Heart perhaps in rogue broken by lover, finally (4)
I believe the answer is:
Here is my best explanation:
'heart perhaps' is the definition.
(heart is a kind of card)
'rogue broken by lover finally' is the wordplay.
'rogue' becomes 'cad' (I've seen this before**).
'broken by' is an insertion indicator.
'finally' says to take the final letters.
The last letter of 'lover' is 'r'.
'cad' going around 'r' is 'CARD'.
'in' is the link.
(Other definitions for card that I've seen before include "A bit of a wag", "showing heart, say", "Something (usually) folded with a special message", "club perhaps", "one in a suit", "One taken in hand", "Greetings ----", "programme at race meeting", "Character" and "king or queen, for example".)