Munson Health
Myocarditis -- Adult

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by Calvagna M


Many cases of myocarditis have no identifiable cause. This is called idiopathic myocarditis. When a cause is identified, it falls into one of three categories: infectious, toxic, or immune-mediated.



  • Drugs, including chemotherapeutic drugs , lithium , or cocaine
  • Heavy metals, including copper, iron, or lead
  • Toxic substances, including arsenic, carbon monoxide, or other inhalants
  • Physical agents, including electric shock or radiation


  • Allergic reactions to penicillin or streptomycin
  • Alloantigens, including heart transplant rejection
  • Autoantigens, including Chagas’ disease, scleroderma, or lupus


The symptoms of myocarditis vary from person-to-person depending on the cause and the severity. Symptoms may appear slowly or come on suddenly.
If you have any of these symptoms you should contact your doctor right away.
Sudden, intense myocarditis can lead to congestive heart failure .
Some people have no symptoms (asymptomatic).


The diagnosis of myocarditis is often difficult. There is no specific test for it. Many other causes of heart problems must be ruled out. To do this, your doctor will ask about your symptoms and medical history, and perform a physical exam.
Tests may include the following:
  • Electrocardiogram (ECG) —a test that records the heart’s activity by measuring electrical currents through the heart muscle.
  • Chest x-ray —a test that uses radiation to take pictures of structures inside the body.
  • Cardiac enzyme blood test—in some cases certain enzymes are elevated.
  • Echocardiogram —a test that uses high-frequency sound waves (ultrasound) to examine the size, shape, and motion of the heart.
  • Biopsy —removal of a sample of heart tissue to test for infection.
  • Cardiovascular magnetic resonance—the use of magnetic waves to take pictures of structures inside the body.


American Heart Association

National Heart, Lung, and Blood Institute



Canadian Cardiovascular Society

Health Canada



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Myocardim and myocarditis. American Heart Association website. Available at: . Accessed August 4, 2005.


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