SA node vs sinoatrial node

SA node and sinoatrial node both are nouns.

Word	Noun	Adjective	Verb	Adverb
SA node	Yes	No	No	No
sinoatrial node	Yes	No	No	No

As nouns, SA node and sinoatrial node are synonyms defined as:

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

Other synonyms of SA node include cardiac pacemaker, pacemaker.

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