I42.1
Obstructive hypertrophic cardiomyopathy
Billable FY2026 2025-10-01 → 2026-09-30
Exclusions 13 never code together
I42code
I00-I99chapter
Excludes2
- certain conditions originating in the perinatal period (P04-P96)P04-P96
- certain infectious and parasitic diseases (A00-B99)A00-B99
- complications of pregnancy, childbirth and the puerperium (O00-O9A)O00-O9A
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Q00-Q99
- endocrine, nutritional and metabolic diseases (E00-E88)E00-E88
- injury, poisoning and certain other consequences of external causes (S00-T88)S00-T88
- neoplasms (C00-D49)C00-D49
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)R00-R94
- systemic connective tissue disorders (M30-M36)M30-M36
- transient cerebral ischemic attacks and related syndromes (G45.-)G45.-
Excludes2 — not included here, but the patient may have both. Code both when documented.
Instructional notes 3
Index entries leading here 4
- Cardiomyopathy (familial) (idiopathic) I42.9
- Stricture — see also Stenosis
- Stenosis, stenotic (cicatricial) — see also Stricture
- Myocardiopathy (congestive) (constrictive) (familial) (hypertrophic nonobstructive) (idiopathic) (infiltrative) (obstructive) (primary) (restrictive) (sporadic) I42.9
- hypertrophic obstructive I42.1
Alongside this code 9 same parent — I42
I42.0 Dilated cardiomyopathy I42.2 Other hypertrophic cardiomyopathy I42.3 Endomyocardial (eosinophilic) disease I42.4 Endocardial fibroelastosis I42.5 Other restrictive cardiomyopathy I42.6 Alcoholic cardiomyopathy I42.7 Cardiomyopathy due to drug and external agent I42.8 Other cardiomyopathies I42.9 Cardiomyopathy, unspecified
Medications 1
MED-RT files conditions by MeSH, which carves the world differently from ICD-10. These are name matches on this code's description, offered as candidates — not as an assertion that they are this code.
Additional references
AHA Coding Clinic® Licence required
Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.