NPPB and hydrops fetalis: Those with a BNP <100 pg/mL will be excluded.10 In addition to elevated BNP, patients must meet the ESC echocardiographic criteria for the diagnosis of HF.10, 82 Patients with a confirmed diagnosis of HF will be invited to participate in the study, and a further sample of blood and urine will be taken and stored for later batched analysis of biomarkers, which have prognostic importance in HF.