NPPB and hydrops fetalis: Furthermore, the Fushimi AF Registry reported that not only age and history of stroke, but also unstable heart failure (HF) (within 30 days after hospitalization due to HF), type B natriuretic peptide (BNP) level, or N-terminal fragment of the prohormone B natriuretic peptide (NT-pro BNP) level were independent risk factors [20].