Atrioventricular (AV) node
Nodus atrioventricularis
CardiovascularOrgansThorax
- What it is
- A compact knot of conducting tissue in the lower interatrial septum, inside the triangle of Koch just above the septal leaflet of the tricuspid valve and near the coronary sinus opening.
- Function
- Delays the electrical impulse by ~0.1 s so the atria finish emptying before the ventricles contract; it is the only normal electrical path from atria to ventricles.
- Size
- About 5 × 3 × 1 mm.
- Clinical note
- The delay shows as the PR interval on an ECG; damage to it causes heart block, often treated with a pacemaker.