The heart is, to this biased writer, the most important organ in the body. It is carefully constructed with valves, vessels, electrical circuits, and powerful muscle tissue. The muscle of the heart is called the myocardium. The outer lining of the heart is called the pericardium. 

What is myocarditis and pericarditis?

Myocarditis occurs when the heart muscle becomes inflamed. Pericarditis occurs when the heart’s outer lining is affected. Myocarditis and pericarditis can occur together or in isolation. Significant myocarditis can affect the heart’s function. 

What causes myocarditis?

There are many potential causes of myocarditis, including:

  • viral or bacterial infections
  • immune system response to an infection
  • autoimmune disorders
  • drugs or medications
  • other unknown causes 

Also, in the past two years, there has been particular attention to COVID-associated myocarditis, either linked to COVID-19 infection or following the COVID-19 vaccination. 

The signs and symptoms of myocarditis 

When myocarditis occurs, the heart tissue sees an increase of immune cells from the body, which creates an inflammatory response. Signs and symptoms can include:

  • chest pain
  • fever
  • fatigue
  • shortness of breath
  • palpitations or skipped beats
  • dizziness
  • syncope (passing out)

How is myocarditis diagnosed?

Myocarditis is diagnosed based on symptoms and physical exam findings, as well as testing:

  • Blood work: Results of blood testing will help determine how much inflammation is present, and whether cardiac enzymes are leaking out of damaged heart cells
  • Electrocardiogram (EKG): This imaging test shows whether the electrical patterns in the heart are normal or abnormal 
  • Echocardiogram or 3D imaging including MRI or CT: These cardiovascular diagnostic imaging studies give actual pictures of the structure and function of the heart tissue. MRI is especially useful, as specific regions of injured areas can be identified.

Myocarditis treatment

Treatment for myocarditis is based on the severity of symptoms and test results. Treatment ranges from simple observation to medications that reduce inflammation or treat the infection that is causing the symptoms. Depending on severity, hospitalization and even ICU admission may be necessary during the acute phase of illness. Medications are available to help the heart pump blood more efficiently, and other medications can be used to prevent or treat arrhythmias. 

The effects of myocarditis

Fortunately, symptoms of myocarditis typically resolve rapidly, within several days. Mild cases have no lasting effect on the heart muscle, and a full recovery is expected. In cases with more severe involvement of the heart tissue, poor heart function and abnormal heart rhythms (arrhythmias) can result and persist.

Hospitalization, when necessary, ranges from several days to weeks, and should be followed by several months of exercise restriction after hospital discharge. This allows for complete myocardial healing prior to restarting exercise and athletics. Though complete recovery is most common, occasionally prolonged hospitalization with longstanding cardiac damage occurs, which can require advanced treatments. 

Myocarditis and the COVID-19 vaccine

COVID-19 vaccines have been associated with rare cases of myocarditis, which may occur after either the Pfizer or Moderna mRNA COVID-19 vaccination. Initial studies suggest that vaccine-associated myocarditis is more common in male adolescents and young adults, and more frequently occurs after the second dose of the vaccine series. 

Patients with vaccine-associated myocarditis typically respond very well, with minimal treatments and a full recovery. It is recommended that these patients NOT receive further COVID vaccine doses. Despite the infrequent occurrence of myocarditis following COVID vaccination, the CDC recommends COVID-19 vaccination in most patients, as the health benefits gained through vaccination significantly outweigh vaccine-associated risks. 

For more heart health information and how the Lifespan Cardiovascular Institute can help you, visit our website

Brett W. Goudie, MD

Dr. Brett Goudie is a general outpatient cardiologist with additional focus on noninvasive imaging and exercise physiology with the Brown University Health Cardiovascular Institute. He is board certified in pediatrics and pediatric cardiology.