Subsequent STEMI of sites

This code signifies a new ST elevation myocardial infarction (STEMI) occurring after a previous myocardial infarction, affecting an area of the heart muscle other than those specified by more granular codes. It indicates a recurrent ischemic event with characteristic ECG changes and cardiac enzyme elevation.

Use this code when a patient experiences a new STEMI at a different site following a prior MI, and the specific site of the new STEMI is not precisely documented or falls outside of the more common anterior, inferior, or lateral wall locations. Documentation should clearly state "subsequent STEMI" and specify "other sites" or provide insufficient detail for a more specific location.

• Always sequence this code after the code for the initial myocardial infarction (I21.-) if the patient is still within the 28-day window for the initial MI.
• Distinguish carefully between a subsequent MI and an extension of an existing MI; this code is for a new event.
• Ensure documentation specifies "STEMI" and not NSTEMI, as subsequent NSTEMIs are coded differently.