RYR3 and hydrops fetalis: In the subgroup of patients with a pre‐existing heart disease (MI, angina or HF) at the start of dCCB prescribing, RYR3 TT homozygotes had an increased risk of developing incident heart diseases compared to common CC homozygotes (75.4 vs. 67.8) with a HR 1.25 (95% CI 1.09 to 1.44, P = .002; Table 3; see Table S7).