What Is Myocarditis?

Myocarditis is a condition that occurs when the heart muscle, known as the myocardium, becomes inflamed. This condition can weaken the heart muscle, making it difficult for the heart to pump blood through the body.

It is a rare disease that can develop quickly or slowly over time. Myocarditis is typically caused by a viral infection, an inflammatory condition, or a reaction to medication. Common symptoms include chest pain, rapid or irregular heartbeat, shortness of breath, or fatigue.

Severe myocarditis can cause the heart to be unable to pump blood to parts of the body, which increases the chances of blood clots or stroke. The condition can occur in different areas of the heart. There are effective treatments for myocarditis, including medications, procedures, or surgery.

Causes of Myocarditis

Myocarditis is a rare disease. The most common cause of the condition is a viral infection (a cold, influenza, or COVID-19). Other causes that may lead to developing myocarditis include bacteria, fungus, parasites, certain chemicals or toxins, or allergens.

Symptoms of Myocarditis

Often, people with myocarditis do not experience symptoms and usually do not know they have the condition. Most symptoms resolve on their own. However, in other cases, people may experience mild to severe symptoms which include:

• Chest pain
• Irregular or rapid heartbeat
• Shortness of breath during activity or rest
• Fatigue
• Dizziness or lightheadedness
• Swelling of the legs, ankles, and feet
• Headache
• Sore throat
• Body aches or joint pain
• Fever
• Weakness
• No appetite

Diagnosis of Myocarditis

Myocarditis can be challenging to diagnose due to its non-specific symptoms or symptoms that overlap with other conditions. Your doctor will conduct a physical examination and take a thorough medical history, as well as listen to your symptoms. It may be recommended for further testing if your doctor suspects myocarditis.

Testing may include:

• Blood tests
• Chest X-ray
• Echocardiogram (ultrasound of the heart)
• Electrocardiogram (ECG)
• Cardiac MRI
• Biopsy

Types of Myocarditis

There are several different types of myocarditis, ranging from treatable to life-threatening.

Acute Myocarditis

This type of myocarditis has a fast onset and typically develops because of a viral infection. Symptoms usually resolve quickly and may or may not require treatment.

Chronic Myocarditis

This type of myocarditis persists over time and takes much longer to treat. Often people experience symptom flares or episodes with this type. It is more common for people with autoimmune conditions to experience this type. Autoimmune conditions cause the immune system to attack healthy cells and tissues in the body.

Giant Cell Myocarditis

This type of myocarditis is extremely rare and often fatal. Most people who develop this condition will need a heart transplant. The cause of this type of myocarditis remains unknown. In this condition, inflammatory cells come together and form giant cells that attack the heart muscle and cause scarring.

Eosinophilic Myocarditis

This type of myocarditis is a rare acute life-threatening inflammatory disease of the heart. It is caused by the infiltration and destructive properties of a white blood cell known as eosinophil. It progresses through stages and can be fatal if not treated.

Treatment of Myocarditis

Often, myocarditis symptoms resolve on their own. However, for some mild to severe cases, it requires treatment. Treatments typically consist of medication, implanting medical devices, surgery, or other therapies. More specifically, treatments include:

• Medications - Medications are typically used to treat the heart muscle, although some medications may be used to treat underlying conditions, such as lupus, that directly or indirectly support the development of myocarditis. Examples of medications include corticosteroids to reduce inflammation, anticoagulants to prevent blood clots or strokes, and heart medications such as beta blockers, diuretics, ACE inhibitors, and angiotensin 2 receptor blockers.
• Therapies - This therapy uses an extracorporeal membrane oxygenation (ECMO) machine that may help the heart to recover or buy time while waiting for a heart transplant. This machine works similarly to the lungs by removing carbon dioxide from the heart and adding oxygen to the blood.
• Surgeries or procedures - There are several different types of surgeries or procedures used in treating myocarditis. Treatments include implanting a ventricular assist device (VAD), which aids the heart in pumping blood throughout the body, an intra-aortic balloon pump (IABP), which helps to increase blood flow and reduce the strain on the heart, and a heart transplant, which is used in the most severe cases.

Complications of Myocarditis

Typically, myocarditis resolves on its own without complications. However, in rare instances, some people may experience complications.

Complications include:

• Heart attack or stroke
• Heart failure
• Rapid or irregular heartbeat (arrhythmias)
• Sudden cardiac arrest

Recovery and Outlook

Many people recover from myocarditis and never experience symptoms again. However, there are some people who may require the continued use of medication. Most myocarditis cases resolve on their own without complications or the need for long-term treatments. In rarer cases, some people develop dilated cardiomyopathy, which requires a heart transplant.

Prevention of Myocarditis

There is not a clear way to fully prevent developing myocarditis. However, there are several measures you can take to decrease your risk of developing myocarditis. These measures include:

• Regular handwashing
• Avoiding people who are sick
• Masking
• Staying updated on vaccines, specifically for influenza, COVID-19, and rubella
• Avoiding risky behaviors (excessive alcohol intake, drug usage, not practicing safe sex)