Myocarditis, Adult

Myocarditis 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 can be caused by a viral, bacterial, or fungal infection.


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.

  • Sore throat.

  • 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.

  • An electrocardiogram (ECG) that shows your heart's electrical patterns and rhythms.

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

  • An echocardiogram to look at how well your heart is working.

  • Your caregiver also may recommend a heart (cardiac) catheterization. In this test, a flexible tube (catheter) is inserted into a vein in the groin and is then threaded into the heart. A special instrument can then remove a tiny sample of heart muscle tissue (biopsy). The biopsy is sent to a lab for analysis to see if there are signs of inflammation or infection.


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

  • Rest.

  • Antibiotic medicine.

  • Being on a low-salt diet.

  • Quitting smoking, if you smoke. Talk to your caregiver about smoking cessation.

  • Avoiding alcohol.

  • Hospitalization.

  • Heart medicine such as beta blockers or 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.

  • A left ventricular assist device (LVAD). An LVAD is a mechanical pumping device that is surgically implanted to help the heart pump. For severe cases of myocarditis, an LVAD device may be put in temporarily to help the heart pump as it heals.

  • A heart transplant (rare).


  • Understand these discharge instructions.

  • Will monitor your condition.

  • Seek immediate medical care if necessary.