Myocarditis belongs among the heart diseases. It is either infectious or non-infectious inflammation of the heart muscle. As the heart is a vital organ pumping blood into the whole body, the myocarditis may be very dangerous.


There are many possible causes of heart muscle inflammation. Infections are important causative factors. Some types of microorganisms preferentially attack the heart muscle, particularly the group of viruses known as Coxsackie, rubella virus, Epstein-Barr virus and many others. In addition, the inflammation can be caused by some bacteria, for example by Borrelia in Lyme disease. Non-infectious myocarditis may be of an autoimmune origin when our own immune system damages the myocardial cells. A great example is disease known as systemic lupus erythematosus. Rheumatic fever is also an autoimmune disease, but I would like to mention it separately. It is caused by errant immune reactions after an untreated streptococcal tonsillitis. Our immune system may mistake the streptococci bacteria with the myocardial cells and damages them. Both the cells of heart valves and heart muscle may be damaged. Myocarditis may be also related to some medications, especially in cytostatic therapy used in cancer treatment.


Inflammation of the heart muscle may be asymptomatic. However, in some cases it may manifest with fever, chest pain and symptoms of heart failure. The most obvious symptom is shortness of breath due to accumulation of blood in the lungs (dysfunction of the left ventricle) and fatigue or fainting due to a decrease of cardiac output. Myocarditis is also related to occurrence of arrhythmias. The severity of arrhythmias ranges from simple palpitations to sudden death.


The doctors examine the patient suffering from the above mentioned symptoms. ECG is a very important examination method, especially in patients suffering from chest pain. Heart functions may be evaluated by echocardiography. Blood tests may show elevations of cardiac markers (that reflect damage of the heart muscle) and they may also serologically determine presence of various causative microorganisms. When the diagnosis is uncertain, the cardiologists may perform a biopsy of the heart muscle by a fine needle to obtain a tissue sample for histological examination to confirm signs of inflammation. As the symptoms may sometimes mimic heart attack, coronary angiography may be performed to rule out ischemic causes of patient’s troubles.


The therapy is usually coordinated by skilled doctors (cardiologists). The patient should obey bed rest and avoid physical exercise. Immune disorders may be treated by medications that suppress the immune system such as the corticosteroids. Some microorganism-related cases of myocardial may be treated by antibiotics or anti-viral medications. If the patient starts experiencing arrhythmias, the doctors may prescribe antiarrhythmics.


Jiri Stefanek, MD  Author of texts: Jiri Stefanek, MD
 Sources: basic text sources