Joker influencing Agamemnon's Clytemnestra leads revolution in four stages - it does the heart good presumably (7,5)

'joker influencing agamemnon's clytemnestra leads' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.

'revolution in four stages it does the heart good presumably' is the wordplay.
I cannot really understand how this works, but
'revolution' could be 'cycle' (I've seen this before) and 'cycle' is found within the answer.
'heart' could be 'cardiac' (I've seen this before) and 'cardiac' is located in the answer.
This accounts for all the letters.
This may be the basis of clue (or it may be nonsense).

Can you help me to learn more?