Myocarditis is an inflammation of the heart’s muscular wall, the myocardium. Although rare, it can be devastating. Myocarditis can occur with no symptoms and remain undiagnosed.

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.

• Viral infection from viruses like measles , rabies , or HIV .
• Bacterial infection from bacteria like diphtheria or Mycobacterium .
• Fungal infection from Aspergillus or Candida .

• 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 .

A risk factor is something that increases your chance of getting a disease or condition.

There are no known risk factors for developing myocarditis.

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.

• Flu-like complaints, including fever, fatigue, muscle pain, vomiting, diarrhea , and weakness
• Rapid heart rate
• Chest pain
• Shortness of breath and respiratory distress
• Loss of consciousness
• Sudden, unexpected death

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.

The universally recommended therapy for myocarditis is bedrest, no physical activity, and supplemental oxygen. Corticosteroids may be given to help inflammation. You will most likely be admitted to a hospital.

Specific treatment is directed at the underlying cause if possible. For instance:

• If the cause is a bacterial infection, antibiotics are prescribed.
• If it is viral, antiviral agents will be prescribed.
• Immunosuppressive therapy may be used if myocarditis is due to an autoimmune disorder such as lupus or scleroderma.

If heart failure symptoms are present, medications are given to support the function of the heart. These include diuretics, ACE-inhibitors, beta-blockers, and antiarrhythmic agents.

Additionally, a defibrillator, which helps maintain the normal rhythm of the heart, may be implanted into your chest. Severe cases may require a cardiac transplant.