atrionector

sin·u·a·tri·al node

[TA]
the mass of specialized cardiac muscle fibers that normally acts as the "pacemaker" of the cardiac conduction system; it lies under the epicardium at the upper end of the sulcus terminalis.

atrionector

(ā″trē-ō-nek′tŏr, tor″) [ atrium + nectere, to connect]
An obsolete term for sinoatrial node.