Atrioventricular node, AV node

The AV node is located between atrium and ventricle of the excitation conduction system of the heart, where the delaying (negative dromotropice) effect of the vagus and the accelerating (positive dromotropice) effect of the sympathetic nervous system occurs. It is the secondary centre of stimulation in the heart.

https://en.wikipedia.org/wiki/Atrioventricular_node _([1])