In order to provide firm evidence that changes in mRNA expression associated with LV RR in BB-treated patients with dilated cardiomyopathy were from genes regulated by β1-AR signaling, we used ADRB1 Arg389 and Gly389 cardiac overexpressor Tg mice (4, 5) as a biologic filter. Here, ADRB1 is linked to dilated cardiomyopathy.