heart specialist vs cardiologist

heart specialist and cardiologist both are nouns.

Word	Noun	Adjective	Verb	Adverb
heart specialist	Yes	No	No	No
cardiologist	Yes	No	No	No

As nouns, heart specialist and cardiologist are synonyms defined as:

heart specialist and cardiologist: a specialist in cardiology; a specialist in the structure and function and disorders of the heart

Other synonyms of heart specialist include heart surgeon.

heart specialist (noun)	cardiologist (noun)
a specialist in cardiology; a specialist in the structure and function and disorders of the heart	a specialist in cardiology; a specialist in the structure and function and disorders of the heart