The median values of cTnI, NT‐proBNP, CK, and CK‐MB were higher in the severe myocarditis group than in the mild myocarditis group (median values: 1284.5 [157.5–8218.8] vs. 168.1 [67.8–391.3], p = 0.003; 33.6 [11.3–89.4] vs. 7.0 [5.0–33.0], p = 0.002; 661.0 [195.0–3470.0] vs. 185.0 [70.5–895.8], p = 0.009; and 44.5 [5.1–142.2] vs. 6.3 [2.9–20.3], p = 0.006, respectively). Here, TNNI3 is linked to myocarditis.