For purple category calls, the primary measure will be the percentage of people to have a heartbeat restored after a period of cardiac arrest which is subsequently retained until arrival at hospital.
Ar gyfer galwadau categori porffor, y prif ddull mesur fydd canran y bobl y mae eu curiad calon yn cael ei adfer ar ôl cyfnod o ataliad y galon a'i gynnal wedyn nes cyrraedd yr ysbyty.