CKB and hydrops fetalis: No significant additive interaction between PRS and ICVHMs was observed as shown in Supplementary Table 5, indicating that the risk of HF attributed to the combination of increased genetic risk and low ICVHMs was similar to the addition of the risk associated with each factor (RERI and 95% CI were 0.05 [−0.22, 0.33] in CKB and 0.04 [−0.14, 0.22] in UKB).