triangle of Koch


triangle of atrioventricular node

[TA] three-sided zone of right atrium bounded by the base of the septal leaflet of the tricuspid valve, the anteromedial margin of the coronary sinus orifice, and the palpable subendocardial collagen bundle (tendon of Todaro) coursing from the right fibrous trigone of the fibrous skeleton of the heart to the valve of the inferior vena cava. The atrioventricular node lies within the interatrial septum in this zone. Synonym(s): triangle of Koch

triangle of Koch

A triangular region on the septal wall of the right atrium demarcated by the tendon of Todaro, septal leaflet of the tricuspid valve, and the orifice of the coronary sinus occupied by the atrioventricular node. The entire atrial component of the atrioventricular conduction tissues is contained within the triangle of Koch, which must be avoided to prevent surgical damage to atrioventricular conduction.