The mild and severe myocarditis groups showed significant differences in concurrent targeted therapy (hazard ratio [HR]: 0.058, 95% confidence interval [CI]: 0.006–0.523, p = 0.011), sinus arrhythmia (HR: 3.257, 95% CI: 1.137–9.325, p = 0.028), QTc interval prolongation (HR: 14.185, 95% CI: 2.046–98.339, p = 0.007), and high NT‐proBNP Level (HR: 10.743, 95% CI: 1.382–83.5204, p = 0.023) (Table 4). This evidence concerns the gene NPPB and myocarditis.