Myocarditis Symptoms: Is there a link with COVID-19?

Myocarditis, an inflammation of the heart muscle, is a critical health condition that can affect individuals of all ages. The condition has gained significant attention due to its association with COVID-19. Despite its potential severity, myocarditis often goes unrecognised due to its various symptoms which are often similar to other health conditions. Myocarditis can range from mild to life-threatening and requires immediate medical attention. Here we will share comprehensive insights into myocarditis symptoms, its causes, diagnostic procedures, and treatment options, and the emerging concerns related to COVID-19.

In this article we will explore:

• What is Myocarditis?
• Myocarditis Symptoms and Complications
• What are the causes and risk factors for myocarditis?
• How is myocarditis diagnosed?
• Myocarditis Treatment, prevention and management

Myocarditis is characterised by the inflammation of the myocardium, the heart’s muscle layer, which can impact heart function and overall health.

Pericarditis is a similar condition, that is characterised by inflammation of the pericardium (the thin sac surrounding the heart muscle)

This inflammation can also disrupt the normal electrical pathways in the heart, potentially causing irregular heart rhythms (arrhythmias). In Australia, myocarditis is most prevalent amongst young adults, affecting people from puberty to those in their early 30’s. There is a much higher incidence reported in males, even those who are athletic and healthy (1). Since COVID-19, there have been some reported myocarditis cases, which may be linked to the vaccine. While the cases linked to COVID-19 have been mild, in severe cases, myocarditis can lead to complications such as heart failure and arrhythmias, making early detection crucial (2,3).

Myocarditis symptoms may vary between adults and children, making it challenging to diagnose. 

Adults typically experience symptoms such as:

• Chest pain or discomfort
• Fatigue and weakness
• Shortness of breath
• Palpitations or irregular heartbeats
• Swelling of the lower limbs, typically in the ankles and feet

Children, on the other hand, may present with symptoms such as:

• Fever and fatigue
• Breathing difficulties
• Rapid or irregular heartbeats
• Fainting or seizures in severe cases

The complications of myocarditis can be severe, including heart failure, where the heart struggles to pump blood effectively; arrhythmias, which are abnormal heart rhythms; cardiomyopathy, a chronic disease of the heart muscle; and pericarditis, inflammation of the lining around the heart. These complications highlight the importance of recognising and addressing myocarditis symptoms quickly (4).

Myocarditis can be caused by a variety of factors, with COVID-19 being one risk factor of interest. Studies have shown a correlation between COVID-19 infection and a heightened incidence of myocarditis. There are several reports that patients who contracted COVID-19 exhibited a higher likelihood of developing myocarditis compared to those who did not contract the virus (5). The mechanisms behind this include the direct viral invasion of heart tissues and the severe inflammatory response triggered by the virus. The World Health Organization (WHO) also acknowledged the link between COVID-19 and cardiovascular complications, including myocarditis, noting that such complications can persist even after recovery from the initial infection. However, WHO reports that incidences have been very rare and cases have been mild, with individuals recovering rapidly with myocarditis treatment. (6). 

Most often, myocarditis is triggered by (7): 

• Infections: Including but not limited to:
  • Viruses Coxsackie virus, HIV, Hepatitis C, Influenza.
  • Bacterial infections: Streptococcus, Staphylococcus, Borrelia burgdorferi (Lyme disease).
  • Parasites: Trypanosoma cruzi (Chagas disease), Toxoplasma gondii.
• Environmental Toxins: Exposure to heavy metals (like lead and arsenic), certain chemicals, and pollutants.
• Autoimmune Diseases: Conditions like lupus or rheumatoid arthritis can trigger myocarditis.
• Medications: Some medications, including certain antibiotics and chemotherapy drugs, can induce myocarditis.

Understanding these causes and risk factors, and the impact of COVID-19 on heart health, is essential for prevention and early intervention.

Diagnosing myocarditis involves a combination of clinical assessment and diagnostic tests (8): 

• Electrocardiograms (ECGs): This test records the electrical activity of the heart, identifying irregular rhythms.
• MRI Scans: A detailed imaging test that helps visualise inflammation and damage in the heart muscle.
• Blood Tests: These tests measure levels of cardiac enzymes and inflammatory markers indicative of heart muscle stress or damage.
• Heart Biopsy: A small sample of heart tissue is examined to confirm inflammation and its cause.

These diagnostic methods, alongside assessment of myocarditis symptoms, are critical in identifying myocarditis and formulating an appropriate treatment plan with your healthcare professional.

Myocarditis treatment strategies depend on the severity and cause (9):

• Mild Cases: Focus on symptom management and rest.
• Severe Cases: Medications to support heart function and address the underlying cause, such as ACE inhibitors, beta-blockers, diuretics or immunosuppressants in autoimmune myocarditis.
• Infection-Induced Myocarditis: Antibiotics, antivirals, or antiparasitic medications may be prescribed, depending on the infection type.

Preventing myocarditis involves managing risk factors and maintaining a healthy lifestyle. This includes:

• Vaccinations: staying up-to-date with vaccinations, especially if you plan to travel overseas, as this can prevent developing infections that lead to myocarditis.
• Hygiene: Simple practices such as hand-washing are essential to avoid developing infections.
• Regular medical check-ups: This is especially important for individuals with risk factors and those who develop myocarditis symptoms. For example, those with autoimmune diseases or chronic conditions like diabetes may be more susceptible to complications associated with myocarditis.

It is always important to consult with a cardiologist and other health specialists for targeted advice and management.

Understanding the myocarditis symptoms and available treatment options, particularly in the context of COVID-19, is crucial. Early detection and intervention can greatly reduce the risk of severe complications. Consulting healthcare professionals for any myocarditis symptoms or concerns, especially post-COVID-19 infection, is imperative for effective management and recovery.