The compound noun 'heart attack' is a common noun, a general word for a sudden severe occurrence of damage to heart; a word for a thing.
A proper noun is the unique name of a person, a place, or a thing.
heart is a common noun
"Bosom" is a common noun. It refers to the chest or a person's heart or emotions.
"Park Avenue" is a proper noun, because it is a place. Proper nouns like this should always be capitalized.
Common
It is a proper noun, because it is the name of a specific thing.
proper
Proper noun
Pencil proper or common noun
it's a common noun. a proper noun would be Spider-Man.
Proper noun or common noun
The noun cassette is a common noun.
It can be concrete or abstract depending on the use, because heart is widely used metaphorically.The "heart" as an organ is a concrete noun.The noun "heart" to mean a disposition (light of heart), or an emotional response (guided by the heart), or perseverance (having the heart), would all be abstract nouns.