The BEAT-HF-II trial (NCT03926754) is the phase II/III clinical study assessing the efficacy and safety of mirabegron, enrolling 22 HFrEF patients with LVEF of less than 35%, NYHA class III-IV, and increased N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels, to evaluate the hemodynamic response to mirabegron [73]. The gene discussed is NPPB; the disease is hydrops fetalis.