ICD-10 Code I22 – Subsequent ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I22 – Subsequent ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction
What it is
I22 identifies a new myocardial infarction that occurs within four weeks of a first acute MI. Use it when the record shows a subsequent STEMI or NSTEMI event during that recovery period.
Clinical signs
Typical findings include recurrent ischemic chest pain, new ECG changes, and evidence of myocardial injury after a recent infarction. Clinical features vary; refer to documentation.
When to use this code
Use I22 when the provider documents a second acute MI within 28 days of the initial event, including a new STEMI or NSTEMI. Confirm that the earlier infarction is recent and that the later episode is not just ongoing care for the first MI. If the note is unclear, check documentation.
Do not use for
Do not use I22 for an old MI, routine follow-up after a completed infarction, or chest pain without documented new infarction. Do not code it when the event is outside the 28-day window.
Coding tip
Verify the timing of the prior MI and the wording of the new event before assigning I22.