The p-STAT3 level was highest in the nicotine group, followed by the myocarditis group and then the methyllycaconitine group; there were significant differences in the p-STAT3 levels among these four groups (p-STAT3: Nicotine 0.048±0.003 vs Myocarditis 0.034±0.003 vs Methyllycaconitine 0.023±0.003 vs Normal 0.015±0.001, P<0.05) (Figure 5). Here, STAT3 is linked to myocarditis.