megalocardia vs megacardia

megalocardia and megacardia both are nouns.

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

As nouns, megalocardia and megacardia are synonyms defined as:

Other synonyms of megalocardia include cardiomegaly, enlarged heart.

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