Thank you for your inquiry regarding CMS996v4, Appropriate Treatment for ST-Segment Elevation Myocardial Infarction (STEMI) Patients in the Emergency Department (ED). In alignment with clinical best practice, the measure intends to capture the time from ED arrival to reperfusion, which typically starts with crossing the lesion and balloon inflation. However, we recognize that the “Procedure, Performed” QDM datatype does not have any attributes related to balloon inflation time since it is meant to represent all procedure types and is not specific to PCI. Therefore, it is ideal to capture the earliest time of reperfusion, and map to the relevantPeriod.startTime attribute of the “Procedure, Performed” QDM data element. The value set for Percutaneous Coronary Intervention (2.16.840.1.113883.3.3157.2000.5) includes CPT codes for balloon dilation. With regard to timestamps in the electronic health record (EHR), we recommend working with your EHR vendor on determining the best way to capture this information since we are aware that it is captured in other ways clinically. We will consider refinements in a future Annual Update.