Inflammation is a normal bodily response to any sort of wound or infection. Imagine when you cut your finger. Normally, within a short time, the tissue around the cut swells up and turns red—classic signs of inflammation. The immune system in your body is producing special cells to rush to the site of the wound and implement repairs. Sometimes this can help speed along the healing process, but other times, inflammation can be very dangerous.

Myocarditis is a disease marked by the inflammation of heart muscle, the “myocardium,” which is the muscular layer of the heart wall. This muscle is responsible for contracting and releasing to pump blood in and out of the heart and to the rest of the body. When this muscle becomes inflamed, it can no longer pump blood as well, causing problems like an irregular heartbeat, trouble breathing, and in extreme cases, blood clots, heart attack, stroke, or damage to the heart.

What Causes Myocarditis?

Myocarditis is most often caused by viral, bacterial, or fungal infections that somehow make their way to the heart. As the infection tries to take hold, the immune system fights back, releasing chemicals to try to get rid of the disease. This results in inflammation. However, it can backfire and weaken the heart itself. Some autoimmune diseases, like lupus, can cause the immune system to turn against the heart, resulting in inflammation and damage. Often it can be difficult to determine exactly what’s causing the myocarditis, but potential culprits include the following causes.


Viruses are the most common cause of myocarditis in the United States. They include coxsackievirus B, the adenovirus (which causes the common cold), and parvovirus B19 (which causes a rash called fifth disease). Other possibilities include echoviruses (gastrointestinal diseases), Epstein-Barr virus (mononucleosis), and rubella (measles). People with AIDS are also at a higher risk.


Rarely, myocarditis can result from staphylococcus, streptococcus, the bacteria that cause Lyme disease, and the one that causes diphtheria


Candida yeast infections, molds, and other fungi can sometimes cause myocarditis


Parasites are little bugs transmitted by insects that cause other diseases can also cause myocarditis, though this is rare in the United States and is more likely in Central and South America.

Inflammatory Diseases

Diseases that cause inflammation in other parts of the body, like rheumatoid arthritis, can also sometimes cause myocarditis

What Are the Symptoms?

The dangerous thing about myocarditis is that it can affect anyone, occur at any age, and often proceeds without displaying any symptoms. If symptoms do develop, they often resemble those symptoms one might experience with the flu, such as fatigue, fever, joint pain or swelling, and an achy feeling in the chest. This can also make myocarditis difficult to diagnose. Because the disease often attacks otherwise healthy people, it can take its victim by surprise, and is often the culprit in cases of sudden death in young adults.

Many times, myocarditis may subside on its own without treatment, much like a cut on your finger would eventually heal. Even more serious cases that go on for a long time may never create symptoms of heart failure, but secretly may cause damage to the heart muscle. Other times, however, the heart will start to reveal its struggles, with symptoms like:

  • fatigue
  • shortness of breath
  • heart palpitations or rapid heartbeat
  • fever
  • chest pain
  • congestive heart failure

How Is It Diagnosed?

Though myocarditis can be difficult to diagnose, your doctor can use several tests to narrow down the source of your symptoms. Blood tests can check for signs of infection or inflammation and a chest X-ray can show any signs of heart failure. An electrocardiogram (ECG) can also detect any abnormal heart rhythms or indicate a damaged heart muscle, and an echocardiogram (ultrasound) may detect any enlargement of the heart. In some cases, an endomyocardial biopsy may be performed so the doctor can examine a small piece of tissue from the heart.

Treatments for Myocarditis

Treatment for myocarditis depends on how severe the inflammation is. In many cases, the swelling will go down on its own and you’ll recover completely. If you’re having trouble, your doctor may prescribe anti-inflammatory medications to help the process along. They’ll also likely recommend rest and a low-salt diet and you may take diuretics to remove the excess fluids from the body. Antibiotics may help treat the infection if it’s caused by bacteria, and corticosteroid drugs can help reduce inflammation.

If the heart is having trouble pumping as it should, your doctor may also prescribe medications to help the blood vessels relax and the blood to flow more easily. Other medications can help control any irregular heart rhythms. Almost all these treatments work to ease the workload on the heart so it can heal itself. In more severe cases, a pacemaker or a defibrillator may be necessary. Or, if the heart is failing, other procedures may be performed in the hospital. When the heart is extremely damaged, doctors may recommend a heart transplant.