

The atrioventricular (AV) nodal artery (Atrioventricular nodal branch) is a coronary artery branch that supplies blood to the atrioventricular node and proximal portions of the cardiac conduction system. This artery most commonly originates from the right coronary artery (RCA) in approximately 80-90% of individuals, arising from the distal RCA at the level of the crux cordis (the junction of the atrial and ventricular septa with the atrioventricular groove). In the remaining 10-20% of cases, it arises from the left circumflex artery (LCX).

The AV nodal artery has a mean diameter of 1.4-2.0 mm at its origin and an average length of approximately 22.6 mm.  The artery arises from the U- or V-shaped segment of the coronary artery at the crux cordis and courses toward the AV node, which is located within the triangle of Koch in the right atrium. Most AV nodal arteries (approximately 71.8%) immediately exit the distal compact node, suggesting they primarily supply the proximal part of the AV conduction axis.

Anatomical studies have identified two main types based on length: a "long-length" variant that supplies almost all the AV conducting tissue (found in 72% of cases), and a "short-length" variant that perfuses exclusively the AV node and sometimes the nonpenetrating main bundle of His. The artery may have multiple branches, with studies showing a mean of 1.6-2.3 branches depending on the examination method used.

The course of the AV nodal artery is clinically significant—in approximately 54% of cases it passes under the coronary sinus, while in 46% it passes underneath the right atrium endocardium. This anatomical relationship makes the artery susceptible to injury during cardiac surgery, catheter ablation procedures, and interventions involving the coronary sinus area.

The atrioventricular nodal branch (atrioventricular (AV) nodal artery) must not be confused with the atrioventricular branches of right or left coronary arteries.