One pulsation of the heart; especially an irregular one, hence the emotion which causes it.
He alone gives me such heartbeats
The rhythm at which a heart pulsates, a cardiac indicator
If your heartbeat doesn't normalize soon, consult a doctor!
A driving impulse or vital force.
Music is the heartbeat of the people.
A very short space of time; an instant.
The ambulance arrived in a heartbeat.
A periodic signal generated by hardware or software to indicate normal operation or to synchronize other parts of a system.