The European Society of Cardiology (ESC) guideline has set an NT-proBNP cut-off value of 125 ng/mL to rule out HF with slow (i.e., not acute) onset [21] but also recommended NT-proBNP > 220 pg/mL (sinus rhythm) or BNP > 660 pg/mL (in atrial fibrillation) as a major criterion for diagnosing HF [20]. Here, NPPB is linked to hydrops fetalis.