Myocarditis is an inflammation of the heart muscle that decreases the ability of the heart to pump blood normally. It can be caused by:
Another type of myocarditis is peri-partum cardiomyopathy. For unexplained reasons, some women in the very last phase of pregnancy or soon after delivery of the baby develop poor heart muscle function. This condition is unusual.
The symptoms of myocarditis depend on the cause and severity. For example, many people with uncomplicated myocarditis caused by coxsackievirus don't have any symptoms. The only sign of heart inflammation may be a temporary abnormal result on an electrocardiogram (EKG), a test that measures the heart's electrical activity. Or an echocardiogram may show some abnormalities, such as decreased strength of heart contractions. Other people have fever, chest pain, cardiac arrhythmias (abnormally fast, slow or irregular heartbeats), sudden loss of consciousness (syncope) or signs of heart failure (shortness of breath, leg swelling).
Your doctor will suspect myocarditis based on your medical history and symptoms. To confirm the diagnosis, your doctor will examine you, paying special attention to your heart. This will be followed by an EKG, a chest X-ray, an echocardiogram and blood tests.
In some patients, your doctor may order tests to determine if a virus or other infectious agent is the cause. These tests in include blood tests and attempts at isolating certain types of viruses from stool, throat washings or other body fluids.
How long myocarditis lasts depends on the cause and on the patient's general health. For example, in many typically healthy adults with uncomplicated coxsackievirus myocarditis, symptoms can start to improve over a couple weeks. In other cases, the heart takes a few months to recover. Sometimes, the damage to the heart muscle is permanent and heart failure persists after the inflammation has resolved.
Myocarditis caused by infections can theoretically be avoided by practicing good hygiene, especially washing your hands often. Diphtheria myocarditis can be prevented by undergoing diphtheria immunization, and HIV can be prevented by following safe sex practices and avoiding intravenous drug use. Myocarditis caused by insect-borne Chagas' disease can be prevented by using effective insecticides in Latin American countries where the illness is common.
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. They will need to limit strenuous activities.
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:
Call your doctor immediately if you have chest pain, even if you think that you are too young to be having heart problems. People of any age can get the chest pain of myocarditis, with or without other symptoms (fever, shortness of breath, abnormal heartbeat, leg swelling).
In many people with uncomplicated viral myocarditis, the heart muscle changes improve without specific therapy and myocarditis-related EKG and echocardiogram abnormalities eventually disappear. However, more severe forms of myocarditis can cause permanent damage to the heart muscle.
National Heart, Lung, and Blood Institute (NHLBI)
P.O. Box 30105
Bethesda, MD 20824-0105