ICD-10 Code I42 – Cardiomyopathy (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I42 – Cardiomyopathy
What it is
Cardiomyopathy is a disease of the heart muscle that weakens its ability to pump blood effectively. Use this code for documented cardiomyopathy when the record does not specify a more detailed subtype.
Clinical signs
Clinical features vary; refer to documentation. Common findings may include heart failure symptoms, reduced exercise tolerance, abnormal heart size, or rhythm disturbances noted on exam, imaging, or cardiology assessment.
When to use this code
Use I42 when the provider documents cardiomyopathy without naming a specific category such as dilated or hypertrophic. It may also apply when the note confirms cardiomyopathy as the active diagnosis being evaluated or managed. Check documentation if the subtype is unclear.
Do not use for
Do not use this code for cardiomyopathy caused by another condition if a more specific code is documented. Do not use it when the record identifies a different heart disease diagnosis instead of cardiomyopathy.
Coding tip
Review the full cardiology note for the exact subtype and any underlying cause before assigning the unspecified code.