My doctor told me I have a virus that is attacking my heart! It was causing shortness of breath, heart palpitations, tachycardia, dizziness and fatigue. What is this virus, and where I can find out more information about it? My doctor told me that in some people it turns their hearts to mush.

Sheila

Let me start by saying that I hope your doctor was not so crude to say your heart could turn to mush. It sounds as though you have myocarditis, or inflammation of the muscle of the heart, which is most often caused by a viral infection. If this inflammation damages the heart, it may have several important consequences. Because a damaged heart cannot pump blood as forcefully as normal, the organs of the body don't receive enough blood, and fluid builds up in the lungs, a process called congestive heart failure. In addition, inflammation can interfere with the conduction of electrical impulses controlling the rhythmic beating of the heart. Abnormal heart rhythms, some of which can be fatal, may result.

Virtually any virus can cause myocarditis, but the most common are enteroviruses, influenza (flu) virus, and the common viruses of childhood, such as rubeola (which causes measles) and varicella (which causes chickenpox). Other causes include bacterial infections such as Lyme disease, toxins such as cocaine, and autoimmune diseases (diseases in which the body's disease-fighting immune system attacks the body's own tissues) such as lupus. In most cases, no definitive cause is found, and the agent responsible is presumed to be a virus.

Most cases of viral myocarditis are mild or asymptomatic (without symptoms) and the condition is never suspected. Usually, there is some damage to the heart muscle, which can cause enlargement of the heart, shortness of breath, and heart palpitations and arrhythmias (irregular heart rhythms). Sometimes, the non-cardiac manifestations of the viral infection -- such as rash, fever and sore throat -- are most prominent. Chest pain, when present, can make it difficult to distinguish myocarditis from a heart attack.

The most distressing thing about viral myocarditis is whom it strikes. Most patients have had no significant previous illness and may be in the prime of life. Then, without warning, heart failure develops.

Definitive diagnosis can be made by biopsy (removal of a small piece of tissue for examination) of the inside lining of the heart. This procedure is performed by inserting a catheter (a flexible tube) into a blood vessel in the groin and pushing it along until it reaches the heart.

Most cases of myocarditis apparently resolve without serious complications. The patient recovers fully over several weeks to months, often with no residual heart problems. In rare instances, the patient's heart disease may progress so rapidly that it requires a heart transplant to save his or her life. In other cases, the inflammation persists, causing heart failure later in life. Medical scientists believe that a sizable number of cases of idiopathic (due to no known cause) heart failure are actually the result of a long-term viral infection. The reverse is not true -- that is, most cases of myocarditis do not eventually cause heart failure.

Treatment of myocarditis can be difficult. Certainly, if a specific treatable cause is found, such as Lyme disease (which is caused by a bacterium), the appropriate antibiotics are given. But there is no known effective treatment for most cases of viral myocarditis. Some experts believe that the virus does not directly cause heart damage. Rather, it may be the body's own immune system that damages the heart while trying to wipe out the infection. For this reason, many experts have tried to treat viral myocarditis with immunosuppressive drugs such as corticosteroids. Unfortunately, controlled scientific trials have yielded conflicting results. In fact, some studies have shown that corticosteroids make the problem worse.

Today, the best treatment is probably "supportive," that is, to stabilize the patient and give medications that enable the heart to function as well as possible, without trying to stop the disease process itself. Stabilizing heart failure -- if present -- is done with several different drugs commonly used to treat heart failure due to other causes. When more is known about how the heart damage occurs, we may be able to treat it more effectively. You should be followed closely to detect early any worsening of your condition.