Myocarditis has been recognized as a complication of COVID-19 mRNA vaccinations, particularly in adolescent and young adult male patients.[1] Cardiovascular sequelae after an acute episode of myocarditis, regardless of pathogenesis, remain as issues of concern. Although the reported short-term clinical trajectory after COVID-19 vaccine–associated myocarditis appears reassuring, with resolution of cardiac symptoms and normalization of left ventricular ejection fraction (LVEF) in most of the adolescent patients,[2] the long-term cardiovascular outcomes remain unclear.
We evaluated the cardiovascular outcomes at up to 1 year in adolescent patients diagnosed with COVID-19 vaccine–associated myocarditis. Their electrocardiographic, echocardiographic, and cardiac magnetic resonance (CMR) findings at diagnosis were reviewed. At latest follow-up, clinical assessment, ECG, echocardiogram (Vivid E9, GE Medical System, Horten, Norway), and CMR (Siemens Magnetom Aera 1.5 T MRI system, Germany) were performed. The study was approved by the Institutional Review Board and the parents of subjects gave informed consent. Data that support our findings are available from the corresponding authors on reasonable request.
Forty patients (33 male) 15.1±1.6 (range, 12.7–17.9) years of age and followed up for 10.0±1.3 (range, 5.6–12.3) months, representing all cases identified in Hong Kong during the period of study, were included. Twenty-nine (73%) patients were asymptomatic, whereas 7 (18%) reported noncardiac chest pain, 3 (8%) reported palpitations, and 1 (3%) reported fatigue during follow-up, with none having cardiac arrhythmias, angina, or heart failure. The ECG results were abnormal, with ST-segment or T-wave abnormalities in 31 (78%) patients at presentation and normalized in all at latest follow-up.
