AVP and hydrops fetalis: Studies have investigated whether NT-proBNP and copeptin levels have the ability to optimize beta-blocker (BB) up-titration in patients with HF, but they came to inconsistent conclusions in terms of the performance of copeptin (205, 206), indicating the need for further well-designed studies with longer follow-up periods to elucidate the role of copeptin in guiding BB therapy.