the av node lies at the lower back section of the interatrial septum near the opening of the coronary sinus, which conducts the normal electrical impulse from the atria to the ventricles. the av node is quite compact (~1 x 3 x 5 mm). it is located at the center of koch's triangle—a triangle enclosed by the septal leaflet of the tricuspid valve, the coronary sinus, and the membranous part of the interatrial septum.