megacardia vs megalocardia

megacardia and megalocardia both are nouns.

Word	Noun	Adjective	Verb	Adverb
megacardia	Yes	No	No	No
megalocardia	Yes	No	No	No

As nouns, megacardia and megalocardia are synonyms defined as:

Other synonyms of megacardia include cardiomegaly, enlarged heart.

megacardia (noun)	megalocardia (noun)
an abnormal enlargement of the heart	an abnormal enlargement of the heart