NPPB and hydrops fetalis: In our study, participants with potassium (3.50–4.00 mmol/L) possessed lower levels of BNP or NT-proBNP, lesser share of NYHA IV, and rehospitalization for HF, which may partly explain the association of the divergence of serum potassium levels from 3.50 to 4.00 mmol/L with an increased risk of hospitalization for worsening HF.