ICD-10 Code I51.89 – Other ill-defined heart diseases (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I51.89 – Other ill-defined heart diseases
What it is
I51.89 is used for heart conditions that are documented as other ill-defined or unspecified structural or functional disorders of the heart. It captures a diagnosis when the record does not fit a more specific ICD-10-CM heart disease code.
Clinical signs
Clinical features vary; refer to documentation. You may see nonspecific cardiac findings such as abnormal exam results, imaging changes, or provider-described heart disease without a clearer subtype.
When to use this code
Use this code when the clinician documents an ill-defined heart disease and no more specific diagnosis is available in the chart. It is appropriate when the record confirms a heart disorder but does not identify a precise category such as cardiomyopathy, valvular disease, or ischemic disease. Check documentation before coding a nonspecific term.
Do not use for
Do not use I51.89 if the provider documents a more specific heart condition that can be coded elsewhere. It is also not the right choice for symptoms alone, such as chest pain or palpitations, without a documented heart disease.
Coding tip
Code the most specific documented heart diagnosis first; use I51.89 only when the record stays nonspecific after review.