Thank you for your inquiry regarding CMS996v6, Appropriate Treatment for ST-Segment Elevation Myocardial Infarction (STEMI) Patients in the Emergency Department (ED). Our understanding is that the intent of your inquiry is to seek clarification on which scenarios meet the criteria for the “Emergency department encounters with a documented reason for not performing a PCI within 90 minutes of ED arrival” denominator exception. The “emergency department encounters with a documented reason for not performing a PCI within 90 minutes of ED arrival” denominator exception is defined using the logic 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 A Documented Reason For No PCI Performed Within 90 Minutes Of ED Arrival   "ED Encounter With STEMI Diagnosis" EDwSTEMI   with (["Procedure, Not Performed": "Percutaneous Coronary Intervention"] NoPCI           where (NoPCI.negationRationale in "Patient Refusal" or NoPCI.negationRationale in "Procedure Not Indicated/Contraindicated")) PCIRefused     such that PCIRefused.authorDatetime during EDwSTEMI.relevantPeriod Reasons for not performing a PCI are captured using the “Procedure, Not Performed” data type together with the “Patient Refusal” (OID: 2.16.840.1.113883.3.117.1.7.1.93) and “Procedure Not Indicated/Contraindicated" (OID: 2.16.840.1.113762.1.4.1282.2) value sets. The negation rationale (NoPCI.negationRationale) attribute of the “Procedure: Not Performed” data type indicates a one-time documentation of a reason an activity is not performed. Additionally, the “Patient Refusal” (OID: 2.16.840.1.113883.3.117.1.7.1.93) and “Procedure Not Indicated/Contraindicated" (OID: 2.16.840.1.113762.1.4.1282.2) value sets cover scenarios where a PCI is not performed because it is not clinically appropriate or a patient refuses the procedure. Please note that the reason must documented during the ED encounter to meet the criteria. Therefore, scenario #4 (“patient does not end up having the PCI b/c arteries are clear)” would meet the denominator exception criteria. Scenario #3 (“there was a false activation of STEMI”) could meet the denominator exception criteria if the STEMI was addressed, but further examination revealed that it was a “false STEMI” and a PCI was not deemed medically appropriate during the ED encounter. The denominator exception does not cover scenarios where PCI is performed, but does not meet the “within 90 minutes of ED arrival” timing criterion (scenario #1 and scenario #2). Regarding scenario #5 (“cases where the STEMI is being coded from a prior encounter”), we highlight that it is the intent of the measure to capture STEMI diagnoses addressed during the ED encounter. A patient with a STEMI diagnosis may be captured in the measure in two ways, as indicated by the measure logic definition below. 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 encounter, using the “Encounter, Performed”: “Emergency Department Evaluation and Management Visit” diagnoses attribute. Please note that, per the QDM 5.6, “the "Encounter, Performed" diagnoses attribute is intended to capture ALL diagnoses, including the principal diagnosis, i.e., all diagnoses addressed during the encounter represented by the diagnosis code used in the expression”. 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”: “Emergency Department Evaluation and Management Visit” datatype and signifies the startTime that the encounter began (admission time) to the stopTime that the encounter ended (discharge time). To differentiate between active and historic diagnoses in the problem list, it’s important for both the onset and abatement times to be populated in the EHR and mapped to the appropriate QDM data elements to avoid misattribution.