Natriuretic peptides (NPs) play a key role as initial diagnostic markers, and the ESC guidelines state that elevated NP concentrations (N-terminal pro–B-type NP [NT-proBNP] ≥125 pg/ml [≥365 pg/ml in individuals with atrial fibrillation]; brain NP [BNP] ≥35 pg/ml [≥105 pg/ml in atrial fibrillation]) support a diagnosis of HF (Fig. 1) [17]. This evidence concerns the gene NPPB and hydrops fetalis.