More than one in three healthy young athletes had pericardial inflammation after COVID-19 infection, a US imaging study has found.

However, although concerns have been raised about cardiovascular involvement in young people with COVID-19 disease, none of the 48 individuals in the study showed imaging features to suggest an ongoing myocarditis.

Cardiologists from the West Virginia University Medicine Heart & Vascular Institute performed screening echocardiograms and cardiac magnetic resonance (CMR) imaging in 48 student-athletes (mean age: 19 years, 85% males) who tested positive for SARS-CoV-2.

Almost all the young people with COVID19 had either mild symptoms (66%) or were asymptomatic (30%), with only 4% having moderate symptoms.

Abnormal findings on cardiac imaging were seen in 27 (56.3%) of the young people, including 19  (39.5%) showing pericardial late enhancements with pockets of pericardial effusion and patchy or a diffuse pattern of myocardial segmental strain abnormalities.

Of the individuals with pericardial enhancements, six had reduced global longitudinal strain (GLS) and/or an increased native T1. Reduced left ventricular ejection fraction or reduced GLS with or without increased native T1 were also identified in additional 7 (14.6%) individuals.

Published in JACC: Cardiovascular Imaging, the study showed native T2 were normal in all subjects and no specific imaging features of myocardial inflammation were identified.

The study investigators said that while they did not see evidence of myocarditis, another recent study of college athletes with COVID-19 had CMR findings consistent with myocarditis reported in four of 26 (15%) athletes.

“While the immediate and long-term clinical relevance of these findings remain unclear, our study underscores that a mild or asymptomatic COVID-19 is not a benign illness considering that over half of the younger individuals showed subclinical myocardial and pericardial disease,” they wrote.

And although pericarditis usually resolves within a few weeks with no residual effects, in some cases, there can be long-term effects, such as recurrent and constrictive pericarditis, they warned.

Based on this and other emerging evidence, the authors noted that expert recommendations have been published on heart testing and recovery times for student athletes before return to play.

Writing in The Conversation, they summarised the advice for young athletes with COVID19 as:

• Before returning to play, athletes who test positive for COVID-19 should consult with their physicians to determine if heart screening tests are needed. Although routine testing is not recommended for all asymptomatic individuals, a physician should determine on an individual basis when the risks are high enough.
• If an athlete has active myocarditis, we recommend no competition or strenuous training for three to six months, with follow-up exams with a cardiologist. Exercise can worsen the disease’s progression and create arrhythmias, or irregular heartbeat. After that period, the athlete can gradually resume exercise and play if he or she has no lingering inflammation or arrhythmia.
• If an athlete has active features of pericarditis, we also recommend restricting exercise, since it can exacerbate inflammation or cause inflammation to return. Athletes should avoid competitive sports during the acute phase. Once tests show no inflammation or excess fluid, the athlete should be able to return to play.