Here in Denmark there's a volunteer "heart runner" programme. If someone calls 911 and has a cardiac arrest, people in the programme that nearby can be notified

Here in Denmark there's a volunteer "heart runner" programme. If someone calls 911 and has a cardiac arrest, people in the programme that nearby can be notified to fetch an available public AED and run to the patient (or attempt manual resuscitation). According to their material, the 30-day survival rate in Denmark has gone from 3.8% (2001) to 10.4% in 2016, with 67.5% bystander assistance: https://hjertestarter.dk/english/you-can-save-lives https://hjertestarter.dk/english/you-can-save-lives though it's not clear how much the programme itself can claim. According to various papers, rapid CPR/AED after a heart attack can triple survival rates. It's still pretty bleak outcome, but better than e.g. in 2002 Detroit, where 1 out of 471 out of hospital cardiac arrests (OHCA) survived to hospital discharge. In USA, all those stats are apparently being tracked by a programmed called CARES.