Myocarditis

Myocarditis is inflammation or degeneration of the heart muscle. Myocarditis is focal or diffuse inflammation of the cardiac muscle (myocardium). It may be acute or chronic and can occur at any age. Frequently, myocarditis fails to produce specific cardiovascular symptoms or electrocardiogram (ECG) abnormalities, and recovery is usually spontaneous, without residual defects. Occasionally, myocarditis is complicated by heart failure; rarely, it may lead to cardiomyopathy.

Myocarditis may develop as a complication of an infectious disease, usually caused by a virus. It can occur in people of all ages and is diagnosed more often in men than in women. Treatment of myocarditis depends on the underlying cause.

Causes

Myocarditis is a caused by inflammation of the muscle of the heart. Although a variety of medical conditions can cause myocarditis, the most common cause is infection by viruses. Enteroviruses are recognized as the most common cause of myocarditis. Over many years, a chronic enterovirus heart infection and the body's response to that infection in the heart can lead to irreversible heart muscle damage and heart failure.

Signs and symptoms

Myocarditis usually causes nonspecific symptoms - such as fatigue, dyspnea, palpitations, and fever-that reflect the accompanying systemic infection. Occasionally, it may produce mild, continuous pressure or soreness in the chest (unlike the recurring, stress related pain of angina pectoris).

Although myocarditis is usually self limiting, it may induce myofibril degeneration that results in right and left heart failure, with cardiomegaly, neck vein distention, dyspnea, persistent fever with resting or exertional tachycardia disproportionate to the degree of fever, and supraventricular and ventricular arrhythmias.

Sometimes myocarditis recurs or produces chronic valvulitis (when it results from rheumatic fever), cardiomyopathy, arrhythmias, and thromboembolism.

Diagnosis

The ECG will show transient changes which are usually non-specific and occur in many other cardiac diseases, however, in light of the patient's symptoms and the presence of a fever may raise the suspicion of Myocarditis. An echocardiogram (ultrasound of the heart) will reveal an enlarged heart which is poorly contracting. In very mild cases both the ECG and the echocardiogram may be normal and in these situations one should exercise caution and not participate in any sporting activity when symptoms of a flu like illness are present. In patients presenting with florid cardiac symptoms and signs the diagnosis can be confirmed by a biopsy (small specimen of the heart) taken from the right ventricle.

Treatment

In MI, treatment includes antibiotics for bacterial infection, modified bed rest to decrease the cardiac workload, and careful management of complications. Heart failure requires restriction of activity to minimize myocardial oxygen consumption, supplemental oxygen therapy, sodium restriction, diuretics to decrease fluid retention, and digitalis glycosides to increase myocardial contractility. However, digitalis glycosides must be administered cautiously because some patients with myocarditis show a paradoxical sensitivity to even small doses.

Arrhythmias necessitate prompt but cautious administration of antiarrhythmics, such as quinidine or procainamide, because these drugs depress myocardial contractility. Thromboembolism requires anticoagulation therapy. Treatment with corticosteroids or other immunosuppressants is controversial and therefore limited to combating life threatening complications such as intractable heart failure.

Prevention

There's no easy prevention for most cases of myocarditis. The risk is rare, but you can take some steps to decrease your risk and the risk to others:

• Prompt treatment of causative disorders may reduce the risk of myocarditis.
• To minimize your likelihood of contracting an HIV-related myocardial infection, practice safe sex and refrain from intravenous drug use.
• Maintain current immunizations against diphtheria , tetanus, measles, rubella , and polio .
• Regular hand washing is a good way to help prevent spreading illness.
• Avoid anything that may cause the abnormal heart to work too hard, including salt and vigorous exercise.
• Limit alcohol consumption to no more than one or two drinks a day, if any.