The results of cardiac biopsies suggest that myocardial β1-adrenoceptor (AR) density is reduced in patients with chronic heart failure, while changes in cardiac β2-ARs vary. A technique for visualization and quantification of β1-AR populations rather than total β-AR densities in the human heart would be of great clinical interest. Molecular imaging techniques, either single photon emission computed tomography (SPECT) or positron ...