NPPB and hydrops fetalis: The key inclusion criteria are stable GDMT for at least 4 weeks, NYHA class III or class II if hospitalized for HF within the previous 12 months, LVEF ≤35%, LV end diastolic diameter <8.0 cm, NT-proBNP ≥800 pg/ml, and 6MWD of 150–450 m, limited by HF symptoms.