To the Editor We would like to thank Than and colleagues1-3 for their efforts to safely streamline the emergency department (ED) evaluation of low-risk patients with chest pain. We are concerned, however, that their data could be read to suggest that 30-day major adverse cardiac events (MACEs) can be safely excluded in emergency department (ED) patients with possible acute coronary syndrome based purely on low-risk results using their accelerated diagnostic protocol. Such an interpretation of this study would be misleading.