Thank you for your inquiry regarding CMS996: 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. In the example you provide, the balloon inflation time may be more informative since it may better indicate that the culprit lesion has been crossed as opposed to just introducing the wire into a coronary. 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.