COCHIN CARDIAC CLUB: MYOCARDITIS

The myocardium is the muscular wall of the heart, or the heart muscle, which contracts to pump blood out of the heart. After pumping, it relaxes as the heart refills with returning blood. The myocardium’s smooth outer membrane is called epicardium, while its inner lining is endocardium.

Myocarditis is an inflammation of the myocardium, or middle lining. When the heart becomes inflamed, it cannot pump as well because of the damage done to its cells and swelling. The heart muscle may damage even more if the body’s immune system sends antibodies to try and fight whatever started the inflammation. Sometimes these antibodies attack the tissues of heart instead the cause of myocarditis. If too many heart muscle cells are damaged, the heart muscle weakens. In some cases, this process happens very quickly and results in heart failure or even sudden death. More often, the heart tries to heal itself; the heart muscle heals by changing the damaged or dead heart muscle cells into scar tissue. Scar tissue is not like heart muscle tissue because it does not contract and it cannot help the heart pump blood. If enough scar tissue forms in the heart, it can ultimately lead to congestive heart failure or dilated cardiomyopathy as a consequence of myocarditis.Many people with myocarditis recover completely but it can cause serious problems and even death in some cases. It can occur in people of all ages and is diagnosed more often in men than in women.

Causes

Many organisms can infect and injure the heart. Type B, a virus among those that usually infect the gastrointestinal tract, is believed to be the most common offending agent. Many other viruses, such as those of polio, rubella and influenza, have been associated with myocarditis.

It is not clear why the same viruses cause myocarditis in some patients and different diseases - gastroenteritis, pneumonia, or hepatitis, for example - in others.

Myocarditis can occur as a rare complication of bacterial infections, including diphtheria, tuberculosis, typhoid fever, and tetanus. Other infectious organisms, such as rickettsiae and parasites, may also cause inflammation in the heart muscle.

Myocarditis is also caused due to Chagas disease, an infectious illness that is transmitted by insects.

Symptoms

In mild cases, myocarditis may have no noticeable symptoms. You may feel ill and have general symptoms of a viral infection and never realize your heart is affected.

In serious cases, the signs and symptoms of myocarditis vary, depending on the cause of the disease. Common myocarditis symptoms include:

Chest pain
A rapid or abnormal heartbeat (arrhythmia)
Shortness of breath, at rest or during physical activity
Fluid retention with swelling of your legs, ankles and feet
Fatigue
Other signs and symptoms you'd have with a viral infection, such as a headache, body aches, joint pain, fever, a sore throat or diarrhea

When children develop myocarditis, they may have these signs and symptoms:

Fever
Fainting
Breathing difficulties
Rapid breathing
Bluish or grayish discoloration of the skin

Diagnosis

The best way to diagnose myocarditis may be through a person's observation of his or her own symptoms, followed by a thorough medical history and physical exam conducted by a doctor. Further tests usually include laboratory blood studies and echocardiography. An electrocardiogram (ECG) is also routinely used due to its ability to detect a mild case of the disease. Cardiac catheterization and angiography are additional diagnostic tests used to determine the presence of myocarditis, or to rule out other possible heart diseases that may lead to heart failure.

Another measure used to diagnosis myocarditis is the endomyocardial biopsy procedure. This invasive catheterization procedure examines a biopsied, or "snipped," piece of the endocardium (the lining membrane of the inner surface of the heart). The tissue sample is examined to verify the presence of the disease, as well as to try to determine the infective cause. An approach used only with a patient's consent, this procedure may also confirm acute myocarditis, allowing close monitoring of potential congestive heart failure.

Treatment

Treatment of myocarditis depends on the cause and severity. For example, people with only mild viral myocarditis may be allowed to rest at home. They will be advised not to smoke or to drink alcohol, and they will need to limit strenuous activities until an EKG test is normal.

People with myocarditis that causes heart failure or cardiac arrhythmias will be treated in a hospital. There they will receive one or more of the following: