Check on heartbeat (7)

I believe the answer is:

repulse

'check' is the definition.
(I've seen this before)

'on heartbeat' is the wordplay.
'on' becomes 're' ('on' can be mean 'with reference to').
'heartbeat' becomes 'pulse' (synonyms).
're'+'pulse'='REPULSE'

(Other definitions for repulse that I've seen before include "Repel" , "kick in the teeth" , "Ward off" , "Check" , "Drive back or reject" .)

I've seen this clue in The Times, The Independent, The Telegraph and The Sun.

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