Thank you for your inquiry regarding CMS996v6, Appropriate Treatment for ST-Segment Elevation Myocardial Infarction (STEMI) Patients in the Emergency Department (ED). The measure’s initial population includes all emergency department (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). As such, the measure does not capture a STEMI that presents outside of an ED encounter, such as a subsequent inpatient encounter, as this is not the measure’s intent. It is however the measure’s intent to include ED encounters in the denominator of patients with a STEMI diagnosis who have an ongoing ED encounter, such as those boarding or being evaluated in the ED. In terms of the first scenario described in the inquiry, the issue of capturing the time to intervention starting with STEMI onset as opposed to ED arrival has previously been brought to the measure developer. EHR limitations for recording the onset time of the diagnosis make it challenging to account for this situation. The measure developer will continue to evaluate feedback and recommendations during the annual update cycle and update the measure as needed to align with clinical guidelines and workflow. In relation to the inquiry’s second scenario, if the STEMI presented during the inpatient encounter after the patient was admitted, it should not be included in the measure denominator. A patient with a STEMI diagnosis may be captured in the measure in two ways, as indicated by the measure logic definition below found in the measure’s HTML file posted on the eCQI Resource Center [ https://ecqi.healthit.gov/sites/default/files/ecqm/measures/CMS996-v6.3.000-QDM.html ]: ED Encounter With STEMI Diagnosis "ED Encounter During MP" EDEncounterinMP     where (exists (["Diagnosis": "STEMI"] DxSTEMI       where DxSTEMI.prevalencePeriod starts during EDEncounterinMP.relevantPeriod))     or (exists( EDEncounterinMP.diagnoses EncounterDiagnosis       where EncounterDiagnosis.code in "STEMI" )) First, a STEMI diagnosis can be pulled directly from the ED encounter if a STEMI diagnosis was coded at any point during the ED encounter. Second, the patient can have a diagnosis pulled from a claim, problem list, or other source in the EHR as long as the prevalencePeriod of the STEMI diagnosis started during the ED encounter relevantPeriod. PrevalencePeriod is an attribute of the “Diagnosis” datatype and signifies the onset dateTime to abatement dateTime of the STEMI diagnosis. RelevantPeriod is an attribute of the “Encounter, Performed” datatype and signifies the startTime that the encounter began (admission time) to the stopTime that the encounter ended (discharge time). Therefore, to ensure that STEMIs occurring after ED encounter are not captured by the measure, we recommend working with your EHR vendor to ensure proper documentation of the end of an ED encounter even if a patient receives inpatient care following the ED encounter. A patient disposition to inpatient admission can indicate the end of the ED encounter, and in such cases, the date/time of admission, rather than the decision to admit time, should be used to indicate the end of the ED encounter. We also recommend appropriate documentation of STEMI diagnosis onset and abatement times.