In the subgroup analysis, the incidence rate of cardiomyopathy was 2.5% (95% CI: 0.000–0.063) for the CD19 subgroup, 9.1% (95% CI: 0.011–0.292) for the BCMA subgroup, and 4.0% (95% CI: 0.009–0.071) for others (Supplementary Table S3). Here, CD19 is linked to cardiomyopathy.