The broad objectives of this multicenter and multidisciplinary observational cohort study are to investigate patient, provider, and system-related factors that are associated with the quality and safety of initial management for suspected ST-segment elevation myocardial infarction (STEMI) evolving for less than 12 hours in daily practice. The findings of this study should help identifying areas with room for improvement in clinical pathway for STEMI patients. The specific aims of this project are: