ADRB3 and heart failure: Previous studies have shown that autoantibodies against β-adrenoceptors (anti-β-AR autoantibodies) display antagonist activity on the corresponding receptor and influence cardiac function [3], [5], [6] It has been well established that β-adrenoceptor (β-AR) belongs to the family of G-protein coupled receptors, and 3 subtypes (β1, β2 and β3-AR) have been associated with different changes in heart failure.