pacemaker

Noun

• a horse used to set the pace in racing

• an implanted electronic device that takes over the function of the natural cardiac pacemaker

• a specialized bit of heart tissue that controls the heartbeat

• a leading instance in its field
  • the new policy will be a pacesetter in community relations
    

Related words

• Synonyms: 
  pacer , pacesetter , artificial pacemaker , cardiac pacemaker , sinoatrial node , SA node