ADRB1 and dilated cardiomyopathy: Critical steps in fatty acid β-oxidation, respiratory chain function, branched chain amino acid metabolism, and metabolism with peroxisomal and membrane compartments were downregulated in β1-AR–overexpressing mice that ultimately develop a dilated cardiomyopathy (4, 5) and then upregulated on reverse LV remodeling in NDC patients treated with β1-AR antagonist treatment.