While myocarditis has been in the headlines lately due to rare occurrences in mRNA COVID-19 vaccine recipients, it’s viruses that are the most common cause of the condition in children, the American Heart Association (AHA) said. And while many cases resolve on their own, a statement from the group, which was published in Circulation, addressed treatment guidelines in recovering patients.
Myocarditis, which is along with pericarditis and endocarditis is one of the main types of heart inflammation, can temporarily or permanently weaken the heart muscle and the heart’s electrical system which could impact how the heart pumps. In the U.S., approximately 10 to 20 per 100,000 people are diagnosed with it each year, with children accounting for 1 to 2 per 100,000 incidents, according to the AHA.
Signs and symptoms may present as fatigue, shortness of breath, fever, chest pain and palpitations, but they can range in children from minimal to showing signs of heart failure, life-threatening arrhythmias or cardiogenic shock, the AHA warned.
In patients with suspected myocarditis, diagnosing the condition could include non-invasive testing or blood screening to measure for elevated cardiac enzymes, or an echocardiogram or an MRI. Electrocardiography (ECG) can also assess heart rhythm and show signs of injury to the heart or signs of pericarditis as well. Previously, biopsies were usually taken, which would also indicate if a virus was present.
“In children, myocarditis is most often the result of a viral infection, and it is most often acute or sudden-onset, rather than chronic myocarditis, which is seen more often in adults,” the AHA stated.
Acute myocarditis should be monitored closely, possibly in an inpatient setting as it can deteriorate rapidly, the AHA advised, and antiviral therapy should be considered if an acute viral infection is found.
Myocarditis could be secondary to systemic autoimmune diseases and is associated with rheumatic fever or Kawasaki disease, and possibly COVID-19-linked multisystem inflammatory syndrome (MIS-C).
“A new condition has emerged during the COVID-19 pandemic – multisystem inflammatory syndrome in children (MIS-C) – that involves the myocardium and coronary arteries in some infected patients,” the AHA stated. “Therapies may consist of antiviral, IVIG (intravenous immunoglobulin), steroid and other anti-inflammatory medications used in atypical Kawasaki disease.”
If a diagnosis is made, the AHA recommends that patients do not participate in competitive sports until after it has resolved, and after 24-hour Holter monitoring and exercise stress testing has been performed no sooner than 3 to 6 months after diagnosis.
For other patients, the AHA recommends that there be regular cardiology follow-up including ECG, echocardiography and laboratory tests every 1 to 3 months after onset, and then as needed.