Coronavirus disease 2019 (COVID-19) associated myocardial injury was caused by various mechanisms. We herein describe 2 cases presenting different types of myocardial injury due to Omicron variant. In both patients, diffuse reduced left ventricular (LV) wall motion in transthoracic echocardiography, electrocardiographic abnormality, and elevated myocardial enzymes were demonstrated. In addition, cardiovascular magnetic resonance (CMR) findings fulfilled the 2018 Lake Louise Criteria (LLC) for myocarditis. However, histological findings in 1 patient showed inflammatory cell infiltration with myocyte degeneration, while those in the other showed interstitial edema without inflammatory cell infiltration. Histological findings were crucial for a differential diagnosis of myocardial injury due to Omicron variant.
Keywords: COVID-19; Cardiovascular magnetic resonance; Histology; Myocarditis.