CD19 and Arrhythmia: In the subgroup analysis, the incidence rate of arrhythmias was 24.1% (95% CI: 0.110–0.372) for the CD19 subgroup, 13.6% (95% CI: 0.029–0.349) for the BCMA subgroup, and 19.2% (95% CI: 0.107–0.277) for others (Supplementary Table S3).