heroic verse vs epic poem

heroic verse and epic poem both are nouns.

Word	Noun	Adjective	Verb	Adverb
heroic verse	Yes	No	No	No
epic poem	Yes	No	No	No

As nouns, epic poem is a hypernym of heroic verse; that is, epic poem is a word with a broader meaning than heroic verse:

heroic verse: a verse form suited to the treatment of heroic or elevated themes; dactylic hexameter or iambic pentameter
epic poem: a long narrative poem telling of a hero's deeds

Other hypernyms of heroic verse include epic, epos, heroic poem.

heroic verse (noun)	epic poem (noun)
a verse form suited to the treatment of heroic or elevated themes; dactylic hexameter or iambic pentameter	a long narrative poem telling of a hero's deeds