Thank you for your inquiry regarding CMS996: Appropriate Treatment for ST-Segment Elevation Myocardial Infarction (STEMI) Patients in the Emergency Department (ED). The measure’s population includes all ED encounters for patients 18 years and older at the start of the encounter with a diagnosis of STEMI during the ED encounter, that ends during the measurement period (aside from those meeting measure denominator exclusions or exceptions). Therefore, if the EHR does not document clinical codes indicating that the patient had an ED encounter, as captured by the “Encounter, Performed” QDM datatype and the Emergency Department Evaluation and Management Visit value set OID: 2.16.840.1.113883.3.464.1003.101.12.1010), they will not be captured in the measure denominator. It is not the measure’s intent to capture non-ED encounters in the measure denominator such as inpatient encounters. In terms of the numerator, the measure defines appropriate STEMI treatment using three numerators: fibrinolytic therapy within 30 minutes of ED arrival, percutaneous coronary intervention (PCI) within 90 minutes of ED arrival, or discharge from the ED to acute care within 45 minutes of ED arrival. Therefore, if a patient meeting measure denominator criteria had a PCI performed within 90 minutes of their ED arrival, this encounter would be captured in the measure numerator. In the scenario that a patient was admitted to the inpatient setting at the same facility within 45 minutes of ED arrival (i) after being discharged from the ED with a discharge disposition of “Discharge to Acute Care Facility” and (ii) following timely performance of a PCI, the encounter would only be captured by the numerator once.