myocardiopathy vs heart disease

myocardiopathy and heart disease both are nouns.

Word	Noun	Adjective	Verb	Adverb
myocardiopathy	Yes	No	No	No
heart disease	Yes	No	No	No

As nouns, heart disease is a hypernym of myocardiopathy; that is, heart disease is a word with a broader meaning than myocardiopathy:

myocardiopathy: a disorder (usually of unknown origin) of the heart muscle (myocardium)
heart disease: a disease of the heart

Other hypernyms of myocardiopathy include cardiopathy.

myocardiopathy (noun)	heart disease (noun)
a disorder (usually of unknown origin) of the heart muscle (myocardium)	a disease of the heart