ICD-10-CM 2027
ICD-10 code for heart ischemia
From the official ICD-10-CM alphabetic index entry “Ischemia, ischemic › heart (chronic or with a stated duration of over 4 weeks)”. Page updated September 29, 2026.
About coding heart ischemia
The ICD-10-CM code for heart ischemia is I25.9 (Chronic ischemic heart disease, unspecified). The official index lists 2 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on I25.9.
Within I25, choose I25.9 (unspecified) only when documentation doesn't support a more specific option: Atherosclerotic heart disease of native coronary artery (I25.1), old myocardial infarction (I25.2), aneurysm of heart (I25.3), coronary artery aneurysm and dissection (I25.4), ischemic cardiomyopathy (I25.5), Silent myocardial ischemia (I25.6), atherosclerosis of coronary artery bypass graft(s) and coronary artery of transplanted heart with angina pectoris (I25.7) and other forms of chronic ischemic heart disease (I25.8).
Use an additional code to identify: chronic total occlusion of coronary artery (I25.82), exposure to environmental tobacco smoke (Z77.22), history of tobacco dependence (Z87.891), occupational exposure to environmental tobacco smoke (Z57.31), tobacco dependence (F17.-) and 1 more.
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
More specific heart ischemia codes (official index)
Common questions about heart ischemia ICD-10 codes
What is the ICD-10 code for heart ischemia?
- I25.9 — Chronic ischemic heart disease, unspecified. More specific codes apply when the documentation supports them: I24.9, I24.9.
What is the ICD-10 code for subacute heart ischemia?
- I24.9 — Acute ischemic heart disease, unspecified.
Is I25.9 billable?
- Yes. I25.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can I25.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict I25.9 as a principal diagnosis.
Is I25.9 a CC or MCC?
- No. I25.9 is neither a CC nor an MCC under MS-DRG v44.0.