β2-AR play an important role in the regulation of the angiogenic response in HF, as showed by the evidence that β2-AR overexpression was associated with a markedly increased capillary and arteriolar length density and enhanced in vivo myocardial blood flow and coronary reserve (Rengo et al., 2012b) and β-blockade promotes cardiac angiogenesis in heart failure via activation of VEGF signaling pathway (Rengo et al., 2013a). Here, ADRB2 is linked to hydrops fetalis.