The results demonstrated that advanced age (≥65 years old), history of arrhythmia, moderate disease severity and higher hs-CRP, Mb and hs-cTnI levels were independent risk factors for poor prognosis in Omicron-infected patients suffering from arrhythmia (p < 0.05), while vaccination was a protective factor (Table 4; p < 0.05). Here, MB is linked to cardiac arrhythmia.