I21.21
✓ BillableST elevation (STEMI) myocardial infarction involving left circumflex coronary artery
Diseases of the circulatory system (I00-I99)
Also Known As
ST elevation (STEMI) myocardial infarction involving oblique marginal coronary artery
✅ No additional coding notes for I21.21
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CodeI21.21
BillableYes
ParentI21.2
CategoryDiseases of the circulatory system (I00-I99)
Excludes10 rule(s)
Excludes20 note(s)
Data Source
CMS ICD-10-CM 2026 Tabular List
Updated October 1, 2025 (FY2026)