I51.8
Other ill-defined heart diseases
Not billable — category only FY2026 2025-10-01 → 2026-09-30
Exclusions 11 never code together
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
No further instructional notes apply.
Index entries leading here filed at null
No alphabetic index entry points at this code.
Alongside this code 8 same parent — I51
I51.0 Cardiac septal defect, acquired I51.1 Rupture of chordae tendineae, not elsewhere classified I51.2 Rupture of papillary muscle, not elsewhere classified I51.3 Intracardiac thrombosis, not elsewhere classified I51.4 Myocarditis, unspecified I51.5 Myocardial degeneration I51.7 Cardiomegaly I51.9 Heart disease, unspecified
Subordinate codes 2
Additional references
AHA Coding Clinic® Licence required
Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.