Thank you for your inquiry regarding CMS996v5, Appropriate Treatment for ST-Segment Elevation Myocardial Infarction (STEMI) Patients in the Emergency Department (ED). This measure captures the percentage of emergency department (ED) encounters for patients 18 years and older with a diagnosis of ST-segment elevation myocardial infarction (STEMI) that received appropriate treatment, defined as fibrinolytic therapy within 30 minutes of ED arrival, percutaneous coronary intervention (PCI) within 90 minutes of ED arrival, or discharge to an acute care facility within 45 minutes of ED arrival. Our understanding is that your question intends to understand the distinction between the two ED value sets: "Encounter, Performed: Emergency Department Evaluation and Management Visit" using "Emergency Department Evaluation and Management Visit (2.16.840.1.113883.3.464.1003.101.12.1010)", and "Encounter, Performed: Emergency Department Visit" using "Emergency Department Visit (2.16.840.1.113883.3.117.1.7.1.292)"   The "Emergency Department Evaluation and Management Visit" is for identifying emergency department encounters from the problem list and hospital encounters. The "Emergency Department Visit" is specifically for the ED location. This is needed to capture location time and obtain the elapsed between ED arrival and the three numerator events. More information can be found in the measure’s HTML file posted on the eCQI Resource Center ( https://ecqi.healthit.gov/sites/default/files/ecqm/measures/CMS996v5.html ).