A recent JACC: Advances Viewpoint examines the challenges associated with implementing revisions to the definition of first medical contact (FMC) introduced in the 2025 ACC/AHA ACS Guideline and its implications for NCDR data collection, specifically for the ACC's Chest Pain – MI Registry.

NCDR Chest Pain – MI Registry Steering Committee Chair-Elect Nathaniel R. Smilowitz, MD, MS, FACC, et al., state that the updated FMC definition shifts from the earliest time an emergency medical services (EMS) provider arrives at a patient's side to the point when a health care professional capable of obtaining and interpreting an electrocardiogram (ECG) first assesses the patient. This change poses new obstacles for accurately capturing FMC data within the registry.

"Evolving, narrower definitions of FMC data element complicate assessments of quality of [myocardial infarction (MI)] care and may obscure true pre-hospital ischemic times and opportunities for performance improvement," write Smilowitz and colleagues. "Moreover, the revised definition of FMC may be impractical to assess in the real world. Until more discrete data are made widely available on the training and capabilities of first responders, it will be difficult for hospitals to operationalize the 2025 ACS guidelines FMC-to-device times."

The authors also highlight potential implications for patients who arrive to the emergency department by self-transport. In these cases, delays in care may be overlooked when MI is not recognized during the triage process.

In response to these concerns, Smilowitz and colleagues opted to maintain the existing Chest Pain – MI Registry Data Dictionary definition of FMC as the "date and time when the patient was first evaluated by EMS prior to arrival at the first facility" for patients transported by EMS.

"Measuring performance based on the time of first EMS arrival provides a standardized, objective timestamp that can be consistently documented across EMS agencies," they write. "The arrival time of EMS with capabilities of ECG interpretation can then be recorded as an ancillary measure."

According to the authors, this approach encourages quality improvement across both prehospital and hospital phases of care, promotes coordination between EMS and receiving hospitals, and emphasizes reducing total ischemic time rather than focusing on a single prehospital process.