Moreover “in vivo” studies demonstrated a greater efficiency of carvedilol, a non-selective β-AR antagonist, in ameliorating myocardial insulin sensitivity and glucose extraction in animal model of HF as compared to metoprolol, a selective β1-AR antagonist, indicating that antagonism of β2AR positively regulates cardiac glucose metabolism in an animal model HF (Nikolaidis et al., 2006). This evidence concerns the gene ADRB2 and hydrops fetalis.