[1] Ambulance Victoria, Dept Res & Evaluat, 375 Manningham Rd, Doncaster, Vic 3108, Australia
[2] Monash Univ, Dept Epidemiol & Prevent Med, Level 6,99 Commercial Rd, Melbourne, Vic 3004, Australia
[3] Natl Heart Fdn Australia, Level 12,500 Collins St, Melbourne, Vic 3000, Australia
[4] Monash Med Ctr, Dept Cardiol MonashHeart, 246 Clayton Rd, Clayton, Vic 3168, Australia
[5] Univ Western Australia, Dept Emergency Med, 35 Stirling Highway, Crawley, WA 6009, Australia