I51.8
Other ill-defined heart diseases
Non-billable headerNot valid on its own. Use one of the more specific codes under it.
I51.8 is a non-billable ICD-10-CM code header for other ill-defined heart diseases. Report a more specific code from it instead. It is part of the FY2027 code set, effective October 1, 2026. The more specific codes under it are I51.81 Takotsubo syndrome and I51.89 Other ill-defined heart diseases. Its coding notes include 11 Excludes2 entries.
Guidelines tip
From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.
Hypertension with heart failure or certain other heart conditions is assigned to category I11, with an additional code for the heart condition, unless the provider documents they are unrelated.
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Inherited from I51 Complications and ill-defined descriptions of heart disease
- heart disease specified as rheumatic (I00-I09)
Also from chapter/block level (10 notes)
Inherited from Chapter 9 Diseases of the circulatory system
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
- systemic connective tissue disorders (M30-M36)
- transient cerebral ischemic attacks and related syndromes (G45.-)