I'd be very suspect about that 40 % statistic. Doesn't jibe with any of the stats I've seen regarding the survival rate of patients where CPR and an AED was used.

A lot of stats are tossed around when it comes to things like survival rates, the reality is that unless the event is witnessed and CPR and an AED are used properly with additional medical treatment the survival rate hovers around 4-5 %. Those numbers go up to around 10% in some studies.