These definitions complement the traditional New York Health Association (NYHA) functional classifications, which are related to severity of symptoms and physical limitations in those with manifest HF.154 Natriuretic peptides (NT-proBNP and BNP) may be used to identify and stratify patients at risk for HF as well as to determine prognosis in those with manifest HF. The gene discussed is NPPB; the disease is hydrops fetalis.