What is Myocarditis and How Does it Affect the Heart?

Myocarditis is a rare heart condition that can vary greatly from person to person.

You may have heard the term “myocarditis” recently and been curious about what it means. Myocarditis is a rare heart condition that has received a great deal of publicity in recent months because of its connection to COVID-19 disease. Myocarditis has also emerged as a rare side effect of some COVID-19 vaccines, however, the risk of getting myocarditis from COVID-19 illness, itself, is higher than the risk of getting myocarditis from the COVID-19 vaccine.

At Lompoc Valley Medical Center, our primary care providers, emergency medicine, and cardiology teams are highly skilled at identifying the symptoms of heart conditions, including myocarditis. Read on for what you should know about myocarditis and how it affects the heart.

What is Myocarditis?

Myocarditis is a condition that describes, literally, an inflammation of the heart muscle—“myo” meaning muscle, “card,” referring to the heart, and “itis” meaning inflammation. When the heart muscle becomes inflamed, its electrical system can change, causing an abnormal heartbeat also known as an arrhythmia. Inflammation of the heart muscle can also cause scar tissue, interfering with the heart’s function and weakening its ability to pump blood throughout the body. When the heart’s function gets impacted, it can also cause other problems, such as the formation of blood clots that can trigger a heart attack or stroke.

What Typically Causes Myocarditis?

According to the National Library of Medicine, myocarditis, or inflammation of the heart muscle, is most commonly caused by a virus. Myocarditis can also be caused by bacteria, fungi, Lyme disease, medications like chemotherapy drugs, illegal drugs, excessive alcohol intake, toxic chemical exposures, or some autoimmune conditions such as lupus or sarcoidosis.

You may be familiar with some of the viruses that cause myocarditis, including Varicella (the chickenpox virus), influenza (the flu virus), adenovirus (one of many common cold viruses), and HIV. Researchers have also found that the SARS-CoV-2 virus that causes COVID-19 illness can trigger myocarditis.

Who Gets Myocarditis?

You may think of heart conditions as being more common in the elderly. However, myocarditis is more common in young people. According to the Myocarditis Foundation, myocarditis is more common in young people between puberty and the early thirtieth decade. It is twice as likely to affect young men than young women. While this demographic group is more likely to get myocarditis, it is a condition that can affect anyone.

What are the Symptoms of Myocarditis?

Many people who have myocarditis will never be aware of the condition because they will have no symptoms. However, when symptoms of myocarditis are present, they can vary greatly. Symptoms of myocarditis can include feeling tired, having muscle aches, having chest pain, having an abnormal heart rhythm, swelling in the extremities, shortness of breath, lightheadedness, fainting, shock, or even death. People may also experience the symptoms of the viral infection that has triggered the myocarditis—such as sore throat, cough, or fever. Often, a clinician will piece together a suspected diagnosis of myocarditis when these symptoms occur within a few weeks of a viral infection.

When symptoms of myocarditis occur in children, they may be harder to immediately detect. Infants, who are vulnerable to the viruses that cause myocarditis because they have immature immune systems, may have pale skin, tiredness, irritability, or changes in their eating or breathing patterns. According to the Children’s Hospital of Pennsylvania, children with myocarditis who are older may have a fever, breathing changes, cough, or pale or cool hands and feet.

How is Myocarditis Typically Diagnosed?

If you have myocarditis, your healthcare provider may pick up on some nonspecific signs on your physical exam, such as a new heart murmur. You may also have blood work that hints at inflammation present, but no specific blood test can diagnose myocarditis. Myocarditis can be diagnosed more formally using many diagnostic methods. Tools such as an electrocardiogram (ECG, or EKG), a chest x-ray, an echocardiogram, a coronary angiogram, a cardiac MRI, or a biopsy of the heart muscle can give information about whether you have myocarditis, with a biopsy as the most specific way to diagnose the condition.

How is Myocarditis Typically Managed?

If you or a loved one has received a diagnosis of myocarditis, it can feel intimidating. This can be especially true if your symptoms have been mild—it can be hard to accept that you have a heart condition when only feeling slightly ill. The good news is that when myocarditis is mild, it can be managed very readily, and it often goes away on its own. If the infection is determined to be bacterial, antibiotics may be needed. Antiviral medications may be helpful if the culprit is a virus. It will be critical for you to rest (often bed rest is advised) to avoid straining your heart. Your healthcare provider may also counsel you to avoid alcohol and tobacco while healing.

