HEART & BLOOD Cardiovascular System • Aortic aneurysm • High blood pressure (hypertension) • High blood cholesterol • Thrombophlebitis • Rheumatic fever • Varicose veins • Heart arrhythmias • Atrial fibrillation • Endocarditis • Aortic valve stenosis • Aortic valve regurgitation • Mitral valve stenosis • Mitral valve regurgitation • Pulmonary hypertension • Raynaud's disease • Long QT syndrome • Mitral valve prolapse • Pericarditis • Cardiomyopathy • Myocarditis • Arteriosclerosis / Atherosclerosis • Peripheral arterial disease (PAD) • Low blood pressure (hypotension) • Aortic dissection • Lymphedema • Pulmonary valve stenosis • Ventricular septal defect (VSD) • Tetralogy of Fallot • Coarctation of the aorta • Atrial septal defect (ASD) • Patent ductus arteriosus (PDA) • Left ventricular hypertrophy • Bundle branch block • Heart murmurs • Patent foramen ovale • Transposition of the great arteries • Hypoplastic left heart syndrome • Sudden cardiac arrest • Prehypertension • Tricuspid atresia • Ebstein's anomaly • Buerger's disease

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Myocarditis is an inflammation of the myocardium, the thick muscular layer of the heart wall. This uncommon condition can result in a variety of signs and symptoms, including vague chest pain, an abnormal heartbeat and congestive heart failure.

When myocarditis is severe enough, the pumping action of your heart weakens and your heart is unable to supply the rest of your body with enough oxygen-rich blood. Clots can form in the heart as well, potentially leading to a stroke or heart attack.

Myocarditis may develop as a complication of an infectious disease, usually caused by a virus. It can occur in people of all ages and is diagnosed more often in men than in women. Treatment of myocarditis depends on the underlying cause.

The signs and symptoms of myocarditis may vary, depending on the cause and the severity of the disease. The most common signs and symptoms include:

• Vague chest pains
• A rapid or abnormal heartbeat (arrhythmia)
• Shortness of breath, particularly during physical activity
• Fluid retention, with swelling of your legs, ankles and feet
• Fatigue

Other signs and symptoms may occasionally occur as well, such as:

• Fainting or a sudden loss of consciousness, which may be associated with irregular heart rhythms
• Other symptoms associated with a viral infection, such as a headache, body aches, joint pain, fever, a sore throat or diarrhea

Myocarditis can be accompanied by pericarditis, which is an inflammation of the membrane covering the heart (pericardium). Pericarditis may cause sharp pains over the center of your chest.

In mild cases, myocarditis produces no noticeable symptoms. People may be ill with the general symptoms of a viral infection and never realize that their heart is affected. Some people may never seek medical care and may recover without ever knowing they had myocarditis.

Myocarditis in children
When children develop myocarditis, they may experience the following signs and symptoms:

• High temperature
• Loss of appetite
• Breathing difficulties
• Bluish or grayish discoloration of the skin

Years ago, rheumatic fever was a common cause of myocarditis. But today there are usually other reasons for the condition. Most often it develops secondary to an underlying infection caused by:

• Viruses. The virus most often associated with myocarditis is coxsackievirus B. But adenovirus, parvovirus B19, echovirus, influenza virus, Epstein-Barr virus and rubella virus are also causes of myocarditis. HIV, the virus that causes AIDS, can directly infiltrate the heart muscle.
• Bacteria. These include Staphylococcus aureus, which can also cause an infection of the heart valves called endocarditis, and a tick-borne bacterium called Borrelia burgdorferi, which is responsible for Lyme disease. Myocarditis also occurs in more than one-fourth of all people with diphtheria, a disease caused by the bacterium Corynebacterium diphtheriae.
• Parasites. Among these are such parasites as Trypanosoma cruzi and toxoplasma, including some that are transmitted by insects and can cause a condition called Chagas' disease. This disease is much more prevalent in Central and South America than in the United States, but it can occur in travelers and in immigrants from that part of the world. Chagas' disease is the most common global cause of congestive heart failure.
• Fungi. Candida, aspergillus and histoplasma are rare causes of myocarditis.

Myocarditis also sometimes occurs when a person is exposed to:

• Certain chemicals. These may include substances such as arsenic and hydrocarbons.
• Medications that may cause an allergic or toxic reaction. These include antibiotics such as penicillin and sulfonamide drugs, as well as some illegal substances, such as cocaine.
• Systemic diseases. These include lupus, other connective tissue disorders, inflammation of blood vessels (vasculitis), and rare inflammatory conditions such as Wegener's granulomatosis.

Call your doctor if you have any of the signs and symptoms of myocarditis, particularly chest pain and shortness of breath. If you've had an infection that sometimes leads to myocarditis, be alert for the symptoms of myocarditis and let your doctor know at once if they occur. When the symptoms are severe, go to the nearest emergency room.

