However, the notion that a single mechanism underlies the heart failure-induced defects in signaling by both the β1AR (the predominant βAR subtype and principal driver of catecholamine-driven sympathetic responses in the healthy heart) and the β2AR subtype is difficult to reconcile with clinical studies showing that β1ARs and β2ARs are regulated differently in heart failure; heart failure leads to a selective downregulation of the β1AR subtype that is not accompanied by a commensurate loss of β2ARs. Here, ADRB2 is linked to heart failure.