STUDY OBJECTIVE: Demonstrate improved efficiency of initial and subsequent in-hospital care following emergency department (ED) physician-initiated primary angioplasty (1 PCI). METHODS: An observational study was undertaken in ST-elevation myocardial infarction patients presenting to a community hospital emergency department. Outcomes of patients who received ED physician-directed 1 PCI were compared with patients previously treated by a mix of ED physician and cardiologist co-determined thrombolysis or 1 PCI. A process improvement initiative supported the change to ED-directed 1 PCI. RESULTS: The study included 287 eligible acute reperfusion patients. Median door-to-balloon time (MDBT) improved from 88 minutes (95% CI, 80 96) to 61 minutes (95% CI, 57 70; p < 0.0001). Necessary subsequent in-hospital interventions (NSI) occurred in 70 of 107 (65.4%; 95% CI, 55.6 74.4%) thrombolytic patients, versus 3 of 99 (3.0%; 95% CI, 0.6 8.6%) 1 PCI patients at baseline, and 1 of 81 (1.2%; 95% CI, 0.0 6.7%) 1 PCI patients after process change. Median length of stay (LOS) decreased from 4 days for thrombolytic patients and 3 days for 1 PCI patients at baseline, to 2 days for 1 PCI after adopting the improved process (p < 0.0001). Effectiveness outcomes demonstrating improvement included discharge on beta-blocker (p = 0.0039), angiotensin-converting-enzyme inhibitor (p < 0.0001) and anti-lipid therapy (p = 0.0039), with favorable trends in survival to discharge, and 30-day major adverse cardiac events (MACE). CONCLUSIONS: Conversion to ED physician-initiated 1 PCI for ST-elevation myocardial infarction significantly improved efficiency of care as measured by MDBT, NSI and LOS. Effectiveness measures, including survival to discharge, discharge medications and 30-day MACE, demonstrated improvement or favorable trends.