If symptoms of myocarditis have been more profound, including chest pain, heart rhythm changes or shortness of breath, more intensive management may be required. A healthcare provider may prescribe medications such as angiotensin-converting enzyme (ACE) inhibitors, beta-blockers, diuretics, or steroids to support the heart. Sometimes, people may need to come into the hospital to be monitored on a special heart monitor for an extended period. Medications given through an IV can help improve the rhythm of their heart, and certain devices (such as a pacemaker or implantable cardioverter-defibrillator) can be implanted to help support a person’s heartbeat further. Physical therapy may be needed to help a person regain their strength after a long period of rest.

What is the Outlook for Someone with Myocarditis?

Usually, myocarditis goes away on its own after a few weeks or months. However, sometimes symptoms persist for a longer time (this is a condition of chronic myocarditis) or recur. For a small percentage of people, myocarditis can cause a heart condition known as dilated cardiomyopathy, making a heart transplant necessary. In fact, according to the Myocarditis Foundation, experts believe that this condition accounts for 45 percent of the heart transplants performed in the US. Rarely, myocarditis can cause a fatal heart rhythm or severe heart failure event that leads to death. This may seem intimidating—however, for the grand majority, myocarditis resolves either on its own or with medical support, and people can go on with their lives as usual.

What is the Connection Between Myocarditis and COVID-19 Disease?

You may have heard about myocarditis during the pandemic because experts believe that having COVID-19 illness can increase a person’s risk of developing this heart condition. The SARS-CoV-2 virus that causes COVID-19 disease appears to infect the heart muscle and cause inflammation. A report published by the US Centers for Disease Control and Prevention (CDC) found that people with COVID-19 were 16 times more likely to develop myocarditis compared to people of the same age, gender, and background who did not have COVID-19 disease. However, the illness is still rare in both populations, with 150 cases per 100,000 patients with COVID-19, and 9 cases per 100,000 patients without COVID-19 disease.

What is the Connection Between Myocarditis and COVID-19 Vaccines?

You may have also heard about the relationship between myocarditis and the mRNA vaccines developed to protect people from COVID-19. The CDC notes that it is monitoring the relationship between vaccines and the development of myocarditis, and it has found that vaccines are more likely to affect adolescent males and young adults who receive an mRNA vaccine (Pfizer-BioNTech or Moderna). The CDC has also found that myocarditis is more likely to occur after the second vaccine dose, and it typically occurs within a week of getting vaccinated. The type of myocarditis that occurs after the COVID-19 vaccine appears to be mild and self-limited, meaning that people have recovered well with medications and rest and have been able to return to their daily life. Emerging research has even hinted that this type of vaccine-related myocarditis is different from other forms of myocarditis. The CDC still recommends that everyone ages 5 years and older get vaccinated against COVID-19 illness because the risk of getting myocarditis from the virus itself is higher than the risk of getting it from the vaccine.

What is the Bottom Line When it Comes to Myocarditis?

Myocarditis is a rare heart condition that has received attention recently due to its connection to COVID-19 illness and COVID-19 vaccinations. The majority of people who contract myocarditis are younger, and they are more likely to be male. Usually, myocarditis resolves on its own with rest and careful monitoring, however, sometimes people require more intensive support for their hearts. Rarely, it can be fatal. In the current pandemic era, you need to talk with your healthcare provider about your myocarditis risk. Many people can reduce their chances of contracting myocarditis by getting vaccinated against COVID-19. However, for select populations, careful considerations should be made in conjunction with a healthcare provider to ensure that all risk factors are accounted for.

How to Learn More About Myocarditis

At Lompoc Valley Medical Center, we are humbled to be your go-to resource when it comes to learning about myocarditis, as well as other medical conditions. We are also dedicated to keeping you informed about all matters related to the current COVID-19 pandemic. To learn more about myocarditis, COVID-19 disease, or to be evaluated for related symptoms, contact our primary care team at Lompoc Valley Medical Center today.