The atrioventricular node (Latin nodus atrioventricularis, atrioventricular node '), in short: AV node or Aschoff - Tawara node (after Ludwig Aschoff and Japanese pathologists Sunao Tawara ), is located in the Koch triangle and is part of the conduction system of the heart. It consists of specialized cardiac muscle cells and is located in the wall between the right and left atrium on the border of the ventricles. The AV node continues in the bundle of His, which in turn divides into two bundle branch.
The hazards arising from the sinus node excitation is passed through the working muscles of the atria. Since these are but electrically isolated by the fibrous heart skeleton against the chambers, the excitement can not spread to the muscles of the chambers.
The AV node is the only electrical connection between the atria and ventricles and, with 0.04-0.1 m / s is by far the lowest conduction velocity of the heart. Thus, the excitation is transferred with considerable delay in the Chambers. This delay, which corresponds to the ECG the PR interval is of great importance for the coordinated contraction of atrial and ventricular muscle: After the contraction of the atria (diastole of the chamber ) are the contraction of the chambers ( systole) only with some time lag, which contributes to improved ventricular filling.
Turns out the sinus node, the AV node takes over its function, but with a significantly lower frequency of 40-50 min -1. Thus, The AV node also has the ability to spontaneous electrical depolarization, but does not come in the normal case for carrying since the sinus node to the AV node to its higher frequency " imposing ".
Is the electrical conduction in the AV node to slow or blocked, it is called an AV block. An accelerated transition between the atrium and ventricles, bypassing the AV node is a condition in the Wolff- Parkinson -White syndrome.