Your doctor may suspect myocarditis if you've recently had a viral or other type of infection and have developed symptoms that suggest an inflamed heart muscle. To make the diagnosis, your doctor begins by taking a medical history and then performs a physical examination. Your doctor will listen to your heart with a stethoscope, trying to detect abnormal heart rhythms and sounds, including murmurs.

To make or confirm a diagnosis of myocarditis and determine its severity, your doctor may also order one or more tests, most commonly:

• Electrocardiogram (ECG). This test evaluates your heart's electrical patterns and can detect abnormal rhythms, as well as a weakened or damaged heart muscle.
• Chest X-ray. An X-ray of your chest will image your heart, showing its size, shape and structure. An X-ray of your lungs can indicate whether there's a buildup of fluid in your lungs.
• Echocardiogram. Sound waves, or ultrasound, can create moving images of the beating heart. An echocardiogram may detect enlargement of your heart, poor pumping function, valve problems or fluid around your heart.
• Blood tests. These tests measure white and red blood counts, as well as levels of certain enzymes that indicate damage to your heart muscle. Blood tests can also detect antibodies against viruses and other organisms that may indicate a myocarditis-related infection.

Your doctor also may recommend a cardiac (heart) catheterization, in which a small tube (catheter) is inserted into a vein in your leg or neck, and then is threaded into your heart. A special instrument can remove a tiny sample of heart muscle tissue (biopsy) for analysis in the laboratory to see if there are signs of inflammation or infection.

When myocarditis is severe, it can permanently impair your heart muscle. As its pumping action weakens, strain is put on your heart, causing progressive heart failure. Your heart becomes unable to pump efficiently enough to supply your body with the oxygen-rich blood it requires. A failing heart can also trigger the formation of blood clots that may lead to a stroke or a heart attack.

People with myocarditis may develop serious heart arrhythmias, which occasionally cause sudden death. In very advanced cases, myocarditis-related cardiac failure requires a heart transplant.

Management of myocarditis involves treating the underlying cause, such as the particular infection that may have set the stage for your heart inflammation.

There's no specific therapy for coxsackievirus B — the most common type of virus that causes myocarditis — other than treatment to relieve pain and other symptoms.

Treating mild cases
In mild cases of inflammation, your doctor may advise rest and prescription medications to give your body a chance to fight off the underlying infection while your heart recovers. If bacteria are causing the infection, your doctor will prescribe antibiotics. Certain rare types of viral myocarditis, such as giant cell and eosinophilic myocarditis, respond to corticosteroids or other medications to suppress the immune system. In some cases the treatment is directed at the underlying systemic disease, such as lupus.

Once your heart inflammation has subsided, you can gradually resume a more active lifestyle. In the meantime, your doctor may recommend that you limit the amount of salt in your diet, and avoid alcohol, cigarettes and vigorous exercise. Taking these steps can reduce the workload on your heart.

Drugs to help your heart
If you have rapid or irregular heartbeats as a symptom, your doctor may advise hospitalization. You'll receive anti-arrhythmia drugs, and your heartbeat will be monitored until it normalizes. If your heart is weak, your doctor may prescribe medications to strengthen the pumping ability of your heart, reduce your heart's workload or help you eliminate excess fluid. These medications may include:

• Angiotensin-converting enzyme (ACE) inhibitors, such as enalapril (Vasotec), captopril (Capoten), lisinopril (Zestril, Prinivil) and ramipril (Altace)
• Beta blockers such as metoprolol (Lopressor, Toprol XL) and carvedilol (Coreg)
• Diuretics such as furosemide (Lasix)
• Digoxin (Digitek, Lanoxin), which increases the strength of your heart muscle contractions and tends to slow the heartbeat

Treating severe cases
In many cases, the myocardial inflammation subsides, leading to a complete recovery. In people without symptoms, their hearts get better spontaneously. Even people with very severe congestive heart failure may improve dramatically, often in just a few days. In some severe cases, however, aggressive therapy may be necessary, such as:

• Intravenous medications to improve the heart pumping function
• Placement of a pump in the aorta (intra-aortic balloon pump)
• Use of a temporary artificial heart (assist device)
• Consideration of urgent heart transplantation

Some people may have chronic and irreversible damage to the heart muscle requiring lifelong medications, while other people need medications for just a few months and then recover completely. This variability in the disease makes it difficult for your doctor to predict how you'll do.

There's no easy prevention for most cases of myocarditis. The risk is rare, but you can take some steps to decrease your risk and the risk to others:

• Avoid people who have a viral or flu-like illness until they have recovered. If you're sick with viral symptoms, try to avoid exposing others.
• Follow good hygiene. Regular hand washing is a good way to help prevent spreading illness.
• Avoid risky behaviors. To minimize your likelihood of contracting an HIV-related myocardial infection, practice safe sex and refrain from intravenous drug use.
• Dress sensibly for the outdoors. If you spend time in tick-infested areas, wear long-sleeved shirts and long pants to cover as much of your skin as possible. Apply tick or insect repellents that contain DEET.
• Get your immunizations. Stay up-to-date on the recommended immunizations, including those that protect against rubella and influenza, which are sometimes the underlying infections causing myocarditis.