pacemaker
pace-mak-er
noun
A small electronic device implanted to regulate the heart's rhythm.
"She had a pacemaker fitted last year."
noun
A person or thing that sets the speed or standard for others.
"The lead runner acted as a pacemaker."
Thesaurus
Synonyms: cardiac pacemaker, sinoatrial node, SA node, pacer, pacesetter, artificial pacemaker