n
(a) (also `pace-setter) runner, rider or driver in a race who moves at a (usu fast) speed which others try to follow （速度赛中）定速度者（使其他参赛者跟从）
*(fig 比喻) That firm was the pace-setter in car design for many years, ie introduced new ideas which were copied by others. 那家公司在汽车设计上多年来一直领先.
(b) electronic device placed on the heart to make weak or irregular heartbeats stronger or more regular （心脏）起搏器.

n[C]
a small machine that is placed inside someone's chest in order to help their heart beat regularly
alsopacesetter
a person or horse who goes to the front in a race and sets the speed that the others must try to achieve