1. Research Department, Copenhagen University Hospital, Emergency Medical Services Capital Region of Denmark (A.J.G., F.F., J.S.K., L.A., A.K.E., C.M.H.).
2. Department of Clinical Medicine (A.J.G., F.F., J.S.K., C.M.H.), University of Copenhagen, Denmark.
3. Department of Cardiology, Gentofte Hospital (F.F., C.M.H.), Copenhagen University, Denmark.
4. PULS, Austrian Cardiac Arrest Awareness Association (M.K., F.E., P.S.).
5. Emergency Medical Service Vienna, Austria (M.K.).
6. Department of Emergency Medicine (F.E.) Medical University of Vienna, Austria.
7. Department of Internal Medicine II, Division of Cardiology (P.S., K.A.K.) Medical University of Vienna, Austria.
8. Duke Clinical Research Institute, Durham, NC (K.A.K.).
9. American Heart Association, Denver, CO (C.S.).
10. Department of Anesthesiology (R.S., H.v.S.), Amsterdam University Medical Center, University of Amsterdam, the Netherlands.
11. Department of Clinical and Experimental Cardiology (H.L.T.), Amsterdam University Medical Center, University of Amsterdam, the Netherlands.
12. Netherlands Heart Institute, Utrecht, the Netherlands (H.L.T.).
13. Department of Cardiology, Heart Centre, (C.v.d.W.), Amsterdam University Medical Center, University of Amsterdam, the Netherlands.
14. Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, the Netherlands (C.v.d.W.).
15. Department of Public Health (C.T.-P.), University of Copenhagen, Denmark.
16. Department of Cardiology, North Zealand Hospital, Denmark (C.T.-P.).
17. National Institute of Public Health, University of Southern Denmark (A.K.E.).
18. Department of Cardiology, Rigshospitalet (C.M.H.), Copenhagen University, Denmark.