Eccentric CIA operation is from the heart (7)
I believe the answer is:
cardiac
'the heart' is the definition.
(I've seen this before)
'eccentric cia operation is' is the wordplay.
I cannot quite understand how this works, but
'eccentric' could be 'card' (card can mean an eccentric person) and 'card' is located in the answer.
an anagram of 'cia' is 'iac' which is located in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
'from' is the link.
Can you help me to learn more?
(Other definitions for cardiac that I've seen before include "one with a heart disorder" , "Appertaining to the heart" , "of hearts" , "Of the heat, perhaps illness" , "Relating to 8 down, part one" .)