NPPA and hydrops fetalis: Next, the expression difference and diagnostic efficacy of the four cardiac function markers, namely, natriuretic peptide A (NPPA), natriuretic peptide B (NPPB), myosin heavy chain 6 (MYH6), and myosin heavy chain 7 (MYH7), were examined between samples of patients with HF and NFD samples in the five sequencing databases.