Attack causing rapid loss of heart (4)

I believe the answer is:

raid

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'attack' is the definition.
(I know that raid is a more specific form of the action attack)

'causing rapid loss of heart' is the wordplay.
'causing rapid' becomes 'ra' (I can't explain this - if you can you should believe this answer much more).
'loss' becomes 'residual' (residual is a kind of loss).
'of heart' says to take the centre (I've seen 'heart' mean this).
The middle letters of 'residual' are 'id'.
'ra'+'id'='RAID'

Can you help me to learn more?

(Other definitions for raid that I've seen before include "Finch and Bronson starred in . . . . On Entebbe" , "A sudden military attack and withdrawal" , "Stock Exchange activity" , "Rifle" , "military operation" .)

I've seen this clue in The Globe and Mail.

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