Pogue Mahone
The caf's Camus.
Chest compressions are about trying to keep the brain perfused when the heart stops doing that job. They serve no other purpose.I'm no medic so I wouldn't assume I know what I'm talking about but I think the main aim of cpr is to maintain some flow of oxygenated blood with the hope of creating or maintaining a shockable beat (defibs can't be used if there isn't a shock able beat). I'd guess that the high failure rate relates to the cause of the heart stopping and if permanent heart damage has occurred and/or if the brain was damaged by a lack of oxygen.
Getting the heart back functioning again is more complicated. Sometimes defibrillation can help but not always. You can also inject drugs which kick the heart back into action. There may even need to be a surgical intervention. Generally the more interventions needed the lower the chance of a good outcome.
The best possible scenario is an arrhythmia (messed up electrical circuit in the heart) which a defibrillator can shock back to normality, without any other interventions needed. This seems to be what happened with Eriksen.
For me the most important thing for anyone to remember is the initial ABC assessment. When you’re in an (understandable) panic that might get forgotten and doing chest compressions on someone who doesn’t need them can do a fair bit of harm.