Gatekeeper of the hea is

The atrioventricular (AV) node is the "gatekeeper" between the atria and the ventricles and is located at the AV junction on the right side of the hea (Figure 1A). The primary role of the node is to conduct the action potential from the atria to the ventricles. However, the AV node also acts as a backup pacemaker in the case of failure of the sinus node and stops arrhythmias in the atria, such as atrial fibrillation, from being conducted into the ventricles at dangerously high rates. Atrial conductive system is organised so that the cardiac impulse do not travel frim atria to ventricle too rapidly. This delay allows time for the atria to empty their blood into ventricle before ventricular contravtion begins .