cardiac pacemaker vs SA node

cardiac pacemaker and SA node both are nouns.

Word	Noun	Adjective	Verb	Adverb
cardiac pacemaker	Yes	No	No	No
SA node	Yes	No	No	No

As nouns, cardiac pacemaker and SA node are synonyms defined as:

cardiac pacemaker and SA node: a specialized bit of heart tissue that controls the heartbeat

Other synonyms of cardiac pacemaker include pacemaker, sinoatrial node.

cardiac pacemaker (noun)	SA node (noun)
a specialized bit of heart tissue that controls the heartbeat	a specialized bit of heart tissue that controls the heartbeat