Isolated myocarditis

This code signifies an inflammatory condition of the heart muscle (myocardium) that is not associated with a systemic disease or other specific underlying cause. It represents a primary inflammation of the myocardium, often viral in origin, leading to impaired cardiac function.

Use this code when documentation clearly indicates myocarditis without an identified systemic cause, such as autoimmune disease, toxic exposure, or infection elsewhere in the body. Supporting documentation would include diagnostic findings like elevated cardiac enzymes, abnormal ECG, cardiac MRI showing myocardial inflammation, and exclusion of other etiologies.

• Ensure documentation explicitly states "isolated" or "primary" myocarditis to differentiate from myocarditis secondary to other conditions.
• Do not use this code if the myocarditis is a manifestation of a systemic disease (e.g., lupus, sarcoidosis); instead, code the underlying systemic disease with an appropriate myocarditis manifestation code.
• Always review the medical record for any identified infectious agents or toxic exposures that would necessitate a more specific myocarditis code.