Cardiac MRI sheds new light on vaccine-related myocarditis

COVID-19 (new coronavirus infection) Vaccine-related myocarditis Cardiac Magnetic Resonance Imaging (MRI) Similar to other causes of myocarditis, but the abnormalities are less serious.This is due to a new study published in the journal Radiology..[1]

Myocardial inflammation often results from viral infections, including COVID-19. It can cause arrhythmias and the heart’s ability to pump blood, leaving permanent damage in the form of myocardial scarring. Myocarditis has also been reported as a rare complication of the messenger RNA (mRNA) -based COVID-19 vaccine...

Cardiac MRI plays an important role in the assessment of acute myocarditis with unparalleled ability for non-invasive characterization of myocardial tissue. Understanding the patterns and extent of myocardial injury and their effects can improve the care of these patients and may help address vaccine hesitation.

Cardiac radiologist Kate Haneman, MD, MPHAnd colleagues at the University Health Network determine the pattern and extent of cardiac MRI findings of myocarditis associated with COVID-19 vaccination and compare these findings with other causes of myocarditis, including COVID-19. Has begun.

“We know that the risk of myocarditis after COVID-19 vaccination is very low, but data on the degree of heart damage is very limited compared to other causes of myocarditis. “I am,” explains Hannemann. statement.. “MRI can be used to examine detailed tissue characteristics of the heart, such as checking the amount of fluid and edema in the heart, which provides detailed information when there is active inflammation. It also gives us information about the damage that may have occurred. If there was inflammation or scarring in the past, MRI can tell us about both of them. “

This retrospective study analyzed data from 92 consecutive adult patients with myocarditis and cardiac MRI abnormalities performed at a tertiary referral hospital between 2019 and 2021. Patients were divided into one of three groups: myocarditis after COVID-19 vaccination, myocarditis after COVID-19 disease, and myocarditis not associated with COVID-19 vaccination or disease.

Of the 92 patients, 21 (22%) had myocarditis after COVID-19 vaccination (mean age 31 years). Ten patients (11%) had COVID-19 disease (mean age 51 years) followed by myocarditis, and 61 (66%) had other myocarditis (mean age 44 years). Patients with post-vaccinated myocarditis were younger and more often male compared to the other groups.

Chest pain occurred in all 21 patients with vaccine-related myocarditis. The pain started 1-7 days after vaccination and lasted 1-6 days. Fourteen (67%) of the patients were hospitalized with a median length of stay of 3 days. No patient was admitted to the intensive care unit.

It was noted that troponin levels increased in all hospitalized patients and decreased significantly by the time of discharge.

MRI findings of vaccine-related myocarditis included late-stage gadolinium enhancement in 17 (81%) and left ventricular dysfunction in 6 (29%). Cardiac MRI showed that patients with vaccine-related myocarditis had less dysfunction and less widespread myocardial abnormalities than other causes of myocarditis.

Patients with COVID-19 disease and other myocarditis had a higher prevalence of abnormalities, including the interventricular septum, and exacerbated myocardial damage as measured by T1 mapping.

At short follow-up (median 22 days), all patients with vaccine-related myocarditis were asymptomatic and had no adverse events.

Myocarditis due to COVID vaccine is very mild

“Because we are a very large center, we used MRI to look for myocarditis in this group of patients based on clinical practice, but the number of patients with myocardial edema and injury is very small. That’s what Hanneman explained. “These results indicate that myocarditis after COVID-19 vaccination is relatively mild and tends to resolve quickly.”

Lead author and Fellow of Cardiac Imaging, Matteo Fronza, MD, said the resolution of all symptoms and the lack of adverse events during follow-up were encouraging. However, long-term follow-up is required.