also: ペースメーカ
pacemaker (medical device)
Refers to the implanted cardiac device that regulates heartbeat.
My grandfather has a pacemaker in his heart.
pacesetter; pacemaker (runner)
Used in sports, especially running, for a person or competitor who sets the pace.
In a marathon, the pacemaker leads the front group.
My grandfather had surgery last year to have a pacemaker implanted.
He served as the pacesetter for the first half of the race.