I only ask because my neighbour (remember cardiac arrest on Friday) - he is having a pacemaker fitted today at Barts - but I know I am jumping the gun, but when he comes home if, god forbid, this ever happened again, I would know what to do.
the pacemaker only provides the signal the cpr maintains circulation if the heart stops beating so it looks like a series of single spikes on an ecg its only when proper heart rhythm is restored the familiar wave form shows..