Myocarditis, Adult

ExitCare ImageMyocarditis is a swelling (inflammation) of the heart muscle (myocardium). When the heart becomes inflamed, it cannot pump as well. Severe cases of myocarditis can cause heart failure.


It is usually caused by a viral infection, although other causes are possible.


Mild cases of myocarditis may not have symptoms. If symptoms do occur, they may include:

  • Chest pain.

  • Shortness of breath.

  • Fast or abnormal heart rhythms.

  • Fatigue.

  • Fluid retention or swelling in the feet or legs.

  • Fever.

  • Body aches.

  • Fainting.


Myocarditis can be hard to diagnose because it can mimic other diseases. Myocarditis may be suspected if the above symptoms have appeared after a recent infection. A physical exam and other tests may be used to confirm the diagnosis. Some of these tests are:

  • Blood tests to check for signs of infection or heart damage.

  • Electrocardiography that shows your heart's electrical patterns and rhythms.

  • A chest X-ray exam to look at your heart and lungs.

  • Echocardiography or other imaging tests to look at how well your heart is working.

  • Your health care provider also may recommend a heart (cardiac) catheterization. In this test, a flexible tube (catheter) is inserted into a blood vessel then threaded into the heart. A special instrument can then remove tiny samples of heart muscle tissue (biopsy). The samples are sent to a lab for analysis.


Treatment of myocarditis is aimed at treating the underlying cause and may involve:

  • Heart medicine such as beta blockers or angiotensin-converting enzyme (ACE) inhibitors. These help strengthen the heart and help it beat more regularly.

  • Diuretic medicine. Extra fluid in the body can make the heart work harder. Diuretic medicine can help get rid of the extra fluid.

  • Steroid medicine. In some cases of myocarditis, steroid medicine is used to reduce swelling.


  • Understand these discharge instructions.

  • Will monitor your condition.

  • Will seek immediate medical care if necessary.