heartbeat

noun

1. One pulsation of the heart; especially an irregular one, hence the emotion which causes it.

   “The policeman waited for a heartbeat in vain.”

   “He alone gives me such heartbeats.”

   “Both CRT-Ds and ICDs are implanted under the skin, in the patient’s upper chest area. The devices have wires called leads that attach to the heart and regulate the rhythm of the muscle. Defibrillators help patients with bradycardia – a slow heartbeat – by pacing the heartbeat and those with tachycardia – a fast heartbeat – by delivering shocks that reset heartbeats to normal.”

2. The rhythm at which a heart pulsates, a cardiac indicator.

   “If your heartbeat doesn't normalize soon, consult a doctor!”

3. A driving impulse or vital force; the vital center of something.

   “Music is the heartbeat of the people.”

   “Dream Body Recovery is just one of countless recovery houses that have cropped up in Miami, which has become the heartbeat of the B.B.L. boom in the United States. The average price of a B.B.L. nationwide is around $5,000, according to the American Society of Plastic Surgeons.”

4. A very short space of time; an instant.

   “The ambulance arrived in a heartbeat.”

   “Cause I love you more than life Take a bullet for you I swear, I swear In a heartbeat”

5. A periodic signal generated by hardware or software to indicate normal operation or to synchronize other parts of a system.