Definition

Myocarditis is a disease in which the heart muscle known as the myocardium becomes inflamed. The myocardium is the layer located in the center of the heart wall. This heart muscle contracts and relaxes to move blood into and out of the heart and throughout the body. Myocarditis affects the heart's electrical system and muscle cells, causing irregular heart rhythms and pumping issues. When the myocardium becomes inflamed, its ability to pump blood becomes less effective. This can cause a variety of issues, including irregular heartbeat, chest pain, and difficulty breathing, and in severe cases, blood clots, which can lead to a heart attack or stroke, heart damage, and even death. Myocarditis can also cause chest pain, shortness of breath, and a rapid or irregular heartbeat (arrhythmia).

Causes

Myocarditis can be caused by various reasons, such as infections, certain medications and chemicals, or other conditions that cause inflammation throughout the body. Often, the cause of myocarditis is not found. Possible causes of myocarditis include:

• Viruses. Many viruses have been associated with the incidence of myocarditis, including Adenovirus; COVID-19; hepatitis B and C; parvovirus; herpes simplex virus; Echovirus; mononucleosis (Epstein-Barr virus); German measles (Rubella); HIV; Coxsackie B virus; and Cytomegalovirus (CMV).
• Bacteria that can cause myocarditis include Staphylococcus, Streptococcus, Mycoplasma, Chlamydia, and bacteria that cause diphtheria and Lyme disease.
• Parasites include Trypanosoma cruzi and Toxoplasma. Some parasites are transmitted by insects and can cause a condition called Chagas disease.
• Fungi. Fungal infections can cause myocarditis, especially in people with weakened immune systems. Fungal infections associated with myocarditis include Candida, Aspergillus, and Histoplasma.
• Certain medications or drugs (drug-induced myocarditis), including drugs used to treat cancer; antibiotics, such as penicillin and sulfonamide drugs; some anti-seizure drugs; drugs for weight loss; diuretic drugs; alcohol and cocaine.
• Chemicals or radiation. Exposure to carbon monoxide and radiation can sometimes cause inflammation of the heart muscle. Exposure to lead can also trigger the onset of myocarditis.
• Other inflammatory diseases. Conditions that can cause myocarditis include lupus, rheumatoid arthritis, Wegener's granulomatosis, Giant cell arteritis, and Takayasu's arteritis.
• Insect bites, such as spiders, wasps, or certain types of snake bites.

Risk Factor

Some factors that may increase your risk of developing myocarditis include:

• A young adult. However, people of all ages can get it
• Male gender. But women can also get it
• Your body doesn't react well to inflammation. Although you don't inherit myocarditis, your genes influence how your body handles inflammation and how likely you are to get myocarditis
• Excessive alcohol consumption that exceeds your doctor's recommendations

Some medical treatments may also increase the risk of myocarditis, including:

• Dialysis
• Having a device implanted in the heart
• Treatment for heart problems
• Having a central venous line implant

Having any of these medical conditions may also increase your risk of developing myocarditis.

• Diabetes
• HIV/AIDS
• Skin injury or infection
• Cancer treated with certain medications
• Eating disorders
• End-stage kidney disease
• Chest injury

Symptoms

Some people with early-stage myocarditis may have no symptoms, and others may have mild symptoms. Common myocarditis symptoms include:

• Sharp or stabbing chest pain, which may spread to the neck and shoulders
• Fatigue
• Weakness
• Abdominal pain
• No appetite
• Swollen feet, ankles, and soles of the feet
• Rapid or irregular heartbeat (arrhythmia)
• Shortness of breath, at rest or on exertion
• Dizziness or feeling like you're going to pass out
• Flu-like symptoms such as headache, body aches, joint pain, fever, or sore throat

If children develop myocarditis, symptoms may include:

• Difficulty breathing
• Chest pain
• Fainting
• Fever
• Rapid breathing
• Rapid or irregular heart rhythm (arrhythmia)

Diagnosis

When diagnosing myocarditis, the doctor will first conduct an interview with you, asking about your symptoms, when they began, and any risk factors that may have contributed to the onset of myocarditis.

Next, the doctor will perform a physical examination. The doctor will use a stethoscope to listen to your heartbeat. Other supporting tests that may be used to diagnose myocarditis may include:

• Blood tests are usually done to check for signs of heart attack, inflammation, and infection. Heart enzyme tests can detect proteins associated with heart muscle damage. Antibody blood tests can help determine if you have an infection associated with myocarditis
• Electrocardiogram (ECG). This quick and painless test can show how your heart is beating. The doctor may examine the ECG for signal patterns to determine whether you have an irregular heartbeat (arrhythmia)
• Chest X-rays can reveal the size and shape of the heart and lungs. A chest X-ray can reveal whether there is fluid in or around the heart, which may be associated with heart failure
• Cardiac MRI. This exam uses magnetic fields and radio waves to create detailed images of the heart. A cardiac MRI can reveal information about the size, shape, and structure of the heart, as well as signs of inflammation in the muscle. A sound-wave-assisted echocardiogram produces a moving image of a beating heart
• An echocardiogram can show the size of the heart and how well blood is flowing through the heart and heart valves. An echocardiogram can help determine if there is fluid around the heart
• Cardiac catheterization and heart muscle biopsy. The doctor will insert a thin tube (catheter) through a blood vessel in the arm or groin and into an artery in the heart. A dye will be administered through the catheter to help the heart's arteries (coronaries) appear more clearly on X-rays. A small sample of heart muscle tissue (biopsy) may be taken during this test. The sample is then sent to the lab to be examined for signs of inflammation or infection

Management

The management of myocarditis will depend on the source and severity of the inflammation in the heart muscle. In most cases, myocarditis will improve with proper treatment, and you will fully recover.

Some of the management options for myocarditis include:

• Corticosteroids, which are medications that can reduce the intensity or dampen the immune response and help lower the level of inflammation
• Heart medications. If you have myocarditis and signs of heart failure, the doctor may prescribe heart medication to reduce the amount of work your heart does. Beta-blockers, ACE inhibitors, ARBs, and cardiac inotropes are examples of these drugs
• Diuretics. Therapy with diuretics can help reduce fluid accumulation
• Ventricular assist device (VAD). If the symptoms of myocarditis are more severe or if your heart requires help during recovery, a VAD may be used to help pump blood from the heart chambers to the rest of your body
• Treating other conditions. If myocarditis is caused by a medical condition such as an infection or an autoimmune disease, your doctor will also take measures to treat it

Complications

Some of the complications that can result from myocarditis include:

• Arrhythmia, a condition where your heartbeat can be too fast, too slow, or irregular
• Cardiomyopathy, a condition where your heart muscle is weakened and unable to pump blood effectively
• Heart failure, where your heart has difficulty pumping enough blood to your organs and tissues
• Heart attack, where the blood supply to part of your heart is cut off, causing heart tissue to die

Prevention

There is no definitive way to prevent myocarditis. The best way is to maintain good health and avoid infections that can lead to myocarditis. Other ways to reduce the risk of myocarditis include limiting alcohol consumption and not taking illegal drugs.

When to See a Doctor?

Consult with a doctor if you experience symptoms that point to myocarditis.