Acute rheumatic myocarditis

This code signifies an acute inflammatory process affecting the heart muscle (myocardium) that arises as a complication of rheumatic fever. It indicates active myocardial involvement during the acute phase of the rheumatic disease.

Apply this code when documentation explicitly states acute myocarditis in the context of rheumatic fever. Supporting clinical evidence includes recent streptococcal infection, cardiac symptoms (e.g., chest pain, dyspnea, palpitations), and diagnostic findings consistent with myocardial inflammation.

• Ensure documentation specifies "acute" to differentiate from chronic or inactive rheumatic heart conditions.
• Always code the underlying rheumatic fever (e.g., 390) first, as this condition is a manifestation.
• Do not confuse with other forms of myocarditis not related to rheumatic fever.