Early reperfusion of the myocardium is crucial in treating patients with acute ST segment elevation myocardial infarction (STEMI). Emergency medical services (EMS) plays an important role in minimizing delays to reperfusion. This study demonstrates that a large proportion of patients presenting with STEMI do not use EMS. Thus, such patients cannot benefit from many mechanisms designed to minimize time delays. Healthcare providers are challenged with both implementing strategies for improving care (minimizing delays to reperfusion) for patients not using EMS, and encouraging patients to access care via EMS in the event of acute chest pain.