Myocarditis

What is Myocarditis?

Myocarditis - a focal or diffuse inflammation of the myocardium - is typically uncomplicated and self limiting. It may be acute or chronic and can occur at any age. In many patients. myocarditis fails to produce specific cardiovascular symptoms or electrocardiogram (ECG) abnormalities. Recovery usually is spontaneous and without residual defects.

Causes of Myocarditis

Myocarditis may result from any of the following:

• viruses - the most common cause in the United States and western Europe - including coxsackievirus A and B and, possibly. poliomyelitis, influenza, rubeola, rubella, human immunodeficiency virus, adenoviruses and echoviruses
• bacteria, including diphtheria, tuberculosis, typhoid fever, tetanus, Lyme disease, and staphylococcal, pneumococcal, and gonococcal bacteria
• hypersensitive immune reactions, such as acute rheumatic fever and postcardiotomy syndrome
• radiation therapy, especially large doses to the chest during treatment of lung or breast cancer
• chronic alcoholism
• parasitic infections, especially toxoplasmosis and South American trypanosomiasis (Chagas' disease) in infants and immunosuppressed adults
• helminthic infections such as trichinosis.

Signs & Symptoms of Myocarditis

Patients with acute myocarditis and chronic myocarditis experience different symptoms. In acute myocarditis, individuals may experience fever, chest pains, a sensation of skipped heart beat (palpitations), dyspnea and fatigue. In patients with chronic myocarditis, fatigue, a sensation of skipped heart beats, shortness of breath and chest pains may be experienced.

Diagnostic Tests

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

For most patients, treatment includes anti-infectives for the underlying causative infection, modified bed rest to decrease the heart's workload, and careful management of complications. Left-sided heart failure requires activity restriction to minimize myocardial oxygen consumption, supplemental oxygen therapy, sodium restriction, diuretics to decrease fluid retention, and digitalis compounds to increase myocardial contractility. However, these compounds must be administered carefully because some patients with myocarditis may show a paradoxical sensitivity even to small doses.

Arrhythmias necessitate prompt but cautious administration of antiarrhythmics. such as quinidine or procainamide, to depress myocardial irritability. Thromboembolism requires anticoagulant therapy.

Treatment with corticosteroids or other immunosuppressants is controversial and therefore limited to combating life-threatening complications such as intractable heart failure.

Prevention Tips

• Prompt treatment of causative disorders may reduce the risk of myocarditis.
• Regular hand washing is a good way to help prevent spreading illness.
• Avoid people who have a viral or flu-like illness until they have recovered.