heart ‧ beat /ˈhɑːtbiːt $ ˈhɑːrt-/ BrE AmE noun [uncountable and countable]
1 . the action or sound of your heart as it pumps blood through your body
2 . be a heartbeat away from something to be very close to a situation or position
3 . in a heartbeat American English very quickly, without delay:
Things can change in a heartbeat.
4 . the heartbeat of something American English the main origin of activity or excitement in a place or organization