[citation needed] The origin of the sinoatrial node artery is not related to coronary artery dominance, which means the side (right or left) that provides the circulation to the back of the heart.

[citation needed] In more than 50% of human hearts, the artery actually courses close to the superior posterior aspect of the interatrial septum.

[4] A left S-shaped sinoatrial artery, originating from the proximal left circumflex or LCx artery, has been described as a common variant in approximately 10% of human hearts.

[5] This artery is larger than normal and supplies a good part of the left atrium, but also right-sided structures like part of the sinoatrial node and the atrioventricular nodal areas.

In this variant, the artery courses in the sulcus between the left superior pulmonary vein and the left atrial appendage where it could be susceptible to injury during catheter or surgical ablation procedures on the left atrium, especially for atrial fibrillation ablation or open-heart cardiac surgery.