Origin of the sinoatrial node and atrioventricular node arteries in right, mixed, and left inferior emphasis systems.

The origin of the sinoatrial node artery (SAN) and atrioventricular node artery (AVN) was determined for 118 patients with normal coronary arteriograms. The coronary arteriograms of the 118 patients were divided into right (66.1%), mixed (26.3%), and left (7.6%) inferior emphasis systems. The SAN arose from the right coronary artery in 53%, the left coronary artery in 35%, and had a dual origin in 11%. The proximal right coronary artery was the origin of the SAN in 48.7% of right, 60.5% of mixed, and 55.6% of left inferior emphasis systems. The left coronary artery was the origin of the SAN in 38.5% of right, 25.8% of mixed, and 44.4% of left inferior emphasis systems. The AVN arose from the right coronary artery in 84%, the left coronary artery in 8%, and from both in 8% of the 118 patients. The right coronary artery was the origin of the AVN in 98.7% of right, 74.2% of mixed, and 0% of left inferior emphasis systems. The left coronary artery was the origin of the AVN in 0% of right, 25.8% of mixed, and 100% of left inferior emphasis systems.