Health Encyclopedia

Myocarditis

Definition

Myocarditis is inflammation of the heart muscle.

Alternative Names

Inflammation - heart muscle

Causes, incidence, and risk factors

Myocarditis is an uncommon disorder that is usually caused by viral infections that reach the heart, including those due to the Coxsackie virus, adenovirus, and echovirus. It may also occur during or after various viral, bacterial, or parasitic infections (such as polio, influenza, or rubella).

When you have an infection, your body's immune system produces special cells that release certain chemicals to fight off disease. If the infection affects your heart, the disease-fighting cells enter the heart. However, the chemicals they produce can damage heart muscle, causing it to become thick, swollen, and weak. This leads to symptoms of heart failure.

Other causes of myocarditis may include:

Allergic reactions to certain medications
Being around certain chemicals
Certain diseases that cause inflammation throughout the body

Symptoms

There may be no symptoms. Symptoms thay may occur include:

Fever and other signs of infection including headache, muscle aches, sore throat, diarrhea, or rashes
Chest pain that may resemble a heart attack
Joint pain or swelling
Abnormal heart beats
Fatigue
Shortness of breath
Leg swelling

Additional symptoms that may be associated with this disease:

Fainting, often related to irregular heart rhythms
Low urine output

Signs and tests

A physical examination may reveal the following:

Rapid heartbeat (tachycardia)
Abnormal heart beats or abnormal heart sounds (murmurs, extra heart sounds)
Fluid in the lungs
Swelling (edema) in the legs

Tests used to diagnosis myocarditis include:

Electrocardiogram (ECG)
Chest x-ray
Ultrasound of the heart (echocardiogram)
White blood cell count
Red blood cell count
Blood cultures for infection
Blood tests for antibodies against the heart muscle and the body itself
Heart muscle biopsy

Treatment

Treatment is aimed at the underlying cause. Treatment may involve:

Antibiotics
Anti-inflammatory medicines to reduce swelling
Diuretics to remove excess water from the body
Low salt diet
Reduced activity

If the heart muscle is very weak, medicines to treat heart failure are also prescribed. Abnormal heart rhythms may require the use of additional medications, a pacemaker, or defibrillator. If a blood clot is in the heart chamber, blood thinning medicine is given as well.

Expectations (prognosis)

How well a patient does depends on the cause and the person's overall health. The outlook varies. Some may recover completely, while others may have permanent heart failure.

Complications

Calling your health care provider

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

Seek immediate medical help if you have severe symptoms or have been diagnosed with myocarditis and have increased swelling, chest pain, difficulty breathing, or other concerning symptoms.

Prevention

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

Review Date:7/17/2006
Reviewed By:Glenn Gandelman, MD, MPH, Assistant Clinical Professor of Medicine, New York Medical College, Valhalla, NY. Review provided by VeriMed Healthcare Network.

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