Key points:  
  • The term “myocarditis” refers to active inflammation of the heart muscle.  
  • Viruses have long been known to cause myocarditis. When it occurs, it is almost always a mild condition with complete resolution, sometimes even without symptoms. However, in rare cases it can cause complications such heart failure and life-threatening heart rhythms.   
  • Myocarditis is a rare complication of COVID-19. It has also been seen in rare cases after vaccination from COVID. In both cases, it likely occurs due to activation of our own immune system.  
  • According to the CDC, vaccine-related myocarditis appears to occur slightly more frequently with mRNA vaccines, particularly after the second dose. The highest risk group is young males, age 12 to 30, depending on the study.  
  • The most common symptom is chest pain, which doesn’t have to be severe. Other symptoms include difficulty breathing, dizziness, and palpitations. Any of these symptoms that occur after a recent diagnosis of COVID, or vaccination, should be taken seriously.  
  • Active myocarditis has been recognized as a risk factor for sudden death in athletes. Usually, it is recommended that individuals with myocarditis avoid intense physical activity for 3-6 months after the active phase, so a timely diagnosis is important.  
  • There is a growing consensus around the best way to recognize, diagnosis and address potential cases, and most importantly keep young athletes safe. The Cardiology Team at Tulio Health can help guide you through the best pathway for you and your athlete.  


The coronavirus pandemic has raised public awareness of many new medical conditions in the last 2 years.  One such term that has entered the public consciousness is “myocarditis”. A simple translation would be “inflammation of the heart muscle”.  Myocarditis has long been recognized as a potential consequence of infection with a virus. In fact, when people are diagnosed with heart failure from an unclear cause, it is often assumed that it was due to a previous, unrecognized viral infection. Therefore, it’s not surprising that we have seen cases in the setting of COVID-19.  

What is myocarditis? 

As most people know, the heart is a muscle. And while it is comprised of several types of specialized cells, it is mostly made of muscle cells called “cardiac myocytes”. These cells are responsible for the squeezing and relaxing function that allow the heart to act as a pump.  

Heart cells can be damaged or diseased through multiple mechanisms. Heart attacks occur when the heart cells die due to a lack of oxygen. Many genetic conditions cause heart cells to form abnormally or lose their function over time. And sometimes, heart cells can become “inflamed”, damaged either by our body’s immune cells or as a result of substances those cells produce. Many illnesses are characterized by an immune system gone wrong. In fact, much of the severe illness seen with COVID is a direct response to unregulated, excessive immune system effects.  


Why do viruses and vaccines cause myocarditis? 

It is worth noting that myocarditis is not a condition isolated to COVID-19, or coronaviruses in general. Many viruses have been implicated in causing heart inflammation. Sometimes, this is due to direct effect of the virus on the heart muscle. Viruses either know or learn how to attach to cells in our body, and either destroy them directly or use them the help replicate. In the case of COVID, the virus has been shown to attach to a particular receptor (ACE2) found on heart muscle cells. But more commonly, it is our immune system, in its effort to kill the virus, that leads to “collateral damage” involving the heart. Whether it is through infection-fighting chemicals (known as cytokines), antibodies, or direct action from immune cells themselves, heart cells are damaged in the process of fighting off the virus.  


What are the complications of myocarditis? 

People who develop myocarditis can have a wide range of presentations, and in some respects, it is rather random as to who develops severe complications. It is important to note that the overwhelming majority of people do just fine.  

The most common symptom of myocarditis is pain in the chest. If the inflammation also involves the lining of the heart (pericarditis) this pain can be worsened by taking a deep breath or lying down. This usually resolves with minimal to no treatment, although sometimes anti-inflammatory medications are used to reduce the duration of symptoms.  

In some cases, however, the damage to the heart cells can have more significant consequences. If enough heart cells are involved, the heart muscle overall can become weak (heart failure). Also, heart cells that are inflamed or damaged are more likely to lead to heart rhythm abnormalities, which can cause palpitations, dizziness, or even life-threatening rhythm changes.   


How is myocarditis diagnosed and treated? 

The American College of Cardiology has put forth an Expert Consensus Statement that provides a wealth of guidance while we continue to study and learn about the best approach to COVID related coronavirus, as well as other cardiovascular complications of COVID infection. This link shares the complete statement, but in summary, the extent of diagnostic testing and scope of treatments are based on the presence and severity of symptoms of heart disease.  

If there is any suspicion of myocarditis, simple tests can be performed such as an electrocardiogram (known as EKG or ECG), a heart ultrasound (echocardiogram) or a simple blood test to look for levels of troponin, a protein that is in heart muscle. Elevated levels of this protein in the blood stream suggest heart injury. If these tests are abnormal, then further testing, perhaps with MRI can be performed.  

As noted, the treatment for myocarditis is very closely tied to the severity of symptoms. For most, it would generally be supportive, meaning anti-inflammatory medications and rest. Those with moderate or severe symptoms would generally be hospitalized and treated more aggressively. 


What is the impact for young athletes? 

Myocarditis has been well recognized as an important clinical condition when considering the safety of participating in competitive athletics. An inflamed heart muscle has been shown to be at increased risk for developing abnormal heart rhythms when placed under excessive demand, which occurs during intense physical activity. Therefore, we usually restrict the activity of young athletes when there is evidence of myocardial inflammation. The bad news is that it can take up to 6 months to return to play. The good news is that almost everyone can eventually get back on the field.  

Developing myocarditis after COVID infection or vaccination is rare, but is it is important to recognize it if it occurs.  

  • Be Aware – it’s always important to make sure your young athletes monitor for symptoms of chest pain, trouble breathing, palpitations or dizziness with exercise. This is especially true after a COVID diagnosis or vaccine.  
  • Pause – any symptoms of myocarditis (or any cardiac condition) develop, stop exercising and/or playing sports until you can get evaluated.  
  • Evaluate – connect with your doctor. We have pathways and reliable testing to determine if there is a problem.  
  • Treat – usually treatment with rest and support medication is enough, but other options are available for more significant cases.  
  • Monitor – stay connected with your health care team to determine the right time to return to sports. A short pause in playing may feel like a major inconvenience but almost everyone will get back on the field safely.   


This article is not meant to be construed as medical advice, rather printed for informational purposes only. Everyone’s health situation is different. As always, it is critical to discuss the use of any supplements with a licensed health care provider to ensure that any use is safe and potential effective in your medical status and condition. 


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