1. The Department of Epidemiology; Biostatistics and Occupational Health; McGill University; Montréal Québec
2. St. Mary's Research Centre; Montréal Québec
3. Emergency Medicine Services; Montreal Institute of Cardiology; Montréal Québec
4. The Centre de Recherche du CHUM et Institut National de Santé Publique du Québec; Montréal Québec Canada