1. From the Department of Cardiology and Stockholm Prehospital Centre, Karolinska Institute, South General Hospital (K.B.); Department of Cardiology, Karolinska Institute, South General Hospital (M.R., J. Hollenberg); Department of Cardiology, University of Göteborg, Salgrenska Hospital (J. Herlitz); and Stockholm Prehospital Centre, Karolinska Institute, South General Hospital (L.S.), Stockholm, Sweden.