Alternate Names: Inflammation of the heart muscle

Causes and Risks: Viral infections such as coxsackie virus, adenovirus, and echovirus are the most common cause. Myocarditis may also occur during or after various viral, bacterial, or parasitic infections (such as polio, influenza, or rubella). It may also be caused by radiation, exposure to chemicals or medication, or connective tissue diseases.

The middle layer of heart muscle becomes inflamed and irritated, causing symptoms similar to a heart attack or even heart failure. It is a fairly uncommon disorder.

Prevention: Prompt treatment of causative disorders may reduce the risk of myocarditis.

Symptoms:

• Fever
• Vague chest pain
• Severe chest pain as in a heart attack
• Joint pain
• Palpitations, rapid heartbeat
• Fatigue, often from the viral infection
• Signs and symptoms of congestive heart failure
• Sudden death (rare)
• Total absence of symptoms is common

Additional symptoms that may be associated with this disease:

• Syncope (fainting), often related to arrhytmias
• Urine output, decreased
• If the cause is viral, there may be signs of brain involvement (encephalopathy)

Signs and Tests: The diagnosis is made on the basis of symptoms that appear within 6 months of recent infection. A physical examination may detect a rapid heartbeat (tachycardia). Sometimes there are signs of heart failure, including congestion in the systemic (body) or pulmonary (lung) veins.

Tests used in the diagnosis of myocarditis include:

• ECG, showing abnormalities (transient ST-segment changes and T wave changes, and reduced QRS voltage)
• Echocardiogram to observe heart function and rule out clots
• CBC
• Endomyocardial biopsy (biopsy of the heart muscle): this test can confirm the diagnosis
• Cultures (may be performed if infection is suspected as a cause of the disorder)
• Serum auto-antibodies against the heart muscle components

Treatment:

The goal of treatment is to reduce both inflammation and the amount of heart damage. The cause must be identified and treated. This may include antibiotics or other treatments.

Analgesics and anti-inflammatory medications (often including steroids) may be used to reduce symptoms. There may be a need to treat arrhythmias with antiarrhythmic medications. Activity may be restricted to bedrest to reduce cardiac workload, and the diet may be salt/sodium restricted.

In cases complicated with heart failure, oxygen may be given to reduce the workload on the heart (when the oxygen level in the body is high, demands on the heart are less). Patients who have heart clots during myocatrditis may need to take anticoagulants (blood thinners).

Immunosuppression (a treatment similar to that for cancer) or antiviral therapy may help select patients with myocarditis.

Prognosis: Myocarditis can be very serious, and the outcome depends on the cause. The likelihood of complications varies.

Complications:

• Heart failure
• Pericarditis
• Cardiomyopathy

Call your health care provider if symptoms of myocarditis occur, especially after a recent infection.

If you have myocarditis, call your health care provider if you experience increased swelling, chest pain, difficulty breathing, or other new symptoms.