Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Autoimmune myocarditis ?
    ### Response:
    Autoimmune myocarditis is an autoimmune disease that affects the heart. The condition is characterized by inflammation of the heart muscle (myocardium). Some people with autoimmune myocarditis have no noticeable symptoms of the condition. When present, signs and symptoms may include chest pain, abnormal heartbeat, shortness of breath, fatigue, signs of infection (i.
    