ICD-10 Code I23 – Certain current complications following ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction (within the 28 day period) (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I23 – Certain current complications following ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction (within the 28 day period)
What it is
I23 identifies specific complications that occur during the 28 days after an acute STEMI or NSTEMI. Use it when the record links a current post-infarction complication to the recent heart attack.
Clinical signs
Clinical features vary; refer to documentation. Commonly documented complications include mechanical or structural problems after myocardial infarction, such as rupture, septal defect, or papillary muscle dysfunction.
When to use this code
Use I23 when the provider documents a complication as current and related to a STEMI or NSTEMI within the 28-day window. The complication should be clearly described in the note, discharge summary, or problem list. If the record only shows a prior infarction without a current complication, check documentation.
Do not use for
Do not use this code for old myocardial infarction without a current complication, or for complications outside the 28-day period. Do not guess the complication type if the documentation is unclear.
Coding tip
Code the specific post-MI complication first when documented, and verify that the infarction is recent enough to support I23.